[Moq] Re: MOQT redundancy implementation

[Gwendal Simon <[e-mail]>]

Hi Jordi,

Thanks for the demo. I am glad to see a player receive the same track from two relays and merge the copies. In your code, do you compare the payloads of duplicate Objects? A conflict can happen at the player when the two relays receive the track from different encoders (or when one relay corrupts an Object). If the player detects a conflict, the draft says it MUST cancel its subscription from that publisher. Which of the two relays would it cancel?

More generally, conflicts are likely to happen when two encoders publish the same track (which is a common setup in broadcast deployments). A single encoder is safe, because it assigns every group and object ID once. With two encoders, a relay MUST subscribe to both. If the two encoders assign the same IDs but produce one Object differently, the relay MUST treat the track as Malformed and immediately terminate every downstream subscription. To sum up, a backup encoder (added for resilience) becomes a risk: one conflicting Object can break the entire stream.

I opened an issue on this topic: https://github.com/moq-wg/moq-transport/issues/2003

Gwendal



________________________________
From: Jordi Cenzano Ferret <jcenzano=[e-mail]>
Sent: Thursday, October 15, 2026 6:35 PM
To: [e-mail] <[e-mail]>
Subject: [Moq] MOQT redundancy implementation

Just wanted to let you know I took advantage of the interim interop time and implemented MOQT-level redundancy. You can find a demo in this video<https://youtu.be/Br8xqAgCMA0>.
The redundancy is implemented at the MOQT layer and is payload agnostic. It is based on the fact that groupID-ObjID are preserved throughout the pipeline.

Test URLS:

  *   Encoder sending data to 2 relays (to Madrid & Los Angeles): https://moq-madrid.jordicenzano.name/demo/encoder/index.html?host=https://moq-madrid.jordicenzano.name:4433/moq&hostbackup=https://moq-losangeles.jordicenzano.name:4433/moq
  *   Player consuming from 2 relays (from: Madrid & Los Angeles - double bandwidth): https://moq-madrid.jordicenzano.name/demo/player/index.html?host=https://moq-madrid.jordicenzano.name:4433/moq&hostbackup=https://moq-losangeles.jordicenzano.name:4433/moq

Thanks
Jordi