[MPlayer-dev-eng] Re: MPlayer-dev-eng digest, Vol 1 #1573 - 18 msgs

[David Toso]

Hi Rich,

D Richard Felker III <dalias at aerifal.cx> wrote:
> > Actually, they are avi files with MPEG1 codec. I mention it just in case that makes a difference
> > to what would have to be hacked in the demuxer (probably not).
>
> It'll definitely make things trickier. With plain mpeg files you could
> probably just pipe the data to mplayer through a fifo and have a
> program switch which stream is getting sent into the fifo.

Hmmm, I like this fifo idea... (better than stupid symlink switching :-).

> > Here is the (snipped) output of 'mplayer -identify':
> > 
> >     Detected AVI file format!
> >     VIDEO:  [mpg1]  352x240  24bpp  25.00 fps  856.0 kbps (104.5 kbyte/s)
> >     VIDEO:  MPEG1  352x240  (aspect 1)  25.00 fps  1000.0 kbps (125.0 kbyte/s)
> >     Clip info: 
> >       Software: MEncoder CVS-021124-23:55-2.95.4 
> 
> Who on earth made such nonsense files? The only point of mpeg1 is for
> stuff that doesn't support mpeg4, but the only thing that will play
> mpeg1-in-avi is mplayer!!
> 

Well I chose MPEG1 specifically because of the extremely low amount (0.3% according 
to 'top' - but with some substantial I/O) of CPU mplayer uses when playing it back. I will 
have 6 of these mplayer playing concurrently (maybe one more for an animated logo :-).

The problem then becomes that the machine could also be capturing MJPEG from a 
capture card at 720x576 @30fps, and there still needs to be CPU/IO left to run all the 
menu code that makes up the PVR display. I am not sure, but the MJPEG stream may
_also_ have to be transcoded to DivX 5 or WMV8 on the fly.

With this in mind, MPEG4 does not seem a viable candidate for the 6 concurrent 
preview movies on the "recorded movies" menu page.

I would _love_ to have plain MPEG files, however (yes I have RTFM) I have not 
been able to figure out how to get mencoder to encode such beasts. I currently use
  mencoder  ... -lavcopts vcodec=mpeg1video ...
in order to create the preview files. It encodes extremely fast (uses 5% CPU to do 
so) and as I said, the playback of the files uses very little CPU. 

Any advice here (either on mencoder, or on different codec ideas) would be very 
much apreciated.

David Toso.