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Encoding in multi pass with forced keyframes

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Encoding in multi pass with forced keyframes

Postby Nico » Tue Aug 06, 2013 8:13 am

Hello,

My problem is when I encode a WEBM in multi pass, I don't have any key frames.
I don't read any warning about the use of these two options, in the documentation.
Does anyone have an idea ?

Pass1 command line is
Code: Select all
ffmpeg -i "C:\MyPNGSequence\Toto_%5d.png" -r 25 -filter_complex "[0:0]format=rgba, scale=w=640:h=384:flags=bicubic+accurate_rnd+full_chroma_int+full_chroma_inp, pad=640:576:0:0, setsar=1:1[color] ; [0:0]format=rgba, lutrgb=r=255:g=255:b=255, scale=w=640:h=192:flags=bicubic+accurate_rnd+full_chroma_int+full_chroma_inp, pad=640:576:0:384:0x00000000, setsar=1:1[alpha] ; [color][alpha]overlay=format=rgb" -g 25 -c:v libvpx -force_key_frames 00:00:01.12,00:00:11.88,00:00:20.92,00:00:30.00,00:00:39.04,00:00:48.08,00:00:57.16,00:01:06.20 -profile:v 3 -f webm -quality good -lag-in-frames 16 -an -metadata title="Toto meta data" -qmax 51 -qmin 11 -pass 1 -auto-alt-ref 1 -b:v 1400k -minrate 500k -maxrate 2M -passlogfile "C:\Toto" -threads 6 -cpu-used 0 -y "NUL"


Pass2 command line is:
Code: Select all
ffmpeg -i "C:\MyPNGSequence\Toto_%5d.png" -r 25 -filter_complex "[0:0]format=rgba, scale=w=640:h=384:flags=bicubic+accurate_rnd+full_chroma_int+full_chroma_inp, pad=640:576:0:0, setsar=1:1[color] ; [0:0]format=rgba, lutrgb=r=255:g=255:b=255, scale=w=640:h=192:flags=bicubic+accurate_rnd+full_chroma_int+full_chroma_inp, pad=640:576:0:384:0x00000000, setsar=1:1[alpha] ; [color][alpha]overlay=format=rgb" -g 25 -c:v libvpx -force_key_frames 00:00:01.12,00:00:11.88,00:00:20.92,00:00:30.00,00:00:39.04,00:00:48.08,00:00:57.16,00:01:06.20 -profile:v 3 -f webm -quality good -lag-in-frames 16 -an -metadata title="Toto meta data" -qmax 51 -qmin 11 -pass 2 -auto-alt-ref 1 -b:v 1400k -minrate 500k -maxrate 2M -passlogfile "C:\Toto" -threads 6 -cpu-used 0 -y "C:\Toto.webm"


Thanks
Nico
 
Posts: 4
Joined: Tue Aug 06, 2013 8:01 am

Re: Encoding in multi pass with forced keyframes

Postby Nico » Tue Aug 06, 2013 3:28 pm

I have investigated, on my issue.
Maybe it does not come from FFMpeg, but MkClean.

I have omitted to precise that, I clean produced WEBM with MkClean.
FFMpeg simple pass produces a WEBM where keyframe information is stored in a SimpleBlock chunk.
FFMpeg double pass produces a WEBM where keyframe information is stored in a BlockGroup chunk.

MkClean only keeps keyframe information inside SimpleBlock.

Thanks
Nico
 
Posts: 4
Joined: Tue Aug 06, 2013 8:01 am

Re: Encoding in multi pass with forced keyframes

Postby Nico » Wed Aug 07, 2013 2:46 pm

Finally the latest FFMpeg for windows available in (Zeranoe web site) does not work :(
If used with command lines described in my previous post, I have strange artifacts inside the video.

If anyone has an idea.
Thanks
Nico
 
Posts: 4
Joined: Tue Aug 06, 2013 8:01 am


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