Add "on-demand boadcast" aka "uni-instance VOD" to VLM types

[scaroo]

Hello everyone.

I am currently trying to achieve the following behaviour with VLM:
When there is one or more clients interested in a particular stream, create a SHARED broadcast, thus a unique access/decoding/encoding/muxing instance shared by multiple clients.
When no client is watching a stream, the broadcast should be disabled/stopped, so to reduce network/CPU/memory consumption.

For now, this logic is implemented within the VLM controlling code, by refcounting the clients and stopping the broadcast when this number falls to zero.

Currently VLM provides two types of media : Broadcast and VOD.
Broadcast have exactly one instance running when played even if there is no client watching.
VOD creates an instance for each client connection. Each of those instances gets the data (presumably from network, thus consuming bandwidth), decodes it, then reencodes it and finally stream it. This costs a lot uselessly if the source is the same live stream (for example coming for ip cameras).

A perfect solution would be to have some kind of "on-demand boadcast" or "uni-instance VOD" VLM media type. I wonder if I am the only one having such requirements and if such a proposition would be considerable enough to be integrated in VLM main tree.

[Sébastien Escudier]

VOD creates an instance for each client connection. Each of those instances gets the data (presumably from network, thus consuming bandwidth), decodes it, then reencodes it and finally stream it. This costs a lot uselessly if the source is the same live stream (for example coming for ip cameras).

Not true.
- VOD is designed to serve files. So every user can view the file from the beginning.
- There is no decode/reencode with broadcast and VOD.

[scaroo]

Not true.
- VOD is designed to serve files. So every user can view the file from the beginning.

Indeed, that's why VOD doesn't match my requirements. Nor does Broadcast as I need to manage their state (stopped/started) manually depending on the existence of client watching.[/quote]
That's why "on-demand broadcast" might be a solution worth investigating, ain't it ?

- There is no decode/reencode with broadcast and VOD.

Well, not by default indeed, but what if I specify a transcoding or rescalling step in my output chain.

[Sébastien Escudier]

Vlc can't to this, you would need to modify the sources, but I don't know how hard it would be.

[vranik]

Did make VLC some progress about this function? I would like to use VOD on DVB-T, or internet streams. But when other user try create instance, then is impossible access twice on this device. Or when i use internet stream, VLC open another connection, so internet source has still same load and it has no point use VOD on internet stream.

Another problem is when i try access on dvb-t adapter more then one in the same time, then dvb-t adapter is blocked and isn't no more accessible. Only i can do is restart whole computer...

i'm using Win7 prof.