mirror of https://git.ffmpeg.org/ffmpeg.git
h261dec: Optimize new RL_VLC based decoding.
Together with the switch to RL_VLC this results in about 10% speedup for this inner loop. Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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@ -318,27 +318,25 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
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/* The remaining combinations of (run, level) are encoded with a
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* 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
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* level. */
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run = SHOW_UBITS(re, &s->gb, 6);
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run = SHOW_UBITS(re, &s->gb, 6) + 1;
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SKIP_CACHE(re, &s->gb, 6);
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level = SHOW_SBITS(re, &s->gb, 8);
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SKIP_COUNTER(re, &s->gb, 6 + 8);
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} else if (level == 0) {
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break;
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} else {
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run--;
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if (SHOW_UBITS(re, &s->gb, 1))
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level = -level;
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SKIP_COUNTER(re, &s->gb, 1);
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}
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i += run;
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if (i >= 64) {
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if (i > 64) {
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av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n",
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s->mb_x, s->mb_y);
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return -1;
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}
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j = scan_table[i];
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j = scan_table[i-1];
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block[j] = level;
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i++;
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}
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CLOSE_READER(re, &s->gb);
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}
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