[vox-tech] wincast tv: video4linux and copying movies

[Ryan Castellucci]

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On Monday 13 October 2003 11:19 pm, p@dirac.org wrote:
> ok, i've been playing around with this for awhile, and the results are
> not great.  i recorded the opening theme of southpark under different
> settings.  the default settings of:
>
>    samplerate: 44100
>    frames: 12 fps
>
> produce a file of 72MB for about 26s of video.  the video is bad,
> but watchable if i'm jonesing for southpark.  if it weren't a cartoon,
> it would truly be unwatchable.
>
> i bumped the sample rate up to 48000, however both the video quality an=
d
> filesize don't change.  what exactly is the difference between
> samplerate and fps anyhow?  so then i bumped it up:

Sample rate is audio...

> i'm exhausted and about to call it a night.  does anybody have
> suggestions on how to get good quality video at reasonable filesize?
>
> should i be working in a format other than AVI?

Try recording with nupplevideo. It uses very little CPU power.

You should then recompress it into something like MPEG-4. You probably do=
n't=20
want to do this in realtime. Your machine probably won't be able to handl=
e it

Here are some options to try with mplayer, along with explination

mencoder infile.avi
# encode this file
- -vop hqdn3d,pp=3Dfd/al
# Deinterlace and auto adjust brightness/contrast, then remove noise
# (improves visual quality, and compression rate)
- -ovc lavc -lavcopts vcodec=3Dmpeg4:vbitrate=3D900:keyint=3D120
# Enocde to 900 kbps MPEG-4 using libavcodec, keyframes every 120 frames
- -oac mp3lame -lameopts aq=3D9:cbr:br=3D128
# Good quality MP3 audio track
- -o outfile.avi
# The encoded video

This is a basic set of options, you can get better quality with some=20
different options to libavcodec.

The above mplayer options will compress one hour of video to less then=20
500MB

There's a program called avidemux which is good for editing out comercial=
s,=20
and it has a nifty feature where it does not reencode the video, just the=
=20
frames between the cut and the nearest keyframe.


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