[NUUG video] [Savonet-users] Bug#574628: liquidsoap: Drop video when processing Ogg Theora file

[David Baelde]

Hi Petter,

I'm not sure of what you want exactly, and where you are right now.
But let me confirm that we'd be happy to help you experiment with
liquidsoap SVN: getting the video in a production state is our goal
right now.

2010/3/19 Petter Reinholdtsen <pere at hungry.com>:
>> It seems liquidsoap could be used for that, indeed. Because liquidsoap
>> decompress the video files, it allows it to recompose streams continously,
>> which is what tools like VLC or ezstream, which only concatenate the streams,
>> cannot do.

I confirm this. Also, by continuous you might mean "without new
tracks", which is useful with players which do not really support
streams containing tracks such as VLC and most of them really. This is
also possible, for example using add(normalize=false,[blank(),s])
creates a new sources that is like s but has no track limits (and
blank when s doesn't produce anything). There is however a non-trivial
extra cost incurred by add(), which probably matters when you're doing
video: in this case we could design quickly a direct, costless, way of
erasing track limits.

>> The video support in the current SVN should already allow some most of what I
>> describe here. We would be very interested to help you acheiving that and
>> fixing any issue you may encounter along the way.

The main limitation is efficiency. Many operators haven't been
optimized yet, so we don't know exactly what's possible. But I
wouldn't expect to decode and encode in real time larger than around
500x500, and even that will require a good CPU.

> I've attached our current perl implementation, to give you an idea of
> what we want to do.  It include both the vlc and the ezstream
> prototypes.

If you have a script that gives the current file to play you can
directly use it with liquidsoap using the request.dynamic() operator
combined with get_process_output(). You'll find examples in the doc.

This is all rather vague, but please be more specific about what
you're doing and what you currently cannot do with liquidsoap.

Cheers,
-- 
David