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flac.c
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/*
* This file is part of the Aaru Data Preservation Suite.
* Copyright (c) 2019-2026 Natalia Portillo.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "aaruformat.h"
#include "flac.h"
#include "FLAC/metadata.h"
#include "FLAC/stream_decoder.h"
#include "FLAC/stream_encoder.h"
static FLAC__StreamDecoderReadStatus read_callback(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[],
size_t *bytes, void *client_data);
static FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame,
const FLAC__int32 *const buffer[], void *client_data);
static void error_callback(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status,
void *client_data);
AARU_EXPORT size_t AARU_CALL aaruf_flac_decode_redbook_buffer(uint8_t *dst_buffer, size_t dst_size,
const uint8_t *src_buffer, size_t src_size)
{
FLAC__StreamDecoder *decoder = NULL;
FLAC__StreamDecoderInitStatus init_status = FLAC__STREAM_DECODER_INIT_STATUS_OK;
aaru_flac_ctx *ctx = (aaru_flac_ctx *)malloc(sizeof(aaru_flac_ctx));
size_t ret_size = 0;
memset(ctx, 0, sizeof(aaru_flac_ctx));
ctx->src_buffer = src_buffer;
ctx->src_len = src_size;
ctx->src_pos = 0;
ctx->dst_buffer = dst_buffer;
ctx->dst_len = dst_size;
ctx->dst_pos = 0;
ctx->error = 0;
decoder = FLAC__stream_decoder_new();
if(!decoder)
{
free(ctx);
return -1;
}
FLAC__stream_decoder_set_md5_checking(decoder, false);
init_status = FLAC__stream_decoder_init_stream(decoder, read_callback, NULL, NULL, NULL, NULL, write_callback, NULL,
error_callback, ctx);
if(init_status != FLAC__STREAM_DECODER_INIT_STATUS_OK)
{
free(ctx);
return -1;
}
// TODO: Return error somehow
FLAC__stream_decoder_process_until_end_of_stream(decoder);
FLAC__stream_decoder_delete(decoder);
ret_size = ctx->dst_pos;
free(ctx);
return ret_size;
}
static FLAC__StreamDecoderReadStatus read_callback(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[],
size_t *bytes, void *client_data)
{
aaru_flac_ctx *ctx = (aaru_flac_ctx *)client_data;
if(ctx->src_len - ctx->src_pos < *bytes) *bytes = ctx->src_len - ctx->src_pos;
if(*bytes == 0) return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
memcpy(buffer, ctx->src_buffer + ctx->src_pos, *bytes);
ctx->src_pos += *bytes;
return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}
static FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame,
const FLAC__int32 *const buffer[], void *client_data)
{
aaru_flac_ctx *ctx = (aaru_flac_ctx *)client_data;
uint16_t *buffer16 = (uint16_t *)(ctx->dst_buffer + ctx->dst_pos);
// Why FLAC does not interleave the channels as PCM do, oh the mistery, we could use memcpy instead of looping
for(size_t i = 0; i < frame->header.blocksize && ctx->dst_pos < ctx->dst_len; i++)
{
// Left channel
*(buffer16++) = (FLAC__int16)buffer[0][i];
// Right channel
*(buffer16++) = (FLAC__int16)buffer[1][i];
ctx->dst_pos += 4;
/* TODO: Big-endian (use bswap?)
// Left channel
ctx->dst_buffer[ctx->dst_pos++] = (FLAC__uint16)(FLAC__int16)buffer[0][i];
ctx->dst_buffer[ctx->dst_pos++] = (FLAC__uint16)(FLAC__int16)buffer[0][i] >> 8;
// Right channel
ctx->dst_buffer[ctx->dst_pos++] = (FLAC__uint16)(FLAC__int16)buffer[1][i];
ctx->dst_buffer[ctx->dst_pos++] = (FLAC__uint16)(FLAC__int16)buffer[1][i] >> 8;
*/
}
return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}
static void error_callback(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
{
aaru_flac_ctx *ctx = (aaru_flac_ctx *)client_data;
fprintf(stderr, "Got error callback: %s\n", FLAC__StreamDecoderErrorStatusString[status]);
ctx->error = 1;
}
static FLAC__StreamEncoderWriteStatus encoder_write_callback(const FLAC__StreamEncoder *encoder,
const FLAC__byte buffer[], size_t bytes, uint32_t samples,
uint32_t current_frame, void *client_data);
AARU_EXPORT size_t AARU_CALL aaruf_flac_encode_redbook_buffer(
uint8_t *dst_buffer, size_t dst_size, const uint8_t *src_buffer, size_t src_size, uint32_t blocksize,
int32_t do_mid_side_stereo, int32_t loose_mid_side_stereo, const char *apodization, uint32_t max_lpc_order,
uint32_t qlp_coeff_precision, int32_t do_qlp_coeff_prec_search, int32_t do_exhaustive_model_search,
uint32_t min_residual_partition_order, uint32_t max_residual_partition_order, const char *application_id,
uint32_t application_id_len)
{
FLAC__StreamEncoder *encoder = NULL;
aaru_flac_ctx *ctx = (aaru_flac_ctx *)malloc(sizeof(aaru_flac_ctx));
FLAC__StreamEncoderInitStatus init_status = FLAC__STREAM_ENCODER_INIT_STATUS_OK;
size_t ret_size = 0;
FLAC__int32 *pcm = NULL;
int i = 0;
int16_t *buffer16 = (int16_t *)src_buffer;
FLAC__StreamMetadata *metadata[1];
memset(ctx, 0, sizeof(aaru_flac_ctx));
ctx->src_buffer = src_buffer;
ctx->src_len = src_size;
ctx->src_pos = 0;
ctx->dst_buffer = dst_buffer;
ctx->dst_len = dst_size;
ctx->dst_pos = 0;
ctx->error = 0;
encoder = FLAC__stream_encoder_new();
if(!encoder)
{
free(ctx);
return -1;
}
// TODO: Error detection here
FLAC__stream_encoder_set_verify(encoder, false);
FLAC__stream_encoder_set_streamable_subset(encoder, false);
FLAC__stream_encoder_set_channels(encoder, 2);
FLAC__stream_encoder_set_bits_per_sample(encoder, 16);
FLAC__stream_encoder_set_sample_rate(encoder, 44100);
FLAC__stream_encoder_set_blocksize(encoder, blocksize);
// true compresses more
FLAC__stream_encoder_set_do_mid_side_stereo(encoder, do_mid_side_stereo);
// false compresses more
FLAC__stream_encoder_set_loose_mid_side_stereo(encoder, loose_mid_side_stereo);
// Apodization
FLAC__stream_encoder_set_apodization(encoder, apodization);
FLAC__stream_encoder_set_max_lpc_order(encoder, max_lpc_order);
FLAC__stream_encoder_set_qlp_coeff_precision(encoder, qlp_coeff_precision);
FLAC__stream_encoder_set_do_qlp_coeff_prec_search(encoder, do_qlp_coeff_prec_search);
FLAC__stream_encoder_set_do_exhaustive_model_search(encoder, do_exhaustive_model_search);
FLAC__stream_encoder_set_min_residual_partition_order(encoder, min_residual_partition_order);
FLAC__stream_encoder_set_max_residual_partition_order(encoder, max_residual_partition_order);
FLAC__stream_encoder_set_total_samples_estimate(encoder, src_size / 4);
/* TODO: This is ignored by FLAC, need to replace it
if((metadata[0] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT)) != NULL)
{
memset(&vorbis_entry, 0, sizeof(FLAC__StreamMetadata_VorbisComment_Entry));
vorbis_entry.entry = (unsigned char *)"Aaru.Compression.Native";
vorbis_entry.length = strlen("Aaru.Compression.Native");
FLAC__metadata_object_vorbiscomment_set_vendor_string(metadata[0], vorbis_entry, true);
}
*/
if(application_id_len > 0 && application_id != NULL)
if((metadata[0] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_APPLICATION)) != NULL)
FLAC__metadata_object_application_set_data(metadata[0], (unsigned char *)application_id, application_id_len,
true);
FLAC__stream_encoder_set_metadata(encoder, metadata, 1);
init_status = FLAC__stream_encoder_init_stream(encoder, encoder_write_callback, NULL, NULL, NULL, ctx);
if(init_status != FLAC__STREAM_ENCODER_INIT_STATUS_OK)
{
free(ctx);
return -1;
}
pcm = malloc((src_size / 2) * sizeof(FLAC__int32));
for(i = 0; i < src_size / 2; i++) pcm[i] = (FLAC__int32) * (buffer16++);
FLAC__stream_encoder_process_interleaved(encoder, pcm, src_size / 4);
FLAC__stream_encoder_finish(encoder);
FLAC__stream_encoder_delete(encoder);
ret_size = ctx->dst_pos;
free(ctx);
free(pcm);
FLAC__metadata_object_delete(metadata[0]);
return ret_size;
}
static FLAC__StreamEncoderWriteStatus encoder_write_callback(const FLAC__StreamEncoder *encoder,
const FLAC__byte buffer[], size_t bytes, uint32_t samples,
uint32_t current_frame, void *client_data)
{
aaru_flac_ctx *ctx = (aaru_flac_ctx *)client_data;
if(bytes > ctx->dst_len - ctx->dst_pos) bytes = ctx->dst_len - ctx->dst_pos;
memcpy(ctx->dst_buffer + ctx->dst_pos, buffer, bytes);
ctx->dst_pos += bytes;
return FLAC__STREAM_ENCODER_WRITE_STATUS_OK;
}
aaruformat.h
AARU_CALL
#define AARU_CALL
Definition decls.h:46
AARU_EXPORT
#define AARU_EXPORT
Definition decls.h:55
aaruf_flac_encode_redbook_buffer
size_t aaruf_flac_encode_redbook_buffer(uint8_t *dst_buffer, size_t dst_size, const uint8_t *src_buffer, size_t src_size, uint32_t blocksize, int32_t do_mid_side_stereo, int32_t loose_mid_side_stereo, const char *apodization, uint32_t max_lpc_order, uint32_t qlp_coeff_precision, int32_t do_qlp_coeff_prec_search, int32_t do_exhaustive_model_search, uint32_t min_residual_partition_order, uint32_t max_residual_partition_order, const char *application_id, uint32_t application_id_len)
Encodes a Red Book audio buffer to FLAC format.
Definition flac.c:175
read_callback
static FLAC__StreamDecoderReadStatus read_callback(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
Definition flac.c:97
encoder_write_callback
static FLAC__StreamEncoderWriteStatus encoder_write_callback(const FLAC__StreamEncoder *encoder, const FLAC__byte buffer[], size_t bytes, uint32_t samples, uint32_t current_frame, void *client_data)
Definition flac.c:275
write_callback
static FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 *const buffer[], void *client_data)
Definition flac.c:112
error_callback
static void error_callback(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
Definition flac.c:141
aaruf_flac_decode_redbook_buffer
size_t aaruf_flac_decode_redbook_buffer(uint8_t *dst_buffer, size_t dst_size, const uint8_t *src_buffer, size_t src_size)
Decodes a FLAC-compressed Red Book audio buffer.
Definition flac.c:48
flac.h
aaru_flac_ctx
Definition flac.h:23
aaru_flac_ctx::dst_pos
size_t dst_pos
Definition flac.h:29
aaru_flac_ctx::error
uint8_t error
Definition flac.h:30
aaru_flac_ctx::dst_len
size_t dst_len
Definition flac.h:28
aaru_flac_ctx::src_buffer
const uint8_t * src_buffer
Definition flac.h:24
aaru_flac_ctx::src_pos
size_t src_pos
Definition flac.h:26
aaru_flac_ctx::src_len
size_t src_len
Definition flac.h:25
aaru_flac_ctx::dst_buffer
uint8_t * dst_buffer
Definition flac.h:27