[vls-devel] Re: Occasional crazy problem with vls

[Jean-Paul Saman]

Andrew de Quincey wrote:
>>What I am interested in is knowing if your video clients expierence a
>>temporarly lack in video (like a big hole)? This would support my theory
>>above.
> 
> 
> If you use VLC as a test client, you can see the video suddenly speeds up.

So there is a delay smaller then 3 secs in the disk reading time.

> You can duplicate the problem partly by running VLS in the foreground. If you 
> ctrl-z it and leave it for 10 seconds, then 'fg' it again, the video in VLC 
> will speed up for a bit until it catches up with where VLS "thinks" it should 
> be. (I can't replicate the problem I originally reported in this way, but it 
> looks related).

> I don't think this the correct behaviour. VLS should either just skip the 
> video, or realise its been delayed for a bit, and compensate its timings. I 
> don't think suddenly sending a massive burst is right. My normal video 
> clients (which are STBs with hardware decoders) don't really like the burst 
> very much.

STB's don't like the speed up I agree on that. But just skipping does 
not solve your problem. The problem is in your server setup, it is 
clearly not capable of handling that load. The proper fix would be the 
enlarge the streaming capacity of the server side, e.g: by adding new 
servers.

> What do people think? I can easly implement a fix if people agree this is a 
> problem...

I suggest to make it an option (either compile time, or configuration 
time) on how to handle late packets in a high load situation. Not always 
late means sending at 20 Mbps, so you will need some 
adjustabe/configurable window, perhaps based on the streams average 
bitrate + plus some worstcase *normal* peak. At least to make sure the 
stream does not exceed some worst case bandwidth situations. And if it 
does LOG it, so people now what happened.

-- 
Kind greetings,

Jean-Paul Saman


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