Re: [FFmpeg-devel] [PATCH] h261dec, ituh263dec: Avoid unnecessary -1 inside inner loop.
On Mon, Sep 01, 2014 at 03:01:15PM +0200, Michael Niedermayer wrote: > On Sun, Aug 31, 2014 at 08:36:01PM +0200, Reimar Döffinger wrote: > > 3646 -> 3597 decicycles in inner loop when decoding > > vsynth1-flv. > > > > Signed-off-by: Reimar Döffinger > > --- > > libavcodec/h261dec.c| 7 --- > > libavcodec/ituh263dec.c | 9 + > > 2 files changed, 9 insertions(+), 7 deletions(-) > > > LGTM > > thx Pushed. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] h261dec, ituh263dec: Avoid unnecessary -1 inside inner loop.
On Sun, Aug 31, 2014 at 08:36:01PM +0200, Reimar Döffinger wrote: > 3646 -> 3597 decicycles in inner loop when decoding > vsynth1-flv. > > Signed-off-by: Reimar Döffinger > --- > libavcodec/h261dec.c| 7 --- > libavcodec/ituh263dec.c | 9 + > 2 files changed, 9 insertions(+), 7 deletions(-) LGTM thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Old school: Use the lowest level language in which you can solve the problem conveniently. New school: Use the highest level language in which the latest supercomputer can solve the problem without the user falling asleep waiting. signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] h261dec, ituh263dec: Avoid unnecessary -1 inside inner loop.
On Sun, Aug 31, 2014 at 12:23:48PM -0700, Timothy Gu wrote: > On Aug 31, 2014 11:36 AM, "Reimar Döffinger" > wrote: > > > > 3646 -> 3597 decicycles in inner loop when decoding > > vsynth1-flv. > > Wow. Note sure what way you meant it, but unfortunately it's not much really. On the other hand it's not much or tricky code... ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH] h261dec, ituh263dec: Avoid unnecessary -1 inside inner loop.
On Aug 31, 2014 11:36 AM, "Reimar Döffinger" wrote: > > 3646 -> 3597 decicycles in inner loop when decoding > vsynth1-flv. Wow. [...] Timothy ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
[FFmpeg-devel] [PATCH] h261dec, ituh263dec: Avoid unnecessary -1 inside inner loop.
3646 -> 3597 decicycles in inner loop when decoding
vsynth1-flv.
Signed-off-by: Reimar Döffinger
---
libavcodec/h261dec.c| 7 ---
libavcodec/ituh263dec.c | 9 +
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c
index f286d23..c9470b1 100644
--- a/libavcodec/h261dec.c
+++ b/libavcodec/h261dec.c
@@ -305,6 +305,7 @@ static int h261_decode_block(H261Context *h, int16_t
*block, int n, int coded)
}
{
OPEN_READER(re, &s->gb);
+i--; // offset by -1 to allow direct indexing of scan_table
for (;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TCOEFF_VLC_BITS, 2,
0);
@@ -330,17 +331,17 @@ static int h261_decode_block(H261Context *h, int16_t
*block, int n, int coded)
SKIP_COUNTER(re, &s->gb, 1);
}
i += run;
-if (i > 64) {
+if (i >= 64) {
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n",
s->mb_x, s->mb_y);
return -1;
}
-j= scan_table[i-1];
+j= scan_table[i];
block[j] = level;
}
CLOSE_READER(re, &s->gb);
}
-s->block_last_index[n] = i - 1;
+s->block_last_index[n] = i;
return 0;
}
diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c
index 083f5ae..bea4d5a 100644
--- a/libavcodec/ituh263dec.c
+++ b/libavcodec/ituh263dec.c
@@ -481,6 +481,7 @@ static int h263_decode_block(MpegEncContext * s, int16_t *
block,
retry:
{
OPEN_READER(re, &s->gb);
+i--; // offset by -1 to allow direct indexing of scan_table
for(;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
@@ -529,9 +530,9 @@ retry:
SKIP_COUNTER(re, &s->gb, 1);
}
i += run;
-if (i > 64){
-// redo update without last flag
-i = i - run + ((run-1)&63);
+if (i >= 64){
+// redo update without last flag, revert -1 offset
+i = i - run + ((run-1)&63) + 1;
if (i < 64) {
// only last marker, no overrun
block[scan_table[i]] = level;
@@ -549,7 +550,7 @@ retry:
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n",
s->mb_x, s->mb_y, s->mb_intra);
return -1;
}
-j = scan_table[i-1];
+j = scan_table[i];
block[j] = level;
}
CLOSE_READER(re, &s->gb);
--
2.1.0
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