#7797: AVC->MPEG-2 transcoding with VA-API 2-3x slower than with QSV -------------------------------------+------------------------------------- Reporter: eero-t | Owner: Type: defect | Status: new Priority: normal | Component: | undetermined Version: git-master | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+-------------------------------------
Comment (by eero-t): Replying to [comment:2 eero-t]: > There's been a clear improvement to AVC -> MPEG2 performance this last week, between... [...] > Especially in multi-process VA-API encoding, where it's now about same perf as MSDK and FFmpeg QSV. In multi-process case, VA-API is now slightly faster than QSV on SKL GT2 & KBL GT3e, on SKL GT4e, it's still slight slower. I.e. that was 2x perf perf improvement to earlier. > (Single process encoding is still behind a bit, I guess that's mostly due threading differences between QSV & VA-API backends and resulting kernel power management handling.) Single process AVC->MPEG2 VA-API encode+downscale performance improved from <1/2 to 2/3 of the QSV perf. (Gap is now close to the gap with same conversion where output is AVC, VA- API perf there is 3/4 of QSV perf.) --- Replying to [comment:3 fulinjie]: > Would you please help to verify whether this issue is also benefited from the patch mentioned in #7706: > https://patchwork.ffmpeg.org/patch/16156/ Your patch increased single process performance by 5-10%, from slightly over 2/3rd to almost 3/4th of the QSV perf. (For the same conversion with AVC output, your patch improvement is 10-15%, from 3/4th to 7/8th of QSV performance.) --- In FullHD MPEG2 -> AVC bitrate conversion with VA-API: {{{ffmpeg -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -hwaccel_output_format vaapi -i 1920x1080i_29.97_20mb_mpeg2_high.mpv -c:v h264_vaapi -b:v 6000K -compression_level 7 output.h264}}} vs. QSV: {{{ffmpeg -hwaccel qsv -qsv_device /dev/dri/renderD128 -c:v mpeg2_qsv -i 1920x1080i_29.97_20mb_mpeg2_high.mpv -c:v h264_qsv -b:v 6000K -compression_level 7 output.h264}}} VA-API is also slower, 2/3rd of QSV performance in single process transcode. Most of that gap is naturally due to #7706 regression, but it was (1/8th, 10-15%) slower than QSV also earlier. Your patch improves it to 3/4th of QSV performance. In my other test-cases, VA-API is close to QSV speed (or better). -- Ticket URL: <https://trac.ffmpeg.org/ticket/7797#comment:4> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker _______________________________________________ FFmpeg-trac mailing list FFmpeg-trac@avcodec.org https://ffmpeg.org/mailman/listinfo/ffmpeg-trac To unsubscribe, visit link above, or email ffmpeg-trac-requ...@ffmpeg.org with subject "unsubscribe".