Streaming live content

[Xavier Castellan]

Hi all,
I will be interested to stream & encode live content. Today, I am more familiar with broadcast MPEG-TS standard and UDP streaming.
So for encoding, I have no trouble of understanding, but for streaming, I do not know the recommandations.
The file server question was just answered today.
So for streaming live webm content, what kind of server, technology (UDP ...), timing constraint ... do I need ?
Thanks for your help,
Xavier

[Steve Lhomme]

For real live streaming you will need a server. Here are some guidelines on what you should do and not do to stream Matroska/Webm content:

http://www.matroska.org/technical/streaming/index.html

Fluendo already has a live streaming WebM demo that works with Opera and Firefox. I think they will post about it here soon. That means GStreamer in general is (or will soon be) able to stream WebM content even in a live way.

Steve

[zaheer]

Yes, we got live http streaming of webm working within 48 hours of the
WebM announcement. There are details on my blog here:

http://zaheer.merali.org/articles/2010/05/21/webm-and-vp8-streaming-live-from-flumotion/
http://zaheer.merali.org/articles/2010/0http://zaheer.merali.org/articles/2010/05/24/more-exciting-live-streaming-from-flumotion-with-vp8-and-webm/
http://zaheer.merali.org/articles/2010/05/24/n900-and-maemo5-playing-vp8webm-live-stream/

We have a demo live stream re-encoding an English DVB broadcasted
channel to vp8/vorbis/webm. To watch in an HTML5 browser, go to
http://zaheer.merali.org/webm/

Zaheer

[Xavier Castellan]

Hi Zaheer,
- thanks for the live demo, it is great to have integrated the codec so quickly.
- I noticed that when I do a "pause", decoding is stopped (CPU load is low) but it seems that streaming data is not stopped, so it uses bandwith and it is not usefull.
- about video quality, there is a "pumping effect" caused by the bitrate regulation .Is-it a trouble of parameters or bitrate regulation algorithm ? By the way, what are the parameters you use for the encoder?
- I read the spec "VP8 Video Bitstream Specification", but there is no timing information. For bitrate regulation, is there something like a EB buffer like in other standards ? What is the "model" to generate a CBR stream ?

Regards
Xavier

----- Mail Original -----
De: "zaheer" <zaheer...@gmail.com>
À: "WebM Discussion" <webm-d...@webmproject.org>
Envoyé: Mardi 25 Mai 2010 12:32:11 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne
Objet: Re: Streaming live content

[Zaheer Merali]

Hi Xavier,

I am not responsible for the clients. However there should in my
opinion be different buffering for live streams and for progressive
download of seekable files. To detect that it is a live stream, one
only needs to check if there are Cues. If there are Cues, then it is a
file, if not it is a live stream.

I just set a speed and bitrate on the vp8 encoder currently.

Zaheer

[Steve Lhomme]

A live stream should also have no duration. Although it's less safe to check just that between live and file streaming.