为FFMPEG添加Intel QSV支持

Fri, 14 Jan 2022 00:00:00 +0900

为FFMPEG添加Intel QSV支持

简介

使用CPU转码的速度过于慢，在使用12核心的i7-10710U CPU全力转码也只有75fps的情况下，使用自带的Mesa Intel® UHD Graphics (CML GT2)进行转码在CPU占用率只有1/3的情况下，就可以达到400+fps的转码速度，速度提升了6倍。

视频压制技术笔记

Sat, 09 Apr 2022 00:00:00 +0900

视频压制技术笔记

不同视频网站的不同标准

Youtube

Youtube

Progressive scan (no interlacing)
- Default: https://blog.p2hp.com/archives/7328
High Profile
2 consecutive B frames
- https://www.reddit.com/r/ffmpeg/comments/g708bz/show_the_consecutive_bframes_before_encoding/
- https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping
Closed GOP. GOP of half the frame rate.
- Default: https://streaminglearningcenter.com/blogs/open-and-closed-gops-all-you-need-to-know.html
CABAC
- Default: https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping
Variable bitrate. No bitrate limit required, though we offer recommended bit rates below for reference
- Default
Chroma subsampling: 4:2:0
- https://trac.ffmpeg.org/wiki/Chroma%20Subsampling

Test commands:

ffmpeg -hwaccel_output_format qsv -hwaccel qsv -i input.mp4 -c:v h264_qsv -bf 2 -b:v 6M -maxrate 24M -global_quality 25 -look_ahead 1 -pix_fmt yuv420p output.mp4
ffmpeg -i input.mp4 -c:v libx264 -bf 2 -b:v 7M -maxrate 24M -crf 30 -movflags +faststart -pix_fmt yuv420p output.mp4
# Youtube compress
ffmpeg -i input.mp4 -vf yadif,format=yuv422p -force_key_frames 'expr:gte(t,n_forced/2)' -c:v libx264 -crf ${CRF_VALUE} -maxrate 12M -bf 2 -c:a aac -ac 2 -ar 44100 -use_editlist 0 -movflags +faststart output.mp4

Bilibili

References

https://trac.ffmpeg.org/wiki/Encode/H.264

FFMPEG on 清雨影的Blog

为FFMPEG添加Intel QSV支持

为FFMPEG添加Intel QSV支持

简介

视频压制技术笔记

视频压制技术笔记

不同视频网站的不同标准

Youtube

Bilibili

References