Add support for AC-3 codec in MPEG-TS

[erankor]

This PR will...

Add support for AC-3 codec in MPEG-TS

Why is this Pull Request needed?

Are there any points in the code the reviewer needs to double check?

Resolves issues:

Checklist

• changes have been done against master branch, and PR does not conflict
• new unit / functional tests have been added (whenever applicable)
• API or design changes are documented in API.md

[erankor]

@robwalch, I applied the changes from #1102 on latest master + fixed the CI comments (looks like the CI has advanced significantly since I opened the original pull :))
I didn't change "type supported" to work lazily, IMHO it makes sense to do it for all formats, not just AC-3, and then it should probably be in a separate PR.

[erankor]

One more thing, I looked again at this code now (it's been a few years since i wrote it...) and this looks wrong to me -
const frameDuration = (1536 / sampleRate) * 1000;
I think it should be 90000 instead of 1000, don't really remember why I used 1000... Maybe when I initially opened the PR, the tsdemuxer converted the 90kHz timestamps to millis?

[robwalch]

One more thing, I looked again at this code now (it's been a few years since i wrote it...) and this looks wrong to me -
const frameDuration = (1536 / sampleRate) * 1000;
I think it should be 90000 instead of 1000, don't really remember why I used 1000... Maybe when I initially opened the PR, the tsdemuxer converted the 90kHz timestamps to millis?

I'll look into it for v1.5.0. Thank you for updating the PR.

[ccr-hls-crufter]

Hi @erankor And first of all, thanks for your work on this. I have build out your commits and have a few comments:

• https://github.com/erankor/hls.js/blob/add-ac3-support/src/controller/stream-controller.js#L1041 Causes issues with your branch. It creates a fatal error that results in not only the audio failing to load, but the entire media resource as a whole.

• I do have issues that are difficult to reproduce or diagnose when a video frame is dropped. As it waits to get the video frame, the audio does not come back in sync with the video but stays ahead.

These are the two issues I have found playing around for a day with this. Again, thanks.

[fegauthier]

Hi @erankor !

Thanks for your awesome work! I have some stream that has audio E-AC3 (0x87) which seems to be Dolby Digital Plus. Do you know if the parsing is the same as AC-3? If not, do you know if it's complex to implement it?

Thanks!