[vlc-devel] LibVLC vmem vout and Elementary Stream ID

Rémi Denis-Courmont remi at remlab.net
Mon Feb 24 18:15:50 CET 2014

Le lundi 24 février 2014, 17:30:37 Jérôme Forissier a écrit :
> The ID is all I need for now, but if a new API is to be added, I guess it
> should expose more than the ID.

The track ID is already exposed where it makes sense with the current design, 
I think. That is to say at the level of the media player instance.

But as I already wrote, a video output instance does not map to an elementary 
stream. It does not even map to an input medium. This is a deliberate and 
concious design choice, to improve the user experience for the common case of 
a single (active) video track.

So I do not really get how you would even define the ES ID of a video output. 
As far as I can tell, such a notion makes no sense within the current VLC 

> And indeed I would rather avoid using deprecated features (smem).

smem is not deprecated, it is unsupported. It was never supported externally.

In any case, smem would exhibit similar limitations as the regular video 
output. In general, there is no 1:1 mapping between output elementary streams 
and input elementary streams (due to sout-keep, the gather, duplicate, mosaic 
plugins, etc).

> So, wrt. adding the proper callback to the LibVLC API -- while I am not that
> familiar with the VLC internals, I am willing to give it a try.
> Would you mind sketching out the API you would recommend? Any pointer to
> previous work? Thanks.

I can't think of any similar example.

Rémi Denis-Courmont

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