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avcodec/smacker: Optimize constant 16bit audio output 

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Reviewed-by: Tomas Härdin <tjoppen@acc.umu.se>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2022-05-03 18:30:59 +02:00
parent 5c2fa59f32
commit 08e82e5b57
1 changed files with 22 additions and 2 deletions
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24
libavcodec/smacker.c
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@ -601,7 +601,7 @@ static int smka_decode_frame(AVCodecContext *avctx, AVFrame *frame,
int i, res, ret;
int unp_size;
int bits, stereo;
unsigned pred[2], val;
unsigned pred[2], val, val2;
if (buf_size <= 4) {
av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
@ -672,7 +672,11 @@ static int smka_decode_frame(AVCodecContext *avctx, AVFrame *frame,
pred[i] = av_bswap16(get_bits(&gb, 16));
for(i = 0; i <= stereo; i++)
*samples++ = pred[i];
for(; i < unp_size / 2; i++) {
unp_size /= 2;
if (vlc[0 ].table || vlc[ 1].table ||
vlc[2*stereo].table || vlc[2*stereo+1].table) {
for(; i < unp_size ; i++) {
unsigned idx = 2 * (i & stereo);
if (get_bits_left(&gb) < 0) {
ret = AVERROR_INVALIDDATA;
@ -691,6 +695,22 @@ static int smka_decode_frame(AVCodecContext *avctx, AVFrame *frame,
pred[idx / 2] += val;
*samples++ = pred[idx / 2];
}
} else if (stereo) {
val = 256*values[1] + values[0];
val2 = 256*values[3] + values[2];
for(; i < unp_size; i+=2) {
pred[0] += val;
pred[1] += val2;
*samples++ = pred[0];
*samples++ = pred[1];
}
} else {
val = 256*values[1] + values[0];
for(; i < unp_size; i++) {
pred[0] += val;
*samples++ = pred[0];
}
}
} else { //8-bit data
for(i = stereo; i >= 0; i--)
pred[i] = get_bits(&gb, 8);