Improve support for low-latency DASH live streams

[ojw28]

This issue tracks allowing playback of DASH live streams with lower latency (i.e. closer to the live edge). It's spun out from #4839. See in particular: #4839 (comment) which lists some items, although I'm not promising they're all correct! The referenced patch may also be helpful as a guide.

[jyiu-harmonicinc]

Hi @ojw28

When playing CMAF close to live edge, segments will be downloaded when it's not complete.
Therefore, time to download whole segment is likely to be duration of segment.

This makes defaultDandwidthMeter underestimate bandwidth as it's estimation logic is (segment size) / (elapsed time), and eventually exoplayer will drop video quality.

Do you have any plan to implement bandwidth estimation logic for CMAF?

[tonihei]

We'll look into supporting low-latency live streaming techniques soon. The problem you mention is one of things that need to be solved. We'll post this issue once we have better support for low-latency DASH streams.

[tonihei]

We published our design doc on our webpage - open for comments!

[julianD77]

It will be great to have this support for live streams - is there any update on the planned timeline for delivery of these feature??

[tonihei]

We moved this feature a bit further down our priority list and will probably only get around to finish the started work later this year. Please subscribe to this issue to see any updates. Thanks.