VP9 broken


Hi guys,

Is VP9 still supported by jitsi?

I’ve posted messages and issues about VP9 not working after refactoring code of libjitsi (january 17).
I am willing to help to debug, but i have no idea how and where to start.



ping @gpolitis @Boris_Grozev @bbaldino


Hi guys,

I’ve managed to figure out the problème: key pictures for VP9 were not detected. So the rtp packets were dropped systematically. Here is a simple patch vp9_fix.patch.txt (3.4 KB).

The key image detection is based on this https://tools.ietf.org/html/draft-ietf-payload-vp9-06#page-6. Especially this phrase

A key picture is a picture whose base spatial layer
frame is a key frame, and which thus completely resets the encoder
state. This packet will have its P bit equal to zero, SID or D
bit (described below) equal to zero, and B bit (described below)
equal to 1.

However desktop sharing isn’t working with VP9 as in Chrome it uses VP9 SVC. I am definitely getting my hands dirty to debug that too. I’am looking for some help on this part.

BTW all rtp video packets are processed by a java object called SimulcastController. Even for VP9. I would say that part of code still remains very VP8 specific and may need some refactoring.

Could this go for a PR?



Hi Arthur, yes please do open a PR and I can help with VP9 screen sharing in case you finally decide to dig into it a bit further. Thanks very much for looking into it!



As you may have noticed i’ve proposed a PR that fixes VP9 with recent version of libjitsi.
I was facing issues with SVC so had problems with screen sharing.

With latest jitsi components (+PR) it seems to work.

Hope someone can test and confirm this.