On 13/11/2023 14:37, Evgeny Pavlov wrote:
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
v2: use timeBeginPeriod/timeEndPeriod for increasing precision of Sleep()
Signed-off-by: Evgeny Pavlov <lucenti...@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
Is it reasonable to set this global state from a library without the parent
program knowing? We'd really prefer not to affect the global state
unexpectedly.
It's also unclear to me what the effect of this tradeoff on power is, given
that the whole reason why this happens is that Windows is trying to keep the
CPU asleep for as long as possible to save power.
Thanks,
- Mark
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