[Live-devel] Query for Live555 forum

[Morgan Tørvolt]

Hi

64kB or even 256kB could still be way to little if you have a highly
variable bitrate stream. Is it buffer underrun you get or is it buffer
overrun? You can sort of check this
Try one without variable bitrate first to see if that works, and also
with single service transportstream.
I have never tested live with multiple service files. There could be
something going wrong in the transportstreamframer if one of the
services has wierd PCR timestamps or something like that.

Ross:
I don't think many STB producer has much more buffer than that. It is:
64kB / (8Mbit/s)/(8bit/byte) = 64ms buffer on a high bandwidth stream,
and of course double that or more on a low bandwidth stream. I guess
you have access to the same NDA documents from Amino that I do, so you
can check what they use yourself. Amino is definately still going
strong, so I do not agree with your assessment there.
There is of course also a decoding buffer that keeps the I and P
frames for decoding of the B frames, but it must still be fed data
according to the DTS in the PES headers.
Most local area lans and ADSL network connections have maximum 5ms
delay from server, and usually the network jitter is much less than
that. The reason for making the buffer like this is as noted earlier,
the low delay trick play functionality. Having a two second buffer is
not ideal when going ffwd at 32x and pressing play when you see where
you want to watch from. It will take you a minute forward before you
are back at 1x. That would give a bad user experience.
There is some logic behind it all I believe. It puts alot of
responsibility on the server though, but in a total system cost
analysis you would also want a more expensive server rather than more
expensive clients most of the time. Especially in big installations
with multicast and thousands of clients. This is why I have been
trying to push for better timing of the transportstream data in Live.

-Morgan-

On 20/03/07, Susovan Ghosh <susovan at tataelxsi.co.in> wrote:
> hi,
>   Thank you very much for reply.I checked that audio video buffer size in
> the stb client is 64KB.I changed that valu upto
>   three times,and got the same result.What should be the size of the audio
> video buffer?
>                  I made an experiment with VLS server instade of live 555
> server, and STB client could play it.Then what will
>   be the proper cause.
>
>                                                                         Than
> k You
>
> SUSOVAN GHOSH
> PH No-9986667320
> Engineer (D&D)
> PRDE
> TATAELXSI LIMITED
>
>
> -----Original Message-----
> From: live-devel-bounces at ns.live555.com
> [mailto:live-devel-bounces at ns.live555.com]On Behalf Of Morgan Torvolt
> Sent: Sunday, March 18, 2007 9:26 PM
> To: LIVE555 Streaming Media - development & use
> Subject: Re: [Live-devel] Query for Live555 forum
>
>
> >         But for the same stream to stream to the set top box its giving
> > glitches and giving blurred video and sometimes it will not start
> >         decoding, and still server is streaming.I can not under stand the
> > problem.
>
> Check if the stream has variable bitrate. Try without variable
> bitrate. Some of the stbs have as little as 64kB buffer, and some even
> less, which could cause problems with VBR streams.
>
> -Morgan-
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>