[theora] Add an intro to a theora file without re-encoding?

[Conrad Parker]

2009/7/17 Michael Opdenacker <michael at free-electrons.com>:
> Hello,
>
> I would like to add a introduction video (typically a title with fade-in
> / fade-out) at the beginning of an Ogg/Theora video. I generated this
> intro video in Ogg/Theora from a sequence of png files.
>
> I would need to do this in an automatic script, because I have many such
> videos to process, and without doing any re-encoding step (which would
> be very costly because my videos are huge).
>
> I tried to use oggCat:
> oggCat final.ogv intro.ogv video.ogv
>
> Unfortunately, this doesn't work well because my intro video has no
> sound track to be concatenated with the one in the real video. As a
> consequence, the concatenated video only has a video track.
>
> It tried to add a silent track to my introduction video (same bitrate)
> with oggzmerge, but oggCat doesn't like the result:
> Warning: found unknown stream, this stream will be ignored
> Warning: found unknown stream, this stream will be ignored
> StreamSerializer::fillStreams: we got a real problem with the stream
>

what was the silent track? What encoder did you use, and was it the
same version as was used for the audio track of the main video?

Conrad.