1338005 - Video is not played in Firefox developer version 53 after SDP renegotiation

Status: RESOLVED FIXED

(Core :: WebRTC: Signaling, defect, P1)

Description

[ushunmugan]

Attachment: firefox54n_novideo_on_renego.txt

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.76 Safari/537.36

Steps to reproduce:

1. Establish a WebRTC call between Firefox 53 and a peer with both audio and video.
2. Make Firefox client create a new SDP offer, send it to peer, and process the answer.
Note, this might not sound like a sensible call flow, but the same problem happens when the peer sends an updated SDP and renegotiation takes place.


Actual results:

Audio is still played in Firefox, but video is not.  The peer is still receiving audio and video fine.  
This problem exists in nightly version 54, but not in 52 beta or earlier.


Expected results:

Video should be played along with audio.

Comment 1

[ushunmugan]

Attachment: Firefox debug log for the scenario.

This Firefox debug log corresponds to the SDP renegotiation scenario, of which the SDPs involved are in the previously attached text file.  Note the following type of errors in this log, that happen after renegotiation (2nd createOffer):
[Socket Thread]: E/signaling [Socket Thread|WebrtcVideoSessionConduit] VideoConduit.cpp:1727: mozilla::WebrtcVideoConduit::DeliverPacket DeliverPacket Failed, 1
[Socket Thread]: E/signaling [Socket Thread|WebrtcVideoSessionConduit] VideoConduit.cpp:1741: mozilla::WebrtcVideoConduit::ReceivedRTPPacket RTP Processing Failed

Comment 2

[Byron Campen [:bwc]]

Looks like the webrtc.org code is barfing. Getting us a test page that can reproduce this would let us figure out why pretty quickly.

Comment 3

[ushunmugan]

I tried to reproduce the issue with a standalone PC SDP munge page, but I couldn't (I expected this, as you haven't obviously seen this issue in your tests).  After thinking about it a bit, I figured it must be the changing SSRCs from the gateway that was causing this. So, I used a "hidden" gateway option which would keep using the same SSRC during a call with the browser, and the video problem on renegotiation didn't happen anymore!

I believe changing of SSRC during a renegotiation should be allowed, and I hope you would fix this.  Note that this has been working in Firefox up until now, and it works fine in Firefox 52 beta (as well as Chrome and Canary).  Also, changing SSRC doesn't seem to affect receiving and playing audio in Firefox 53 or 54.

Comment 4

[Byron Campen [:bwc]]

We should definitely support changing the SSRC in renegotiation, I'm surprised that no longer works.

Comment 5

[Andreas Pehrson [:pehrsons]]

This sounds like fallout from the webrtc.org 49 update. Randell, can you take a look?

Comment 6

[Iñaki Baz Castillo]

May be related to https://bugzilla.mozilla.org/show_bug.cgi?id=1347578 ?

Comment 7

[ushunmugan]

This problem does not seem to be there anymore in 53 beta, 54 developer, or 55 nightly.  I suppose you could close this ticket.