[BUG] Video is not streamed from master if viewer does not stream video back

[idonahum1]

Hi,

Use case:
Streaming video from IP camera using Webrtc C sdk as master to a web browser using Webrtc JS as viewer.

Logging
logs.txt

Describe the bug
Video is not streamed from master if viewer does not stream video back.

SDK version number
Latest : v1.7.3

To Reproduce
Steps to reproduce the behavior:

• Use viewer JS example and set sendvideo=False flag in viewer.js
• Use master c example or gstmaster example to stream video into a browser.
• Check if video from master is working.

Expected behavior
When setting sendvideo= False in js viewer I expect that I only receive video from master (C sdk). But once I set this flag to false, or disabling the viewer camera, I cant get any video from master.

Desktop (please complete the following information):

• OS: ubuntu 20.04
• Browser chrome
• Version 101.0.4951.41 (Official Build) (64-bit)

Additional context
Additionaly I tried to modify RTC_RTP_TRANSCEVER direction to SENDONLY in PeerConnection.C, as well videoRtpTranseiver direction in Common.C, nothing seem have effect.

Tried to modify viewer.js%3B,-//%20When%20trickle%20ICE) based on this PR, doesnt seem to have effect either

I tried to follow other issues:
awslabs/amazon-kinesis-video-streams-webrtc-sdk-js#81
#148

On this issue -
#468
I can understand that the modification I did are not needed, but still, if I set sendvideo = False on the viewer side, I still dont get any video at all.
Tried to debug myself but I couldnt figure if it is something with the C Sdk, JS Sdk, or it is just the browser itself.

Any ideas?

Thanks.

[disa6302]

@idonahum1 ,

The logs do not suggest anything and seem incomplete. Can you provide the complete logs after running export DEBUG_LOG_SDP=TRUE? Do you see any SDP exchange issues?

[idonahum1]

Updated logs
logs.txt
:

[disa6302]

I see the error "0x5600000f" which suggests that the SDP size received exceeds 256 attributes as allowed by the SDK. Have you tried other browsers?

[idonahum1]

Hey, Thanks.
so after changing the viewer code based on this awslabs/amazon-kinesis-video-streams-webrtc-sdk-js#50
and changing the brower to firefox everything seems to work fine. But I wonder why it wouldnt work with chrome? any ideas how to fix this?
Thanks.

[disa6302]

@idonahum1 ,

To confirm, does the JS SDK change make it work with Chrome as well?
It looks like the SDP generated by Chrome is large causing it to fail with the SDK. As a short term fix, you can modify this value to increase number of attributes the SDK can handle.
However, we are still not sure why the size of the SDP is large or what the SDP contains. Can you increase the value and see if it gets through?
It would be useful to also run export DEBUG_LOG_SDP=TRUE when it works so that we can see what is causing the large SDP from Chrome.

[idonahum1]

@disa6302

No, the JS change doesnt make it work with chrome.

It seems like the the value that was define in my SDK was 128 somehow, I change it to 256, and now with the JS change it also works with Chrome.

Thank you!