[FFmpeg-user] ffv1 encode 65% of vp9 ?

[Peter B.]

Hi Sean,

This ratio also seems a bit suspicious to me...

Could you try FFV1 without 2pass?
Did you do a framemd5 comparison to check if nothing was lost during
transcoding?


Nice greetings,
Peter


On 09/05/2019 02:01, sean darcy wrote:
> I've got a bunch of old movies I'm reencoding and archiving. They're
> mpeg2 in mkv. So I ran 2 pass vp9 and ffv1 :
>
> 6432740173 Apr 30 17:46 my-movie.mkv
>  718020678 May  8 19:30 my-movie.nut
> 1119231613 May  1 00:30 my-movie-vp9.mp4
>
> I've never used ffv1 before. Is this expected ? Is it really this
> effective as a lossless encoder ?
>
> Or have I done something stupid ?
>
> sean
>
> vp9 cmd :
> #!/bin/bash
>
> Infile=my-movie
>
> Options='-r 24000/1001 -c:v libvpx-vp9 -b:v 0 -crf 29 -row-mt 1
> -threads 8 -tile-columns 6 -frame-parallel 1'
>
> ffmpeg -i "$Infile".mkv $Options -pass 1 -speed 4  \
>    -g 9999 -aq-mode 0 -an -f webm /dev/null -y
>
> ffmpeg -i "$Infile".mkv $Options -pass 2 -speed 1  \
>    -auto-alt-ref 1 -lag-in-frames 25 \
>    -g 9999 -aq-mode 0 -c:a copy "$Infile"-vp9.mp4
>
>
> ffv1 cmd:
>
> Infile="$1"
> ffmpeg -i $Infile.mkv -c:v ffv1 -level 3 -threads 8 -coder -2 -context
> 1 \
>  -pass 1 -passlogfile ffv1_passlog  \
>  -an -f nut /dev/null -y  -loglevel info
>
> ffmpeg -i $Infile.mkv -c:v ffv1 -level 3 -threads 8 -coder -2 -context
> 1 \
>   -pass 2  -passlogfile ffv1_passlog  \
>   -map 0:1 -map 0:2 -c:a copy "$Infile".nut -loglevel info
>
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