There's a missing duplicate ID check, fix is on the branch.

Then stream 5 only starts producing data 25s in. This is sort of fixed by the 2nd commit on the branch, but this will ignore stream 5 altogether.

We could insert silence for streams that are not producing data, but then what do you do if you decide after 3s of no data to fill with silence, but then some data at 2.5s appears?

Actually I think it's fine. We don't ignore stream 5, as when it starts emitting we accept this and carry on. There's no need to insert any silence at this point because we're mapping the audio to the output anyway.

Seems like just the Studio Canal ident at the start has no audio at all on the IT channel.

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