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->do_mid_side_stereo && encoder->bits_per_sample > 16)
 267                 return encoder->state = FLAC__ENCODER_MID_SIDE_SAMPLE_SIZE_MISMATCH;
 268
 269         if(encoder->loose_mid_side_stereo && !encoder->do_mid_side_stereo)
 270                 return encoder->state = FLAC__ENCODER_ILLEGAL_MID_SIDE_FORCE;
 271
 272         if(encoder->bits_per_sample == 0 || encoder->bits_per_sample > FLAC__MAX_BITS_PER_SAMPLE)
 273                 return encoder->state = FLAC__ENCODER_INVALID_BITS_PER_SAMPLE;
 274
 275         if(encoder->sample_rate == 0 || encoder->sample_rate > FLAC__MAX_SAMPLE_RATE)
 276                 return encoder->state = FLAC__ENCODER_INVALID_SAMPLE_RATE;
 277
 278         if(encoder->blocksize < FLAC__MIN_BLOCK_SIZE || encoder->blocksize > FLAC__MAX_BLOCK_SIZE)
 279                 return encoder->state = FLAC__ENCODER_INVALID_BLOCK_SIZE;
 280
 281         if(encoder->blocksize < encoder->max_lpc_order)
 282                 return encoder->state = FLAC__ENCODER_BLOCK_SIZE_TOO_SMALL_FOR_LPC_ORDER;
 283
 284         if(encoder->qlp_coeff_precision == 0) {
 285                 if(encoder->bits_per_sample < 16) {
 286                         /* @@@ need some data about how to set this here w.r.t. blocksize and sample rate */
 287                         /* @@@ until then we'll make a guess */
 288                         encoder->qlp_coeff_precision = max(5, 2 + encoder->bits_per_sample / 2);
 289                 }
 290                 else if(encoder->bits_per_sample == 16) {
 291                         if(encoder->blocksize <= 192)
 292                                 encoder->qlp_coeff_precision = 7;
 293                         else if(encoder->blocksize <= 384)
 294                                 encoder->qlp_coeff_precision = 8;
 295                         else if(encoder->blocksize <= 576)
 296                                 encoder->qlp_coeff_precision = 9;
 297                         else if(encoder->blocksize <= 1152)
 298                                 encoder->qlp_coeff_precision = 10;
 299                         else if(encoder->blocksize <= 2304)
 300                                 encoder->qlp_coeff_precision = 11;
 301                         else if(encoder->blocksize <= 4608)
 302                                 encoder->qlp_coeff_precision = 12;
 303                         else
 304                                 encoder->qlp_coeff_precision = 13;
 305                 }
 306                 else {
 307                         encoder->qlp_coeff_precision = min(13, 8*sizeof(int32) - encoder->bits_per_sample - 1);
 308                 }
 309         }
 310         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))
 311                 return encoder->state = FLAC__ENCODER_INVALID_QLP_COEFF_PRECISION;
 312
 313         if(encoder->streamable_subset) {
 314                 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)
 315                         return encoder->state = FLAC__ENCODER_NOT_STREAMABLE;
 316                 if(encoder->sample_rate > 655350)
 317                         return encoder->state = FLAC__ENCODER_NOT_STREAMABLE;
 318         }
 319
 320         if(encoder->rice_optimization_level >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN))
 321                 encoder->rice_optimization_level = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN) - 1;
 322
 323         encoder->guts = (FLAC__EncoderPrivate*)malloc(sizeof(FLAC__EncoderPrivate));
 324         if(encoder->guts == 0)
 325                 return encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 326
 327         encoder->guts->input_capacity = 0;
 328         for(i = 0; i < encoder->channels; i++) {
 329                 encoder->guts->integer_signal[i] = 0;
 330                 encoder->guts->real_signal[i] = 0;
 331         }
 332         for(i = 0; i < 2; i++) {
 333                 encoder->guts->integer_signal_mid_side[i] = 0;
 334                 encoder->guts->real_signal_mid_side[i] = 0;
 335         }
 336         for(i = 0; i < encoder->channels; i++) {
 337                 encoder->guts->residual_workspace[i][0] = encoder->guts->residual_workspace[i][1] = 0;
 338                 encoder->guts->best_subframe[i] = 0;
 339         }
 340         for(i = 0; i < 2; i++) {
 341                 encoder->guts->residual_workspace_mid_side[i][0] = encoder->guts->residual_workspace_mid_side[i][1] = 0;
 342                 encoder->guts->best_subframe_mid_side[i] = 0;
 343         }
 344         for(i = 0; i < encoder->channels; i++) {
 345                 encoder->guts->subframe_workspace_ptr[i][0] = &encoder->guts->subframe_workspace[i][0];
 346                 encoder->guts->subframe_workspace_ptr[i][1] = &encoder->guts->subframe_workspace[i][1];
 347         }
 348         for(i = 0; i < 2; i++) {
 349                 encoder->guts->subframe_workspace_ptr_mid_side[i][0] = &encoder->guts->subframe_workspace_mid_side[i][0];
 350                 encoder->guts->subframe_workspace_ptr_mid_side[i][1] = &encoder->guts->subframe_workspace_mid_side[i][1];
 351         }
 352         encoder->guts->abs_residual = 0;
 353         encoder->guts->current_frame_can_do_mid_side = true;
 354         encoder->guts->loose_mid_side_stereo_frames_exact = (double)encoder->sample_rate * 0.4 / (double)encoder->blocksize;
 355         encoder->guts->loose_mid_side_stereo_frames = (unsigned)(encoder->guts->loose_mid_side_stereo_frames_exact + 0.5);
 356         if(encoder->guts->loose_mid_side_stereo_frames == 0)
 357                 encoder->guts->loose_mid_side_stereo_frames = 1;
 358         encoder->guts->loose_mid_side_stereo_frame_count = 0;
 359         encoder->guts->current_sample_number = 0;
 360         encoder->guts->current_frame_number = 0;
 361
 362         if(!encoder_resize_buffers_(encoder, encoder->blocksize)) {
 363                 /* the above function sets the state for us in case of an error */
 364                 return encoder->state;
 365         }
 366         FLAC__bitbuffer_init(&encoder->guts->frame);
 367         encoder->guts->write_callback = write_callback;
 368         encoder->guts->metadata_callback = metadata_callback;
 369         encoder->guts->client_data = client_data;
 370
 371         /*
 372          * write the stream header
 373          */
 374         if(!FLAC__bitbuffer_clear(&encoder->guts->frame))
 375                 return encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 376
 377         if(!FLAC__bitbuffer_write_raw_uint32(&encoder->guts->frame, FLAC__STREAM_SYNC, FLAC__STREAM_SYNC_LEN))
 378                 return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 379
 380         encoder->guts->metadata.type = FLAC__METADATA_TYPE_STREAMINFO;
 381         encoder->guts->metadata.is_last = (encoder->padding == 0);
 382         encoder->guts->metadata.length = FLAC__STREAM_METADATA_STREAMINFO_LENGTH;
 383         encoder->guts->metadata.data.stream_info.min_blocksize = encoder->blocksize; /* this encoder uses the same blocksize for the whole stream */
 384         encoder->guts->metadata.data.stream_info.max_blocksize = encoder->blocksize;
 385         encoder->guts->metadata.data.stream_info.min_framesize = 0; /* we don't know this yet; have to fill it in later */
 386         encoder->guts->metadata.data.stream_info.max_framesize = 0; /* we don't know this yet; have to fill it in later */
 387         encoder->guts->metadata.data.stream_info.sample_rate = encoder->sample_rate;
 388         encoder->guts->metadata.data.stream_info.channels = encoder->channels;
 389         encoder->guts->metadata.data.stream_info.bits_per_sample = encoder->bits_per_sample;
 390         encoder->guts->metadata.data.stream_info.total_samples = encoder->total_samples_estimate; /* we will replace this later with the real total */
 391         memset(encoder->guts->metadata.data.stream_info.md5sum, 0, 16); /* we don't know this yet; have to fill it in later */
 392         MD5Init(&encoder->guts->md5context);
 393         if(!FLAC__add_metadata_block(&encoder->guts->metadata, &encoder->guts->frame))
 394                 return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 395
 396         /* add a PADDING block if requested */
 397         if(encoder->padding > 0) {
 398                 padding.type = FLAC__METADATA_TYPE_PADDING;
 399                 padding.is_last = true;
 400                 padding.length = encoder->padding;
 401                 if(!FLAC__add_metadata_block(&padding, &encoder->guts->frame))
 402                         return encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 403         }
 404
 405         assert(encoder->guts->frame.bits == 0); /* assert that we're byte-aligned before writing */
 406         assert(encoder->guts->frame.total_consumed_bits == 0); /* assert that no reading of the buffer was done */
 407         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)
 408                 return encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_WRITING;
 409
 410         /* now that the metadata block is written, we can init this to an absurdly-high value... */
 411         encoder->guts->metadata.data.stream_info.min_framesize = (1u << FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN) - 1;
 412         /* ... and clear this to 0 */
 413         encoder->guts->metadata.data.stream_info.total_samples = 0;
 414
 415         return encoder->state;
 416 }
 417
 418 void FLAC__encoder_finish(FLAC__Encoder *encoder)
 419 {
 420         unsigned i, channel;
 421
 422         assert(encoder != 0);
 423         if(encoder->state == FLAC__ENCODER_UNINITIALIZED)
 424                 return;
 425         if(encoder->guts->current_sample_number != 0) {
 426                 encoder->blocksize = encoder->guts->current_sample_number;
 427                 encoder_process_frame_(encoder, true); /* true => is last frame */
 428         }
 429         MD5Final(encoder->guts->metadata.data.stream_info.md5sum, &encoder->guts->md5context);
 430         encoder->guts->metadata_callback(encoder, &encoder->guts->metadata, encoder->guts->client_data);
 431         if(encoder->guts != 0) {
 432                 for(i = 0; i < encoder->channels; i++) {
 433                         if(encoder->guts->integer_signal[i] != 0) {
 434                                 free(encoder->guts->integer_signal[i]);
 435                                 encoder->guts->integer_signal[i] = 0;
 436                         }
 437                         if(encoder->guts->real_signal[i] != 0) {
 438                                 free(encoder->guts->real_signal[i]);
 439                                 encoder->guts->real_signal[i] = 0;
 440                         }
 441                 }
 442                 for(i = 0; i < 2; i++) {
 443                         if(encoder->guts->integer_signal_mid_side[i] != 0) {
 444                                 free(encoder->guts->integer_signal_mid_side[i]);
 445                                 encoder->guts->integer_signal_mid_side[i] = 0;
 446                         }
 447                         if(encoder->guts->real_signal_mid_side[i] != 0) {
 448                                 free(encoder->guts->real_signal_mid_side[i]);
 449                                 encoder->guts->real_signal_mid_side[i] = 0;
 450                         }
 451                 }
 452                 for(channel = 0; channel < encoder->channels; channel++) {
 453                         for(i = 0; i < 2; i++) {
 454                                 if(encoder->guts->residual_workspace[channel][i] != 0) {
 455                                         free(encoder->guts->residual_workspace[channel][i]);
 456                                         encoder->guts->residual_workspace[channel][i] = 0;
 457                                 }
 458                         }
 459                 }
 460                 for(channel = 0; channel < 2; channel++) {
 461                         for(i = 0; i < 2; i++) {
 462                                 if(encoder->guts->residual_workspace_mid_side[channel][i] != 0) {
 463                                         free(encoder->guts->residual_workspace_mid_side[channel][i]);
 464                                         encoder->guts->residual_workspace_mid_side[channel][i] = 0;
 465                                 }
 466                         }
 467                 }
 468                 if(encoder->guts->abs_residual != 0) {
 469                         free(encoder->guts->abs_residual);
 470                         encoder->guts->abs_residual = 0;
 471                 }
 472                 FLAC__bitbuffer_free(&encoder->guts->frame);
 473                 free(encoder->guts);
 474                 encoder->guts = 0;
 475         }
 476         encoder->state = FLAC__ENCODER_UNINITIALIZED;
 477 }
 478
 479 bool FLAC__encoder_process(FLAC__Encoder *encoder, const int32 *buf[], unsigned samples)
 480 {
 481         unsigned i, j, channel;
 482         int32 x, mid, side;
 483         const bool ms = encoder->do_mid_side_stereo && encoder->channels == 2;
 484         const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
 485         const int32 max_side =  ((int64)1 << (encoder->bits_per_sample-1)) - 1;
 486
 487         assert(encoder != 0);
 488         assert(encoder->state == FLAC__ENCODER_OK);
 489
 490         j = 0;
 491         do {
 492                 for(i = encoder->guts->current_sample_number; i < encoder->blocksize && j < samples; i++, j++) {
 493                         for(channel = 0; channel < encoder->channels; channel++) {
 494                                 x = buf[channel][j];
 495                                 encoder->guts->integer_signal[channel][i] = x;
 496                                 encoder->guts->real_signal[channel][i] = (real)x;
 497                         }
 498                         if(ms && encoder->guts->current_frame_can_do_mid_side) {
 499                                 side = buf[0][j] - buf[1][j];
 500                                 if(side < min_side || side > max_side) {
 501                                         encoder->guts->current_frame_can_do_mid_side = false;
 502                                 }
 503                                 else {
 504                                         mid = (buf[0][j] + buf[1][j]) >> 1; /* NOTE: not the same as 'mid = (buf[0][j] + buf[1][j]) / 2' ! */
 505                                         encoder->guts->integer_signal_mid_side[0][i] = mid;
 506                                         encoder->guts->integer_signal_mid_side[1][i] = side;
 507                                         encoder->guts->real_signal_mid_side[0][i] = (real)mid;
 508                                         encoder->guts->real_signal_mid_side[1][i] = (real)side;
 509                                 }
 510                         }
 511                         encoder->guts->current_sample_number++;
 512                 }
 513                 if(i == encoder->blocksize) {
 514                         if(!encoder_process_frame_(encoder, false)) /* false => not last frame */
 515                                 return false;
 516                 }
 517         } while(j < samples);
 518
 519         return true;
 520 }
 521
 522 /* 'samples' is channel-wide samples, e.g. for 1 second at 44100Hz, 'samples' = 44100 regardless of the number of channels */
 523 bool FLAC__encoder_process_interleaved(FLAC__Encoder *encoder, const int32 buf[], unsigned samples)
 524 {
 525         unsigned i, j, k, channel;
 526         int32 x, left = 0, mid, side;
 527         const bool ms = encoder->do_mid_side_stereo && encoder->channels == 2;
 528         const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
 529         const int32 max_side =  ((int64)1 << (encoder->bits_per_sample-1)) - 1;
 530
 531         assert(encoder != 0);
 532         assert(encoder->state == FLAC__ENCODER_OK);
 533
 534         j = k = 0;
 535         do {
 536                 for(i = encoder->guts->current_sample_number; i < encoder->blocksize && j < samples; i++, j++, k++) {
 537                         for(channel = 0; channel < encoder->channels; channel++, k++) {
 538                                 x = buf[k];
 539                                 encoder->guts->integer_signal[channel][i] = x;
 540                                 encoder->guts->real_signal[channel][i] = (real)x;
 541                                 if(ms && encoder->guts->current_frame_can_do_mid_side) {
 542                                         if(channel == 0) {
 543                                                 left = x;
 544                                         }
 545                                         else {
 546                                                 side = left - x;
 547                                                 if(side < min_side || side > max_side) {
 548                                                         encoder->guts->current_frame_can_do_mid_side = false;
 549                                                 }
 550                                                 else {
 551                                                         mid = (left + x) >> 1; /* NOTE: not the same as 'mid = (left + x) / 2' ! */
 552                                                         encoder->guts->integer_signal_mid_side[0][i] = mid;
 553                                                         encoder->guts->integer_signal_mid_side[1][i] = side;
 554                                                         encoder->guts->real_signal_mid_side[0][i] = (real)mid;
 555                                                         encoder->guts->real_signal_mid_side[1][i] = (real)side;
 556                                                 }
 557                                         }
 558                                 }
 559                         }
 560                         encoder->guts->current_sample_number++;
 561                 }
 562                 if(i == encoder->blocksize) {
 563                         if(!encoder_process_frame_(encoder, false)) /* false => not last frame */
 564                                 return false;
 565                 }
 566         } while(j < samples);
 567
 568         return true;
 569 }
 570
 571 bool encoder_process_frame_(FLAC__Encoder *encoder, bool is_last_frame)
 572 {
 573         assert(encoder->state == FLAC__ENCODER_OK);
 574
 575         /*
 576          * Accumulate raw signal to the MD5 signature
 577          */
 578         if(!FLAC__MD5Accumulate(&encoder->guts->md5context, encoder->guts->integer_signal, encoder->channels, encoder->blocksize, (encoder->bits_per_sample+7) / 8)) {
 579                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 580                 return false;
 581         }
 582
 583         /*
 584          * Process the frame header and subframes into the frame bitbuffer
 585          */
 586         if(!encoder_process_subframes_(encoder, is_last_frame)) {
 587                 /* the above function sets the state for us in case of an error */
 588                 return false;
 589         }
 590
 591         /*
 592          * Zero-pad the frame to a byte_boundary
 593          */
 594         if(!FLAC__bitbuffer_zero_pad_to_byte_boundary(&encoder->guts->frame)) {
 595                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 596                 return false;
 597         }
 598
 599         /*
 600          * Write it
 601          */
 602         assert(encoder->guts->frame.bits == 0); /* assert that we're byte-aligned before writing */
 603         assert(encoder->guts->frame.total_consumed_bits == 0); /* assert that no reading of the buffer was done */
 604         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) {
 605                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_WRITING;
 606                 return false;
 607         }
 608
 609         /*
 610          * Get ready for the next frame
 611          */
 612         encoder->guts->current_frame_can_do_mid_side = true;
 613         encoder->guts->current_sample_number = 0;
 614         encoder->guts->current_frame_number++;
 615         encoder->guts->metadata.data.stream_info.total_samples += (uint64)encoder->blocksize;
 616         encoder->guts->metadata.data.stream_info.min_framesize = min(encoder->guts->frame.bytes, encoder->guts->metadata.data.stream_info.min_framesize);
 617         encoder->guts->metadata.data.stream_info.max_framesize = max(encoder->guts->frame.bytes, encoder->guts->metadata.data.stream_info.max_framesize);
 618
 619         return true;
 620 }
 621
 622 bool encoder_process_subframes_(FLAC__Encoder *encoder, bool is_last_frame)
 623 {
 624         FLAC__FrameHeader frame_header;
 625         unsigned channel, max_partition_order;
 626         bool do_independent, do_mid_side;
 627
 628         /*
 629          * Calculate the max Rice partition order
 630          */
 631         if(is_last_frame) {
 632                 max_partition_order = 0;
 633         }
 634         else {
 635                 unsigned limit = 0, b = encoder->blocksize;
 636                 while(!(b & 1)) {
 637                         limit++;
 638                         b >>= 1;
 639                 }
 640                 max_partition_order = min(encoder->rice_optimization_level, limit);
 641         }
 642
 643         /*
 644          * Setup the frame
 645          */
 646         if(!FLAC__bitbuffer_clear(&encoder->guts->frame)) {
 647                 encoder->state = FLAC__ENCODER_MEMORY_ALLOCATION_ERROR;
 648                 return false;
 649         }
 650         frame_header.blocksize = encoder->blocksize;
 651         frame_header.sample_rate = encoder->sample_rate;
 652         frame_header.channels = encoder->channels;
 653         frame_header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT; /* the default unless the encoder determines otherwise */
 654         frame_header.bits_per_sample = encoder->bits_per_sample;
 655         frame_header.number.frame_number = encoder->guts->current_frame_number;
 656
 657         /*
 658          * Figure out what channel assignments to try
 659          */
 660         if(encoder->do_mid_side_stereo) {
 661                 if(encoder->loose_mid_side_stereo) {
 662                         if(encoder->guts->loose_mid_side_stereo_frame_count == 0) {
 663                                 do_independent = true;
 664                                 do_mid_side = true;
 665                         }
 666                         else {
 667                                 do_independent = (encoder->guts->last_channel_assignment == FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT);
 668                                 do_mid_side = !do_independent;
 669                         }
 670                 }
 671                 else {
 672                         do_independent = true;
 673                         do_mid_side = true;
 674                 }
 675         }
 676         else {
 677                 do_independent = true;
 678                 do_mid_side = false;
 679         }
 680         if(do_mid_side && !encoder->guts->current_frame_can_do_mid_side) {
 681                 do_independent = true;
 682                 do_mid_side = false;
 683         }
 684
 685         assert(do_independent || do_mid_side);
 686
 687         /*
 688          * First do a normal encoding pass of each independent channel
 689          */
 690         if(do_independent) {
 691                 for(channel = 0; channel < encoder->channels; channel++) {
 692                         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))
 693                                 return false;
 694                 }
 695         }
 696
 697         /*
 698          * Now do mid and side channels if requested
 699          */
 700         if(do_mid_side) {
 701                 assert(encoder->channels == 2);
 702
 703                 for(channel = 0; channel < 2; channel++) {
 704                         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))
 705                                 return false;
 706                 }
 707         }
 708
 709         /*
 710          * Compose the frame bitbuffer
 711          */
 712         if(do_mid_side) {
 713                 FLAC__ChannelAssignment channel_assignment;
 714
 715                 assert(encoder->channels == 2);
 716
 717                 if(encoder->loose_mid_side_stereo && encoder->guts->loose_mid_side_stereo_frame_count > 0) {
 718                         channel_assignment = (encoder->guts->last_channel_assignment == FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT? FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT : FLAC__CHANNEL_ASSIGNMENT_MID_SIDE);
 719                 }
 720                 else {
 721                         unsigned bits[4]; /* WATCHOUT - indexed by FLAC__ChannelAssignment */
 722                         unsigned min_bits;
 723                         FLAC__ChannelAssignment ca;
 724
 725                         assert(do_independent && do_mid_side);
 726
 727                         /* We have to figure out which channel assignent results in the smallest frame */
 728                         bits[FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT] = encoder->guts->best_subframe_bits         [0] + encoder->guts->best_subframe_bits         [1];
 729                         bits[FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE  ] = encoder->guts->best_subframe_bits         [0] + encoder->guts->best_subframe_bits_mid_side[1];
 730                         bits[FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE ] = encoder->guts->best_subframe_bits         [1] + encoder->guts->best_subframe_bits_mid_side[1];
 731                         bits[FLAC__CHANNEL_ASSIGNMENT_MID_SIDE   ] = encoder->guts->best_subframe_bits_mid_side[0] + encoder->guts->best_subframe_bits_mid_side[1];
 732
 733                         for(channel_assignment = 0, min_bits = bits[0], ca = 1; ca <= 3; ca++) {
 734                                 if(bits[ca] < min_bits) {
 735                                         min_bits = bits[ca];
 736                                         channel_assignment = ca;
 737                                 }
 738                         }
 739                 }
 740
 741                 frame_header.channel_assignment = channel_assignment;
 742
 743                 if(!FLAC__frame_add_header(&frame_header, encoder->streamable_subset, is_last_frame, &encoder->guts->frame)) {
 744                         encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 745                         return false;
 746                 }
 747
 748                 switch(channel_assignment) {
 749                         /* note that encoder_add_subframe_ sets the state for us in case of an error */
 750                         case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
 751                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [0][encoder->guts->best_subframe         [0]], &encoder->guts->frame))
 752                                         return false;
 753                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [1][encoder->guts->best_subframe         [1]], &encoder->guts->frame))
 754                                         return false;
 755                                 break;
 756                         case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
 757                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [0][encoder->guts->best_subframe         [0]], &encoder->guts->frame))
 758                                         return false;
 759                                 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))
 760                                         return false;
 761                                 break;
 762                         case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
 763                                 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))
 764                                         return false;
 765                                 if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample  , &encoder->guts->subframe_workspace         [1][encoder->guts->best_subframe         [1]], &encoder->guts->frame))
 766                                         return false;
 767                                 break;
 768                         case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
 769                                 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))
 770                                         return false;
 771                                 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))
 772                                         return false;
 773                                 break;
 774                         default:
 775                                 assert(0);
 776                 }
 777         }
 778         else {
 779                 if(!FLAC__frame_add_header(&frame_header, encoder->streamable_subset, is_last_frame, &encoder->guts->frame)) {
 780                         encoder->state = FLAC__ENCODER_FRAMING_ERROR;
 781                         return false;
 782                 }
 783
 784                 for(channel = 0; channel < encoder->channels; channel++) {
 785                         if(!encoder_add_subframe_(encoder, &frame_header, encoder->bits_per_sample, &encoder->guts->subframe_workspace[channel][encoder->guts->best_subframe[channel]], &encoder->guts->frame)) {
 786                                 /* the above function sets the state for us in case of an error */
 787                                 return false;
 788                         }
 789                 }
 790         }
 791
 792         if(encoder->loose_mid_side_stereo) {
 793                 encoder->guts->loose_mid_side_stereo_frame_count++;
 794                 if(encoder->guts->loose_mid_side_stereo_frame_count >= encoder->guts->loose_mid_side_stereo_frames)
 795                         encoder->guts->loose_mid_side_stereo_frame_count = 0;
 796         }
 797
 798         encoder->guts->last_channel_assignment = frame_header.channel_assignment;
 799
 800         return true;
 801 }
 802
 803 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)
 804 {
 805         real fixed_residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1];
 806         real lpc_residual_bits_per_sample;
 807         real autoc[FLAC__MAX_LPC_ORDER+1];
 808         real lp_coeff[FLAC__MAX_LPC_ORDER][FLAC__MAX_LPC_ORDER];
 809         real lpc_error[FLAC__MAX_LPC_ORDER];
 810         unsigned min_lpc_order, max_lpc_order, lpc_order;
 811         unsigned min_fixed_order, max_fixed_order, guess_fixed_order, fixed_order;
 812         unsigned min_qlp_coeff_precision, max_qlp_coeff_precision, qlp_coeff_precision;
 813         unsigned rice_parameter;
 814         unsigned _candidate_bits, _best_bits;
 815         unsigned _best_subframe;
 816
 817         /* verbatim subframe is the baseline against which we measure other compressed subframes */
 818         _best_subframe = 0;
 819         _best_bits = encoder_evaluate_verbatim_subframe_(integer_signal, frame_header->blocksize, bits_per_sample, subframe[_best_subframe]);
 820
 821         if(!verbatim_only && frame_header->blocksize >= FLAC__MAX_FIXED_ORDER) {
 822                 /* check for constant subframe */
 823                 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);
 824                 if(fixed_residual_bits_per_sample[1] == 0.0) {
 825                         /* the above means integer_signal+FLAC__MAX_FIXED_ORDER is constant, now we just have to check the warmup samples */
 826                         unsigned i, signal_is_constant = true;
 827                         for(i = 1; i <= FLAC__MAX_FIXED_ORDER; i++) {
 828                                 if(integer_signal[0] != integer_signal[i]) {
 829                                         signal_is_constant = false;
 830                                         break;
 831                                 }
 832                         }
 833                         if(signal_is_constant) {
 834                                 _candidate_bits = encoder_evaluate_constant_subframe_(integer_signal[0], bits_per_sample, subframe[!_best_subframe]);
 835                                 if(_candidate_bits < _best_bits) {
 836                                         _best_subframe = !_best_subframe;
 837                                         _best_bits = _candidate_bits;
 838                                 }
 839                         }
 840                 }
 841                 else {
 842                         /* encode fixed */
 843                         if(encoder->do_exhaustive_model_search) {
 844                                 min_fixed_order = 0;
 845                                 max_fixed_order = FLAC__MAX_FIXED_ORDER;
 846                         }
 847                         else {
 848                                 min_fixed_order = max_fixed_order = guess_fixed_order;
 849                         }
 850                         for(fixed_order = min_fixed_order; fixed_order <= max_fixed_order; fixed_order++) {
 851                                 if(fixed_residual_bits_per_sample[fixed_order] >= (real)bits_per_sample)
 852                                         continue; /* don't even try */
 853                                 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 */
 854                                 rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
 855                                 if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
 856                                         rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
 857                                 _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]);
 858                                 if(_candidate_bits < _best_bits) {
 859                                         _best_subframe = !_best_subframe;
 860                                         _best_bits = _candidate_bits;
 861                                 }
 862                         }
 863
 864                         /* encode lpc */
 865                         if(encoder->max_lpc_order > 0) {
 866                                 if(encoder->max_lpc_order >= frame_header->blocksize)
 867                                         max_lpc_order = frame_header->blocksize-1;
 868                                 else
 869                                         max_lpc_order = encoder->max_lpc_order;
 870                                 if(max_lpc_order > 0) {
 871                                         FLAC__lpc_compute_autocorrelation(real_signal, frame_header->blocksize, max_lpc_order+1, autoc);
 872                                         FLAC__lpc_compute_lp_coefficients(autoc, max_lpc_order, lp_coeff, lpc_error);
 873                                         if(encoder->do_exhaustive_model_search) {
 874                                                 min_lpc_order = 1;
 875                                         }
 876                                         else {
 877                                                 unsigned guess_lpc_order = FLAC__lpc_compute_best_order(lpc_error, max_lpc_order, frame_header->blocksize, bits_per_sample);
 878                                                 min_lpc_order = max_lpc_order = guess_lpc_order;
 879                                         }
 880                                         if(encoder->do_qlp_coeff_prec_search) {
 881                                                 min_qlp_coeff_precision = FLAC__MIN_QLP_COEFF_PRECISION;
 882                                                 max_qlp_coeff_precision = min(32 - bits_per_sample - 1, (1u<<FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN)-1);
 883                                         }
 884                                         else {
 885                                                 min_qlp_coeff_precision = max_qlp_coeff_precision = encoder->qlp_coeff_precision;
 886                                         }
 887                                         for(lpc_order = min_lpc_order; lpc_order <= max_lpc_order; lpc_order++) {
 888                                                 lpc_residual_bits_per_sample = FLAC__lpc_compute_expected_bits_per_residual_sample(lpc_error[lpc_order-1], frame_header->blocksize-lpc_order);
 889                                                 if(lpc_residual_bits_per_sample >= (real)bits_per_sample)
 890                                                         continue; /* don't even try */
 891                                                 rice_parameter = (lpc_residual_bits_per_sample > 0.0)? (unsigned)(lpc_residual_bits_per_sample+0.5) : 0; /* 0.5 is for rounding */
 892                                                 rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
 893                                                 if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
 894                                                         rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
 895                                                 for(qlp_coeff_precision = min_qlp_coeff_precision; qlp_coeff_precision <= max_qlp_coeff_precision; qlp_coeff_precision++) {
 896                                                         _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]);
 897                                                         if(_candidate_bits > 0) { /* if == 0, there was a problem quantizing the lpcoeffs */
 898                                                                 if(_candidate_bits < _best_bits) {
 899                                                                         _best_subframe = !_best_subframe;
 900                                                                         _best_bits = _candidate_bits;
 901                                                                 }
 902                                                         }
 903                                                 }
 904                                         }
 905                                 }
 906                         }
 907                 }
 908         }
 909
 910         *best_subframe = _best_subframe;
 911         *best_bits = _best_bits;
 912
 913         return true;
 914 }
 915
 916 bool encoder_add_subframe_(FLAC__Encoder *encoder, const FLAC__FrameHeader *frame_header, unsigned bits_per_sample, const FLAC__Subframe *subframe, FLAC__BitBuffer *frame)
 917 {
 918         switch(subframe->type) {
 919                 case FLAC__SUBFRAME_TYPE_CONSTANT:
 920                         if(!FLAC__subframe_add_constant(&(subframe->data.constant), bits_per_sample, frame)) {
 921                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 922                                 return false;
 923                         }
 924                         break;
 925                 case FLAC__SUBFRAME_TYPE_FIXED:
 926                         if(!FLAC__subframe_add_fixed(&(subframe->data.fixed), frame_header->blocksize - subframe->data.fixed.order, bits_per_sample, frame)) {
 927                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 928                                 return false;
 929                         }
 930                         break;
 931                 case FLAC__SUBFRAME_TYPE_LPC:
 932                         if(!FLAC__subframe_add_lpc(&(subframe->data.lpc), frame_header->blocksize - subframe->data.lpc.order, bits_per_sample, frame)) {
 933                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 934                                 return false;
 935                         }
 936                         break;
 937                 case FLAC__SUBFRAME_TYPE_VERBATIM:
 938                         if(!FLAC__subframe_add_verbatim(&(subframe->data.verbatim), frame_header->blocksize, bits_per_sample, frame)) {
 939                                 encoder->state = FLAC__ENCODER_FATAL_ERROR_WHILE_ENCODING;
 940                                 return false;
 941                         }
 942                         break;
 943                 default:
 944                         assert(0);
 945         }
 946
 947         return true;
 948 }
 949
 950 unsigned encoder_evaluate_constant_subframe_(const int32 signal, unsigned bits_per_sample, FLAC__Subframe *subframe)
 951 {
 952         subframe->type = FLAC__SUBFRAME_TYPE_CONSTANT;
 953         subframe->data.constant.value = signal;
 954
 955         return FLAC__SUBFRAME_TYPE_LEN + bits_per_sample;
 956 }
 957
 958 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)
 959 {
 960         unsigned i, residual_bits;
 961         const unsigned residual_samples = blocksize - order;
 962
 963         FLAC__fixed_compute_residual(signal+order, residual_samples, order, residual);
 964
 965         subframe->type = FLAC__SUBFRAME_TYPE_FIXED;
 966
 967         subframe->data.fixed.entropy_coding_method.type = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE;
 968         subframe->data.fixed.residual = residual;
 969
 970         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);
 971
 972         subframe->data.fixed.order = order;
 973         for(i = 0; i < order; i++)
 974                 subframe->data.fixed.warmup[i] = signal[i];
 975
 976         return FLAC__SUBFRAME_TYPE_LEN + (order * bits_per_sample) + residual_bits;
 977 }
 978
 979 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)
 980 {
 981         int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
 982         unsigned i, residual_bits;
 983         int quantization, ret;
 984         const unsigned residual_samples = blocksize - order;
 985
 986         ret = FLAC__lpc_quantize_coefficients(lp_coeff, order, qlp_coeff_precision, bits_per_sample, qlp_coeff, &quantization);
 987         if(ret != 0)
 988                 return 0; /* this is a hack to indicate to the caller that we can't do lp at this order on this subframe */
 989
 990         FLAC__lpc_compute_residual_from_qlp_coefficients(signal+order, residual_samples, qlp_coeff, order, quantization, residual);
 991
 992         subframe->type = FLAC__SUBFRAME_TYPE_LPC;
 993
 994         subframe->data.lpc.entropy_coding_method.type = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE;
 995         subframe->data.lpc.residual = residual;
 996
 997         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);
 998
 999         subframe->data.lpc.order = order;
1000         subframe->data.lpc.qlp_coeff_precision = qlp_coeff_precision;
1001         subframe->data.lpc.quantization_level = quantization;
1002         memcpy(subframe->data.lpc.qlp_coeff, qlp_coeff, sizeof(int32)*FLAC__MAX_LPC_ORDER);
1003         for(i = 0; i < order; i++)
1004                 subframe->data.lpc.warmup[i] = signal[i];
1005
1006         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;
1007 }
1008
1009 unsigned encoder_evaluate_verbatim_subframe_(const int32 signal[], unsigned blocksize, unsigned bits_per_sample, FLAC__Subframe *subframe)
1010 {
1011         subframe->type = FLAC__SUBFRAME_TYPE_VERBATIM;
1012
1013         subframe->data.verbatim.data = signal;
1014
1015         return FLAC__SUBFRAME_TYPE_LEN + (blocksize * bits_per_sample);
1016 }
1017
1018 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[])
1019 {
1020         unsigned residual_bits, best_residual_bits = 0;
1021         unsigned i, partition_order;
1022         unsigned best_parameters_index = 0, parameters[2][1 << FLAC__MAX_RICE_PARTITION_ORDER];
1023         int32 r;
1024
1025         /* compute the abs(residual) for use later */
1026         for(i = 0; i < residual_samples; i++) {
1027                 r = residual[i];
1028                 abs_residual[i] = (uint32)(r<0? -r : r);
1029         }
1030
1031         for(partition_order = 0; partition_order <= max_partition_order; partition_order++) {
1032                 if(!encoder_set_partitioned_rice_(abs_residual, residual_samples, predictor_order, rice_parameter, partition_order, parameters[!best_parameters_index], &residual_bits)) {
1033                         assert(best_residual_bits != 0);
1034                         break;
1035                 }
1036                 if(best_residual_bits == 0 || residual_bits < best_residual_bits) {
1037                         best_residual_bits = residual_bits;
1038                         *best_partition_order = partition_order;
1039                         best_parameters_index = !best_parameters_index;
1040                 }
1041         }
1042         memcpy(best_parameters, parameters[best_parameters_index], sizeof(unsigned)*(1<<(*best_partition_order)));
1043
1044         return best_residual_bits;
1045 }
1046
1047 #ifdef ESTIMATE_RICE_BITS
1048 #undef ESTIMATE_RICE_BITS
1049 #endif
1050 #define ESTIMATE_RICE_BITS(value, parameter) ((value) >> (parameter))
1051
1052 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)
1053 {
1054         unsigned bits_ = FLAC__ENTROPY_CODING_METHOD_TYPE_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN;
1055
1056         if(partition_order == 0) {
1057                 unsigned i;
1058 #ifdef ESTIMATE_RICE_BITS
1059                 const unsigned rice_parameter_estimate = rice_parameter-1;
1060                 bits_ += (1+rice_parameter) * residual_samples;
1061 #endif
1062                 parameters[0] = rice_parameter;
1063                 bits_ += FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
1064                 for(i = 0; i < residual_samples; i++)
1065 #ifdef ESTIMATE_RICE_BITS
1066                         bits_ += ESTIMATE_RICE_BITS(abs_residual[i], rice_parameter_estimate);
1067 #else
1068                         bits_ += FLAC__bitbuffer_rice_bits(residual[i], rice_parameter);
1069 #endif
1070         }
1071         else {
1072                 unsigned i, j, k = 0, k_last = 0;
1073                 unsigned mean, parameter, partition_samples;
1074                 const unsigned max_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
1075                 for(i = 0; i < (1u<<partition_order); i++) {
1076                         partition_samples = (residual_samples+predictor_order) >> partition_order;
1077                         if(i == 0) {
1078                                 if(partition_samples <= predictor_order)
1079                                         return false;
1080                                 else
1081                                         partition_samples -= predictor_order;
1082                         }
1083                         mean = partition_samples >> 1;
1084                         for(j = 0; j < partition_samples; j++, k++)
1085                                 mean += abs_residual[k];
1086                         mean /= partition_samples;
1087                         /* calc parameter = floor(log2(mean)) + 1 */
1088                         parameter = 0;
1089                         while(mean) {
1090                                 parameter++;
1091                                 mean >>= 1;
1092                         }
1093                         if(parameter > max_parameter)
1094                                 parameter = max_parameter;
1095                         parameters[i] = parameter;
1096                         bits_ += FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
1097 #ifdef ESTIMATE_RICE_BITS
1098                         bits_ += (1+parameter) * partition_samples;
1099                         --parameter;
1100 #endif
1101                         for(j = k_last; j < k; j++)
1102 #ifdef ESTIMATE_RICE_BITS
1103                                 bits_ += ESTIMATE_RICE_BITS(abs_residual[j], parameter);
1104 #else
1105                                 bits_ += FLAC__bitbuffer_rice_bits(residual[j], parameter);
1106 #endif
1107                         k_last = k;
1108                 }
1109         }
1110
1111         *bits = bits_;
1112         return true;
1113 }