theora dev - Feb 2003 - NSV and VP3

Hi,
        Quick note: In case anyone has not heard, Nullsoft, the people
behind Winamp, have seen fit to develop their own multimedia container
format. It can hold any kind of data, but their primary codecs are MP3 for
audio and VP3 for video:

  http://www.nullsoft.com/nsv/

I and a few other people are still working out the details of the format:

  http://www.pcisys.net/~melanson/codecs/nsv-format.txt


--
	-Mike Melanson

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I'm working on a higher level than probobally most on the list, building
an "editor" for post-encoded Oggs by allowing users to easily trim and
chain together different ogg files to compile a larger work without
transcoding.

The chaining together is actually quite simply, if you have two legal
ogg files you simply concat'ate them together.. even the traditional
"cat" command can do this legally (correct me if I'm wrong, it
works
with Vorbis).  Trimming/cutting is slightly more difficult since the
BOS/EOS need to be replaced after it's packets are trimmed, but I seem
to have a pretty good grasp on it.

Anyways, all this functionality is for down the road projects as per
compiling a weekly 30-minute video from a title, several 3-5 min
segments, small vid clips inbetween the segments, and credits at the
end.  The segments are being produced by different people from around
the world and will be submitted in Ogg Theora format, then we chain the
bitstreams together to produce a finished work.  Fast, little human
effort required to compile everything.  In a few minutes we could have
something to plop onto an FTP and available for worldwide distro.  Many
syndicates would grab this and record it to tape for putting on the air.

Here's the question, however.  I asked this before, actually.. what
happens when those segments are different resolutions or framerates?  Is
this being considered in players and what would be an intelligent way
for them to cope with a changing frame size, especially when outputting
to an external video device (ie, full screen to NTSC/PAL tape)?

I'm asking here because there's already alot of Vorbis players which
can't properly handle chaining a 44100 stream to a 22050 stream (skips a
few seconds of first track then starts playing second), while ogg123
plays it just fine.  It would seem important to give those designing
players "extreme" examples, such as a chain of Theora bitstreams with
different framerates, resolutions, etc so this is properly tested.  

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