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Code Issues Releases Activity

adpcm: convert adpcm_swf to bytestream2.

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This commit is contained in:
Ronald S. Bultje 2012-03-17 15:38:49 -07:00
parent 8afe2f9002
commit f184735a27
1 changed files with 61 additions and 56 deletions
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117
libavcodec/adpcm.c
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@ -343,6 +343,64 @@ static int xa_decode(AVCodecContext *avctx,
return 0;
}
static void adpcm_swf_decode(AVCodecContext *avctx, const uint8_t *buf, int buf_size, int16_t *samples)
{
ADPCMDecodeContext *c = avctx->priv_data;
GetBitContext gb;
const int *table;
int k0, signmask, nb_bits, count;
int size = buf_size*8;
int i;
init_get_bits(&gb, buf, size);
//read bits & initial values
nb_bits = get_bits(&gb, 2)+2;
//av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", nb_bits);
table = swf_index_tables[nb_bits-2];
k0 = 1 << (nb_bits-2);
signmask = 1 << (nb_bits-1);
while (get_bits_count(&gb) <= size - 22*avctx->channels) {
for (i = 0; i < avctx->channels; i++) {
*samples++ = c->status[i].predictor = get_sbits(&gb, 16);
c->status[i].step_index = get_bits(&gb, 6);
}
for (count = 0; get_bits_count(&gb) <= size - nb_bits*avctx->channels && count < 4095; count++) {
int i;
for (i = 0; i < avctx->channels; i++) {
// similar to IMA adpcm
int delta = get_bits(&gb, nb_bits);
int step = ff_adpcm_step_table[c->status[i].step_index];
long vpdiff = 0; // vpdiff = (delta+0.5)*step/4
int k = k0;
do {
if (delta & k)
vpdiff += step;
step >>= 1;
k >>= 1;
} while(k);
vpdiff += step;
if (delta & signmask)
c->status[i].predictor -= vpdiff;
else
c->status[i].predictor += vpdiff;
c->status[i].step_index += table[delta & (~signmask)];
c->status[i].step_index = av_clip(c->status[i].step_index, 0, 88);
c->status[i].predictor = av_clip_int16(c->status[i].predictor);
*samples++ = c->status[i].predictor;
}
}
}
}
/**
* Get the number of samples that will be decoded from the packet.
* In one case, this is actually the maximum number of samples possible to
@ -479,7 +537,7 @@ static int get_nb_samples(AVCodecContext *avctx, const uint8_t *buf,
case CODEC_ID_ADPCM_SWF:
{
int buf_bits = buf_size * 8 - 2;
int nbits = (buf[0] >> 6) + 2;
int nbits = (bytestream2_get_byte(gb) >> 6) + 2;
int block_hdr_size = 22 * ch;
int block_size = block_hdr_size + nbits * ch * 4095;
int nblocks = buf_bits / block_size;
@ -1140,62 +1198,9 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
}
break;
case CODEC_ID_ADPCM_SWF:
{
GetBitContext gb;
const int *table;
int k0, signmask, nb_bits, count;
int size = buf_size*8;
init_get_bits(&gb, buf, size);
//read bits & initial values
nb_bits = get_bits(&gb, 2)+2;
//av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", nb_bits);
table = swf_index_tables[nb_bits-2];
k0 = 1 << (nb_bits-2);
signmask = 1 << (nb_bits-1);
while (get_bits_count(&gb) <= size - 22*avctx->channels) {
for (i = 0; i < avctx->channels; i++) {
*samples++ = c->status[i].predictor = get_sbits(&gb, 16);
c->status[i].step_index = get_bits(&gb, 6);
}
for (count = 0; get_bits_count(&gb) <= size - nb_bits*avctx->channels && count < 4095; count++) {
int i;
for (i = 0; i < avctx->channels; i++) {
// similar to IMA adpcm
int delta = get_bits(&gb, nb_bits);
int step = ff_adpcm_step_table[c->status[i].step_index];
long vpdiff = 0; // vpdiff = (delta+0.5)*step/4
int k = k0;
do {
if (delta & k)
vpdiff += step;
step >>= 1;
k >>= 1;
} while(k);
vpdiff += step;
if (delta & signmask)
c->status[i].predictor -= vpdiff;
else
c->status[i].predictor += vpdiff;
c->status[i].step_index += table[delta & (~signmask)];
c->status[i].step_index = av_clip(c->status[i].step_index, 0, 88);
c->status[i].predictor = av_clip_int16(c->status[i].predictor);
*samples++ = c->status[i].predictor;
}
}
}
src += buf_size;
adpcm_swf_decode(avctx, buf, buf_size, samples);
bytestream2_seek(&gb, 0, SEEK_END);
break;
}
case CODEC_ID_ADPCM_YAMAHA:
for (n = nb_samples >> (1 - st); n > 0; n--, src++) {
uint8_t v = *src;