[YouTube] Cache deobfuscation code and more fixes

[Stypox]

• I carefully read the contribution guidelines and agree to them.
• I have tested the API against NewPipe.

YouTube's changes :-D :-D

Apparently YouTube stopped providing obfuscated URLs completely! This solves many problems in the YouTubeStreamExtractor, since now there won't be any "could not deobfuscate ..." exception and loading will be much faster. I don't know the reason for this change, but I ran every YouTubeStreamExtractor*Test more than 50 times each, all without errors :-D. Btw, this PR also includes (as a standalone commit which should then be squashed, as it does not make sense) my first attempt at speeding up the fetching process, i.e. caching player urls, which are now not needed anymore at all.

In more detail:

• Cache deobfuscation code and only make the request to get it if needed
• Fix age restricted videos, and correctly determine age limit
• Solve a couple of Andoid Studio warnings
• Do not extract subtitles in onFetchPage(), but only when requested
• Parse upload date for livestreams and ended livestreams
• Improve falling back to video info page in case something is missing from initialAjaxJson
• Add assertNotNull on related streams if they are expected in DefaultStreamExtractorTest

Fixes

• Fixes Unable to view age restricted content NewPipe#4681
• Fixes "This live event has ended" - Crash NewPipe#3336

Testing apk

Since I don't know whether this change is there all over the world, here is an apk for all of you to test. Please try to test it under many different network conditions.
app-debug.zip
@opusforlife2 could you link here users that encountered problems with youtube streams in 0.20.1? So that we have many people to test this ;-)

[opusforlife2]

Do we have any DASH videos in our tests?

[Stypox]

Thank you, that's reproducible. I'll look into it later

[opusforlife2]

Hi dEvS! Great App! Very nice!!11! New updare wHEN? :D

[Stypox]

I readded obfuscation code, and added caching for it: app-debug.zip
I ran every test ~120 times, also adding the above video provided by @xibr, and they all passed.

[opusforlife2]

This apk wants to install over the apk from your fix-detail-open branch.

[Stypox]

This apk wants to install over the apk from your fix-detail-open branch.

Oh, yes, I built it using that base code, hope that's not a problem ;-)

[opusforlife2]

Well, seeing as I'm testing both... it kind of is a problem. 🤐

[xibr]

So far it works fine.

[cmomoney]

Seems to be working for me. Thanks.

[Stypox]

An apk containing both VideoDetailFragment fixes TeamNewPipe/NewPipe#4562 and deobfuscation improvements #447, in case someone (@opusforlife2) wants to test both at the same time: app-debug.zip

[opusforlife2]

Wut bout seprate APK here?

[Stypox]

Why would you need that? Here you just need to test that all videos work, not if the app runs faster or whatever

[opusforlife2]

So I need an apk that is org schabi newpipe debug, or an apk named with this PR's branch name. The APKs you're uploading are named with the fix-video-details branch name, which is another actively updated PR I'm testing as well. So I need to be able to install them side by side. That's what I meant here #447 (comment).

You were using the default debug name earlier. I still have that installed. (The one which crashes on DASH videos.)

[Stypox]

Here you are: app-debug.zip

[xibr]

The video cannot be played with toast message "could not play this stream"
https://youtu.be/7TseTFjNd1Y in Release 0.20.2 It works without any problem.

Same issue #3336 ?!

[xibr]

I cannot play videos that were previously broadcast live.
https://youtu.be/OWJHyYKVcoE
https://youtu.be/dAIBDfzrzJk

The videos open just fine. I just get an error snackbar.

it happens with me only with this apk

Here you are: app-debug.zip

Does not happen on the apk provided in the first comment.

[Stypox]

@opusforlife2 that's caused by updating to java 8 and will be fixed by @Isira-Seneviratne
@xibr ok, I guess I'll have to revert to the old way of detecting livestreams

[Isira-Seneviratne]

@Stypox I added a commit fixing the parsing issue to this PR.

[opusforlife2]

I cannot play videos that were previously broadcast live.

Ah, you're right. I was just assuming that since video details opened fine there was no error. But yeah, trying to play previously live streams fails with that toast.

However, currently live videos play fine, @Stypox.

[Stypox]

@xibr @opusforlife2 I fixed problems with livestreams by reverting the way they are detected:

• NewPipe's fix-detail-open branch: app-debug.zip
• NewPipe's dev branch: app-debug.zip

_{The two APKs have the same extractor implementation, so test only one of those. If you choose the first one you can test both this changes and those in TeamNewPipe/NewPipe#4562 at once.}

[xibr]

no issues about parse date now, and live streams problems work as well.

[opusforlife2]

Yup. All 3 kinds of videos work: live streams, previously live streams, and normal videos.

[Stypox]

This fixes TeamNewPipe/NewPipe#3336, I tested with a livestream that had just ended and, even though such streams are still considered as running livestreams (which are played as DASH by the NewPipe player), there are no errors anymore since the DASH url is extracted correctly and such videos are detected correctly.

[B0pol]

TeamNewPipe/NewPipe#3336

[TobiGr]

Looks good.
Next time, please make more commits, E.g. "Automatically fix more things" and "fix age restriction extraction" could have been in separate commits. That speeds up the review process.