Player hangs indefinitely on a multi-period mpd when skipping ahead and then behind.

[salmoro]

• What version of Shaka Player are you using?
  2.0.2

  • Can you reproduce the issue with our latest release version?
    Yes

  • Can you reproduce the issue with the latest code from master?
    Yes

• Are you using the demo app or your own custom app?
  Custom

• If custom app, can you reproduce the issue using our demo app?
  Believe so but the uniqueness of what triggers the issue needs automatic programmed navigation to reproduced consistently

• What browser and OS are you using?
  Chrome with windows 7&10 + chromium on Archlinux

• What did you do?
  Started playing at precisely the beginning of a period other than the first and then jumped back to a previous period.

• What content did you load?
  Custom MPD edited from the original "https://storage.googleapis.com/shaka-demo-assets/tos-pto-webvtt/dash.mpd" mpd, referencing its periods numerous times adding up to 70 periods and a duration of 89 minutes.

  • If standard demo asset, which one?
    N/A

  • If custom asset, what manifest and license server URIs?
    http://elchonon.com/shakarewind/1.mpd

  • How did you interact with the content, if at all?
    After experiencing this with normal rewind we've created a programmed navigation rule to consistently reproduce.

• What did you expect to happen?
  Play as normal.

• What actually happened?
  Player hangs indefinitely
  See elaborate description bellow

On a multi-period mpd, when skipping ahead and then behind (to a previous period which hasn't been loaded yet) Shaka hangs indefinitely.

Here is an example of player set to reproduce this issue.
http://elchonon.com/shakarewind/

The above player points to an MPD edited from the original "https://storage.googleapis.com/shaka-demo-assets/tos-pto-webvtt/dash.mpd" mpd, referencing its periods numerous times adding up to 70 periods and a duration of 89 minutes.

We were not able to consistently reproduce with the original mpd so we made this very long mpd with many periods which seems to be a factor in being able to consistently reproduce.

The player is Shaka compiled in debug mode, compiled 1/7/2017 from the master branch.

The player is set to begin at 421 seconds and jump back to 411 seconds and then it hangs.

We've encountered this consistently with private content of 1hr+ durations and 20+ periods and we are reproducing it here with this content.

[TheModMaker]

The problem with your custom manifest is you generated the manifest incorrectly. The first two periods should be 60 seconds and the third is 120 seconds. You have it where the second period is 120 seconds, which is causing problems.

You can see the problem by just playing the manifest from the beginning. Once it gets to 120 seconds it stops because it is still looking for more content in that period, but can't find it.

It is also possible the original issue was the same as #649. I cannot reproduce any issue with the original manifest.

[salmoro]

Thanks! Good catch there and my apologies for the bad content. It was edited by hand. Now that we corrected the MPD, the issue on the sample persists no more. Our original issue does seem similar to #649. We'll test our private content with Chrome 56 and see if that resolves it. Otherwise we'll have to figure out another way to reproduce the problem. Thanks very much for your help.

[salmoro]

Here I've managed to reproduce this

See the programmed player here:
https://dwnmi3sz90i0g.cloudfront.net/

And here is the MPD it's pointing to which plays well (beginning to end) on all Shaka versions tested (including Shaka demo player):
https://s3.amazonaws.com/aws-website-shaka-rewind-a9cdr/dash.mpd

Important Note:
We've only been able to reproduce this consistently with slower computers (i5 dual core and some quad) and with cache cleared. Not sure if this is a function of CPU or RAM (or GPU or something else)but it is important to point out that on some computers it's not possible to reproduce.

We've tried this on multiple versions of Chrome including Canary, Version 58.0.2989.0 and we're getting the same results. We've also seen this consistently on Firefox.

Here's what the player does: Begins player at 480.033 (seconds), after an initial delay of 1 seconds it repeats 5 times a rewind of 10 seconds with a 0.5 seconds delay in between. Ultimately the player gets to 7:10 (480-5x10) and will not play.

The player up above is running on shaka-player.compiled.debug.js (compiled 1/7/2017 from the master branch). So you can monitor console for errors and warnings.

Specs of computers that consistently reproduced:
-Intel i5-4210u 2.40 GHz, 8GB RAM - Windows 7-64
-Intel i5-4590 3.30 GHz, 8GB RAM - Windows 7-64
-Intel i3-m370 2.40 GHz, 4GB RAM - Windows 7-64

Specs of computer that consistently didn't reproduce:
-Intel i7-6800k 3.40 GHz, 16GB RAM - Windows 10-64

Please let me know if there's anything else you need.
Thanks

[TheModMaker]

The problem here is that Chrome doesn't seem to jump gaps after a seek. It will usually jump gaps up to 0.5 seconds, even at the beginning of playback. But if you seek to an unbuffered region that is right behind a buffered range, Chrome won't play. You just happen to seek into the <0.1 second range that is needed to cause this. You can see this by seeking to 440 and pausing, letting it buffer, then seeking to 430.05 (just before the buffered segment).

I'll have a fix up soon.

[TheModMaker]

That bug has been fixed on master. Please try again with the latest code.

[salmoro]

Thanks! Will test and confirm.