On 5/6/2023 9:13 AM, Devin Heitmueller wrote:
I added some instrumentation via the attached patch. You can see the
benefits here:
Before=1683378057.243350 After 1683378057.264239
Before=1683378083.335424 After 1683378083.356440
Before=1683378089.675400 After 1683378089.696512
Before=1683378151.792324 After 1683378151.813579
21 ms per run
After patch:
Before=1683378222.167796 After 1683378222.175760
Before=1683378233.131416 After 1683378233.139326
Before=1683378243.591895 After 1683378243.599840
8 ms per run
Note: this is a different platform than I did the original development
on, and apparently the improvement on this particular box is only 2.5x
rather than 4x.
Devin
Can you bench with the START_TIMER and STOP_TIMER macros in timer.h?
Also, define CACHED_BITSTREAM_READER in bitpacked_dec.c before including
git_bits.h and test the actual implementation again, to see if it makes
any difference.
On Sat, May 6, 2023 at 7:53 AM Paul B Mahol <one...@gmail.com> wrote:
On Sat, May 6, 2023 at 1:32 PM Lance Wang <lance.lmw...@gmail.com> wrote:
On Sat, May 6, 2023 at 4:58 AM Devin Heitmueller <
devin.heitmuel...@ltnglobal.com> wrote:
Rework the code a bit to speed up the 10-bit bitpacked decoding
routine. This is probably about as fast as I can get it without
switching to assembly language.
Demonstratable with:
./ffmpeg -f lavfi -i "smptehdbars=size=3840x2160" -c bitpacked -f image2
-frames:v 1 source.yuv
./ffmpeg -f bitpacked -pix_fmt yuv422p10le -s 3840x2160 -c:v bitpacked -i
source.yuv -pix_fmt yuv422p10le out.yuv
On my development system, it went from 80ms for a 2160p frame
down to 20ms (i.e. a 4X speedup). Good enough for now, I hope...
FYI, on my development system, I run two time for the original and modified
version and no obvious difference:
./ffmpeg -f lavfi -i "smptehdbars=size=3840x2160" -c bitpacked -frames:v 25
source.yuv
time ./ffmpeg -f bitpacked -pix_fmt yuv422p10le -s 3840x2160 -c:v bitpacked
-i source.yuv -pix_fmt yuv422p10le out.yuv
frame= 25 fps=0.0 q=-0.0 Lsize= 810000kB time=00:00:00.96
bitrate=6912000.0kbits/s speed=1.13x
real 0m0.961s
user 0m1.086s
sys 0m1.360s
frame= 25 fps=0.0 q=-0.0 Lsize= 810000kB time=00:00:00.96
bitrate=6912000.0kbits/s speed=1.16x
real 0m0.936s
user 0m1.358s
sys 0m1.350s
after apply the patch:
frame= 25 fps=0.0 q=-0.0 Lsize= 810000kB time=00:00:00.96
bitrate=6912000.0kbits/s speed=1.14x
real 0m0.953s
user 0m0.906s
sys 0m1.438s
frame= 25 fps=0.0 q=-0.0 Lsize= 810000kB time=00:00:00.96
bitrate=6912000.0kbits/s speed=1.17x
real 0m0.922s
user 0m0.926s
sys 0m1.066s
Only 25 frames?
This is flawed.
Signed-off-by: Devin Heitmueller <dheitmuel...@ltnglobal.com>
---
libavcodec/bitpacked_dec.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/libavcodec/bitpacked_dec.c b/libavcodec/bitpacked_dec.c
index a1ffef1..96aba27 100644
--- a/libavcodec/bitpacked_dec.c
+++ b/libavcodec/bitpacked_dec.c
@@ -28,7 +28,6 @@
#include "avcodec.h"
#include "codec_internal.h"
-#include "get_bits.h"
#include "libavutil/imgutils.h"
#include "thread.h"
@@ -65,7 +64,7 @@ static int bitpacked_decode_yuv422p10(AVCodecContext
*avctx, AVFrame *frame,
{
uint64_t frame_size = (uint64_t)avctx->width *
(uint64_t)avctx->height * 20;
uint64_t packet_size = (uint64_t)avpkt->size * 8;
- GetBitContext bc;
+ uint8_t *src;
uint16_t *y, *u, *v;
int ret, i, j;
@@ -79,20 +78,18 @@ static int bitpacked_decode_yuv422p10(AVCodecContext
*avctx, AVFrame *frame,
if (avctx->width % 2)
return AVERROR_PATCHWELCOME;
- ret = init_get_bits(&bc, avpkt->data, avctx->width * avctx->height *
20);
- if (ret)
- return ret;
-
+ src = avpkt->data;
for (i = 0; i < avctx->height; i++) {
y = (uint16_t*)(frame->data[0] + i * frame->linesize[0]);
u = (uint16_t*)(frame->data[1] + i * frame->linesize[1]);
v = (uint16_t*)(frame->data[2] + i * frame->linesize[2]);
for (j = 0; j < avctx->width; j += 2) {
- *u++ = get_bits(&bc, 10);
- *y++ = get_bits(&bc, 10);
- *v++ = get_bits(&bc, 10);
- *y++ = get_bits(&bc, 10);
+ *u++ = (src[0] << 2) | (src[1] >> 6);
+ *y++ = ((src[1] << 4) | (src[2] >> 4)) & 0x3ff;
+ *v++ = ((src[2] << 6) | (src[3] >> 2)) & 0x3ff;
+ *y++ = ((src[3] << 8) | (src[4])) & 0x3ff;
+ src += 5;
}
}
--
1.8.3.1
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