mpv/ima4.c

552 lines
14 KiB
C
Raw Normal View History

/*
IMA4:1 audio codec from QuickTime4Linux library. (http://www.heroinewarrior.com/)
*/
#include "ima4.h"
static int quicktime_ima4_step[89] =
{
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};
static int quicktime_ima4_index[16] =
{
-1, -1, -1, -1, 2, 4, 6, 8,
-1, -1, -1, -1, 2, 4, 6, 8
};
/* Known by divine revelation */
#define BLOCK_SIZE 0x22
#define SAMPLES_PER_BLOCK 0x40
/* ================================== private for ima4 */
void ima4_decode_sample(int *predictor, int *nibble, int *index, int *step)
{
int difference, sign;
/* Get new index value */
*index += quicktime_ima4_index[*nibble];
if(*index < 0) *index = 0;
else
if(*index > 88) *index = 88;
/* Get sign and magnitude from *nibble */
sign = *nibble & 8;
*nibble = *nibble & 7;
/* Get difference */
difference = *step >> 3;
if(*nibble & 4) difference += *step;
if(*nibble & 2) difference += *step >> 1;
if(*nibble & 1) difference += *step >> 2;
/* Predict value */
if(sign)
*predictor -= difference;
else
*predictor += difference;
if(*predictor > 32767) *predictor = 32767;
else
if(*predictor < -32768) *predictor = -32768;
/* Update the step value */
*step = quicktime_ima4_step[*index];
}
int ima4_decode_block(int16_t *output, unsigned char *input, int maxlen)
{
int predictor;
int index;
int step;
int i, nibble, nibble_count, block_size;
int olen = 0;
unsigned char *block_ptr;
unsigned char *input_end = input + BLOCK_SIZE;
// quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;
/* Get the chunk header */
predictor = *input++ << 8;
predictor |= *input++;
index = predictor & 0x7f;
if(index > 88) index = 88;
predictor &= 0xff80;
if(predictor & 0x8000) predictor -= 0x10000;
step = quicktime_ima4_step[index];
/* Read the input buffer sequentially, one nibble at a time */
nibble_count = 0;
while(input < input_end)
{
nibble = nibble_count ? (*input++ >> 4) & 0x0f : *input & 0x0f;
ima4_decode_sample(&predictor, &nibble, &index, &step);
if (olen+1 > maxlen)
break;
*output++ = predictor;
olen++;
nibble_count ^= 1;
}
return(olen);
}
#if 0
void ima4_encode_sample(int *last_sample, int *last_index, int *nibble, int next_sample)
{
int difference, new_difference, mask, step;
difference = next_sample - *last_sample;
*nibble = 0;
step = quicktime_ima4_step[*last_index];
new_difference = step >> 3;
if(difference < 0)
{
*nibble = 8;
difference = -difference;
}
mask = 4;
while(mask)
{
if(difference >= step)
{
*nibble |= mask;
difference -= step;
new_difference += step;
}
step >>= 1;
mask >>= 1;
}
if(*nibble & 8)
*last_sample -= new_difference;
else
*last_sample += new_difference;
if(*last_sample > 32767) *last_sample = 32767;
else
if(*last_sample < -32767) *last_sample = -32767;
*last_index += quicktime_ima4_index[*nibble];
if(*last_index < 0) *last_index = 0;
else
if(*last_index > 88) *last_index= 88;
}
#if 0
void ima4_encode_block(quicktime_audio_map_t *atrack, unsigned char *output, int16_t *input, int step, int channel)
{
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;
int i, nibble_count = 0, nibble, header;
/* Get a fake starting sample */
header = codec->last_samples[channel];
/* Force rounding. */
if(header < 0x7fc0) header += 0x40;
if(header < 0) header += 0x10000;
header &= 0xff80;
*output++ = (header & 0xff00) >> 8;
*output++ = (header & 0x80) + (codec->last_indexes[channel] & 0x7f);
for(i = 0; i < SAMPLES_PER_BLOCK; i++)
{
ima4_encode_sample(&(codec->last_samples[channel]),
&(codec->last_indexes[channel]),
&nibble,
*input);
if(nibble_count)
*output++ |= (nibble << 4);
else
*output = nibble;
input += step;
nibble_count ^= 1;
}
}
#endif
/* Convert the number of samples in a chunk into the number of bytes in that */
/* chunk. The number of samples in a chunk should end on a block boundary. */
long ima4_samples_to_bytes(long samples, int channels)
{
long bytes = samples / SAMPLES_PER_BLOCK * BLOCK_SIZE * channels;
return bytes;
}
/* Decode the chunk into the work buffer */
int ima4_decode_chunk(quicktime_t *file, int track, long chunk, int channel)
{
int result = 0;
int i, j;
long chunk_samples, chunk_bytes;
unsigned char *chunk_ptr, *block_ptr;
quicktime_trak_t *trak = file->atracks[track].track;
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)file->atracks[track].codec)->priv;
/* Get the byte count to read. */
chunk_samples = quicktime_chunk_samples(trak, chunk);
chunk_bytes = ima4_samples_to_bytes(chunk_samples, file->atracks[track].channels);
/* Get the buffer to read into. */
if(codec->work_buffer && codec->work_size < chunk_samples)
{
free(codec->work_buffer);
codec->work_buffer = 0;
}
if(!codec->work_buffer)
{
codec->work_size = chunk_samples;
codec->work_buffer = malloc(sizeof(int16_t) * codec->work_size);
}
if(codec->read_buffer && codec->read_size < chunk_bytes)
{
free(codec->read_buffer);
codec->read_buffer = 0;
}
if(!codec->read_buffer)
{
codec->read_size = chunk_bytes;
codec->read_buffer = malloc(codec->read_size);
}
/* codec->work_size now holds the number of samples in the last chunk */
/* codec->read_size now holds number of bytes in the last read buffer */
/* Read the entire chunk regardless of where the desired sample range starts. */
result = quicktime_read_chunk(file, codec->read_buffer, track, chunk, 0, chunk_bytes);
/* Now decode the chunk, one block at a time, until the total samples in the chunk */
/* is reached. */
if(!result)
{
block_ptr = codec->read_buffer;
for(i = 0; i < chunk_samples; i += SAMPLES_PER_BLOCK)
{
for(j = 0; j < file->atracks[track].channels; j++)
{
if(j == channel)
ima4_decode_block(&(file->atracks[track]), &(codec->work_buffer[i]), block_ptr);
block_ptr += BLOCK_SIZE;
}
}
}
codec->buffer_channel = channel;
codec->chunk = chunk;
return result;
}
/* =================================== public for ima4 */
static int quicktime_delete_codec_ima4(quicktime_audio_map_t *atrack)
{
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)atrack->codec)->priv;
if(codec->work_buffer) free(codec->work_buffer);
if(codec->read_buffer) free(codec->read_buffer);
if(codec->last_samples) free(codec->last_samples);
if(codec->last_indexes) free(codec->last_indexes);
codec->last_samples = 0;
codec->last_indexes = 0;
codec->read_buffer = 0;
codec->work_buffer = 0;
codec->chunk = 0;
codec->buffer_channel = 0; /* Channel of work buffer */
codec->work_size = 0; /* Size of work buffer */
codec->read_size = 0;
free(codec);
return 0;
}
static int quicktime_decode_ima4(quicktime_t *file,
int16_t *output_i,
float *output_f,
long samples,
int track,
int channel)
{
int result = 0;
longest chunk, chunk_sample, chunk_bytes, chunk_samples;
longest i, chunk_start, chunk_end;
quicktime_trak_t *trak = file->atracks[track].track;
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)file->atracks[track].codec)->priv;
/* Get the first chunk with this routine and then increase the chunk number. */
quicktime_chunk_of_sample(&chunk_sample, &chunk, trak, file->atracks[track].current_position);
/* Read chunks and extract ranges of samples until the output is full. */
for(i = 0; i < samples && !result; )
{
/* Get chunk we're on. */
chunk_samples = quicktime_chunk_samples(trak, chunk);
if(!codec->work_buffer ||
codec->chunk != chunk ||
codec->buffer_channel != channel)
{
/* read a new chunk if necessary */
result = ima4_decode_chunk(file, track, chunk, channel);
}
/* Get boundaries from the chunk */
chunk_start = 0;
if(chunk_sample < file->atracks[track].current_position)
chunk_start = file->atracks[track].current_position - chunk_sample;
chunk_end = chunk_samples;
if(chunk_sample + chunk_end > file->atracks[track].current_position + samples)
chunk_end = file->atracks[track].current_position + samples - chunk_sample;
/* Read from the chunk */
if(output_i)
{
/*printf("decode_ima4 1 chunk %ld %ld-%ld output %ld\n", chunk, chunk_start + chunk_sample, chunk_end + chunk_sample, i); */
while(chunk_start < chunk_end)
{
output_i[i++] = codec->work_buffer[chunk_start++];
}
/*printf("decode_ima4 2\n"); */
}
else
if(output_f)
{
while(chunk_start < chunk_end)
{
output_f[i++] = (float)codec->work_buffer[chunk_start++] / 32767;
}
}
chunk++;
chunk_sample += chunk_samples;
}
return result;
}
static int quicktime_encode_ima4(quicktime_t *file,
int16_t **input_i,
float **input_f,
int track,
long samples)
{
int result = 0;
longest i, j, step;
longest chunk_bytes;
longest overflow_start;
longest offset;
longest chunk_samples; /* Samples in the current chunk to be written */
quicktime_audio_map_t *track_map = &(file->atracks[track]);
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)track_map->codec)->priv;
int16_t *input_ptr;
unsigned char *output_ptr;
/* Get buffer sizes */
if(codec->work_buffer && codec->work_size < (samples + codec->work_overflow + 1) * track_map->channels)
{
/* Create new buffer */
longest new_size = (samples + codec->work_overflow + 1) * track_map->channels;
int16_t *new_buffer = malloc(sizeof(int16_t) * new_size);
/* Copy overflow */
for(i = 0; i < codec->work_overflow * track_map->channels; i++)
new_buffer[i] = codec->work_buffer[i];
/* Swap pointers. */
free(codec->work_buffer);
codec->work_buffer = new_buffer;
codec->work_size = new_size;
}
else
if(!codec->work_buffer)
{
/* No buffer in the first place. */
codec->work_size = (samples + codec->work_overflow) * track_map->channels;
/* Make the allocation enough for at least the flush routine. */
if(codec->work_size < SAMPLES_PER_BLOCK * track_map->channels)
codec->work_size = SAMPLES_PER_BLOCK * track_map->channels;
codec->work_buffer = malloc(sizeof(int16_t) * codec->work_size);
}
/* Get output size */
chunk_bytes = ima4_samples_to_bytes(samples + codec->work_overflow, track_map->channels);
if(codec->read_buffer && codec->read_size < chunk_bytes)
{
free(codec->read_buffer);
codec->read_buffer = 0;
}
if(!codec->read_buffer)
{
codec->read_buffer = malloc(chunk_bytes);
codec->read_size = chunk_bytes;
}
if(!codec->last_samples)
{
codec->last_samples = malloc(sizeof(int) * track_map->channels);
for(i = 0; i < track_map->channels; i++)
{
codec->last_samples[i] = 0;
}
}
if(!codec->last_indexes)
{
codec->last_indexes = malloc(sizeof(int) * track_map->channels);
for(i = 0; i < track_map->channels; i++)
{
codec->last_indexes[i] = 0;
}
}
/* Arm the input buffer after the last overflow */
step = track_map->channels;
for(j = 0; j < track_map->channels; j++)
{
input_ptr = codec->work_buffer + codec->work_overflow * track_map->channels + j;
if(input_i)
{
for(i = 0; i < samples; i++)
{
*input_ptr = input_i[j][i];
input_ptr += step;
}
}
else
if(input_f)
{
for(i = 0; i < samples; i++)
{
*input_ptr = (int16_t)(input_f[j][i] * 32767);
input_ptr += step;
}
}
}
/* Encode from the input buffer to the read_buffer up to a multiple of */
/* blocks. */
input_ptr = codec->work_buffer;
output_ptr = codec->read_buffer;
for(i = 0;
i + SAMPLES_PER_BLOCK <= samples + codec->work_overflow;
i += SAMPLES_PER_BLOCK)
{
for(j = 0; j < track_map->channels; j++)
{
ima4_encode_block(track_map, output_ptr, input_ptr + j, track_map->channels, j);
output_ptr += BLOCK_SIZE;
}
input_ptr += SAMPLES_PER_BLOCK * track_map->channels;
}
/* Write to disk */
chunk_samples = (longest)((samples + codec->work_overflow) / SAMPLES_PER_BLOCK) * SAMPLES_PER_BLOCK;
/*printf("quicktime_encode_ima4 1 %ld\n", chunk_samples); */
/* The block division may result in 0 samples getting encoded. */
/* Don't write 0 samples. */
if(chunk_samples)
{
offset = quicktime_position(file);
result = quicktime_write_data(file, codec->read_buffer, chunk_bytes);
if(result) result = 0; else result = 1; /* defeat fwrite's return */
quicktime_update_tables(file,
track_map->track,
offset,
track_map->current_chunk,
track_map->current_position,
chunk_samples,
0);
file->atracks[track].current_chunk++;
}
/* Move the last overflow to the front */
overflow_start = i;
input_ptr = codec->work_buffer;
for(i = overflow_start * track_map->channels ;
i < (samples + codec->work_overflow) * track_map->channels;
i++)
{
*input_ptr++ = codec->work_buffer[i];
}
codec->work_overflow = samples + codec->work_overflow - overflow_start;
return result;
}
int quicktime_flush_ima4(quicktime_t *file, int track)
{
quicktime_audio_map_t *track_map = &(file->atracks[track]);
quicktime_ima4_codec_t *codec = ((quicktime_codec_t*)track_map->codec)->priv;
int result = 0;
int i;
/*printf("quicktime_flush_ima4 %ld\n", codec->work_overflow); */
if(codec->work_overflow)
{
/* Zero out enough to get a block */
i = codec->work_overflow * track_map->channels;
while(i < SAMPLES_PER_BLOCK * track_map->channels)
{
codec->work_buffer[i++] = 0;
}
codec->work_overflow = i / track_map->channels + 1;
/* Write the work_overflow only. */
result = quicktime_encode_ima4(file, 0, 0, track, 0);
}
return result;
}
void quicktime_init_codec_ima4(quicktime_audio_map_t *atrack)
{
quicktime_ima4_codec_t *codec;
/* Init public items */
((quicktime_codec_t*)atrack->codec)->priv = calloc(1, sizeof(quicktime_ima4_codec_t));
((quicktime_codec_t*)atrack->codec)->delete_acodec = quicktime_delete_codec_ima4;
((quicktime_codec_t*)atrack->codec)->decode_video = 0;
((quicktime_codec_t*)atrack->codec)->encode_video = 0;
((quicktime_codec_t*)atrack->codec)->decode_audio = quicktime_decode_ima4;
((quicktime_codec_t*)atrack->codec)->encode_audio = quicktime_encode_ima4;
/* Init private items */
codec = ((quicktime_codec_t*)atrack->codec)->priv;
codec->work_buffer = 0;
codec->read_buffer = 0;
codec->chunk = 0;
codec->buffer_channel = 0;
codec->work_overflow = 0;
codec->work_size = 0;
codec->read_size = 0;
codec->last_samples = 0;
codec->last_indexes = 0;
}
#endif