[FFmpeg-user] ffmpeg qsv performance well below expected

[Xu, Guangxin]

Hi Dan, 
Thanks for report this. 
Could you file an issue at http://trac.ffmpeg.org/query?status=new&status=open&status=reopened&col=id&col=summary&col=status&col=type&col=component&col=version&col=time&col=changetime&order=priority&report=1.

So we can tracking it?

thanks

> -----Original Message-----
> From: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> On Behalf Of dan
> Sent: Saturday, January 2, 2021 8:12 AM
> To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
> Subject: [FFmpeg-user] ffmpeg qsv performance well below expected
> 
> In running ubuntu with an i3-10100
> 
> I'm able to transcode 2 MPEG2 to h.265 using the following command ffmpeg -
> hwaccel qsv -i http://hdhomerun:5004/auto/v2.2.ts -c:v hevc_qsv -c:a copy -
> profile:v main -global_quality 30 -g 48 -keyint_min 48 -sc_threshold 0 -hls_time
> 2 -hls_list_size 10 -hls_segment_type mpegts -hls_flags delete_segments -
> hls_segment_filename video_%03d.ts video.m3u8
> 
> but, the third video causes all 3 to start to throw errors in encoding.  CPU usage
> on this quad core CPU is about 35% on 3 different cores, seems there's no issue
> with CPU (general purpose) performance.
> Am I hitting a wall on hevc_qsv here?
> 
> I've switched -hwaccel to vaapi which works but performance is a bit worse.
> I've removed this to push the MPEG2 decode to software, no real effect.
> 
> I've tried to start the 3rd encode with libx265 but that crushes the CPU.
> 
> h264_qsv is able to handle this.
> 
> It appears, at least on the surface, that this CPU w/ 28 video cores can only
> handle 2 h.265 encodes in quicksync but the specs seem to suggest it should do
> more.
> 
> Am I missing something obvious?
> 
> note, the first 2 streams are 1080i MPEG2 from an HDHomeRun.  The third
> stream I selected a 720p MPEG2 stream and even that doesn't work well.  Also, I
> am not using any deinterlacer, I removed them to try to get the third stream
> running.
> 
> Thanks for any feedback.
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