Demo: HLS Live seek is not possible

[avelad]

Using https://shaka-player-demo.appspot.com/demo/#asset=//storage.googleapis.com/shaka-live-assets/player-source.m3u8;lang=es-419;build=uncompiled

Seek is not possible with HLS Live

Shaka Player Demo.zip

[joeyparrish]

This is intended, and is consistent with built-in HLS support in Safari.

Can you give us some details on how you expected it to work?

[avelad]

I expect that works the same way that DASH.
We want offer to the user the same experiencie with DASH and HLS. We offer to the users a n-timeshift over live stream ( the same as Youtube, eg: https://www.youtube.com/watch?v=0tek2aa8hAQ)

https://shaka-player-demo.appspot.com/demo/#asset=//storage.googleapis.com/shaka-live-assets/player-source.mpd;lang=es-419;build=uncompiled

Shaka Player Demo.zip

[joeyparrish]

We can probably make this configurable, and make it apply to all live streams (DASH & HLS). By default, we would allow seeking to any segment we know about. The other option would be to disallow live stream seeking, as we do today for HLS live.

[theodab]

You should be able to seek in HLS live streams now. Just set the manifest.availabilityWindowOverride configuration to an appropriate value before loading the stream.

[avelad]

hi @theodab

it's not working as expected, how can you knowWindow by default in HLS? with the new configuration I can only set a value if the value it's know by the application, but the real availabilityWindow is already included in the stream

By default the behavior it's the same as in previous releases (eg 2.4.2) and the default behavior is different to DASH.

[theodab]

Well, in that case, you should wait on #999.
That issue is currently blocked, awaiting other refactors, but it's also in the 2.5 milestone so you won't be waiting forever.

[joeyparrish]

Yes, the default behavior is intentionally the same as in 2.4.2. This change gives you an explicit override, for both DASH & HLS.

@avelad, try setting the override to Infinity. Does that get you the full seek range you want?

[avelad]

Hi @joeyparrish,

I just tested with Infinity and I get more range than declared in the playlist. This does not work for an EVENT playlist (startover funcionality) because the start is a known value, but the duration change in each update.

I attach a video with the test.
Issue-1307.zip

[joeyparrish]

I think this feature is not working correctly. I will reopen and investigate.

[joeyparrish]

The override set by the player after the initial manifest is parsed is wiped when a live manifest is updated.

[joeyparrish]

@avelad, can you please try again with the latest code? I believe we have fixed the issue.

[joeyparrish]

Actually, we've just discovered what appears to be a related bug in the HLS parser. Setting availabilityWindowOverride to Infinity does what I would expect in DASH: the segments that appear in the manifest can all be seeked to. This is not the case for HLS. Right now, with the same setting and an HLS live stream, the seek range includes all segments that have ever existed, including ones that don't appear in the playlist any longer. We should be able to fix this. @theodab will investigate.

Sorry for the inconvenience. I think (hope?) this should be the last change required for this.

[avelad]

I found thaht it's not possible configure availabilityWindowOverride = Infinity in Demo page, is it possible add Infinity value?

[joeyparrish]

That's a limitation of <input type=number>. You could use a sufficiently large number in the demo, such as 9999999999 (larger than the current Unix time in seconds).

[TheModMaker]

@joeyparrish I would think there would be three distinct use cases for this setting:

1. Not setting anything: Non-seekable HLS and using timeShiftBufferDepth for DASH.
2. Setting availabilityWindowOverride: Using that value to indicate the time that segments remain alive for and determining the seek range.
3. Using Refactor to derive live edge from list of segments #999: The segments that appear in the latest manifest determine the seek range.

So setting to Infinity would mean (to me) to be all segments are available forever, similar to not having a timeShiftBufferDepth in DASH. If I am wrong, how do you see setting to Infinity being different than #999?

[joeyparrish]

@TheModMaker, you are right. For HLS, there is no difference between a window override of Infinity and my plans for #999. For DASH, it is a bit different. Until #999 is solved, the DASH live edge is based on availabilityStartTime, not the segment list. For HLS, it is already based on the segment list.

[theodab]

Okay, with that change, setting availabilityWindowOverride to Infinity (or some other arbitrary large value) should now properly set the start time on an HLS livestream.

[avelad]

I just tested and everything works as expected. Thanks!!