2 days ago i've attempted to make a video recording from VHS player on my Pegasos. I've got horrible results...
Hardware used: Pegasos-2 G4 1 gHz; 512 MB RAM, 40 GB empty destination drive with one ext3 partition; AverTVStudio BT878-based capture card.
Here you say: "PPC is ultra-cool". You state that Pegasos Media Center is capable of recording several broadcasts and playing another stream simultaneously. Well...
The VCR is connected and Zapping is showing the picture from it. Sound is okay, via hardware throughput.
Linux distro is Debian Sarge Stable r00 (the first one). The kernel is self-compiled 2.6.11.1 (since the time i've developed some patches).
As an end result i want to get a DVD.
Okay, let's go. Here are two encoders: ffmpeg (which is directly capable of producing VOBs for DVD) and mencoder. Both claim to work with v4l as input.
ffmpeg simply refuses to work with the v4l device. May be the problem is that it expects v1 API while my kernel has v2?
okay, mencoder is the only one left. I supply no extra agruments since i don't understand them. I simply specify a v4l2 composite input, libavcodec as encoder, audio codec is default (later i've learned that it was a bad choice, i need ac3, but i guess changing this would have a very little influence). The actual problem appeared to be video encoding.
First i've tried mpeg2video codec (this is what is needed for the DVD). I've got a horrible quality (just lots of squares instead of shapes) and tons of video/audio frameskips after ~2 min of recording. This result was inacceptable and i've interrupted it.
The next try was divx encoder (just as an experiment). The same crappy result!
Third attempt was made with raw video recording (in fact i've lend this 40 GB drive at this point, my working drive has ~2 gb free). Well, i thought, i can encode later without any speed limits, i'll just record first. Raw video capturing went well (no quality loss as expected :D ), but this time audio was corrupter horribly. It was all mixed up with loud clicks (i guess these clicks were caused by sampling interruption while saving next data portion to the HDD). This was inacceptable too.
Next day someone on IRC adviced me to use mjpeg compressor. Well, the result i've got is the closest to what i wanted. The recording went okay (90 mins), but near the end video frameskips appeared again. There were also audio frameskips, but not many. I've watched the fragment with mplayer, the result is nearly acceptable. Audio clicks are still heard however there are not a lot of them.
The conclusion i made: my system's computing power does not allow realtime video capture in general. But you state that Media Center works, and it performs much more work in the realtime. The question to constructors: how is it made? May be i do something totally wrong?
My exact mencoder command line is:
--- cut ---
mencoder tv:// -tv driver=v4l2:input=1 -ovc lavc -oac lavc -lavcopts vcodec=<codec>
--- cut ---
BTW, is there any way to view the video while capturing it? Currently i can orient only using sound which i hear via hw throughput while capturing.

It is! It has two TV tuner inputs; and an MPEG decoder and MPEG encoder on the card for each.

http://www.hauppauge.com/pages/products ... 00mce.html

I can't answer your question (seems very complicated set of issues) but the solution on the media center is that the MPEG2 throughput is all offloaded. The G4 can play back everything else just fine, but pulling from the TV card, encoding two channels, possibly decoding another, is too much even for a great deal of PCs out there.

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Matt Sealey

So the verdict is - "your card is crap"? :roll:

Pretty much :)

We know the Hauppauge cards and the IVTV drivers work okay (at least, there were some new patches for the latest kernel etc. recently so they work AGAIN :)

The quality is excellent; and the output MPEG2 files can be directly muxed into VOB files.

I'm not too sure the BT878 is such a great chip; I have always had problems with it and it's derivatives. The video quality is pretty passable but there are always audio clicks (I used to have an old WinTV card and used VirtualDub to capture on my Pentium 4 2.4GHz). It is simply way too heavy on the CPU and PCI bus to take the BT878 output *AND* create a VOB file on the fly.

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Matt Sealey

Hi!
Neko, as you haven't been very interested in the ppc-patches when i told you about them, i didn't tell you this later:
they do work, in fact, but they can lockup the bootprocess!!!
(randomly?). So everybody wanting to try them,
do it carefully ;)
cheers
frostwork

I will ask Pieter how he managed to get it to work.

The solution may be to use an older kernel and driver version for now.

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Matt Sealey

I'm sure it isn't a big problem to get rid of this hang,
I simply didn't have the time to take a closer look at this
as massive improvements in emedia & cdga2 need my attention!
But it makes sense in any case to warn interested people before they run in trouble...

> The solution may be to use an older kernel and driver version for now.

I don't agree with you! PPC has to be at latest state wherever possible to make clear that x86 is in no aspect superior to
POWER!

friendly,
frostwork

By crashing a lot?

Be serious..

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Matt Sealey

It doesn't help much to sit on acient drivers & kernels.
Trying to get rid of problems with uptodate software is in any case better than waiting till its done!

One way to achieve it is to provide elegant PPC related patches upstream. A few times they might break it, but after a while they will develop in a way, that you don't have to fix their software each time a new version comes out. That will save you also a lot of work, what you can spend elsewhere.
This is how it worked in a university environment, I hope that the 'real world' is not much different :-)

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CzP
http://czanik.blogs.balabit.com/

Yes this also works in the real world!
I often contact developers directly w/o mailinglists to
fix ppc-incompatibilities...

Well, can anyone advice me some "anti-clicker" program to process audio track and remove those annoying clicks?

Worked for me: Audacity ( http://audacity.sourceforge.net/ ). Background noise was completely gone, and also most of the clicks, when I tried to clean up some old recordings. When I was done, a few weeks later it appeared on CD :-)

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CzP
http://czanik.blogs.balabit.com/