So my question is, does libvmaf implementation do any kind of detection of audio in the distorted asset before computing a perceptual video quality score.
On Mon, 9 May 2022 at 13:37, Kamaldeep Tumkur <kamaldeep.tum...@gmail.com> wrote: > @Clayton, thanks for your response. > > It turned out that the external encoder was adding an audio track to the > encode. This was throwing the libvmaf scores off. On removing the audio > track and checking the encode, the score jumped from 25 to 77.64. > > Now there is basis to compare the ffmpeg and the external encode. > > Regards > Kamaldeep > > > > On Sun, 8 May 2022 at 15:37, Kamaldeep Tumkur <kamaldeep.tum...@gmail.com> > wrote: > >> Hello, >> >> I'm new to the computation of VMAF scores using libvmaf in ffmpeg. While >> trying out generating scores through libvmaf, I have an issue that I cannot >> seem to find an explanation for. >> >> I encoded the 'crowd_run' HQ MP4 with two different encoders. The >> resulting files were compared with the same source (original). >> >> VMAF score of ffmpeg encoded clip: >> >> [libvmaf @ 0x7fc5d8f2cb00] VMAF score: 90.644028 >> >> >> Command used: >> >> ffmpeg -i crowd_run_1080p50.mp4 -c:v libx264 -g 100 -keyint_min 100 >> -sc_threshold 0 -b:v 12000k -maxrate 15000k -bufsize 15000k -c:a copy -f >> mpegts pass2.ts >> >> >> VMAF score for externally encoded clip: >> >> [libvmaf @ 0x7fc53d729500] VMAF score: 25.168431 >> >> >> >> I just don't know how to explain this disparity in generated scores when >> framerates and resolution of the source were retained. The second clip >> doesn't seem to show such a degradation expected through the score. >> Attaching both the encoded clips here for analysis. >> >> >> Could anyone point me to why the external encoder generates an output >> with low VMAF score. Anything in the frame structure? >> >> >> ffmpeg encode: >> >> >> https://drive.google.com/file/d/15-9YyNhYWJoTMxdmESkc7b0mPKKUMqG7/view?usp=sharing >> >> >> external encode: >> >> >> https://drive.google.com/file/d/1Mt2jP51KZ4vTG7SYPnJkCG1uMWqOadid/view?usp=sharing >> >> >> >> Thank you. >> > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".