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Code Issues Releases Activity

avcodec/mpeg12dec: Optimize mpeg1_decode_block_intra()

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sandybridge i7 274->260 cycles

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer
2014-01-24 18:09:16 +01:00
parent 0a59055167
commit 0c8e5fb211
1 changed files with 14 additions and 7 deletions
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libavcodec/mpeg12dec.c
+14 -7
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@@ -142,29 +142,30 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s, int16_t *block, in
i = 0; i = 0;
{ {
OPEN_READER(re, &s->gb); OPEN_READER(re, &s->gb);
UPDATE_CACHE(re, &s->gb);
if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)
goto end;
/* now quantify & encode AC coefficients */ /* now quantify & encode AC coefficients */
for (;;) { for (;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0); GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
if (level == 127) { if (level != 0) {
break;
} else if (level != 0) {
i += run; i += run;
j = scantable[i]; j = scantable[i];
level = (level * qscale * quant_matrix[j]) >> 4; level = (level * qscale * quant_matrix[j]) >> 4;
level = (level - 1) | 1; level = (level - 1) | 1;
level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
LAST_SKIP_BITS(re, &s->gb, 1); SKIP_BITS(re, &s->gb, 1);
} else { } else {
/* escape */ /* escape */
run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6); run = SHOW_UBITS(re, &s->gb, 6) + 1; LAST_SKIP_BITS(re, &s->gb, 6);
UPDATE_CACHE(re, &s->gb); UPDATE_CACHE(re, &s->gb);
level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8); level = SHOW_SBITS(re, &s->gb, 8); SKIP_BITS(re, &s->gb, 8);
if (level == -128) { if (level == -128) {
level = SHOW_UBITS(re, &s->gb, 8) - 256; LAST_SKIP_BITS(re, &s->gb, 8); level = SHOW_UBITS(re, &s->gb, 8) - 256; SKIP_BITS(re, &s->gb, 8);
} else if (level == 0) { } else if (level == 0) {
level = SHOW_UBITS(re, &s->gb, 8) ; LAST_SKIP_BITS(re, &s->gb, 8); level = SHOW_UBITS(re, &s->gb, 8) ; SKIP_BITS(re, &s->gb, 8);
} }
i += run; i += run;
j = scantable[i]; j = scantable[i];
@@ -184,7 +185,13 @@ static inline int mpeg1_decode_block_intra(MpegEncContext *s, int16_t *block, in
} }
block[j] = level; block[j] = level;
if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF)
break;
UPDATE_CACHE(re, &s->gb);
} }
end:
LAST_SKIP_BITS(re, &s->gb, 2);
CLOSE_READER(re, &s->gb); CLOSE_READER(re, &s->gb);
} }
s->block_last_index[n] = i; s->block_last_index[n] = i;