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FFmpeg/libavcodec/vima.c
Paul B Mahol b18357326c LucasArts SMUSH VIMA audio decoder 
Signed-off-by: Paul B Mahol <onemda@gmail.com>
2012-06-21 01:23:15 +00:00

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/*
* LucasArt VIMA decoder
* Copyright (c) 2012 Paul B Mahol
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/audioconvert.h"
#include "avcodec.h"
#include "get_bits.h"
#include "adpcm_data.h"
typedef struct {
AVFrame frame;
uint16_t predict_table[5786 * 2];
} VimaContext;
static const uint8_t size_table[] =
{
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
};
static const int8_t index_table1[] =
{
-1, 4, -1, 4
};
static const int8_t index_table2[] =
{
-1, -1, 2, 6, -1, -1, 2, 6
};
static const int8_t index_table3[] =
{
-1, -1, -1, -1, 1, 2, 4, 6,
-1, -1, -1, -1, 1, 2, 4, 6
};
static const int8_t index_table4[] =
{
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 2, 2, 4, 5, 6,
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 2, 2, 4, 5, 6
};
static const int8_t index_table5[] =
{
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 2, 2, 2,
2, 4, 4, 4, 5, 5, 6, 6,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 2, 2, 2,
2, 4, 4, 4, 5, 5, 6, 6
};
static const int8_t index_table6[] =
{
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 2, 2, 2, 2, 2, 2,
2, 2, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 6, 6, 6, 6,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 2, 2, 2, 2, 2, 2,
2, 2, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 6, 6, 6, 6
};
static const int8_t* const step_index_tables[] =
{
index_table1, index_table2, index_table3,
index_table4, index_table5, index_table6
};
static av_cold int decode_init(AVCodecContext *avctx)
{
VimaContext *vima = avctx->priv_data;
int start_pos;
for (start_pos = 0; start_pos < 64; start_pos++) {
unsigned int dest_pos, table_pos;
for (table_pos = 0, dest_pos = start_pos;
table_pos < FF_ARRAY_ELEMS(ff_adpcm_step_table);
table_pos++, dest_pos += 64) {
int put = 0, count, table_value;
table_value = ff_adpcm_step_table[table_pos];
for (count = 32; count != 0; count >>= 1) {
if (start_pos & count)
put += table_value;
table_value >>= 1;
}
vima->predict_table[dest_pos] = put;
}
}
avcodec_get_frame_defaults(&vima->frame);
avctx->coded_frame = &vima->frame;
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
return 0;
}
static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *pkt)
{
GetBitContext gb;
VimaContext *vima = avctx->priv_data;
int16_t pcm_data[2];
uint32_t samples;
int8_t channel_hint[2];
int ret, chan, channels = 1;
init_get_bits(&gb, pkt->data, pkt->size * 8);
if (pkt->size < 13)
return AVERROR_INVALIDDATA;
samples = get_bits_long(&gb, 32);
if (samples == 0xffffffff) {
skip_bits_long(&gb, 32);
samples = get_bits_long(&gb, 32);
}
if (samples > pkt->size * 2)
return AVERROR_INVALIDDATA;
channel_hint[0] = get_sbits(&gb, 8);
if (channel_hint[0] & 0x80) {
channel_hint[0] = ~channel_hint[0];
channels = 2;
}
avctx->channels = channels;
avctx->channel_layout = (channels == 2) ? AV_CH_LAYOUT_STEREO :
AV_CH_LAYOUT_MONO;
pcm_data[0] = get_sbits(&gb, 16);
if (channels > 1) {
channel_hint[1] = get_sbits(&gb, 8);
pcm_data[1] = get_sbits(&gb, 16);
}
vima->frame.nb_samples = samples;
if ((ret = avctx->get_buffer(avctx, &vima->frame)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
for (chan = 0; chan < channels; chan++) {
uint16_t *dest = (uint16_t*)vima->frame.data[0] + chan;
int step_index = channel_hint[chan];
int output = pcm_data[chan];
int sample;
for (sample = 0; sample < samples; sample++) {
int lookup_size, lookup, highbit, lowbits;
step_index = av_clip(step_index, 0, 88);
lookup_size = size_table[step_index];
lookup = get_bits(&gb, lookup_size);
highbit = 1 << (lookup_size - 1);
lowbits = highbit - 1;
if (lookup & highbit)
lookup ^= highbit;
else
highbit = 0;
if (lookup == lowbits) {
output = get_sbits(&gb, 16);
} else {
int predict_index, diff;
predict_index = (lookup << (7 - lookup_size)) | (step_index << 6);
predict_index = av_clip(predict_index, 0, 5785);
diff = vima->predict_table[predict_index];
if (lookup)
diff += ff_adpcm_step_table[step_index] >> (lookup_size - 1);
if (highbit)
diff = -diff;
output = av_clip_int16(output + diff);
}
*dest = output;
dest += channels;
step_index += step_index_tables[lookup_size - 2][lookup];
}
}
*got_frame_ptr = 1;
*(AVFrame *)data = vima->frame;
return pkt->size;
}
AVCodec ff_vima_decoder = {
.name = "vima",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_VIMA,
.priv_data_size = sizeof(VimaContext),
.init = decode_init,
.decode = decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("LucasArts VIMA audio"),
};
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