[FFmpeg-devel] [PATCH, v2] avcodec/amfenc: increase precision of Sleep() on Windows
Araz Iusubov
primeadvice at gmail.com
Mon Aug 19 17:23:55 EEST 2024
From: Evgeny Pavlov <lucenticus at gmail.com>
This commit increase precision of Sleep() function on Windows.
This fix reduces the sleep time on Windows to improve AMF encoding
performance on low resolution input videos.
Fix for issue #10622
We evaluated CreateWaitableTimerExW with
CREATE_WAITABLE_TIMER_HIGH_RESOLUTION flag. In fact, this function has
the same precision level as the Sleep() function.
Usually changing the time resolution will only affect the current
process and will not impact other processes, thus it will not cause a
global effect on the current system. Here is an info from
documentation on timeBeginPeriod
https://learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod
"Prior to Windows 10, version 2004, this function affects a global
Windows setting. For all processes Windows uses the lowest value (that
is, highest resolution) requested by any process. Starting with
Windows 10, version 2004, this function no longer affects global timer
resolution. For processes which call this function, Windows uses the
lowest value (that is, highest resolution) requested by any process.
For processes which have not called this function, Windows does not
guarantee a higher resolution than the default system resolution."
We provide the following measurement to show performance improvements
with this patch.
1. Performance tests show that this high precision sleep will improve
performance, especially for low resolution sequences, it can get about
20% improvement.
Frames Per Second (FPS) being encoded by the hardware encoder (Navi 31
RX7900XT ):
Source Type: H.264 , Output Type: H.264
(Sorry for bad formatting)
No. | Sequence Resolution | No. of Frames| FPS Before patch |
FPS after patch | Difference | Improvement %
----|-----------------------|--------------|------------------------|-------------------|---------------|----------
1 | 480x360 | 8290 | 2030 |
2365 | 335 | 16.5%
2 | 720x576 | 8290 | 1440 |
1790 | 350 | 24.3%
3 | 1280x720 | 8290 | 1120 |
1190 | 70 | 6.3%
4 | 1920x1080 | 8290 | 692 |
714 | 22 | 3.2%
5 | 3840x2160 | 8290 | 200 |
200 | 0 | 0.0%
The sample ffmpeg command line:
$ ffmpeg.exe -y -hwaccel d3d11va -hwaccel_output_format d3d11 -i
input.mp4 -c:v h264_amf out.mp4
where input.mp4 should be changed to corresponding resolution input
H.264 format bitstream.
2. The power tests show an increase in power is within limit scope.
The purpose of the power test is to examine the increase in CPU power
consumption due to the improvement in CPU time resolution after using
this patch. We were testing a product from AMD called Phoenix, which
we refer to as an APU. It combines a general-purpose AMD CPU and a 3D
integrated graphics processing unit (IGPU) on a single die. Only the
APU has a DAP connector to the board's power rails.
We got the power test data shown below:
| | 480x360 | 720x576 | 1280x720 |
1920x1080 | 3840x2160 | average
|------------------------|-----------|------------|----------|-----------|-----------|--------
|CPU power change | 1.93% | 2.43% | -1.69% | 3.49%
| 2.92% | 1.82%
|APU power total change | 0.86% | 1.34% | -0.62% | 1.54%
| -0.58% | 0.51
When using a high precision clock by applying the patch, the average
power consumption for CPU increases 1.82%, and the APU total increases
0.51%. We can see the power increase in power not very significant.
Signed-off-by: Evgeny Pavlov <lucenticus at gmail.com>
---
libavcodec/amfenc.c | 31 +++++++++++++++++++++++++++++++
libavcodec/amfenc.h | 3 +++
2 files changed, 34 insertions(+)
diff --git a/libavcodec/amfenc.c b/libavcodec/amfenc.c
index 061859f85c..55e24856e8 100644
--- a/libavcodec/amfenc.c
+++ b/libavcodec/amfenc.c
@@ -42,7 +42,12 @@
#endif
#ifdef _WIN32
+#include <timeapi.h>
#include "compat/w32dlfcn.h"
+
+typedef MMRESULT (*timeapi_fun)(UINT uPeriod);
+#define WINMM_DLL "winmm.dll"
+
#else
#include <dlfcn.h>
#endif
@@ -113,6 +118,9 @@ static int amf_load_library(AVCodecContext *avctx)
AMFInit_Fn init_fun;
AMFQueryVersion_Fn version_fun;
AMF_RESULT res;
+#ifdef _WIN32
+ timeapi_fun time_begin_fun;
+#endif
ctx->delayed_frame = av_frame_alloc();
if (!ctx->delayed_frame) {
@@ -145,6 +153,16 @@ static int amf_load_library(AVCodecContext *avctx)
AMF_RETURN_IF_FALSE(ctx, res == AMF_OK, AVERROR_UNKNOWN, "GetTrace() failed with error %d\n", res);
res = ctx->factory->pVtbl->GetDebug(ctx->factory, &ctx->debug);
AMF_RETURN_IF_FALSE(ctx, res == AMF_OK, AVERROR_UNKNOWN, "GetDebug() failed with error %d\n", res);
+
+#ifdef _WIN32
+ // Increase precision of Sleep() function on Windows platform
+ ctx->winmm_lib = dlopen(WINMM_DLL, RTLD_NOW | RTLD_LOCAL);
+ AMF_RETURN_IF_FALSE(ctx, ctx->winmm_lib != NULL, 0, "DLL %s failed to open\n", WINMM_DLL);
+ time_begin_fun = (timeapi_fun)dlsym(ctx->winmm_lib, "timeBeginPeriod");
+ AMF_RETURN_IF_FALSE(ctx, time_begin_fun != NULL, 0, "DLL %s failed to find function %s\n", WINMM_DLL, "timeBeginPeriod");
+ time_begin_fun(1);
+#endif //_WIN32
+
return 0;
}
@@ -375,6 +393,9 @@ static int amf_init_encoder(AVCodecContext *avctx)
int av_cold ff_amf_encode_close(AVCodecContext *avctx)
{
AmfContext *ctx = avctx->priv_data;
+#ifdef _WIN32
+ timeapi_fun time_end_fun;
+#endif //_WIN32
if (ctx->delayed_surface) {
ctx->delayed_surface->pVtbl->Release(ctx->delayed_surface);
@@ -410,6 +431,16 @@ int av_cold ff_amf_encode_close(AVCodecContext *avctx)
av_frame_free(&ctx->delayed_frame);
av_fifo_freep2(&ctx->timestamp_list);
+#ifdef _WIN32
+ if (ctx->winmm_lib) {
+ time_end_fun = (timeapi_fun)dlsym(ctx->winmm_lib, "timeEndPeriod");
+ AMF_RETURN_IF_FALSE(ctx, time_end_fun != NULL, 0, "DLL %s failed to find function %s\n", WINMM_DLL, "timeEndPeriod");
+ time_end_fun(1);
+ dlclose(ctx->winmm_lib);
+ ctx->winmm_lib = NULL;
+ }
+#endif //_WIN32
+
return 0;
}
diff --git a/libavcodec/amfenc.h b/libavcodec/amfenc.h
index 2dbd378ef8..35bcf1dfe3 100644
--- a/libavcodec/amfenc.h
+++ b/libavcodec/amfenc.h
@@ -50,6 +50,9 @@ typedef struct AmfContext {
AVClass *avclass;
// access to AMF runtime
amf_handle library; ///< handle to DLL library
+#ifdef _WIN32
+ amf_handle winmm_lib; ///< handle to winmm DLL library
+#endif //_WIN32
AMFFactory *factory; ///< pointer to AMF factory
AMFDebug *debug; ///< pointer to AMF debug interface
AMFTrace *trace; ///< pointer to AMF trace interface
--
2.45.2.windows.1
More information about the ffmpeg-devel
mailing list