Any plan to enable uplink FlexFEC by default？

[炫树伍]

In tests with Chrome using H264 under poor networks (10% uplink loss + 100ms delay), enabling uplink FlexFEC via command-line flags(--force-fieldtrials=WebRTC-FlexFEC-03-Advertised/Enabled/WebRTC-FlexFEC-03/Enabled) significantly improved remote video quality. Without it, video froze frequently.

Since FlexFEC works well here, why isn’t it enabled by default? Are there downsides (e.g., bandwidth, compatibility) or plans to change this?

Thanks!!!

[Vitaly Ivanov]

Interesting, I need to look into enabling it in my libwebrtc-based sender.

My guess is that 10% packet loss is kind of extreme - the vast majority of people have much better connections, so this feature is not a priority for the webrtc devs. There's no sense of urgency in this tracking ticket, even though it has tons of votes attached: https://issues.webrtc.org/issues/42233280

--
This list falls under the WebRTC Code of Conduct - https://webrtc.org/support/code-of-conduct.
---
You received this message because you are subscribed to the Google Groups "discuss-webrtc" group.
To unsubscribe from this group and stop receiving emails from it, send an email to discuss-webrt...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/discuss-webrtc/d874a4da-c17e-48b4-a173-42f91b0cc6f2n%40googlegroups.com.

[Harald Alvestrand]

Flexfec-03 was one stage in the development of the flexfec spec.

Before we'd enable it by default, we'd want to update to RFC-version flexfec (at least).

There are a couple of open bugs on flexfec:

https://issues.webrtc.org/42225311
https://issues.webrtc.org/42233280

Feel free to star them and follow them!

To view this discussion visit https://groups.google.com/d/msgid/discuss-webrtc/CAFa3_%3D-BUHgXrffxwG3_3K8eXCc33FE0pAUeG8vE2sxErFC-uA%40mail.gmail.com.

[炫树伍]

Thanks for the reply! I learned a bunch from these issues and will keep tabs on them.

We mainly use WebRTC for meetings, cloud gaming, etc., and since people often use mobile networks where packet loss or latency can be common, we're hoping to use FEC to fix those occasional video freezes.

Luckily, Chromium enables FlexFEC for receiving streams by default! We’ve tested it in some projects and it’s been working pretty well. Now I’m super hyped to try it for sending streams too…
👇 Here's the video from my local test.

[炫树伍]

Any chance we can enable 'flexfec-03' by default first, like incoming streams.
Or is the plan to only enable 'flexfec-21' after the 'FlexFEC - Support multiple streams' feature wraps up?

[Vitaly Ivanov]

What? Are you saying Chromium has FlexFEC enabled by default and Chrome has not?

--

This list falls under the WebRTC Code of Conduct - https://webrtc.org/support/code-of-conduct.
---
You received this message because you are subscribed to the Google Groups "discuss-webrtc" group.
To unsubscribe from this group and stop receiving emails from it, send an email to discuss-webrt...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/discuss-webrtc/cec9305c-a8d1-41f9-9902-3aae2690f2d6n%40googlegroups.com.

[炫树伍]

Oops... was my explanation confusing? By default, flexfec-03 only works on receiving streams — sending streams actually need the 'WebRTC-FlexFEC-03-Advertised' trials enabled.

https://source.chromium.org/chromium/chromium/src/+/main:third_party/webrtc/media/engine/webrtc_video_engine.cc;l=188?q=webrtc_video_engine&ss=chromium%2Fchromium%2Fsrc

[Matt Knowles]

If you are not streaming browser to browser, yes you can enable that field trial and you can replace the default controller 'fec_controller.default.h' FecControllerDefault.

The default controller only injects fec frames when detecting packet loss. Confirm you are sending fec frames through webrtc-internals and you see active FEC stats.