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

Michael Opdenacker michael at free-electrons.com
Thu Jul 16 14:44:55 PDT 2009


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

Any suggestion for a way to add such an intro video in a simple way?

I am also open to doing it when I encode my main video to Theora... I
would then have:

    * An intro video with no sound
    * An h264 video

Thank you in advance for your suggestions....



Michael Opdenacker, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
+ 33 621 604 642

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