[MPlayer-users] tv recording - newbie questions

[R C]

On Thu, 10 Mar 2005 19:16:24 +0100
Mauro Condarelli <mc5686 at mclink.it> wrote:

> 1) I would like to record audio directly from the snd-bt87x device; what 
> should I do?

See the "btaudio" kernel module.

> 2) What are the best parameters to tecord TV? keep in mind that:
>    - I do record rather noisy over-the-air analog TV.
>    - I do not care too much for "the best compression" since i do not 
> plan to store the shows, just to see    them delayed.

A matter of opinion.  If you have lots of noise, the hqdn3d filter might improve things for you.  You might want to use mpeg2 at a higher bitrate, rather than mpeg4, if space isn't too important, and you prefer to use less CPU time.

>    - I would like to record unattended and I have seen that other PVRs 
> offer "commercial removal" how does that work?

Well, really, it doesn't...  It's never been done right.

Commercial removal goes through the video, looking at all the solid-black frames, and scene-changes, and tries to decide if the section of video between black-frames is a block of commercials.  It's very often wrong, so pretty much worthless.  I find manually skiping commercials far faster and infinitely more accurate.

I'm willing to bet that you could make good commercial-delection, by setting mencoder to use infrequent keyframes, and find the commercials by identifying areas a few minutes long that have an unusually high number of keyframes.  That's a tell-tale sign.