Fix resume not working on LG WebOS

[samcon]

Resume wasn't working for me on LG WebOS (via jellyfin-webos) on Jellyfin 10.8.0, jellyfin-webos 1.0.1 and latest jellyfin-web (master)

Description
I believe the issue is that:

• ?t=XXX is ignored on the video element in the WebOS browser
• Flawed logic in setCurrentTimeIfNeeded
• For some reason, changing currentTime in the 'playing' event (of the HTML video element) doesn't seem to do anything. I also tried 'loadeddata', 'loadedmetadata', 'canplay' but none of them worked. Only thing that worked is to delay the execution with setTimeout.
• Also possible that this only effects DirectStream MKV files

Changes

• I'm not sure what the original intention was, but Math.abs(element.currentTime || 0, seconds) is actually Math.abs(element.currentTime || 0). I interpreted the logic was meant to not skip if the diff is smaller than 1 sec.
• Maybe someone has a less hack-y way to change (i.e. without using setTimeout) currentTime

Issues
Probably solves jellyfin/jellyfin-webos#46

[dmitrylyzo]

What webOS version are you testing?
Older versions can behave oddly, so timeouts are not unusual.

Since this is a bug, please rebase this branch on release-10.8.z and edit target branch to the same (without reopening a new PR).

[samcon]

What webOS version are you testing? Older versions can behave oddly, so timeouts are not unusual.

Since this is a bug, please rebase this branch on release-10.8.z and edit target branch to the same (without reopening a new PR).

release-10.8.z

WebOS 4.5

Will do

[dmitrylyzo]

Don't forget to reapply suggestions. You are free to squash commits to a first one.

[dmitrylyzo]

I have played with timeouts: 50ms worked too (once), but 300 worked more often. So there's a chance that 500ms may fail too. It probably depends on buffering time.

I have tried events durationchange, loadeddata, play, loadedmetadata: they all go before seekOnPlaybackStartIfNeeded (play goes first).
I haven't tried timeupdate though 🤔 Something like: seek if needed on the first time update.

[dmitrylyzo]

LGTM.

Maybe also add HACK: somewhere to mark it as an unfinished/non-ideal solution?

[samcon]

I did some more testing and noticed subtitles aren't synced to the resumed time.
If subs aren't supposed to sync automatically when currentTime is set, any pointers on how to "manually" invoke sub sync?

[dmitrylyzo]

Tested unmodified jf-web on emulators of webOS 1.2, 2, 4 and 5 - only 4 fails 🤷‍♂️
If this is true for real TVs, we need to check the web0sVersion.

I did some more testing and noticed subtitles aren't synced to the resumed time. If subs aren't supposed to sync automatically when currentTime is set, any pointers on how to "manually" invoke sub sync?

What subs? SRT or ASS, embedded or external.

[samcon]

External SRT file

[dmitrylyzo]

External SRT file

On webOS this block should be called on timeupdate event:

jellyfin-web/src/plugins/htmlVideoPlayer/plugin.js

Lines 791 to 793 in 7028419

	let timeMs = time * 1000;
	timeMs += ((currentPlayOptions.transcodingOffsetTicks || 0) / 10000);
	this.updateSubtitleText(timeMs);

[dmitrylyzo]

In webOS 4 emulator currentTime and subtitles are synchronized and updates normally, but the video updates slowly.
Progress line (and its text) is out of sync too. Do you have the same?
I tried it from 0s position. With timeout and without - slow video.

Test assets

jf-gray_1080p_h264_m40.mp4

jf-gray_1080p_h264_m40.time.srt.txt

[samcon]

Alright, I did some more digging and it turns out that if you change 'metadata' here:

jellyfin-web/src/plugins/htmlVideoPlayer/plugin.js

Lines 1377 to 1378 in 7028419

	if (!appHost.supports('htmlvideoautoplay')) {
	html += '<video class="' + cssClass + '" preload="metadata" autoplay="autoplay" controls="controls" webkit-playsinline playsinline>';

to 'auto' then resume simply (i.e. w/o the timer) works 🤷‍♂️.

Subtitles still don't sync to the correct position though

[dmitrylyzo]

I like hack-free solutions. 👍

Does it work with transcoding?

autoplay is supposed to force a full preload, but taking into account quirks of browsers, it is better to specify a full preload explicitly. Moreover, I think we can set it to auto for all cases (need testing), because we are definitely going to play it.

Subtitles still don't sync to the correct position though

Have you tried the sample above? In the emulator subtitles are out of sync even from the beginning.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

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