/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2000,2001 Josh Coalson * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifndef FLAC__FORMAT_H #define FLAC__FORMAT_H #include "ordinals.h" /* changing the following values to be higher will break the framing and hence the stream format, so DON'T! */ #define FLAC__MIN_BLOCK_SIZE (16u) #define FLAC__MAX_BLOCK_SIZE (65535u) #define FLAC__MAX_CHANNELS (8u) #define FLAC__MIN_BITS_PER_SAMPLE (4u) /*NOTE: only up to 24 because of the current predictor coefficient quantization and the fact we use int32s for all work */ #define FLAC__MAX_BITS_PER_SAMPLE (24u) /* the following is ((2 ** 20) - 1) div 10 */ #define FLAC__MAX_SAMPLE_RATE (1048570u) #define FLAC__MAX_LPC_ORDER (32u) #define FLAC__MIN_QLP_COEFF_PRECISION (5u) /* changing FLAC__MAX_FIXED_ORDER also means changing all of fixed.c and more, so DON'T! */ #define FLAC__MAX_FIXED_ORDER (4u) #define FLAC__MAX_RICE_PARTITION_ORDER (15u) /* VERSION should come from configure */ #ifdef VERSION #define FLAC__VERSION_STRING VERSION #endif extern const byte FLAC__STREAM_SYNC_STRING[4]; /* = "fLaC" */; extern const unsigned FLAC__STREAM_SYNC; /* = 0x664C6143 */; extern const unsigned FLAC__STREAM_SYNC_LEN; /* = 32 bits */; /***************************************************************************** * * NOTE: Within the bitstream, all fixed-width numbers are big-endian coded. * All numbers are unsigned unless otherwise noted. * *****************************************************************************/ /***************************************************************************** * * Subframe structures * *****************************************************************************/ /*****************************************************************************/ typedef enum { FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE = 0 } FLAC__EntropyCodingMethodType; extern const char *FLAC__EntropyCodingMethodTypeString[]; /***************************************************************************** * * 4: partition order => (2 ** order) subdivisions */ typedef struct { unsigned order; unsigned parameters[1 << FLAC__MAX_RICE_PARTITION_ORDER]; unsigned raw_bits[1 << FLAC__MAX_RICE_PARTITION_ORDER]; } FLAC__EntropyCodingMethod_PartitionedRice; extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN; /* = 4 bits */ extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN; /* = 4 bits */ extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN; /* = 5 bits */ extern const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER; /* = (1< implies constant blocksize throughout stream * 0001: 192 samples (AES/EBU) => implies constant blocksize throughout stream * 0010-0101: 576 * (2^(n-2)) samples, i.e. 576/1152/2304/4608 => implies constant blocksize throughout stream * 0110: get 8 bit (blocksize-1) from end of header => possibly variable blocksize throughout stream unless it's the last frame * 0111: get 16 bit (blocksize-1) from end of header => possibly variable blocksize throughout stream unless it's the last frame * 1000-1111: 256 * (2^(n-8)) samples, i.e. 256/512/1024/2048/4096/8192/16384/32768 => implies constant blocksize throughout stream * 4: sample rate: * 0000: get from stream header * 0001-0011: reserved * 0100: 8kHz * 0101: 16kHz * 0110: 22.05kHz * 0111: 24kHz * 1000: 32kHz * 1001: 44.1kHz * 1010: 48kHz * 1011: 96kHz * 1100: get 8 bit sample rate (in kHz) from end of header * 1101: get 16 bit sample rate (in Hz) from end of header * 1110: get 16 bit sample rate (in tens of Hz) from end of header * 1111: invalid, to prevent sync-fooling string of 1s (use to check for erroneous sync) * 4: channel assignment * 0000-0111: (number of independent channels)-1. when == 0001, channel 0 is the left channel and channel 1 is the right * 1000: left/side stereo : channel 0 is the left channel, channel 1 is the side(difference) channel * 1001: right/side stereo: channel 0 is the side(difference) channel, channel 1 is the right channel * 1010: mid/side stereo : channel 0 is the mid(average) channel, channel 1 is the side(difference) channel * 1011-1111: reserved * 3: sample size in bits * 000: get from stream header * 001: 8 bits per sample * 010: 12 bits per sample * 011: reserved * 100: 16 bits per sample * 101: 20 bits per sample * 110: 24 bits per sample * 111: reserved * 1: zero pad, to prevent sync-fooling string of 1s (use to check for erroneous sync) * ?: if(variable blocksize) * 8-56: 'UTF-8' coded sample number (decoded number is 0-36 bits) (use to check for erroneous sync) * else * 8-48: 'UTF-8' coded frame number (decoded number is 0-31 bits) (use to check for erroneous sync) * ?: if(blocksize bits == 11x) * 8/16 bit (blocksize-1) * ?: if(sample rate bits == 11xx) * 8/16 bit sample rate * 8: CRC-8 (polynomial = x^8 + x^2 + x^1 + x^0, initialized with 0) of everything before the crc, including the sync code */ typedef struct { unsigned blocksize; /* in samples */ unsigned sample_rate; /* in Hz */ unsigned channels; FLAC__ChannelAssignment channel_assignment; unsigned bits_per_sample; union { uint32 frame_number; uint64 sample_number; } number; uint8 crc; } FLAC__FrameHeader; extern const unsigned FLAC__FRAME_HEADER_SYNC; /* = 0x3ffe */ extern const unsigned FLAC__FRAME_HEADER_SYNC_LEN; /* = 14 bits */ extern const unsigned FLAC__FRAME_HEADER_RESERVED_LEN; /* = 2 bits */ extern const unsigned FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /* = 4 bits */ extern const unsigned FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /* = 4 bits */ extern const unsigned FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /* = 4 bits */ extern const unsigned FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /* = 3 bits */ extern const unsigned FLAC__FRAME_HEADER_ZERO_PAD_LEN; /* = 1 bit */ extern const unsigned FLAC__FRAME_HEADER_CRC_LEN; /* = 8 bits */ /***************************************************************************** * * 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 */ typedef struct { uint16 crc; } FLAC__FrameFooter; extern const unsigned FLAC__FRAME_FOOTER_CRC_LEN; /* = 16 bits */ typedef struct { FLAC__FrameHeader header; FLAC__Subframe subframes[FLAC__MAX_CHANNELS]; FLAC__FrameFooter footer; } FLAC__Frame; /*****************************************************************************/ /***************************************************************************** * * Meta-data structures * *****************************************************************************/ typedef enum { FLAC__METADATA_TYPE_STREAMINFO = 0, FLAC__METADATA_TYPE_PADDING = 1, FLAC__METADATA_TYPE_APPLICATION = 2, FLAC__METADATA_TYPE_SEEKTABLE = 3 } FLAC__MetaDataType; extern const char *FLAC__MetaDataTypeString[]; /***************************************************************************** * * 16: minimum blocksize (in samples) of all blocks in the stream * 16: maximum blocksize (in samples) of all blocks in the stream * 24: minimum framesize (in bytes) of all frames in the stream; 0 => unknown * 24: maximum framesize (in bytes) of all frames in the stream; 0 => unknown * 20: sample rate in Hz, 0 is invalid * 3: (number of channels)-1 * 5: (bits per sample)-1 * 36: total samples, 0 => unknown *128: MD5 digest of the original unencoded audio data *---- ----------------- * 34 bytes total */ typedef struct { unsigned min_blocksize, max_blocksize; unsigned min_framesize, max_framesize; unsigned sample_rate; unsigned channels; unsigned bits_per_sample; uint64 total_samples; byte md5sum[16]; } FLAC__StreamMetaData_StreamInfo; extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN; /* = 16 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN; /* = 16 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN; /* = 24 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN; /* = 24 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN; /* = 20 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN; /* = 3 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN; /* = 5 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN; /* = 36 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN; /* = 128 bits */ extern const unsigned FLAC__STREAM_METADATA_STREAMINFO_LENGTH; /* = 34 bytes */ /***************************************************************************** * * n: '0' bits *----- ----------------- * n/8 bytes total */ typedef struct { int dummy; /* conceptually this is an empty struct since we don't store the padding bytes */ /* empty structs are allowed by C++ but not C, hence the 'dummy' */ } FLAC__StreamMetaData_Padding; /***************************************************************************** * * 32: Registered application ID * n: Application data *------- ----------------- * 4+n/8 bytes total */ typedef struct { byte id[4]; byte *data; } FLAC__StreamMetaData_Application; extern const unsigned FLAC__STREAM_METADATA_APPLICATION_ID_LEN; /* = 32 bits */ /***************************************************************************** * * 64: sample number of target frame * 64: offset, in bytes, of target frame with respect to beginning of first frame * 16: number of samples in the target frame *----- ----------------- * 18 bytes total */ typedef struct { uint64 sample_number; uint64 stream_offset; unsigned frame_samples; } FLAC__StreamMetaData_SeekPoint; extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN; /* = 64 bits */ extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN; /* = 64 bits */ extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN; /* = 16 bits */ extern const unsigned FLAC__STREAM_METADATA_SEEKPOINT_LEN; /* = 18 bytes */ extern const uint64 FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER; /* = 0xffffffffffffffff */ /***************************************************************************** * * 0: num_points is implied by the metadata block 'length' field (i.e. num_points = length / 18) * n*18*8: seek points (n = num_points, 18 is the size of a seek point in bytes) * ------- ----------------- * n*18 bytes total * * NOTE: the seek points must be sorted by ascending sample number. * NOTE: each seek point's sample number must be the first sample of the target frame. * NOTE: each seek point's sample number must be unique within the table. * NOTE: existence of a SEEKTABLE block implies a correct setting of total_samples in the stream_info block. * NOTE: behavior is undefined when more than one SEEKTABLE block is present in a stream. */ typedef struct { unsigned num_points; FLAC__StreamMetaData_SeekPoint *points; } FLAC__StreamMetaData_SeekTable; /***************************************************************************** * * 1: =1 if this is the last meta-data block, else =0 * 7: meta-data type (c.f. FLAC__MetaDataType) * 24: length (in bytes) of the block-specific data to follow *---- ----------------- * 4 bytes total */ typedef struct { FLAC__MetaDataType type; bool is_last; unsigned length; /* in bytes */ union { FLAC__StreamMetaData_StreamInfo stream_info; FLAC__StreamMetaData_Padding padding; FLAC__StreamMetaData_Application application; FLAC__StreamMetaData_SeekTable seek_table; } data; } FLAC__StreamMetaData; extern const unsigned FLAC__STREAM_METADATA_IS_LAST_LEN; /* = 1 bits */ extern const unsigned FLAC__STREAM_METADATA_TYPE_LEN; /* = 7 bits */ extern const unsigned FLAC__STREAM_METADATA_LENGTH_LEN; /* = 24 bits */ /*****************************************************************************/ /***************************************************************************** * * Stream structures * *****************************************************************************/ typedef struct { FLAC__StreamMetaData_StreamInfo stream_info; FLAC__Frame *frames; } FLAC__Stream; /*****************************************************************************/ #endif