[FFmpeg-user] libvpx usage

Liam Condron-Farnos 23liam at googlemail.com
Thu Jan 24 00:26:39 CET 2013

>ffmpeg -i '/Volumes/dune/buildserver/autotest/parts/ffmpeg/demo.mp4' -y
-vb >'448k' -ab '96k' -bt '64k' -maxrate
>'544k' -ar '44100' -ac '2' -r '25' -vf
>'scale=480:266,setdar=16:9,pad=480:270:0:2:000000' -async '1' -acodec
>'libvorbis' -vcodec 'libvpx' -threads '4'

Thank you for your reply. This method targets a video bit rate (448kb/s),
whereas I want to target a quality level.

As a workaround, I can use this bit rate-targeting method, but it requires
me to either look at the resolution & frame rate of each input or knock
together a bash script to do that for me - which I can certainly *do*, but
it would be more convenient to be able to use the `-crf` option, as I can
for libx264.

On 6 January 2013 00:45, Reindl Harald <h.reindl at thelounge.net> wrote:

> Am 06.01.2013 00:30, schrieb Liam Condron-Farnos:
> > I've been struggling with this on and off for a few days now: what is the
> > correct way to encode VP8 video? My reading of ffmpeg -h encoder=libvpx
> > would lead me to think that
> >
> >     ffmpeg -i input.mp4 -c:a libvorbis -q:a 5 -q:v libvpx -crf 1
> output.webm
> >
> > should give me a working, ridiculously-high-quality video. However, it
> just
> > spits up errors:
> this is the logged command of my ffmpeg-autotest and i can see
> no difference compared to x264 in size or quality, the -vf param
> is automatically calculated from the input by my php-library
> ffmpeg -i '/Volumes/dune/buildserver/autotest/parts/ffmpeg/demo.mp4' -y
> -vb '448k' -ab '96k' -bt '64k' -maxrate
> '544k' -ar '44100' -ac '2' -r '25' -vf
> 'scale=480:266,setdar=16:9,pad=480:270:0:2:000000' -async '1' -acodec
> 'libvorbis' -vcodec 'libvpx' -threads '4'
> '/Volumes/dune/buildserver/autotest/parts/ffmpeg/targets/test_2p.webm'
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