1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000,2001 Josh Coalson
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.
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.
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.
20 #ifndef FLAC__FORMAT_H
21 #define FLAC__FORMAT_H
25 /* changing the following values to be higher will break the framing and hence the stream format, so DON'T! */
26 #define FLAC__MIN_BLOCK_SIZE (16u)
27 #define FLAC__MAX_BLOCK_SIZE (65535u)
28 #define FLAC__MAX_CHANNELS (8u)
29 #define FLAC__MIN_BITS_PER_SAMPLE (4u)
30 /*NOTE: only up to 24 because of the current predictor coefficient quantization and the fact we use int32s for all work */
31 #define FLAC__MAX_BITS_PER_SAMPLE (24u)
32 /* the following is ((2 ** 20) - 1) div 10 */
33 #define FLAC__MAX_SAMPLE_RATE (1048570u)
34 #define FLAC__MAX_LPC_ORDER (32u)
35 #define FLAC__MIN_QLP_COEFF_PRECISION (5u)
36 /* changing FLAC__MAX_FIXED_ORDER also means changing all of fixed.c and more, so DON'T! */
37 #define FLAC__MAX_FIXED_ORDER (4u)
38 #define FLAC__MAX_RICE_PARTITION_ORDER (15u)
40 /* VERSION should come from configure */
42 #define FLAC__VERSION_STRING VERSION
45 extern const byte FLAC__STREAM_SYNC_STRING[4]; /* = "fLaC" */;
46 extern const unsigned FLAC__STREAM_SYNC; /* = 0x664C6143 */;
47 extern const unsigned FLAC__STREAM_SYNC_LEN; /* = 32 bits */;
50 /*****************************************************************************
52 * NOTE: Within the bitstream, all fixed-width numbers are big-endian coded.
53 * All numbers are unsigned unless otherwise noted.
55 *****************************************************************************/
58 /*****************************************************************************
62 *****************************************************************************/
64 /*****************************************************************************/
67 FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE = 0
68 } FLAC__EntropyCodingMethodType;
69 extern const char *FLAC__EntropyCodingMethodTypeString[];
71 /*****************************************************************************
73 * 4: partition order => (2 ** order) subdivisions
77 unsigned parameters[1 << FLAC__MAX_RICE_PARTITION_ORDER];
78 unsigned raw_bits[1 << FLAC__MAX_RICE_PARTITION_ORDER];
79 } FLAC__EntropyCodingMethod_PartitionedRice;
81 extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN; /* = 4 bits */
82 extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN; /* = 4 bits */
83 extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN; /* = 5 bits */
85 extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER; /* = (1<<FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN)-1 */
87 /*****************************************************************************
89 * 2: entropy coding method:
90 * 00: partitioned rice coding
92 * ?: entropy coding method data
95 FLAC__EntropyCodingMethodType type;
97 FLAC__EntropyCodingMethod_PartitionedRice partitioned_rice;
99 } FLAC__EntropyCodingMethod;
101 extern const unsigned FLAC__ENTROPY_CODING_METHOD_TYPE_LEN; /* = 2 bits */
103 /*****************************************************************************/
106 FLAC__SUBFRAME_TYPE_CONSTANT = 0,
107 FLAC__SUBFRAME_TYPE_VERBATIM = 1,
108 FLAC__SUBFRAME_TYPE_FIXED = 2,
109 FLAC__SUBFRAME_TYPE_LPC = 3
110 } FLAC__SubframeType;
111 extern const char *FLAC__SubframeTypeString[];
113 /*****************************************************************************
115 * n: constant value for signal; n = frame's bits-per-sample
119 } FLAC__Subframe_Constant;
121 /*****************************************************************************
123 * n*i: unencoded signal; n = frame's bits-per-sample, i = frame's blocksize
127 } FLAC__Subframe_Verbatim;
129 /*****************************************************************************
131 * n: unencoded warm-up samples (n = fixed-predictor order * bits per sample)
132 * ?: entropy coding method info
133 * ?: encoded residual ((blocksize minus fixed-predictor order) samples)
134 * The order is stored in the main subframe header
137 FLAC__EntropyCodingMethod entropy_coding_method;
139 int32 warmup[FLAC__MAX_FIXED_ORDER];
140 const int32 *residual;
141 } FLAC__Subframe_Fixed;
143 /*****************************************************************************
145 * n: unencoded warm-up samples (n = lpc order * bits per sample)
146 * 4: (qlp coeff precision in bits)-1 (1111 = invalid, use to check for erroneous sync)
147 * 5: qlp shift needed in bits (signed)
148 * n: unencoded predictor coefficients (n = lpc order * qlp coeff precision)
149 * ?: entropy coding method info
150 * ?: encoded residual ((blocksize minus lpc order) samples)
151 * The order is stored in the main subframe header
154 FLAC__EntropyCodingMethod entropy_coding_method;
156 unsigned qlp_coeff_precision;
157 int quantization_level;
158 int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
159 int32 warmup[FLAC__MAX_LPC_ORDER];
160 const int32 *residual;
161 } FLAC__Subframe_LPC;
163 extern const unsigned FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN; /* = 4 bits */
164 extern const unsigned FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN; /* = 5 bits */
166 /*****************************************************************************
168 * 1: zero pad, to prevent sync-fooling string of 1s (use to check for erroneous sync)
170 * 000000: constant value
174 * 001xxx: fixed predictor, xxx=order <= 4, else reserved
176 * 1xxxxx: lpc, xxxxx=order-1
177 * 1: 'wasted bits' flag
178 * 0: no wasted bits in source subblock
179 * 1: all samples in source subblock contain n 0 least significant bits. n-1 follows, unary coded, i.e. n=3, 001 follows, n=7, 0000001 follows.
180 * ?: unary coded (n-1)
181 * ?: subframe-specific data (c.f. FLAC__Subframe_*)
184 FLAC__SubframeType type;
186 FLAC__Subframe_Constant constant;
187 FLAC__Subframe_Fixed fixed;
188 FLAC__Subframe_LPC lpc;
189 FLAC__Subframe_Verbatim verbatim;
191 unsigned wasted_bits;
194 extern const unsigned FLAC__SUBFRAME_ZERO_PAD_LEN; /* = 1 bit */
195 extern const unsigned FLAC__SUBFRAME_TYPE_LEN; /* = 6 bits */
196 extern const unsigned FLAC__SUBFRAME_WASTED_BITS_FLAG_LEN; /* = 1 bit */
198 extern const unsigned FLAC__SUBFRAME_TYPE_CONSTANT_BYTE_ALIGNED_MASK; /* = 0x00 */
199 extern const unsigned FLAC__SUBFRAME_TYPE_VERBATIM_BYTE_ALIGNED_MASK; /* = 0x02 */
200 extern const unsigned FLAC__SUBFRAME_TYPE_FIXED_BYTE_ALIGNED_MASK; /* = 0x10 */
201 extern const unsigned FLAC__SUBFRAME_TYPE_LPC_BYTE_ALIGNED_MASK; /* = 0x40 */
203 /*****************************************************************************/
206 /*****************************************************************************
210 *****************************************************************************/
213 FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT = 0,
214 FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE = 1,
215 FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE = 2,
216 FLAC__CHANNEL_ASSIGNMENT_MID_SIDE = 3
217 } FLAC__ChannelAssignment;
218 extern const char *FLAC__ChannelAssignmentString[];
220 /*****************************************************************************
222 * 14: sync code '11111111111110'
224 * 00: currently required value
226 * 4: blocksize in samples
227 * 0000: get from stream header => implies constant blocksize throughout stream
228 * 0001: 192 samples (AES/EBU) => implies constant blocksize throughout stream
229 * 0010-0101: 576 * (2^(n-2)) samples, i.e. 576/1152/2304/4608 => implies constant blocksize throughout stream
230 * 0110: get 8 bit (blocksize-1) from end of header => possibly variable blocksize throughout stream unless it's the last frame
231 * 0111: get 16 bit (blocksize-1) from end of header => possibly variable blocksize throughout stream unless it's the last frame
232 * 1000-1111: 256 * (2^(n-8)) samples, i.e. 256/512/1024/2048/4096/8192/16384/32768 => implies constant blocksize throughout stream
234 * 0000: get from stream header
235 * 0001-0011: reserved
244 * 1100: get 8 bit sample rate (in kHz) from end of header
245 * 1101: get 16 bit sample rate (in Hz) from end of header
246 * 1110: get 16 bit sample rate (in tens of Hz) from end of header
247 * 1111: invalid, to prevent sync-fooling string of 1s (use to check for erroneous sync)
248 * 4: channel assignment
249 * 0000-0111: (number of independent channels)-1. when == 0001, channel 0 is the left channel and channel 1 is the right
250 * 1000: left/side stereo : channel 0 is the left channel, channel 1 is the side(difference) channel
251 * 1001: right/side stereo: channel 0 is the side(difference) channel, channel 1 is the right channel
252 * 1010: mid/side stereo : channel 0 is the mid(average) channel, channel 1 is the side(difference) channel
253 * 1011-1111: reserved
254 * 3: sample size in bits
255 * 000: get from stream header
256 * 001: 8 bits per sample
257 * 010: 12 bits per sample
259 * 100: 16 bits per sample
260 * 101: 20 bits per sample
261 * 110: 24 bits per sample
263 * 1: zero pad, to prevent sync-fooling string of 1s (use to check for erroneous sync)
264 * ?: if(variable blocksize)
265 * 8-56: 'UTF-8' coded sample number (decoded number is 0-36 bits) (use to check for erroneous sync)
267 * 8-48: 'UTF-8' coded frame number (decoded number is 0-31 bits) (use to check for erroneous sync)
268 * ?: if(blocksize bits == 11x)
269 * 8/16 bit (blocksize-1)
270 * ?: if(sample rate bits == 11xx)
271 * 8/16 bit sample rate
272 * 8: CRC-8 (polynomial = x^8 + x^2 + x^1 + x^0, initialized with 0) of everything before the crc, including the sync code
275 unsigned blocksize; /* in samples */
276 unsigned sample_rate; /* in Hz */
278 FLAC__ChannelAssignment channel_assignment;
279 unsigned bits_per_sample;
282 uint64 sample_number;
287 extern const unsigned FLAC__FRAME_HEADER_SYNC; /* = 0x3ffe */
288 extern const unsigned FLAC__FRAME_HEADER_SYNC_LEN; /* = 14 bits */
289 extern const unsigned FLAC__FRAME_HEADER_RESERVED_LEN; /* = 2 bits */
290 extern const unsigned FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /* = 4 bits */
291 extern const unsigned FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /* = 4 bits */
292 extern const unsigned FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /* = 4 bits */
293 extern const unsigned FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /* = 3 bits */
294 extern const unsigned FLAC__FRAME_HEADER_ZERO_PAD_LEN; /* = 1 bit */
295 extern const unsigned FLAC__FRAME_HEADER_CRC_LEN; /* = 8 bits */
297 /*****************************************************************************
299 * 16: CRC-16 (polynomial = x^16 + x^15 + x^2 + x^0, initialized with 0) of everything before the crc, back to and including the frame header sync code
305 extern const unsigned FLAC__FRAME_FOOTER_CRC_LEN; /* = 16 bits */
308 FLAC__FrameHeader header;
309 FLAC__Subframe subframes[FLAC__MAX_CHANNELS];
310 FLAC__FrameFooter footer;
313 /*****************************************************************************/
316 /*****************************************************************************
318 * Meta-data structures
320 *****************************************************************************/
323 FLAC__METADATA_TYPE_STREAMINFO = 0,
324 FLAC__METADATA_TYPE_PADDING = 1,
325 FLAC__METADATA_TYPE_APPLICATION = 2,
326 FLAC__METADATA_TYPE_SEEKTABLE = 3
327 } FLAC__MetaDataType;
328 extern const char *FLAC__MetaDataTypeString[];
330 /*****************************************************************************
332 * 16: minimum blocksize (in samples) of all blocks in the stream
333 * 16: maximum blocksize (in samples) of all blocks in the stream
334 * 24: minimum framesize (in bytes) of all frames in the stream; 0 => unknown
335 * 24: maximum framesize (in bytes) of all frames in the stream; 0 => unknown
336 * 20: sample rate in Hz, 0 is invalid
337 * 3: (number of channels)-1
338 * 5: (bits per sample)-1
339 * 36: total samples, 0 => unknown
340 *128: MD5 digest of the original unencoded audio data
341 *---- -----------------
345 unsigned min_blocksize, max_blocksize;
346 unsigned min_framesize, max_framesize;
347 unsigned sample_rate;
349 unsigned bits_per_sample;
350 uint64 total_samples;
352 } FLAC__StreamMetaData_StreamInfo;
354 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN; /* = 16 bits */
355 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN; /* = 16 bits */
356 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN; /* = 24 bits */
357 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN; /* = 24 bits */
358 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN; /* = 20 bits */
359 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN; /* = 3 bits */
360 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN; /* = 5 bits */
361 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN; /* = 36 bits */
362 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN; /* = 128 bits */
363 extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_LENGTH; /* = 34 bytes */
365 /*****************************************************************************
368 *----- -----------------
372 int dummy; /* conceptually this is an empty struct since we don't store the padding bytes */
373 /* empty structs are allowed by C++ but not C, hence the 'dummy' */
374 } FLAC__StreamMetaData_Padding;
376 /*****************************************************************************
378 * 32: Registered application ID
379 * n: Application data
380 *------- -----------------
386 } FLAC__StreamMetaData_Application;
388 extern const unsigned FLAC__STREAM_METADATA_APPLICATION_ID_LEN; /* = 32 bits */
390 /*****************************************************************************
392 * 64: sample number of target frame
393 * 64: offset, in bytes, of target frame with respect to beginning of first frame
394 * 16: number of samples in the target frame
395 *----- -----------------
399 uint64 sample_number;
400 uint64 stream_offset;
401 unsigned frame_samples;
402 } FLAC__StreamMetaData_SeekPoint;
404 extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN; /* = 64 bits */
405 extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN; /* = 64 bits */
406 extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN; /* = 16 bits */
407 extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_LEN; /* = 18 bytes */
409 extern const uint64 FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER; /* = 0xffffffffffffffff */
411 /*****************************************************************************
413 * 0: num_points is implied by the metadata block 'length' field (i.e. num_points = length / 18)
414 * n*18*8: seek points (n = num_points, 18 is the size of a seek point in bytes)
415 * ------- -----------------
418 * NOTE: the seek points must be sorted by ascending sample number.
419 * NOTE: each seek point's sample number must be the first sample of the target frame.
420 * NOTE: each seek point's sample number must be unique within the table.
421 * NOTE: existence of a SEEKTABLE block implies a correct setting of total_samples in the stream_info block.
422 * NOTE: behavior is undefined when more than one SEEKTABLE block is present in a stream.
426 FLAC__StreamMetaData_SeekPoint *points;
427 } FLAC__StreamMetaData_SeekTable;
429 /*****************************************************************************
431 * 1: =1 if this is the last meta-data block, else =0
432 * 7: meta-data type (c.f. FLAC__MetaDataType)
433 * 24: length (in bytes) of the block-specific data to follow
434 *---- -----------------
438 FLAC__MetaDataType type;
440 unsigned length; /* in bytes */
442 FLAC__StreamMetaData_StreamInfo stream_info;
443 FLAC__StreamMetaData_Padding padding;
444 FLAC__StreamMetaData_Application application;
445 FLAC__StreamMetaData_SeekTable seek_table;
447 } FLAC__StreamMetaData;
449 extern const unsigned FLAC__STREAM_METADATA_IS_LAST_LEN; /* = 1 bits */
450 extern const unsigned FLAC__STREAM_METADATA_TYPE_LEN; /* = 7 bits */
451 extern const unsigned FLAC__STREAM_METADATA_LENGTH_LEN; /* = 24 bits */
453 /*****************************************************************************/
456 /*****************************************************************************
460 *****************************************************************************/
463 FLAC__StreamMetaData_StreamInfo stream_info;
467 /*****************************************************************************/