[FFmpeg-devel] [PATCH] avcodec/amfenc: Fix for windows imprecise sleep
Mark Thompson
sw at jkqxz.net
Tue Oct 17 00:24:03 EEST 2023
On 16/10/2023 10:13, Evgeny Pavlov wrote:
> This commit reduces the sleep time on Windows to improve AMF encoding
> performance on low resolution input videos.
> This fix is for Windows only, because sleep() function isn't
> very accurate on Windows OS.
>
> Fix for issue #10622
>
> Signed-off-by: Evgeny Pavlov <lucenticus at gmail.com>
> ---
> libavcodec/amfenc.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/libavcodec/amfenc.c b/libavcodec/amfenc.c
> index 061859f85c..0c95465d6e 100644
> --- a/libavcodec/amfenc.c
> +++ b/libavcodec/amfenc.c
> @@ -770,7 +770,11 @@ int ff_amf_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
> if (query_output_data_flag == 0) {
> if (res_resubmit == AMF_INPUT_FULL || ctx->delayed_drain || (ctx->eof && res_query != AMF_EOF) || (ctx->hwsurfaces_in_queue >= ctx->hwsurfaces_in_queue_max)) {
> block_and_wait = 1;
> +#ifdef _WIN32
> + av_usleep(0); //Sleep() is not precise on Windows OS.
> +#else
> av_usleep(1000);
> +#endif
> }
> }
> } while (block_and_wait);
Wasting lots of power by spinning on a CPU core does not seem like a good answer to this problem. (I mean, presumably that is why Windows isn't honouring your request for a short sleep, because it wants timers to have larger gaps to avoid wasting power.)
Why is there a sleep here at all, anyway? An API for hardware encoding should be providing a way for the caller to wait for an outstanding operation to complete.
Thanks,
- Mark
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