Mailinglist Archive: opensuse-multimedia (44 mails)

[David Haller <dnh@xxxxxxxxxxxx>]

Hello,

On Tue, 01 Mar 2011, jdd wrote:
> Le 01/03/2011 11:25, David Haller a écrit :
> > > so I wonder what are the ffmpeg option I have to use?
> > Use less compression (>= 85%) or a different image format like png or
> > gif. JPEG is especially bad at compressing text or line art images.
> > Don't know about ffmpeg. What did you use?
>
> it's video, not still (the defect is on the original, not on still shot)
>
> /usr/bin/ffmpeg  -f x11grab   -r 25  -s 800x600  -i :0.0+1116,43 \\
> -y /local/data/temp-data/114.mpg

That seems to default to quite a low bitrate, I get ~1500
kbps for those 480k Pixels. Remember: your average mpeg2 PAL-DVD
(720x576 or 415kPixels) use e.g. 6000kbps. So, go figure ;) Testing
with

    ffmpeg -f x11grab ... -b 6000k -y out.mpg

I get about 6000kbps and the video looks _quite_ good. As a good
compromise of encoding time and file size, try Divx (aka
mpeg4). Testing with

    ffmpeg -f x11grab -r 25  -s 800x600  -i :0.0+1116,43 \
        -vcodec mpeg4 -b 2000k -y out.avi

seems to work much better and uses less than 60% CPU on one core of my
3GHz Athlon II x2 250 and gives me a bitrate of about 2000k and a not
so bad image. You could also try -b 2500k, -qscale 15 (or 10) or
so. Or even try H.264, but that takes a lot more CPU to encode but
needs half the bitrate (or even less) than mpeg4 needs.

-dnh

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