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

[Ryan Castellucci <ryan+lMAPSugod@cal.net>]

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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 and
> 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 don't 
want to do this in realtime. Your machine probably won't be able to handle it

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

mencoder infile.avi
# encode this file
- -vop hqdn3d,pp=fd/al
# Deinterlace and auto adjust brightness/contrast, then remove noise
# (improves visual quality, and compression rate)
- -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=900:keyint=120
# Enocde to 900 kbps MPEG-4 using libavcodec, keyframes every 120 frames
- -oac mp3lame -lameopts aq=9:cbr:br=128
# 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 
different options to libavcodec.

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

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


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