[linux-dvb] Re: Audio/Video Sync after remultiplexing (more)

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

"Marcus O.C. Metzler" wrote:
> 
> Axel Gruber writes:
>  > If anyone knows another Multiplexer for Linux pleas contact me by Mail.
>  > (i have tryed MPLEXLO, MPLEXHI, MPLEX(from LEO), VCDMULTIPLEX, STREAMPLEX)
>  >
> 
> OK, I worked on the remux program this week and I got it so far that
> ZDF and ARD are much better now. There is still the occasional video
> buffer underrun, but audio works fine and synching also seems to be
> ok. I will check the new sources into the public CVS as soon as
> possible. You can use it with : remux <filename> PESsize buffersize*x
> or like this :    remux PESsize buffersize*x  < <filename>
> E.g. remux zdf.mpg 2048 1 >/dev/video, also works, so there is no long
> wait for remuxing. I haven't tested vary large files yet, because I
> haven't recorded any.
> 
> If you vary the PESsize you get different results, also depending on
> the original file. The buffer multiplier is not that influential, was
> just for testing. It's not perfect yet, but better than nothing.

Due to the compiling problems I have mentioned in my previous post
I haven't been able to actually play with 'remux' yet, but there's
one question that bothers me:

Are you planning to integrate this functionality into the driver?

There are several reasons why I think that this is pretty important:

- VDR splits long recordings into multiple files to avoid problems
  with the file system and to utilize more than one physical disk.
  I guess remuxing each of these files by themselves would cause
  trouble at the connecting points.

- VDR's "transfer mode" for viewing a (e.g. encrypted) channel that can
  only be received through the second DVB card works by directly copying
  the data stream from e.g. /dev/video1 to /dev/video0.

- When watching a broadcast in "time shift" mode VDR replays the data
  that has just been recorded.

All this IMO requires that the driver itself is capable of handling
the data it previously produced. The functionality of the 'remux'
program could go either into the recording section or the replaying section
of the driver. Doing it in the recording section would mean that it
would be done only once (and that the resulting data stream would
already be "clean"), while doing it in the replay section would
mean that it would be done every time a recording is played back.
My personal favorite would be to have it done in the recording
section.

Maybe you already have plans to do that. If not, please take my
vote for it.

Greetings
Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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