367 lines
14 KiB
C
367 lines
14 KiB
C
/* libFLAC - Free Lossless Audio Coder library
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* Copyright (C) 2000,2001 Josh Coalson
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifndef FLAC__FORMAT_H
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#define FLAC__FORMAT_H
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#include "ordinals.h"
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/* changing the following values to be higher will break the framing and hence the stream format, so DON'T! */
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#define FLAC__MIN_BLOCK_SIZE (16u)
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#define FLAC__MAX_BLOCK_SIZE (65535u)
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#define FLAC__MAX_CHANNELS (8u)
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/*NOTE: only up to 24 because of the current predictor coefficient quantization and the fact we use int32s for all work */
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#define FLAC__MAX_BITS_PER_SAMPLE (24u)
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/* the following is ((2 ** 20) - 1) div 10 */
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#define FLAC__MAX_SAMPLE_RATE (1048570u)
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#define FLAC__MAX_LPC_ORDER (32u)
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#define FLAC__MIN_QLP_COEFF_PRECISION (5u)
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/* changing this also means changing all of fixed.c and more, so DON'T! */
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#define FLAC__MAX_FIXED_ORDER (4u)
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#define FLAC__MAX_RICE_PARTITION_ORDER (15u)
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/* VERSION comes from configure */
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#define FLAC__VERSION_STRING VERSION
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extern const unsigned FLAC__MAJOR_VERSION;
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extern const unsigned FLAC__MINOR_VERSION;
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extern const byte FLAC__STREAM_SYNC_STRING[4]; /* = "fLaC" */;
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extern const unsigned FLAC__STREAM_SYNC; /* = 0x664C6143 */;
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extern const unsigned FLAC__STREAM_SYNC_LEN; /* = 32 bits */;
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/*****************************************************************************
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*
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* NOTE: Within the bitstream, all fixed-width numbers are big-endian coded.
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* All numbers are unsigned unless otherwise noted.
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*
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*****************************************************************************/
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/*****************************************************************************
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*
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* Subframe structures
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*
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*****************************************************************************/
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/*****************************************************************************/
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typedef enum {
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FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE = 0
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} FLAC__EntropyCodingMethodType;
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/*****************************************************************************
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*
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* 4: partition order => (2 ** order) subdivisions
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*/
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typedef struct {
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unsigned order;
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unsigned parameters[1 << FLAC__MAX_RICE_PARTITION_ORDER];
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} FLAC__EntropyCodingMethod_PartitionedRice;
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extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN; /* = 4 bits */
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extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN; /* = 4 bits */
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/*****************************************************************************
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*
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* 2: entropy coding method:
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* 00: partitioned rice coding
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* 01-11: reserved
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* ?: entropy coding method data
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*/
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typedef struct {
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FLAC__EntropyCodingMethodType type;
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union {
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FLAC__EntropyCodingMethod_PartitionedRice partitioned_rice;
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} data;
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} FLAC__EntropyCodingMethod;
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extern const unsigned FLAC__ENTROPY_CODING_METHOD_TYPE_LEN; /* = 2 bits */
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/*****************************************************************************/
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typedef enum {
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FLAC__SUBFRAME_TYPE_CONSTANT = 0,
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FLAC__SUBFRAME_TYPE_VERBATIM = 1,
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FLAC__SUBFRAME_TYPE_FIXED = 2,
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FLAC__SUBFRAME_TYPE_LPC = 3
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} FLAC__SubframeType;
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/*****************************************************************************
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*
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* n: constant value for signal; n = frame's bits-per-sample
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*/
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typedef struct {
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int32 value;
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} FLAC__Subframe_Constant;
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/*****************************************************************************
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*
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* n*i: unencoded signal; n = frame's bits-per-sample, i = frame's blocksize
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*/
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typedef struct {
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int32 *data;
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} FLAC__Subframe_Verbatim;
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/*****************************************************************************
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*
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* n: unencoded warm-up samples (n = fixed-predictor order * bits per sample)
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* ?: entropy coding method info
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* ?: encoded residual ((blocksize minus fixed-predictor order) samples)
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* The order is stored in the main subframe header
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*/
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typedef struct {
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FLAC__EntropyCodingMethod entropy_coding_method;
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unsigned order;
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int32 warmup[FLAC__MAX_FIXED_ORDER];
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int32 *residual;
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} FLAC__Subframe_Fixed;
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/*****************************************************************************
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*
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* n: unencoded warm-up samples (n = lpc order * bits per sample)
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* 4: (qlp coeff precision in bits)-1 (1111 = invalid, use to check for erroneous sync)
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* 5: qlp shift needed in bits (signed)
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* n: unencoded predictor coefficients (n = lpc order * qlp coeff precision)
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* ?: entropy coding method info
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* ?: encoded residual ((blocksize minus lpc order) samples)
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* The order is stored in the main subframe header
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*/
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typedef struct {
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FLAC__EntropyCodingMethod entropy_coding_method;
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unsigned order;
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unsigned qlp_coeff_precision;
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int quantization_level;
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int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
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int32 warmup[FLAC__MAX_LPC_ORDER];
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int32 *residual;
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} FLAC__Subframe_LPC;
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extern const unsigned FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN; /* = 4 bits */
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extern const unsigned FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN; /* = 5 bits */
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/*****************************************************************************
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*
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* 8: subframe type
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* xxxxxxx1: invalid, to prevent sync-fooling string of 1s (use to check for erroneous sync)
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* 00000000: constant value
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* 00000010: verbatim
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* 000001x0: reserved
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* 00001xx0: reserved
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* 0001xxx0: fixed predictor, xxx=order <= 4, else reserved
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* 001xxxx0: reserved
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* 01xxxxx0: lpc, xxxxx=order-1
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* 1xxxxxxx: invalid, to prevent sync-fooling string of 1s (use to check for erroneous sync)
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* ?: subframe-specific data (c.f. FLAC__Subframe_*)
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*/
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typedef struct {
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FLAC__SubframeType type;
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union {
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FLAC__Subframe_Constant constant;
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FLAC__Subframe_Fixed fixed;
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FLAC__Subframe_LPC lpc;
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FLAC__Subframe_Verbatim verbatim;
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} data;
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} FLAC__Subframe;
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extern const unsigned FLAC__SUBFRAME_TYPE_CONSTANT_BITS; /* = 0x00 */
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extern const unsigned FLAC__SUBFRAME_TYPE_VERBATIM_BITS; /* = 0x02 */
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extern const unsigned FLAC__SUBFRAME_TYPE_FIXED_BITS; /* = 0x10 */
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extern const unsigned FLAC__SUBFRAME_TYPE_LPC_BITS; /* = 0x40 */
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extern const unsigned FLAC__SUBFRAME_TYPE_LEN; /* = 8 bits */
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/*****************************************************************************/
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/*****************************************************************************
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*
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* Frame structures
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*
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*****************************************************************************/
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typedef enum {
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FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT = 0,
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FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE = 1,
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FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE = 2,
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FLAC__CHANNEL_ASSIGNMENT_MID_SIDE = 3
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} FLAC__ChannelAssignment;
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/*****************************************************************************
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*
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* 9: sync code '111111110'
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* 3: blocksize in samples
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* 000: get from stream header => implies constant blocksize throughout stream
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* 001: 192 samples (AES/EBU) => implies constant blocksize throughout stream
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* 010-101: 576 * (2^(2-n)) samples, i.e. 576/1152/2304/4608 => implies constant blocksize throughout stream
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* 110: get 8 bit (blocksize-1) from end of header => variable blocksize throughout stream unless it's the last frame
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* 111: get 16 bit (blocksize-1) from end of header => variable blocksize throughout stream unless it's the last frame
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* 4: sample rate:
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* 0000: get from stream header
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* 0001-0011: reserved
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* 0100: 8kHz
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* 0101: 16kHz
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* 0110: 22.05kHz
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* 0111: 24kHz
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* 1000: 32kHz
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* 1001: 44.1kHz
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* 1010: 48kHz
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* 1011: 96kHz
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* 1100: get 8 bit sample rate (in kHz) from end of header
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* 1101: get 16 bit sample rate (in Hz) from end of header
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* 1110: get 16 bit sample rate (in tens of Hz) from end of header
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* 1111: invalid, to prevent sync-fooling string of 1s (use to check for erroneous sync)
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* 4: channel assignment
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* 0000-0111: (number of independent channels)-1. when == 0001, channel 0 is the left channel and channel 1 is the right
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* 1000: left/side stereo : channel 0 is the left channel, channel 1 is the side(difference) channel
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* 1001: right/side stereo: channel 0 is the side(difference) channel, channel 1 is the right channel
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* 1010: mid/side stereo : channel 0 is the mid(average) channel, channel 1 is the side(difference) channel
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* 1011-1111: reserved
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* 3: sample size in bits
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* 000: get from stream header
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* 001: 8 bits per sample
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* 010: 12 bits per sample
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* 011: reserved
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* 100: 16 bits per sample
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* 101: 20 bits per sample
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* 110: 24 bits per sample
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* 111: reserved
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* 1: zero pad, to prevent sync-fooling string of 1s (use to check for erroneous sync)
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* ?: if(variable blocksize)
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* 8-56: 'UTF-8' coded sample number (decoded number is 0-36 bits) (use to check for erroneous sync)
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* else
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* 8-48: 'UTF-8' coded frame number (decoded number is 0-31 bits) (use to check for erroneous sync)
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* ?: if(blocksize bits == 11x)
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* 8/16 bit (blocksize-1)
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* ?: if(sample rate bits == 11xx)
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* 8/16 bit sample rate
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* 8: CRC-8 (polynomial = x^8 + x^2 + x + 1) of everything before the crc, including the sync code
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*/
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typedef struct {
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unsigned blocksize; /* in samples */
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unsigned sample_rate; /* in Hz */
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unsigned channels;
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FLAC__ChannelAssignment channel_assignment;
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unsigned bits_per_sample;
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union {
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uint32 frame_number;
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uint64 sample_number;
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} number;
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} FLAC__FrameHeader;
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extern const unsigned FLAC__FRAME_HEADER_SYNC; /* = 0x1fe */
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extern const unsigned FLAC__FRAME_HEADER_SYNC_LEN; /* = 9 bits */
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extern const unsigned FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /* = 3 bits */
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extern const unsigned FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /* = 4 bits */
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extern const unsigned FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /* = 4 bits */
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extern const unsigned FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /* = 3 bits */
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extern const unsigned FLAC__FRAME_HEADER_ZERO_PAD_LEN; /* = 1 bit */
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extern const unsigned FLAC__FRAME_HEADER_CRC8_LEN; /* = 8 bits */
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typedef struct {
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FLAC__FrameHeader header;
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FLAC__Subframe subframes[FLAC__MAX_CHANNELS];
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} FLAC__Frame;
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/*****************************************************************************/
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/*****************************************************************************
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*
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* Meta-data structures
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*
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*****************************************************************************/
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typedef enum {
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FLAC__METADATA_TYPE_ENCODING = 0
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} FLAC__MetaDataType;
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/*****************************************************************************
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*
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* 16: minimum blocksize (in samples) of all blocks in the stream
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* 16: maximum blocksize (in samples) of all blocks in the stream
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* 24: minimum framesize (in bytes) of all frames in the stream; 0 => unknown
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* 24: maximum framesize (in bytes) of all frames in the stream; 0 => unknown
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* 20: sample rate in Hz, 0 is invalid
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* 3: (number of channels)-1
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* 5: (bits per sample)-1
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* 36: total samples, 0 => unknown
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*128: MD5 digest of the original unencoded audio data
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*---- -----------------
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* 34 bytes total
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*/
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typedef struct {
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unsigned min_blocksize, max_blocksize;
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unsigned min_framesize, max_framesize;
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unsigned sample_rate;
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unsigned channels;
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unsigned bits_per_sample;
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uint64 total_samples;
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byte md5sum[16];
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} FLAC__StreamMetaData_Encoding;
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_MIN_BLOCK_SIZE_LEN; /* = 16 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_MAX_BLOCK_SIZE_LEN; /* = 16 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_MIN_FRAME_SIZE_LEN; /* = 24 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_MAX_FRAME_SIZE_LEN; /* = 24 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_SAMPLE_RATE_LEN; /* = 20 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_CHANNELS_LEN; /* = 3 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_BITS_PER_SAMPLE_LEN; /* = 5 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_TOTAL_SAMPLES_LEN; /* = 36 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_MD5SUM_LEN; /* = 128 bits */
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extern const unsigned FLAC__STREAM_METADATA_ENCODING_LENGTH; /* = 34 bytes */
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/*****************************************************************************
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*
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* 1: =1 if this is the last meta-data block, else =0
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* 7: meta-data type (c.f. FLAC__MetaDataType)
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* 24: length (in bytes) of the block-specific data to follow
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*---- -----------------
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* 4 bytes total
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*/
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typedef struct {
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FLAC__MetaDataType type;
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bool is_last;
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unsigned length; /* in bytes */
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union {
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FLAC__StreamMetaData_Encoding encoding;
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} data;
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} FLAC__StreamMetaData;
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extern const unsigned FLAC__STREAM_METADATA_IS_LAST_LEN; /* = 1 bits */
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extern const unsigned FLAC__STREAM_METADATA_TYPE_LEN; /* = 7 bits */
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extern const unsigned FLAC__STREAM_METADATA_LENGTH_LEN; /* = 24 bits */
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/*****************************************************************************/
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/*****************************************************************************
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*
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* Stream structures
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*
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*****************************************************************************/
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typedef struct {
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FLAC__StreamMetaData_Encoding metadata;
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FLAC__Frame *frames;
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} FLAC__Stream;
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/*****************************************************************************/
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#endif
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