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rockbox/apps/codecs/libm4a/m4a.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Dave Chapman
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <codecs.h>
#include <inttypes.h>
#include "m4a.h"
#if defined(DEBUG) || defined(SIMULATOR)
extern struct codec_api* rb;
#define DEBUGF rb->debugf
#else
#define DEBUGF(...)
#endif
/* Implementation of the stream.h functions used by libalac */
#define _Swap32(v) do { \
v = (((v) & 0x000000FF) << 0x18) | \
(((v) & 0x0000FF00) << 0x08) | \
(((v) & 0x00FF0000) >> 0x08) | \
(((v) & 0xFF000000) >> 0x18); } while(0)
#define _Swap16(v) do { \
v = (((v) & 0x00FF) << 0x08) | \
(((v) & 0xFF00) >> 0x08); } while (0)
/* A normal read without any byte-swapping */
void stream_read(stream_t *stream, size_t size, void *buf)
{
stream->ci->read_filebuf(buf,size);
if (stream->ci->curpos >= stream->ci->filesize) { stream->eof=1; }
}
int32_t stream_read_int32(stream_t *stream)
{
int32_t v;
stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap32(v);
#endif
return v;
}
int32_t stream_tell(stream_t *stream)
{
return stream->ci->curpos;
}
uint32_t stream_read_uint32(stream_t *stream)
{
uint32_t v;
stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap32(v);
#endif
return v;
}
int16_t stream_read_int16(stream_t *stream)
{
int16_t v;
stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap16(v);
#endif
return v;
}
uint16_t stream_read_uint16(stream_t *stream)
{
uint16_t v;
stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap16(v);
#endif
return v;
}
int8_t stream_read_int8(stream_t *stream)
{
int8_t v;
stream_read(stream, 1, &v);
return v;
}
uint8_t stream_read_uint8(stream_t *stream)
{
uint8_t v;
stream_read(stream, 1, &v);
return v;
}
void stream_skip(stream_t *stream, size_t skip)
{
stream->ci->advance_buffer(skip);
}
int stream_eof(stream_t *stream)
{
return stream->eof;
}
void stream_create(stream_t *stream,struct codec_api* ci)
{
stream->ci=ci;
stream->eof=0;
}
/* This function was part of the original alac decoder implementation */
int get_sample_info(demux_res_t *demux_res, uint32_t samplenum,
uint32_t *sample_duration,
uint32_t *sample_byte_size)
{
unsigned int duration_index_accum = 0;
unsigned int duration_cur_index = 0;
if (samplenum >= demux_res->num_sample_byte_sizes) {
return 0;
}
if (!demux_res->num_time_to_samples) {
return 0;
}
while ((demux_res->time_to_sample[duration_cur_index].sample_count
+ duration_index_accum) <= samplenum) {
duration_index_accum +=
demux_res->time_to_sample[duration_cur_index].sample_count;
duration_cur_index++;
if (duration_cur_index >= demux_res->num_time_to_samples) {
return 0;
}
}
*sample_duration =
demux_res->time_to_sample[duration_cur_index].sample_duration;
*sample_byte_size = demux_res->sample_byte_size[samplenum];
return 1;
}
unsigned int get_sample_offset(demux_res_t *demux_res, uint32_t sample)
{
uint32_t chunk = 1;
uint32_t range_samples = 0;
uint32_t total_samples = 0;
uint32_t chunk_sample;
uint32_t prev_chunk;
uint32_t prev_chunk_samples;
uint32_t file_offset;
uint32_t i;
/* First check we have the appropriate metadata - we should always
* have it.
*/
if (sample >= demux_res->num_sample_byte_sizes ||
!demux_res->num_sample_to_chunks ||
!demux_res->num_chunk_offsets)
{
return 0;
}
/* Locate the chunk containing the sample */
prev_chunk = demux_res->sample_to_chunk[0].first_chunk;
prev_chunk_samples = demux_res->sample_to_chunk[0].num_samples;
for (i = 1; i < demux_res->num_sample_to_chunks; i++)
{
chunk = demux_res->sample_to_chunk[i].first_chunk;
range_samples = (chunk - prev_chunk) * prev_chunk_samples;
if (sample < total_samples + range_samples)
{
break;
}
total_samples += range_samples;
prev_chunk = demux_res->sample_to_chunk[i].first_chunk;
prev_chunk_samples = demux_res->sample_to_chunk[i].num_samples;
}
if (sample >= demux_res->sample_to_chunk[0].num_samples)
{
chunk = prev_chunk + (sample - total_samples) / prev_chunk_samples;
}
else
{
chunk = 1;
}
/* Get sample of the first sample in the chunk */
chunk_sample = total_samples + (chunk - prev_chunk) * prev_chunk_samples;
/* Get offset in file */
if (chunk > demux_res->num_chunk_offsets)
{
file_offset = demux_res->chunk_offset[demux_res->num_chunk_offsets - 1];
}
else
{
file_offset = demux_res->chunk_offset[chunk - 1];
}
if (chunk_sample > sample)
{
return 0;
}
for (i = chunk_sample; i < sample; i++)
{
file_offset += demux_res->sample_byte_size[i];
}
if (file_offset > demux_res->mdat_offset + demux_res->mdat_len)
{
return 0;
}
return file_offset;
}
/* Seek to the sample containing sound_sample_loc. Return 1 on success
* (and modify sound_samples_done and current_sample), 0 if failed.
*
* Seeking uses the following arrays:
*
* 1) the time_to_sample array contains the duration (in sound samples)
* of each sample of data.
*
* 2) the sample_byte_size array contains the length in bytes of each
* sample.
*
* 3) the sample_to_chunk array contains information about which chunk
* of samples each sample belongs to.
*
* 4) the chunk_offset array contains the file offset of each chunk.
*
* So find the sample number we are going to seek to (using time_to_sample)
* and then find the offset in the file (using sample_to_chunk,
* chunk_offset sample_byte_size, in that order.).
*
*/
unsigned int alac_seek(demux_res_t* demux_res, stream_t* stream,
uint32_t sound_sample_loc, uint32_t* sound_samples_done,
int* current_sample)
{
uint32_t i;
uint32_t j;
uint32_t new_sample;
uint32_t new_sound_sample;
uint32_t new_pos;
/* First check we have the appropriate metadata - we should always
* have it.
*/
if ((demux_res->num_time_to_samples==0) ||
(demux_res->num_sample_byte_sizes==0))
{
return 0;
}
/* Find the destination block from time_to_sample array */
i = 0;
new_sample = 0;
new_sound_sample = 0;
while ((i < demux_res->num_time_to_samples) &&
(new_sound_sample < sound_sample_loc))
{
j = (sound_sample_loc - new_sound_sample) /
demux_res->time_to_sample[i].sample_duration;
if (j <= demux_res->time_to_sample[i].sample_count)
{
new_sample += j;
new_sound_sample += j *
demux_res->time_to_sample[i].sample_duration;
break;
}
else
{
new_sound_sample += (demux_res->time_to_sample[i].sample_duration
* demux_res->time_to_sample[i].sample_count);
new_sample += demux_res->time_to_sample[i].sample_count;
i++;
}
}
/* We know the new block, now calculate the file position. */
new_pos = get_sample_offset(demux_res, new_sample);
/* We know the new file position, so let's try to seek to it */
if (stream->ci->seek_buffer(new_pos))
{
*sound_samples_done = new_sound_sample;
*current_sample = new_sample;
return 1;
}
return 0;
}
/* Seek to the sample containing file_loc. Return 1 on success (and modify
* sound_samples_done and current_sample), 0 if failed.
*
* Seeking uses the following arrays:
*
* 1) the chunk_offset array contains the file offset of each chunk.
*
* 2) the sample_to_chunk array contains information about which chunk
* of samples each sample belongs to.
*
* 3) the sample_byte_size array contains the length in bytes of each
* sample.
*
* 4) the time_to_sample array contains the duration (in sound samples)
* of each sample of data.
*
* Locate the chunk containing location (using chunk_offset), find the
* sample of that chunk (using sample_to_chunk) and finally the location
* of that sample (using sample_byte_size). Then use time_to_sample to
* calculate the sound_samples_done value.
*/
unsigned int alac_seek_raw(demux_res_t* demux_res, stream_t* stream,
uint32_t file_loc, uint32_t* sound_samples_done,
int* current_sample)
{
uint32_t chunk_sample = 0;
uint32_t total_samples = 0;
uint32_t new_sound_sample = 0;
uint32_t new_pos;
uint32_t chunk;
uint32_t i;
if (!demux_res->num_chunk_offsets ||
!demux_res->num_sample_to_chunks)
{
return 0;
}
/* Locate the chunk containing file_loc. */
for (i = 0; i < demux_res->num_chunk_offsets &&
file_loc < demux_res->chunk_offset[i]; i++)
{
}
chunk = i + 1;
new_pos = demux_res->chunk_offset[chunk - 1];
/* Get the first sample of the chunk. */
for (i = 1; i < demux_res->num_sample_to_chunks &&
chunk < demux_res->sample_to_chunk[i - 1].first_chunk; i++)
{
chunk_sample += demux_res->sample_to_chunk[i - 1].num_samples *
(demux_res->sample_to_chunk[i].first_chunk -
demux_res->sample_to_chunk[i - 1].first_chunk);
}
chunk_sample += (chunk - demux_res->sample_to_chunk[i - 1].first_chunk) *
demux_res->sample_to_chunk[i - 1].num_samples;
/* Get the position within the chunk. */
for (; chunk_sample < demux_res->num_sample_byte_sizes; chunk_sample++)
{
if (file_loc < new_pos + demux_res->sample_byte_size[chunk_sample])
{
break;
}
new_pos += demux_res->sample_byte_size[chunk_sample];
}
/* Get sound sample offset. */
for (i = 0; i < demux_res->num_time_to_samples; i++)
{
if (chunk_sample <
total_samples + demux_res->time_to_sample[i].sample_count)
{
break;
}
total_samples += demux_res->time_to_sample[i].sample_count;
new_sound_sample += demux_res->time_to_sample[i].sample_count
* demux_res->time_to_sample[i].sample_duration;
}
new_sound_sample += (chunk_sample - total_samples)
* demux_res->time_to_sample[i].sample_duration;
/* Go to the new file position. */
if (stream->ci->seek_buffer(new_pos))
{
*sound_samples_done = new_sound_sample;
*current_sample = chunk_sample;
return 1;
}
return 0;
}
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