src/libFLAC/encoder.c

   1 /* libFLAC - Free Lossless Audio Codec library
   2  * Copyright (C) 2000,2001  Josh Coalson
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA  02111-1307, USA.
  18  */
  19
  20 #include <assert.h>
  21 #include <stdio.h>
  22 #include <stdlib.h> /* for malloc() */
  23 #include <string.h> /* for memcpy() */
  24 #include "FLAC/encoder.h"
  25 #include "private/bitbuffer.h"
  26 #include "private/encoder_framing.h"
  27 #include "private/fixed.h"
  28 #include "private/lpc.h"
  29 #include "private/md5.h"
  30
  31 #ifdef min
  32 #undef min
  33 #endif
  34 #define min(x,y) ((x)<(y)?(x):(y))
  35
  36 #ifdef max
  37 #undef max
  38 #endif
  39 #define max(x,y) ((x)>(y)?(x):(y))
  40
  41 typedef struct FLAC__EncoderPrivate {
  42         unsigned input_capacity;                    /* current size (in samples) of the signal and residual buffers */
  43         int32 *integer_signal[FLAC__MAX_CHANNELS];  /* the integer version of the input signal */
  44         int32 *integer_signal_mid_side[2];          /* the integer version of the mid-side input signal (stereo only) */
  45         real *real_signal[FLAC__MAX_CHANNELS];      /* the floating-point version of the input signal */
  46         real *real_signal_mid_side[2];              /* the floating-point version of the mid-side input signal (stereo only) */
  47         int32 *residual_workspace[FLAC__MAX_CHANNELS][2]; /* each channel has a candidate and best workspace where the subframe residual signals will be stored */
  48         int32 *residual_workspace_mid_side[2][2];
  49         FLAC__Subframe subframe_workspace[FLAC__MAX_CHANNELS][2];
  50         FLAC__Subframe subframe_workspace_mid_side[2][2];
  51         FLAC__Subframe *subframe_workspace_ptr[FLAC__MAX_CHANNELS][2];
  52         FLAC__Subframe *subframe_workspace_ptr_mid_side[2][2];
  53         unsigned best_subframe[FLAC__MAX_CHANNELS]; /* index into the above workspaces */
  54         unsigned best_subframe_mid_side[2];
  55         unsigned best_subframe_bits[FLAC__MAX_CHANNELS]; /* size in bits of the best subframe for each channel */
  56         unsigned best_subframe_bits_mid_side[2];
  57         uint32 *abs_residual;                       /* workspace where the abs(candidate residual) is stored */
  58         FLAC__BitBuffer frame;                      /* the current frame being worked on */
  59         bool current_frame_can_do_mid_side;         /* encoder sets this false when any given sample of a frame's side channel exceeds 16 bits */
  60         double loose_mid_side_stereo_frames_exact;  /* exact number of frames the encoder will use before trying both independent and mid/side frames again */
  61         unsigned loose_mid_side_stereo_frames;      /* rounded number of frames the encoder will use before trying both independent and mid/side frames again */
  62         unsigned loose_mid_side_stereo_frame_count; /* number of frames using the current channel assignment */
  63         FLAC__ChannelAssignment last_channel_assignment;
  64         FLAC__StreamMetaData metadata;
  65         unsigned current_sample_number;
  66         unsigned current_frame_number;
  67         struct MD5Context md5context;
  68         FLAC__EncoderWriteStatus (*write_callback)(const FLAC__Encoder *encoder, const byte buffer[], unsigned bytes, unsigned samples, unsigned current_frame, void *client_data);
  69         void (*metadata_callback)(const FLAC__Encoder *encoder, const FLAC__StreamMetaData *metadata, void *client_data);
  70         void *client_data;
  71 } FLAC__EncoderPrivate;
  72
  73 static bool encoder_resize_buffers_(FLAC__Encoder *encoder, unsigned new_size);
  74 static bool encoder_process_frame_(FLAC__Encoder *encoder, bool is_last_frame);
  75 static bool encoder_process_subframes_(FLAC__Encoder *encoder, bool is_last_frame);
  76 static bool encoder_process_subframe_(FLAC__Encoder *encoder, unsigned max_partition_order, bool verbatim_only, const FLAC__FrameHeader *frame_header, unsigned bits_per_sample, const int32 integer_signal[], const real real_signal[], FLAC__Subframe *subframe[2], int32 *residual[2], unsigned *best_subframe, unsigned *best_bits);
  77 static bool encoder_add_subframe_(FLAC__Encoder *encoder, const FLAC__FrameHeader *frame_header, unsigned bits_per_sample, const FLAC__Subframe *subframe, FLAC__BitBuffer *frame);
  78 static unsigned encoder_evaluate_constant_subframe_(const int32 signal, unsigned bits_per_sample, FLAC__Subframe *subframe);
  79 static unsigned encoder_evaluate_fixed_subframe_(const int32 signal[], int32 residual[], uint32 abs_residual[], unsigned blocksize, unsigned bits_per_sample, unsigned order, unsigned rice_parameter, unsigned max_partition_order, FLAC__Subframe *subframe);
  80 static unsigned encoder_evaluate_lpc_subframe_(const int32 signal[], int32 residual[], uint32 abs_residual[], const real lp_coeff[], unsigned blocksize, unsigned bits_per_sample, unsigned order, unsigned qlp_coeff_precision, unsigned rice_parameter, unsigned max_partition_order, FLAC__Subframe *subframe);
  81 static unsigned encoder_evaluate_verbatim_subframe_(const int32 signal[], unsigned blocksize, unsigned bits_per_sample, FLAC__Subframe *subframe);
  82 static unsigned encoder_find_best_partition_order_(const int32 residual[], uint32 abs_residual[], unsigned residual_samples, unsigned predictor_order, unsigned rice_parameter, unsigned max_partition_order, unsigned *best_partition_order, unsigned best_parameters[]);
  83 static bool encoder_set_partitioned_rice_(const uint32 abs_residual[], const unsigned residual_samples, const unsigned predictor_order, const unsigned rice_parameter, const unsigned partition_order, unsigned parameters[], unsigned *bits);
  84
  85 const char *FLAC__EncoderWriteStatusString[] = {
  86         "FLAC__ENCODER_WRITE_OK",
  87         "FLAC__ENCODER_WRITE_FATAL_ERROR"
  88 };
  89
  90 const char *FLAC__EncoderStateString[] = {
  91         "FLAC__ENCODER_OK",
  92         "FLAC__ENCODER_UNINITIALIZED",
  93         "FLAC__ENCODER_INVALID_NUMBER_OF_CHANNELS",
  94         "FLAC__ENCODER_INVALID_BITS_PER_SAMPLE",
  95         "FLAC__ENCODER_INVALID_SAMPLE_RATE",
  96         "FLAC__ENCODER_INVALID_BLOCK_SIZE",
  97         "FLAC__ENCODER_INVALID_QLP_COEFF_PRECISION",
  98         "FLAC__ENCODER_MID_SIDE_CHANNELS_MISMATCH",
  99         "FLAC__ENCODER_MID_SIDE_SAMPLE_SIZE_MISMATCH",
 100         "FLAC__ENCODER_ILLEGAL_MID_SIDE_FORCE",
 101         "FLAC__ENCODER_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER",
 102         "FLAC__ENCODER_NOT_STREAMABLE",
 103         "FLAC__ENCODER_FRAMING_ERROR",
 104         "FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING",
 105         "FLAC__ENCODER_FATAL_ERROR_WHILE_WRITING",
 106         "FLAC__ENCODER_MEMORY_ALLOCATION_ERROR"
 107 };
 108
 109
 110 bool encoder_resize_buffers_(FLAC__Encoder *encoder, unsigned new_size)
 111 {
 112         bool ok;
 113         unsigned i, channel;
 114         int32 *previous_is, *current_is;
 115         real *previous_rs, *current_rs;
 116         int32 *residual;
 117         uint32 *abs_residual;
 118
 119         assert(new_size > 0);
 120         assert(encoder->state == FLAC__ENCODER_OK);
 121         assert(encoder->guts->current_sample_number == 0);
 122
 123         /* To avoid excessive malloc'ing, we only grow the buffer; no shrinking. */
 124         if(new_size <= encoder->guts->input_capacity)
 125                 return true;
 126
 127         ok = 1;
 128         if(ok) {
 129                 for(i = 0; ok && i < encoder->channels; i++) {
 130                         /* integer version of the signal */
 131                         previous_is = encoder->guts->integer_signal[i];
 132                         current_is = (int32*)malloc(sizeof(int32) * new_size);
 133                         if(0 == current_is) {
 134                                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 135                                 ok = 0;
 136                         }
 137                         else {
 138                                 encoder->guts->integer_signal[i] = current_is;
 139                                 if(previous_is != 0)
 140                                         free(previous_is);
 141                         }
 142                         /* real version of the signal */
 143                         previous_rs = encoder->guts->real_signal[i];
 144                         current_rs = (real*)malloc(sizeof(real) * new_size);
 145                         if(0 == current_rs) {
 146                                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 147                                 ok = 0;
 148                         }
 149                         else {
 150                                 encoder->guts->real_signal[i] = current_rs;
 151                                 if(previous_rs != 0)
 152                                         free(previous_rs);
 153                         }
 154                 }
 155         }
 156         if(ok) {
 157                 for(i = 0; ok && i < 2; i++) {
 158                         /* integer version of the signal */
 159                         previous_is = encoder->guts->integer_signal_mid_side[i];
 160                         current_is = (int32*)malloc(sizeof(int32) * new_size);
 161                         if(0 == current_is) {
 162                                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 163                                 ok = 0;
 164                         }
 165                         else {
 166                                 encoder->guts->integer_signal_mid_side[i] = current_is;
 167                                 if(previous_is != 0)
 168                                         free(previous_is);
 169                         }
 170                         /* real version of the signal */
 171                         previous_rs = encoder->guts->real_signal_mid_side[i];
 172                         current_rs = (real*)malloc(sizeof(real) * new_size);
 173                         if(0 == current_rs) {
 174                                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 175                                 ok = 0;
 176                         }
 177                         else {
 178                                 encoder->guts->real_signal_mid_side[i] = current_rs;
 179                                 if(previous_rs != 0)
 180                                         free(previous_rs);
 181                         }
 182                 }
 183         }
 184         if(ok) {
 185                 for(channel = 0; channel < encoder->channels; channel++) {
 186                         for(i = 0; i < 2; i++) {
 187                                 residual = (int32*)malloc(sizeof(int32) * new_size);
 188                                 if(0 == residual) {
 189                                         encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 190                                         ok = 0;
 191                                 }
 192                                 else {
 193                                         if(encoder->guts->residual_workspace[channel][i] != 0)
 194                                                 free(encoder->guts->residual_workspace[channel][i]);
 195                                         encoder->guts->residual_workspace[channel][i] = residual;
 196                                 }
 197                         }
 198                 }
 199                 for(channel = 0; channel < 2; channel++) {
 200                         for(i = 0; i < 2; i++) {
 201                                 residual = (int32*)malloc(sizeof(int32) * new_size);
 202                                 if(0 == residual) {
 203                                         encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 204                                         ok = 0;
 205                                 }
 206                                 else {
 207                                         if(encoder->guts->residual_workspace_mid_side[channel][i] != 0)
 208                                                 free(encoder->guts->residual_workspace_mid_side[channel][i]);
 209                                         encoder->guts->residual_workspace_mid_side[channel][i] = residual;
 210                                 }
 211                         }
 212                 }
 213                 abs_residual = (uint32*)malloc(sizeof(uint32) * new_size);
 214                 if(0 == residual) {
 215                         encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 216                         ok = 0;
 217                 }
 218                 else {
 219                         if(encoder->guts->abs_residual != 0)
 220                                 free(encoder->guts->abs_residual);
 221                         encoder->guts->abs_residual = abs_residual;
 222                 }
 223         }
 224         if(ok)
 225                 encoder->guts->input_capacity = new_size;
 226
 227         return ok;
 228 }
 229
 230 FLAC__Encoder *FLAC__encoder_get_new_instance()
 231 {
 232         FLAC__Encoder *encoder = (FLAC__Encoder*)malloc(sizeof(FLAC__Encoder));
 233         if(encoder != 0) {
 234                 encoder->state = FLAC__ENCODER_UNINITIALIZED;
 235                 encoder->guts = 0;
 236         }
 237         return encoder;
 238 }
 239
 240 void FLAC__encoder_free_instance(FLAC__Encoder *encoder)
 241 {
 242         assert(encoder != 0);
 243         free(encoder);
 244 }
 245
 246 FLAC__EncoderState FLAC__encoder_init(FLAC__Encoder *encoder, FLAC__EncoderWriteStatus (*write_callback)(const FLAC__Encoder *encoder, const byte buffer[], unsigned bytes, unsigned samples, unsigned current_frame, void *client_data), void (*metadata_callback)(const FLAC__Encoder *encoder, const FLAC__StreamMetaData *metadata, void *client_data), void *client_data)
 247 {
 248         unsigned i;
 249         FLAC__StreamMetaData padding;
 250
 251         assert(sizeof(int) >= 4); /* we want to die right away if this is not true */
 252         assert(encoder != 0);
 253         assert(write_callback != 0);
 254         assert(metadata_callback != 0);
 255         assert(encoder->state == FLAC__ENCODER_UNINITIALIZED);
 256         assert(encoder->guts == 0);
 257
 258         encoder->state = FLAC__ENCODER_OK;
 259
 260         if(encoder->channels == 0 || encoder->channels > FLAC__MAX_CHANNELS)
 261                 return encoder->state = FLAC__ENCODER_INVALID_NUMBER_OF_CHANNELS;
 262
 263         if(encoder->do_mid_side_stereo && encoder->channels != 2)
 264                 return encoder->state = FLAC__ENCODER_MID_SIDE_CHANNELS_MISMATCH;
 265
 266         if(encoder->loose_mid_side_stereo && !encoder->do_mid_side_stereo)
 267                 return encoder->state = FLAC__ENCODER_ILLEGAL_MID_SIDE_FORCE;
 268
 269         if(encoder->bits_per_sample == 0 || encoder->bits_per_sample > FLAC__MAX_BITS_PER_SAMPLE)
 270                 return encoder->state = FLAC__ENCODER_INVALID_BITS_PER_SAMPLE;
 271
 272         if(encoder->sample_rate == 0 || encoder->sample_rate > FLAC__MAX_SAMPLE_RATE)
 273                 return encoder->state = FLAC__ENCODER_INVALID_SAMPLE_RATE;
 274
 275         if(encoder->blocksize < FLAC__MIN_BLOCK_SIZE || encoder->blocksize > FLAC__MAX_BLOCK_SIZE)
 276                 return encoder->state = FLAC__ENCODER_INVALID_BLOCK_SIZE;
 277
 278         if(encoder->blocksize < encoder->max_lpc_order)
 279                 return encoder->state = FLAC__ENCODER_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER;
 280
 281         if(encoder->qlp_coeff_precision == 0) {
 282                 if(encoder->bits_per_sample < 16) {
 283                         /* @@@ need some data about how to set this here w.r.t. blocksize and sample rate */
 284                         /* @@@ until then we'll make a guess */
 285                         encoder->qlp_coeff_precision = max(5, 2 + encoder->bits_per_sample / 2);
 286                 }
 287                 else if(encoder->bits_per_sample == 16) {
 288                         if(encoder->blocksize <= 192)
 289                                 encoder->qlp_coeff_precision = 7;
 290                         else if(encoder->blocksize <= 384)
 291                                 encoder->qlp_coeff_precision = 8;
 292                         else if(encoder->blocksize <= 576)
 293                                 encoder->qlp_coeff_precision = 9;
 294                         else if(encoder->blocksize <= 1152)
 295                                 encoder->qlp_coeff_precision = 10;
 296                         else if(encoder->blocksize <= 2304)
 297                                 encoder->qlp_coeff_precision = 11;
 298                         else if(encoder->blocksize <= 4608)
 299                                 encoder->qlp_coeff_precision = 12;
 300                         else
 301                                 encoder->qlp_coeff_precision = 13;
 302                 }
 303                 else {
 304                         encoder->qlp_coeff_precision = min(13, 8*sizeof(int32) - encoder->bits_per_sample - 1);
 305                 }
 306         }
 307         else if(encoder->qlp_coeff_precision < FLAC__MIN_QLP_COEFF_PRECISION || encoder->qlp_coeff_precision + encoder->bits_per_sample >= 8*sizeof(uint32) || encoder->qlp_coeff_precision >= (1u<<FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN))
 308                 return encoder->state = FLAC__ENCODER_INVALID_QLP_COEFF_PRECISION;
 309
 310         if(encoder->streamable_subset) {
 311                 if(encoder->bits_per_sample != 8 && encoder->bits_per_sample != 12 && encoder->bits_per_sample != 16 && encoder->bits_per_sample != 20 && encoder->bits_per_sample != 24)
 312                         return encoder->state = FLAC__ENCODER_NOT_STREAMABLE;
 313                 if(encoder->sample_rate > 655350)
 314                         return encoder->state = FLAC__ENCODER_NOT_STREAMABLE;
 315         }
 316
 317         if(encoder->rice_optimization_level >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN))
 318                 encoder->rice_optimization_level = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN) - 1;
 319
 320         encoder->guts = (FLAC__EncoderPrivate*)malloc(sizeof(FLAC__EncoderPrivate));
 321         if(encoder->guts == 0)
 322                 return encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 323
 324         encoder->guts->input_capacity = 0;
 325         for(i = 0; i < encoder->channels; i++) {
 326                 encoder->guts->integer_signal[i] = 0;
 327                 encoder->guts->real_signal[i] = 0;
 328         }
 329         for(i = 0; i < 2; i++) {
 330                 encoder->guts->integer_signal_mid_side[i] = 0;
 331                 encoder->guts->real_signal_mid_side[i] = 0;
 332         }
 333         for(i = 0; i < encoder->channels; i++) {
 334                 encoder->guts->residual_workspace[i][0] = encoder->guts->residual_workspace[i][1] = 0;
 335                 encoder->guts->best_subframe[i] = 0;
 336         }
 337         for(i = 0; i < 2; i++) {
 338                 encoder->guts->residual_workspace_mid_side[i][0] = encoder->guts->residual_workspace_mid_side[i][1] = 0;
 339                 encoder->guts->best_subframe_mid_side[i] = 0;
 340         }
 341         for(i = 0; i < encoder->channels; i++) {
 342                 encoder->guts->subframe_workspace_ptr[i][0] = &encoder->guts->subframe_workspace[i][0];
 343                 encoder->guts->subframe_workspace_ptr[i][1] = &encoder->guts->subframe_workspace[i][1];
 344         }
 345         for(i = 0; i < 2; i++) {
 346                 encoder->guts->subframe_workspace_ptr_mid_side[i][0] = &encoder->guts->subframe_workspace_mid_side[i][0];
 347                 encoder->guts->subframe_workspace_ptr_mid_side[i][1] = &encoder->guts->subframe_workspace_mid_side[i][1];
 348         }
 349         encoder->guts->abs_residual = 0;
 350         encoder->guts->current_frame_can_do_mid_side = true;
 351         encoder->guts->loose_mid_side_stereo_frames_exact = (double)encoder->sample_rate * 0.4 / (double)encoder->blocksize;
 352         encoder->guts->loose_mid_side_stereo_frames = (unsigned)(encoder->guts->loose_mid_side_stereo_frames_exact + 0.5);
 353         if(encoder->guts->loose_mid_side_stereo_frames == 0)
 354                 encoder->guts->loose_mid_side_stereo_frames = 1;
 355         encoder->guts->loose_mid_side_stereo_frame_count = 0;
 356         encoder->guts->current_sample_number = 0;
 357         encoder->guts->current_frame_number = 0;
 358
 359         if(!encoder_resize_buffers_(encoder, encoder->blocksize)) {
 360                 /* the above function sets the state for us in case of an error */
 361                 return encoder->state;
 362         }
 363         FLAC__bitbuffer_init(&encoder->guts->frame);
 364         encoder->guts->write_callback = write_callback;
 365         encoder->guts->metadata_callback = metadata_callback;
 366         encoder->guts->client_data = client_data;
 367
 368         /*
 369          * write the stream header
 370          */
 371         if(!FLAC__bitbuffer_clear(&encoder->guts->frame))
 372                 return encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 373
 374         if(!FLAC__bitbuffer_write_raw_uint32(&encoder->guts->frame, FLAC__STREAM_SYNC, FLAC__STREAM_SYNC_LEN))
 375                 return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 376
 377         encoder->guts->metadata.type = FLAC__METADATA_TYPE_STREAMINFO;
 378         encoder->guts->metadata.is_last = (encoder->padding == 0);
 379         encoder->guts->metadata.length = FLAC__STREAM_METADATA_STREAMINFO_LENGTH;
 380         encoder->guts->metadata.data.stream_info.min_blocksize = encoder->blocksize; /* this encoder uses the same blocksize for the whole stream */
 381         encoder->guts->metadata.data.stream_info.max_blocksize = encoder->blocksize;
 382         encoder->guts->metadata.data.stream_info.min_framesize = 0; /* we don't know this yet; have to fill it in later */
 383         encoder->guts->metadata.data.stream_info.max_framesize = 0; /* we don't know this yet; have to fill it in later */
 384         encoder->guts->metadata.data.stream_info.sample_rate = encoder->sample_rate;
 385         encoder->guts->metadata.data.stream_info.channels = encoder->channels;
 386         encoder->guts->metadata.data.stream_info.bits_per_sample = encoder->bits_per_sample;
 387         encoder->guts->metadata.data.stream_info.total_samples = encoder->total_samples_estimate; /* we will replace this later with the real total */
 388         memset(encoder->guts->metadata.data.stream_info.md5sum, 0, 16); /* we don't know this yet; have to fill it in later */
 389         MD5Init(&encoder->guts->md5context);
 390         if(!FLAC__add_metadata_block(&encoder->guts->metadata, &encoder->guts->frame))
 391                 return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 392
 393         /* add a PADDING block if requested */
 394         if(encoder->padding > 0) {
 395                 padding.type = FLAC__METADATA_TYPE_PADDING;
 396                 padding.is_last = true;
 397                 padding.length = encoder->padding;
 398                 if(!FLAC__add_metadata_block(&padding, &encoder->guts->frame))
 399                         return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 400         }
 401
 402         assert(encoder->guts->frame.bits == 0); /* assert that we're byte-aligned before writing */
 403         assert(encoder->guts->frame.total_consumed_bits == 0); /* assert that no reading of the buffer was done */
 404         if(encoder->guts->write_callback(encoder, encoder->guts->frame.buffer, encoder->guts->frame.bytes, 0, encoder->guts->current_frame_number, encoder->guts->client_data) != FLAC__ENCODER_WRITE_OK)
 405                 return encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_WRITING;
 406
 407         /* now that the metadata block is written, we can init this to an absurdly-high value... */
 408         encoder->guts->metadata.data.stream_info.min_framesize = (1u << FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN) - 1;
 409         /* ... and clear this to 0 */
 410         encoder->guts->metadata.data.stream_info.total_samples = 0;
 411
 412         return encoder->state;
 413 }
 414
 415 void FLAC__encoder_finish(FLAC__Encoder *encoder)
 416 {
 417         unsigned i, channel;
 418
 419         assert(encoder != 0);
 420         if(encoder->state == FLAC__ENCODER_UNINITIALIZED)
 421                 return;
 422         if(encoder->guts->current_sample_number != 0) {
 423                 encoder->blocksize = encoder->guts->current_sample_number;
 424                 encoder_process_frame_(encoder, true); /* true => is last frame */
 425         }
 426         MD5Final(encoder->guts->metadata.data.stream_info.md5sum, &encoder->guts->md5context);
 427         encoder->guts->metadata_callback(encoder, &encoder->guts->metadata, encoder->guts->client_data);
 428         if(encoder->guts != 0) {
 429                 for(i = 0; i < encoder->channels; i++) {
 430                         if(encoder->guts->integer_signal[i] != 0) {
 431                                 free(encoder->guts->integer_signal[i]);
 432                                 encoder->guts->integer_signal[i] = 0;
 433                         }
 434                         if(encoder->guts->real_signal[i] != 0) {
 435                                 free(encoder->guts->real_signal[i]);
 436                                 encoder->guts->real_signal[i] = 0;
 437                         }
 438                 }
 439                 for(i = 0; i < 2; i++) {
 440                         if(encoder->guts->integer_signal_mid_side[i] != 0) {
 441                                 free(encoder->guts->integer_signal_mid_side[i]);
 442                                 encoder->guts->integer_signal_mid_side[i] = 0;
 443                         }
 444                         if(encoder->guts->real_signal_mid_side[i] != 0) {
 445                                 free(encoder->guts->real_signal_mid_side[i]);
 446                                 encoder->guts->real_signal_mid_side[i] = 0;
 447                         }
 448                 }
 449                 for(channel = 0; channel < encoder->channels; channel++) {
 450                         for(i = 0; i < 2; i++) {
 451                                 if(encoder->guts->residual_workspace[channel][i] != 0) {
 452                                         free(encoder->guts->residual_workspace[channel][i]);
 453                                         encoder->guts->residual_workspace[channel][i] = 0;
 454                                 }
 455                         }
 456                 }
 457                 for(channel = 0; channel < 2; channel++) {
 458                         for(i = 0; i < 2; i++) {
 459                                 if(encoder->guts->residual_workspace_mid_side[channel][i] != 0) {
 460                                         free(encoder->guts->residual_workspace_mid_side[channel][i]);
 461                                         encoder->guts->residual_workspace_mid_side[channel][i] = 0;
 462                                 }
 463                         }
 464                 }
 465                 if(encoder->guts->abs_residual != 0) {
 466                         free(encoder->guts->abs_residual);
 467                         encoder->guts->abs_residual = 0;
 468                 }
 469                 FLAC__bitbuffer_free(&encoder->guts->frame);
 470                 free(encoder->guts);
 471                 encoder->guts = 0;
 472         }
 473         encoder->state = FLAC__ENCODER_UNINITIALIZED;
 474 }
 475
 476 bool FLAC__encoder_process(FLAC__Encoder *encoder, const int32 *buf[], unsigned samples)
 477 {
 478         unsigned i, j, channel;
 479         int32 x, mid, side;
 480         const bool ms = encoder->do_mid_side_stereo && encoder->channels == 2;
 481         const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
 482         const int32 max_side =  ((int64)1 << (encoder->bits_per_sample-1)) - 1;
 483
 484         assert(encoder != 0);
 485         assert(encoder->state == FLAC__ENCODER_OK);
 486
 487         j = 0;
 488         do {
 489                 for(i = encoder->guts->current_sample_number; i < encoder->blocksize && j < samples; i++, j++) {
 490                         for(channel = 0; channel < encoder->channels; channel++) {
 491                                 x = buf[channel][j];
 492                                 encoder->guts->integer_signal[channel][i] = x;
 493                                 encoder->guts->real_signal[channel][i] = (real)x;
 494                         }
 495                         if(ms && encoder->guts->current_frame_can_do_mid_side) {
 496                                 side = buf[0][j] - buf[1][j];
 497                                 if(side < min_side || side > max_side) {
 498                                         encoder->guts->current_frame_can_do_mid_side = false;
 499                                 }
 500                                 else {
 501                                         mid = (buf[0][j] + buf[1][j]) >> 1; /* NOTE: not the same as 'mid = (buf[0][j] + buf[1][j]) / 2' ! */
 502                                         encoder->guts->integer_signal_mid_side[0][i] = mid;
 503                                         encoder->guts->integer_signal_mid_side[1][i] = side;
 504                                         encoder->guts->real_signal_mid_side[0][i] = (real)mid;
 505                                         encoder->guts->real_signal_mid_side[1][i] = (real)side;
 506                                 }
 507                         }
 508                         encoder->guts->current_sample_number++;
 509                 }
 510                 if(i == encoder->blocksize) {
 511                         if(!encoder_process_frame_(encoder, false)) /* false => not last frame */
 512                                 return false;
 513                 }
 514         } while(j < samples);
 515
 516         return true;
 517 }
 518
 519 /* 'samples' is channel-wide samples, e.g. for 1 second at 44100Hz, 'samples' = 44100 regardless of the number of channels */
 520 bool FLAC__encoder_process_interleaved(FLAC__Encoder *encoder, const int32 buf[], unsigned samples)
 521 {
 522         unsigned i, j, k, channel;
 523         int32 x, left = 0, mid, side;
 524         const bool ms = encoder->do_mid_side_stereo && encoder->channels == 2;
 525         const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
 526         const int32 max_side =  ((int64)1 << (encoder->bits_per_sample-1)) - 1;
 527
 528         assert(encoder != 0);
 529         assert(encoder->state == FLAC__ENCODER_OK);
 530
 531         j = k = 0;
 532         do {
 533                 for(i = encoder->guts->current_sample_number; i < encoder->blocksize && j < samples; i++, j++, k++) {
 534                         for(channel = 0; channel < encoder->channels; channel++, k++) {
 535                                 x = buf[k];
 536                                 encoder->guts->integer_signal[channel][i] = x;
 537                                 encoder->guts->real_signal[channel][i] = (real)x;
 538                                 if(ms && encoder->guts->current_frame_can_do_mid_side) {
 539                                         if(channel == 0) {
 540                                                 left = x;
 541                                         }
 542                                         else {
 543                                                 side = left - x;
 544                                                 if(side < min_side || side > max_side) {
 545                                                         encoder->guts->current_frame_can_do_mid_side = false;
 546                                                 }
 547                                                 else {
 548                                                         mid = (left + x) >> 1; /* NOTE: not the same as 'mid = (left + x) / 2' ! */
 549                                                         encoder->guts->integer_signal_mid_side[0][i] = mid;
 550                                                         encoder->guts->integer_signal_mid_side[1][i] = side;
 551                                                         encoder->guts->real_signal_mid_side[0][i] = (real)mid;
 552                                                         encoder->guts->real_signal_mid_side[1][i] = (real)side;
 553                                                 }
 554                                         }
 555                                 }
 556                         }
 557                         encoder->guts->current_sample_number++;
 558                 }
 559                 if(i == encoder->blocksize) {
 560                         if(!encoder_process_frame_(encoder, false)) /* false => not last frame */
 561                                 return false;
 562                 }
 563         } while(j < samples);
 564
 565         return true;
 566 }
 567
 568 bool encoder_process_frame_(FLAC__Encoder *encoder, bool is_last_frame)
 569 {
 570         assert(encoder->state == FLAC__ENCODER_OK);
 571
 572         /*
 573          * Accumulate raw signal to the MD5 signature
 574          */
 575         if(!FLAC__MD5Accumulate(&encoder->guts->md5context, encoder->guts->integer_signal, encoder->channels, encoder->blocksize, (encoder->bits_per_sample+7) / 8)) {
 576                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 577                 return false;
 578         }
 579
 580         /*
 581          * Process the frame header and subframes into the frame bitbuffer
 582          */
 583         if(!encoder_process_subframes_(encoder, is_last_frame)) {
 584                 /* the above function sets the state for us in case of an error */
 585                 return false;
 586         }
 587
 588         /*
 589          * Zero-pad the frame to a byte_boundary
 590          */
 591         if(!FLAC__bitbuffer_zero_pad_to_byte_boundary(&encoder->guts->frame)) {
 592                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 593                 return false;
 594         }
 595
 596         /*
 597          * Write it
 598          */
 599         assert(encoder->guts->frame.bits == 0); /* assert that we're byte-aligned before writing */
 600         assert(encoder->guts->frame.total_consumed_bits == 0); /* assert that no reading of the buffer was done */
 601         if(encoder->guts->write_callback(encoder, encoder->guts->frame.buffer, encoder->guts->frame.bytes, encoder->blocksize, encoder->guts->current_frame_number, encoder->guts->client_data) != FLAC__ENCODER_WRITE_OK) {
 602                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_WRITING;
 603                 return false;
 604         }
 605
 606         /*
 607          * Get ready for the next frame
 608          */
 609         encoder->guts->current_frame_can_do_mid_side = true;
 610         encoder->guts->current_sample_number = 0;
 611         encoder->guts->current_frame_number++;
 612         encoder->guts->metadata.data.stream_info.total_samples += (uint64)encoder->blocksize;
 613         encoder->guts->metadata.data.stream_info.min_framesize = min(encoder->guts->frame.bytes, encoder->guts->metadata.data.stream_info.min_framesize);
 614         encoder->guts->metadata.data.stream_info.max_framesize = max(encoder->guts->frame.bytes, encoder->guts->metadata.data.stream_info.max_framesize);
 615
 616         return true;
 617 }
 618
 619 bool encoder_process_subframes_(FLAC__Encoder *encoder, bool is_last_frame)
 620 {
 621         FLAC__FrameHeader frame_header;
 622         unsigned channel, max_partition_order;
 623         bool do_independent, do_mid_side;
 624
 625         /*
 626          * Calculate the max Rice partition order
 627          */
 628         if(is_last_frame) {
 629                 max_partition_order = 0;
 630         }
 631         else {
 632                 unsigned limit = 0, b = encoder->blocksize;
 633                 while(!(b & 1)) {
 634                         limit++;
 635                         b >>= 1;
 636                 }
 637                 max_partition_order = min(encoder->rice_optimization_level, limit);
 638         }
 639
 640         /*
 641          * Setup the frame
 642          */
 643         if(!FLAC__bitbuffer_clear(&encoder->guts->frame)) {
 644                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 645                 return false;
 646         }
 647         frame_header.blocksize = encoder->blocksize;
 648         frame_header.sample_rate = encoder->sample_rate;
 649         frame_header.channels = encoder->channels;
 650         frame_header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT; /* the default unless the encoder determines otherwise */
 651         frame_header.bits_per_sample = encoder->bits_per_sample;
 652         frame_header.number.frame_number = encoder->guts->current_frame_number;
 653
 654         /*
 655          * Figure out what channel assignments to try
 656          */
 657         if(encoder->do_mid_side_stereo) {
 658                 if(encoder->loose_mid_side_stereo) {
 659                         if(encoder->guts->loose_mid_side_stereo_frame_count == 0) {
 660                                 do_independent = true;
 661                                 do_mid_side = true;
 662                         }
 663                         else {
 664                                 do_independent = (encoder->guts->last_channel_assignment == FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT);
 665                                 do_mid_side = !do_independent;
 666                         }
 667                 }
 668                 else {
 669                         do_independent = true;
 670                         do_mid_side = true;
 671                 }
 672         }
 673         else {
 674                 do_independent = true;
 675                 do_mid_side = false;
 676         }
 677         if(do_mid_side && !encoder->guts->current_frame_can_do_mid_side) {
 678                 do_independent = true;
 679                 do_mid_side = false;
 680         }
 681
 682         assert(do_independent || do_mid_side);
 683
 684         /*
 685          * First do a normal encoding pass of each independent channel
 686          */
 687         if(do_independent) {
 688                 for(channel = 0; channel < encoder->channels; channel++) {
 689                         if(!encoder_process_subframe_(encoder, max_partition_order, false, &frame_header, encoder->bits_per_sample, encoder->guts->integer_signal[channel], encoder->guts->real_signal[channel], encoder->guts->subframe_workspace_ptr[channel], encoder->guts->residual_workspace[channel], encoder->guts->best_subframe+channel, encoder->guts->best_subframe_bits+channel))
 690                                 return false;
 691                 }
 692         }
 693
 694         /*
 695          * Now do mid and side channels if requested
 696          */
 697         if(do_mid_side) {
 698                 assert(encoder->channels == 2);
 699
 700                 for(channel = 0; channel < 2; channel++) {
 701                         if(!encoder_process_subframe_(encoder, max_partition_order, false, &frame_header, encoder->bits_per_sample+(channel==0? 0:1), encoder->guts->integer_signal_mid_side[channel], encoder->guts->real_signal_mid_side[channel], encoder->guts->subframe_workspace_ptr_mid_side[channel], encoder->guts->residual_workspace_mid_side[channel], encoder->guts->best_subframe_mid_side+channel, encoder->guts->best_subframe_bits_mid_side+channel))
 702                                 return false;
 703                 }
 704         }
 705
 706         /*
 707          * Compose the frame bitbuffer
 708          */
 709         if(do_mid_side) {
 710                 FLAC__ChannelAssignment channel_assignment;
 711
 712                 assert(encoder->channels == 2);
 713
 714                 if(encoder->loose_mid_side_stereo && encoder->guts->loose_mid_side_stereo_frame_count > 0) {
 715                         channel_assignment = (encoder->guts->last_channel_assignment == FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT? FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT : FLAC__CHANNEL_ASSIGNMENT_MID_SIDE);
 716                 }
 717                 else {
 718                         unsigned bits[4]; /* WATCHOUT - indexed by FLAC__ChannelAssignment */
 719                         unsigned min_bits;
 720                         FLAC__ChannelAssignment ca;
 721
 722                         assert(do_independent && do_mid_side);
 723
 724                         /* We have to figure out which channel assignent results in the smallest frame */
 725                         bits[FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT] = encoder->guts->best_subframe_bits         [0] + encoder->guts->best_subframe_bits         [1];
 726                         bits[FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE  ] = encoder->guts->best_subframe_bits         [0] + encoder->guts->best_subframe_bits_mid_side[1];
 727                         bits[FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE ] = encoder->guts->best_subframe_bits         [1] + encoder->guts->best_subframe_bits_mid_side[1];
 728                         bits[FLAC__CHANNEL_ASSIGNMENT_MID_SIDE   ] = encoder->guts->best_subframe_bits_mid_side[0] + encoder->guts->best_subframe_bits_mid_side[1];
 729
 730                         for(channel_assignment = 0, min_bits = bits[0], ca = 1; ca <= 3; ca++) {
 731                                 if(bits[ca] < min_bits) {
 732                                         min_bits = bits[ca];
 733                                         channel_assignment = ca;
 734                                 }
 735                         }
 736                 }
 737
 738                 frame_header.channel_assignment = channel_assignment;
 739
 740                 if(!FLAC__frame_add_header(&frame_header, encoder->streamable_subset, is_last_frame, &encoder->guts->frame)) {
 741                         encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 742                         return false;
 743                 }
 744
 745                 switch(channel_assignment) {
 746                         /* note that encoder_add_subframe_ sets the state for us in case of an error */
 747                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 748                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [0][encoder->guts->best_subframe         [0]], &encoder->guts->frame))
 749                                         return false;
 750                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [1][encoder->guts->best_subframe         [1]], &encoder->guts->frame))
 751                                         return false;
 752                                 break;
 753                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 754                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [0][encoder->guts->best_subframe         [0]], &encoder->guts->frame))
 755                                         return false;
 756                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample+1, &encoder->guts->subframe_workspace_mid_side[1][encoder->guts->best_subframe_mid_side[1]], &encoder->guts->frame))
 757                                         return false;
 758                                 break;
 759                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 760                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample+1, &encoder->guts->subframe_workspace_mid_side[1][encoder->guts->best_subframe_mid_side[1]], &encoder->guts->frame))
 761                                         return false;
 762                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [1][encoder->guts->best_subframe         [1]], &encoder->guts->frame))
 763                                         return false;
 764                                 break;
 765                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 766                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace_mid_side[0][encoder->guts->best_subframe_mid_side[0]], &encoder->guts->frame))
 767                                         return false;
 768                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample+1, &encoder->guts->subframe_workspace_mid_side[1][encoder->guts->best_subframe_mid_side[1]], &encoder->guts->frame))
 769                                         return false;
 770                                 break;
 771                         default:
 772                                 assert(0);
 773                 }
 774         }
 775         else {
 776                 if(!FLAC__frame_add_header(&frame_header, encoder->streamable_subset, is_last_frame, &encoder->guts->frame)) {
 777                         encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 778                         return false;
 779                 }
 780
 781                 for(channel = 0; channel < encoder->channels; channel++) {
 782                         if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample, &encoder->guts->subframe_workspace[channel][encoder->guts->best_subframe[channel]], &encoder->guts->frame)) {
 783                                 /* the above function sets the state for us in case of an error */
 784                                 return false;
 785                         }
 786                 }
 787         }
 788
 789         if(encoder->loose_mid_side_stereo) {
 790                 encoder->guts->loose_mid_side_stereo_frame_count++;
 791                 if(encoder->guts->loose_mid_side_stereo_frame_count >= encoder->guts->loose_mid_side_stereo_frames)
 792                         encoder->guts->loose_mid_side_stereo_frame_count = 0;
 793         }
 794
 795         encoder->guts->last_channel_assignment = frame_header.channel_assignment;
 796
 797         return true;
 798 }
 799
 800 bool encoder_process_subframe_(FLAC__Encoder *encoder, unsigned max_partition_order, bool verbatim_only, const FLAC__FrameHeader *frame_header, unsigned bits_per_sample, const int32 integer_signal[], const real real_signal[], FLAC__Subframe *subframe[2], int32 *residual[2], unsigned *best_subframe, unsigned *best_bits)
 801 {
 802         real fixed_residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1];
 803         real lpc_residual_bits_per_sample;
 804         real autoc[FLAC__MAX_LPC_ORDER+1];
 805         real lp_coeff[FLAC__MAX_LPC_ORDER][FLAC__MAX_LPC_ORDER];
 806         real lpc_error[FLAC__MAX_LPC_ORDER];
 807         unsigned min_lpc_order, max_lpc_order, lpc_order;
 808         unsigned min_fixed_order, max_fixed_order, guess_fixed_order, fixed_order;
 809         unsigned min_qlp_coeff_precision, max_qlp_coeff_precision, qlp_coeff_precision;
 810         unsigned rice_parameter;
 811         unsigned _candidate_bits, _best_bits;
 812         unsigned _best_subframe;
 813
 814         /* verbatim subframe is the baseline against which we measure other compressed subframes */
 815         _best_subframe = 0;
 816         _best_bits = encoder_evaluate_verbatim_subframe_(integer_signal, frame_header->blocksize, bits_per_sample, subframe[_best_subframe]);
 817
 818         if(!verbatim_only && frame_header->blocksize >= FLAC__MAX_FIXED_ORDER) {
 819                 /* check for constant subframe */
 820                 guess_fixed_order = FLAC__fixed_compute_best_predictor(integer_signal+FLAC__MAX_FIXED_ORDER, frame_header->blocksize-FLAC__MAX_FIXED_ORDER, fixed_residual_bits_per_sample);
 821                 if(fixed_residual_bits_per_sample[1] == 0.0) {
 822                         /* the above means integer_signal+FLAC__MAX_FIXED_ORDER is constant, now we just have to check the warmup samples */
 823                         unsigned i, signal_is_constant = true;
 824                         for(i = 1; i <= FLAC__MAX_FIXED_ORDER; i++) {
 825                                 if(integer_signal[0] != integer_signal[i]) {
 826                                         signal_is_constant = false;
 827                                         break;
 828                                 }
 829                         }
 830                         if(signal_is_constant) {
 831                                 _candidate_bits = encoder_evaluate_constant_subframe_(integer_signal[0], bits_per_sample, subframe[!_best_subframe]);
 832                                 if(_candidate_bits < _best_bits) {
 833                                         _best_subframe = !_best_subframe;
 834                                         _best_bits = _candidate_bits;
 835                                 }
 836                         }
 837                 }
 838                 else {
 839                         /* encode fixed */
 840                         if(encoder->do_exhaustive_model_search) {
 841                                 min_fixed_order = 0;
 842                                 max_fixed_order = FLAC__MAX_FIXED_ORDER;
 843                         }
 844                         else {
 845                                 min_fixed_order = max_fixed_order = guess_fixed_order;
 846                         }
 847                         for(fixed_order = min_fixed_order; fixed_order <= max_fixed_order; fixed_order++) {
 848                                 if(fixed_residual_bits_per_sample[fixed_order] >= (real)bits_per_sample)
 849                                         continue; /* don't even try */
 850                                 rice_parameter = (fixed_residual_bits_per_sample[fixed_order] > 0.0)? (unsigned)(fixed_residual_bits_per_sample[fixed_order]+0.5) : 0; /* 0.5 is for rounding */
 851 #ifdef FOLDED_RICE
 852                                 rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
 853 #endif
 854                                 if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
 855                                         rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
 856                                 _candidate_bits = encoder_evaluate_fixed_subframe_(integer_signal, residual[!_best_subframe], encoder->guts->abs_residual, frame_header->blocksize, bits_per_sample, fixed_order, rice_parameter, max_partition_order, subframe[!_best_subframe]);
 857                                 if(_candidate_bits < _best_bits) {
 858                                         _best_subframe = !_best_subframe;
 859                                         _best_bits = _candidate_bits;
 860                                 }
 861                         }
 862
 863                         /* encode lpc */
 864                         if(encoder->max_lpc_order > 0) {
 865                                 if(encoder->max_lpc_order >= frame_header->blocksize)
 866                                         max_lpc_order = frame_header->blocksize-1;
 867                                 else
 868                                         max_lpc_order = encoder->max_lpc_order;
 869                                 if(max_lpc_order > 0) {
 870                                         FLAC__lpc_compute_autocorrelation(real_signal, frame_header->blocksize, max_lpc_order+1, autoc);
 871                                         /* if autoc[0] == 0.0, the signal is constant and we usually won't get here, but it can happen */
 872                                         if(autoc[0] != 0.0) {
 873                                                 FLAC__lpc_compute_lp_coefficients(autoc, max_lpc_order, lp_coeff, lpc_error);
 874                                                 if(encoder->do_exhaustive_model_search) {
 875                                                         min_lpc_order = 1;
 876                                                 }
 877                                                 else {
 878                                                         unsigned guess_lpc_order = FLAC__lpc_compute_best_order(lpc_error, max_lpc_order, frame_header->blocksize, bits_per_sample);
 879                                                         min_lpc_order = max_lpc_order = guess_lpc_order;
 880                                                 }
 881                                                 if(encoder->do_qlp_coeff_prec_search) {
 882                                                         min_qlp_coeff_precision = FLAC__MIN_QLP_COEFF_PRECISION;
 883                                                         max_qlp_coeff_precision = min(32 - bits_per_sample - 1, (1u<<FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN)-1);
 884                                                 }
 885                                                 else {
 886                                                         min_qlp_coeff_precision = max_qlp_coeff_precision = encoder->qlp_coeff_precision;
 887                                                 }
 888                                                 for(lpc_order = min_lpc_order; lpc_order <= max_lpc_order; lpc_order++) {
 889                                                         lpc_residual_bits_per_sample = FLAC__lpc_compute_expected_bits_per_residual_sample(lpc_error[lpc_order-1], frame_header->blocksize-lpc_order);
 890                                                         if(lpc_residual_bits_per_sample >= (real)bits_per_sample)
 891                                                                 continue; /* don't even try */
 892                                                         rice_parameter = (lpc_residual_bits_per_sample > 0.0)? (unsigned)(lpc_residual_bits_per_sample+0.5) : 0; /* 0.5 is for rounding */
 893 #ifdef FOLDED_RICE
 894                                                         rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
 895 #endif
 896                                                         if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
 897                                                                 rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
 898                                                         for(qlp_coeff_precision = min_qlp_coeff_precision; qlp_coeff_precision <= max_qlp_coeff_precision; qlp_coeff_precision++) {
 899                                                                 _candidate_bits = encoder_evaluate_lpc_subframe_(integer_signal, residual[!_best_subframe], encoder->guts->abs_residual, lp_coeff[lpc_order-1], frame_header->blocksize, bits_per_sample, lpc_order, qlp_coeff_precision, rice_parameter, max_partition_order, subframe[!_best_subframe]);
 900                                                                 if(_candidate_bits > 0) { /* if == 0, there was a problem quantizing the lpcoeffs */
 901                                                                         if(_candidate_bits < _best_bits) {
 902                                                                                 _best_subframe = !_best_subframe;
 903                                                                                 _best_bits = _candidate_bits;
 904                                                                         }
 905                                                                 }
 906                                                         }
 907                                                 }
 908                                         }
 909                                 }
 910                         }
 911                 }
 912         }
 913
 914         *best_subframe = _best_subframe;
 915         *best_bits = _best_bits;
 916
 917         return true;
 918 }
 919
 920 bool encoder_add_subframe_(FLAC__Encoder *encoder, const FLAC__FrameHeader *frame_header, unsigned bits_per_sample, const FLAC__Subframe *subframe, FLAC__BitBuffer *frame)
 921 {
 922         switch(subframe->type) {
 923                 case FLAC__SUBFRAME_TYPE_CONSTANT:
 924                         if(!FLAC__subframe_add_constant(&(subframe->data.constant), bits_per_sample, frame)) {
 925                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 926                                 return false;
 927                         }
 928                         break;
 929                 case FLAC__SUBFRAME_TYPE_FIXED:
 930                         if(!FLAC__subframe_add_fixed(&(subframe->data.fixed), frame_header->blocksize - subframe->data.fixed.order, bits_per_sample, frame)) {
 931                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 932                                 return false;
 933                         }
 934                         break;
 935                 case FLAC__SUBFRAME_TYPE_LPC:
 936                         if(!FLAC__subframe_add_lpc(&(subframe->data.lpc), frame_header->blocksize - subframe->data.lpc.order, bits_per_sample, frame)) {
 937                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 938                                 return false;
 939                         }
 940                         break;
 941                 case FLAC__SUBFRAME_TYPE_VERBATIM:
 942                         if(!FLAC__subframe_add_verbatim(&(subframe->data.verbatim), frame_header->blocksize, bits_per_sample, frame)) {
 943                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 944                                 return false;
 945                         }
 946                         break;
 947                 default:
 948                         assert(0);
 949         }
 950
 951         return true;
 952 }
 953
 954 unsigned encoder_evaluate_constant_subframe_(const int32 signal, unsigned bits_per_sample, FLAC__Subframe *subframe)
 955 {
 956         subframe->type = FLAC__SUBFRAME_TYPE_CONSTANT;
 957         subframe->data.constant.value = signal;
 958
 959         return FLAC__SUBFRAME_TYPE_LEN + bits_per_sample;
 960 }
 961
 962 unsigned encoder_evaluate_fixed_subframe_(const int32 signal[], int32 residual[], uint32 abs_residual[], unsigned blocksize, unsigned bits_per_sample, unsigned order, unsigned rice_parameter, unsigned max_partition_order, FLAC__Subframe *subframe)
 963 {
 964         unsigned i, residual_bits;
 965         const unsigned residual_samples = blocksize - order;
 966
 967         FLAC__fixed_compute_residual(signal+order, residual_samples, order, residual);
 968
 969         subframe->type = FLAC__SUBFRAME_TYPE_FIXED;
 970
 971         subframe->data.fixed.entropy_coding_method.type = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE;
 972         subframe->data.fixed.residual = residual;
 973
 974         residual_bits = encoder_find_best_partition_order_(residual, abs_residual, residual_samples, order, rice_parameter, max_partition_order, &subframe->data.fixed.entropy_coding_method.data.partitioned_rice.order, subframe->data.fixed.entropy_coding_method.data.partitioned_rice.parameters);
 975
 976         subframe->data.fixed.order = order;
 977         for(i = 0; i < order; i++)
 978                 subframe->data.fixed.warmup[i] = signal[i];
 979
 980         return FLAC__SUBFRAME_TYPE_LEN + (order * bits_per_sample) + residual_bits;
 981 }
 982
 983 unsigned encoder_evaluate_lpc_subframe_(const int32 signal[], int32 residual[], uint32 abs_residual[], const real lp_coeff[], unsigned blocksize, unsigned bits_per_sample, unsigned order, unsigned qlp_coeff_precision, unsigned rice_parameter, unsigned max_partition_order, FLAC__Subframe *subframe)
 984 {
 985         int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
 986         unsigned i, residual_bits;
 987         int quantization, ret;
 988         const unsigned residual_samples = blocksize - order;
 989
 990         ret = FLAC__lpc_quantize_coefficients(lp_coeff, order, qlp_coeff_precision, bits_per_sample, qlp_coeff, &quantization);
 991         if(ret != 0)
 992                 return 0; /* this is a hack to indicate to the caller that we can't do lp at this order on this subframe */
 993
 994         FLAC__lpc_compute_residual_from_qlp_coefficients(signal+order, residual_samples, qlp_coeff, order, quantization, residual);
 995
 996         subframe->type = FLAC__SUBFRAME_TYPE_LPC;
 997
 998         subframe->data.lpc.entropy_coding_method.type = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE;
 999         subframe->data.lpc.residual = residual;
1000
1001         residual_bits = encoder_find_best_partition_order_(residual, abs_residual, residual_samples, order, rice_parameter, max_partition_order, &subframe->data.lpc.entropy_coding_method.data.partitioned_rice.order, subframe->data.lpc.entropy_coding_method.data.partitioned_rice.parameters);
1002
1003         subframe->data.lpc.order = order;
1004         subframe->data.lpc.qlp_coeff_precision = qlp_coeff_precision;
1005         subframe->data.lpc.quantization_level = quantization;
1006         memcpy(subframe->data.lpc.qlp_coeff, qlp_coeff, sizeof(int32)*FLAC__MAX_LPC_ORDER);
1007         for(i = 0; i < order; i++)
1008                 subframe->data.lpc.warmup[i] = signal[i];
1009
1010         return FLAC__SUBFRAME_TYPE_LEN + FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN + FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN + (order * (qlp_coeff_precision + bits_per_sample)) + residual_bits;
1011 }
1012
1013 unsigned encoder_evaluate_verbatim_subframe_(const int32 signal[], unsigned blocksize, unsigned bits_per_sample, FLAC__Subframe *subframe)
1014 {
1015         subframe->type = FLAC__SUBFRAME_TYPE_VERBATIM;
1016
1017         subframe->data.verbatim.data = signal;
1018
1019         return FLAC__SUBFRAME_TYPE_LEN + (blocksize * bits_per_sample);
1020 }
1021
1022 unsigned encoder_find_best_partition_order_(const int32 residual[], uint32 abs_residual[], unsigned residual_samples, unsigned predictor_order, unsigned rice_parameter, unsigned max_partition_order, unsigned *best_partition_order, unsigned best_parameters[])
1023 {
1024         unsigned residual_bits, best_residual_bits = 0;
1025         unsigned i, partition_order;
1026         unsigned best_parameters_index = 0, parameters[2][1 << FLAC__MAX_RICE_PARTITION_ORDER];
1027         int32 r;
1028
1029         /* compute the abs(residual) for use later */
1030         for(i = 0; i < residual_samples; i++) {
1031                 r = residual[i];
1032                 abs_residual[i] = (uint32)(r<0? -r : r);
1033         }
1034
1035         for(partition_order = 0; partition_order <= max_partition_order; partition_order++) {
1036                 if(!encoder_set_partitioned_rice_(abs_residual, residual_samples, predictor_order, rice_parameter, partition_order, parameters[!best_parameters_index], &residual_bits)) {
1037                         assert(best_residual_bits != 0);
1038                         break;
1039                 }
1040                 if(best_residual_bits == 0 || residual_bits < best_residual_bits) {
1041                         best_residual_bits = residual_bits;
1042                         *best_partition_order = partition_order;
1043                         best_parameters_index = !best_parameters_index;
1044                 }
1045         }
1046         memcpy(best_parameters, parameters[best_parameters_index], sizeof(unsigned)*(1<<(*best_partition_order)));
1047
1048         return best_residual_bits;
1049 }
1050
1051 #ifdef ESTIMATE_RICE_BITS
1052 #undef ESTIMATE_RICE_BITS
1053 #endif
1054 #ifdef FOLDED_RICE
1055 #define ESTIMATE_RICE_BITS(value, parameter) ((value) >> (parameter))
1056 #else
1057 /* symmetric Rice coding ala Shorten */
1058 #define ESTIMATE_RICE_BITS(value, parameter) ((value) >> (parameter))
1059 #endif
1060
1061 bool encoder_set_partitioned_rice_(const uint32 abs_residual[], const unsigned residual_samples, const unsigned predictor_order, const unsigned rice_parameter, const unsigned partition_order, unsigned parameters[], unsigned *bits)
1062 {
1063         unsigned bits_ = FLAC__ENTROPY_CODING_METHOD_TYPE_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN;
1064
1065         if(partition_order == 0) {
1066                 unsigned i;
1067 #ifdef ESTIMATE_RICE_BITS
1068 #ifdef FOLDED_RICE
1069                 const unsigned rice_parameter_estimate = rice_parameter-1;
1070                 bits_ += (2+rice_parameter) * residual_samples;
1071 #else
1072                 /* symmetric Rice coding ala Shorten */
1073                 bits_ += (2+rice_parameter) * residual_samples;
1074 #endif
1075 #endif
1076                 parameters[0] = rice_parameter;
1077                 bits_ += FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
1078                 for(i = 0; i < residual_samples; i++)
1079 #ifdef ESTIMATE_RICE_BITS
1080 #ifdef FOLDED_RICE
1081                         bits_ += ESTIMATE_RICE_BITS(abs_residual[i], rice_parameter_estimate);
1082 #else
1083                         /* symmetric Rice coding ala Shorten */
1084                         bits_ += ESTIMATE_RICE_BITS(abs_residual[i], rice_parameter);
1085 #endif
1086 #else
1087                         bits_ += FLAC__bitbuffer_rice_bits(residual[i], rice_parameter);
1088 #endif
1089         }
1090         else {
1091                 unsigned i, j, k = 0, k_last = 0;
1092                 unsigned mean, parameter, partition_samples;
1093                 const unsigned max_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
1094                 for(i = 0; i < (1u<<partition_order); i++) {
1095                         partition_samples = (residual_samples+predictor_order) >> partition_order;
1096                         if(i == 0) {
1097                                 if(partition_samples <= predictor_order)
1098                                         return false;
1099                                 else
1100                                         partition_samples -= predictor_order;
1101                         }
1102                         mean = partition_samples >> 1;
1103                         for(j = 0; j < partition_samples; j++, k++)
1104                                 mean += abs_residual[k];
1105                         mean /= partition_samples;
1106 #ifdef ESTIMATE_RICE_BITS
1107 #ifdef FOLDED_RICE
1108                         /* calc parameter = floor(log2(mean)) + 1 */
1109                         parameter = 0;
1110                         while(mean) {
1111                                 parameter++;
1112                                 mean >>= 1;
1113                         }
1114 #else
1115                         /* symmetric Rice coding ala Shorten */
1116                         /* calc parameter = floor(log2(mean)) + 1 */
1117                         parameter = 0;
1118 mean>>=1;
1119                         while(mean) {
1120                                 parameter++;
1121                                 mean >>= 1;
1122                         }
1123 #endif
1124 #else
1125 #error
1126 #endif
1127                         if(parameter > max_parameter)
1128                                 parameter = max_parameter;
1129                         parameters[i] = parameter;
1130                         bits_ += FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
1131 #ifdef ESTIMATE_RICE_BITS
1132 #ifdef FOLDED_RICE
1133                         bits_ += (2+parameter) * partition_samples;
1134                         --parameter;
1135 #else
1136                         /* symmetric Rice coding ala Shorten */
1137                         bits_ += (2+parameter) * partition_samples;
1138 #endif
1139 #endif
1140                         for(j = k_last; j < k; j++)
1141 #ifdef ESTIMATE_RICE_BITS
1142 #ifdef FOLDED_RICE
1143                                 bits_ += ESTIMATE_RICE_BITS(abs_residual[j], parameter);
1144 #else
1145                                 /* symmetric Rice coding ala Shorten */
1146                                 bits_ += ESTIMATE_RICE_BITS(abs_residual[j], parameter);
1147 #endif
1148 #else
1149                                 bits_ += FLAC__bitbuffer_rice_bits(residual[j], parameter);
1150 #endif
1151                         k_last = k;
1152                 }
1153         }
1154
1155         *bits = bits_;
1156         return true;
1157 }