[Red5] Audio/Video Live Streaming

[Joachim Bauch]

Hi Kai and Raimund,

Kai Londenberg wrote:
> Raimund Kaemmerer wrote:
>> 
>>right now I am playing around with a Live Audio/Videochat application 
>>using Red5. Putting both Audio & Video on a Stream gives me huge 
>>synchronization Issues.
> 
> Raimund and I work together, so I'm adding a few clarifications and 
> comments myself here:
> 
> - The A/V Stream seems to get buffered somewhere (server or client) - 
> and after a while, the receiver lags behind the sender.
> - This lag went up to more than 2 minutes after 5 minutes of A/V Chat or 
> so over a DSL Line. 
> - The desynchronization happened in our internal LAN (1Gbit Ethernet) as 
> well, although not as severely compared to the DSL Line.
> - The video quality can degrade a lot if Audio and Video are played at 
> once.
> - All client buffers have been set to 0, audio quality has been set to 
> 22 khz, and video quality to max (at 100x100px resolution).
> - If audio is emitted from the app, the video never desynchronizes by 
> more than 1 or 2 seconds.

Is the lag between the audio and the video or between the broadcaster
and the subscribers?

> What I'd like to know is, what would happen if we just drop one or the 
> other RTMP Packet in a Video Stream. Would that video stream
> need to be resynchronized (by sending a complete Keyframe) or is it 
> possible to simply drop some (RTMP, not IP) packets server-side in order 
> to do rate limiting ?

Flow control for streams is scheduled for the 0.5 release, Steven is
currentlz working on refactoring the streaming code so this will be
supported in the future.

> Or put another way: Does the Video Stream consist of complete keyframes, 
> does it just stream the difference from one frame to the other, or
> does it a mixture of those two ? How about Audio Streams ?

Currently Red5 passes the received data unmodified to the subscribing
clients.  It contains periodic keyframes with delta frames inbetween
for video streams.  I don't know the encoding of audio streams.

Greetings,
   Joachim
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 4355 bytes
Desc: S/MIME Cryptographic Signature
Url : http://osflash.org/pipermail/red5_osflash.org/attachments/20060322/ed6a3067/smime-0001.bin