[vlc-devel] Re: Packetizer use within demux module

[Sigmund Augdal]

On Sat, Mar 05, 2005 at 01:04:18PM -0600, Neal Symms wrote:
> I'm writing a demux module for VLC that will demux .TY format files (data
> extracted from TiVo devices).  I could submit the source to become part of
> the VLC project if there's interest.
I guess there is. I don't personally have a TiVo, but I do see the value of
such a feature. Could you perhaps say a few words about this format?

> 
> My question, however, is what is the purpose of packetizing the audio &
> video within a demuxer?  I've tried both ways in my module.  That is, just
> sending bits and pieces (non-packetized) MPEG audio & video to the codecs
> and also by employing a packetizer and thus sending only complete packets to
> the codecs.  Both methods appear to produce the same results.  The result is
> great either way.  So what's the advantage (if any) of using a packetizer?

Some decoder libraries require entire frames to be passed in order to work.
There is however some support for automatically inserting a packetizer when
needed, the demux only have to set some flag somewhere telling that it's
output isn't packetized. If any of the current demuxers use a packetizer
directly, this is either because the demuxer hasen't been updated to use
this automatic feature, or because the container it self doesn't contain
enough information to easily support demux (raw formats).


Sigmund

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Sigmund Augdal
Edgar B. Schieldropsv 29-14
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