[FFmpeg-devel] [RFC PATCH] ffmpeg_videotoolbox: skip memory copy if hwaccel_output_format match

[Steven Liu]

> 2021年4月27日 下午1:09，Zhao Zhili <quinkblack at foxmail.com> 写道：
> 
> From: zhilizhao <zhilizhao at tencent.com>
> 
> Simple test results:
> 
> Command:
> ./ffmpeg -y -hwaccel videotoolbox -hwaccel_output_format videotoolbox_vld \
>  -i test.mp4 -an -c:v h264_videotoolbox -benchmark out.mp4
> 
> Before:
> frame= 1221 fps= 66 q=-0.0 Lsize=    3144kB time=00:00:20.33 bitrate=1266.6kbits/s dup=4 drop=0 speed= 1.1x
> bench: utime=2.714s stime=1.218s rtime=18.574s
> 
> After:
> frame= 1221 fps=137 q=-0.0 Lsize=    3144kB time=00:00:20.33 bitrate=1266.4kbits/s dup=4 drop=0 speed=2.28x
> bench: utime=1.450s stime=1.440s rtime=8.924s
> 
> It has limited usecase since there is no video filter support, so
> a log message is added to notify the user.
> ---
> It has a good performance with limited usecases like transcoding without
> autoscale/autorotate, and I don't know if it break some special usecase,
> since the RFC.
> 
> fftools/ffmpeg_videotoolbox.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
> 
> diff --git a/fftools/ffmpeg_videotoolbox.c b/fftools/ffmpeg_videotoolbox.c
> index a6b78d0f7d..4ba8618539 100644
> --- a/fftools/ffmpeg_videotoolbox.c
> +++ b/fftools/ffmpeg_videotoolbox.c
> @@ -29,6 +29,7 @@
> 
> typedef struct VTContext {
>     AVFrame *tmp_frame;
> +    int log_once;
> } VTContext;
> 
> char *videotoolbox_pixfmt;
> @@ -44,6 +45,13 @@ static int videotoolbox_retrieve_data(AVCodecContext *s, AVFrame *frame)
>     int linesize[4] = { 0 };
>     int planes, ret, i;
> 
> +    if (frame->format == ist->hwaccel_output_format) {
> +        av_log_once(s, AV_LOG_INFO, AV_LOG_TRACE, &vt->log_once,
> +            "There is no video filter for videotoolbox pix_fmt now, remove the "
> +            "-hwaccel_output_format option if video filter doesn't work\n");
> +        return 0;
> +    }
> +
>     av_frame_unref(vt->tmp_frame);
> 
>     switch (pixel_format) {
> -- 
> 2.31.1
> 
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> 

lgtm & test ok

Thanks

Steven Liu