IssueTracker

I can confirm this on Build NPC56P on Nexus 6P

To replicate just run any app that is compatible with multi-window and run youtube with it, play a video and then interact with the other window.

Expected: Continue to play video normally while using another window.

Outcome: Video continues to play but the screen is black, no video is showing, only sound.

This sounds more like a compatibility issue however with background playing on YouTube and not necessarily an issue with Android N. It's also worth mentioning I am using YouTube Red, not sure if that has any impact on this however.

Sorry if I didnt Mention it, im using a Nexus 9 LTE on the N preview (OTA),
and no sound no video for me on youtube at all.

Hi Yes thats intended behavior. In multi-window mode, only the activity the user has most recently interacted with is active at a given time. This activity is considered topmost. All other activities are in the paused state, even if they are visible.Please read more about this on
URL: http://developer.android.com/preview/features/multi-window.html

This should be fixed in today's release, OTAs coming soon: https://developer.android.com/preview/support.html#dp2

I updated to N Preview 2 today and it still pauses or rather skips a ton of frames. It could be a YouTube specific issue because while scrolling within the app, not in multi-window mode, frame skipping also occurs. I checked the "stats for nerds" to see if the frames were dropping and the amount of frames dropped doesn't go up in either case. Removing my thumb or just simply not scrolling(with thumb still on screen) does cause the video to resume playing as normal.

Dev Preview 2 includes the version of YouTube that corrects its behavior to follow the guidelines at http://developer.android.com/preview/features/multi-window.html#lifecycle

"we recommend that activities that play video not pause the video in their onPause() handlers. Instead, they should pause video in onStop(), and resume playback in onStart()."

I launch YouTube in Multi-Window mode, when I press the Home Key, the YouTube is not visible, but it is still playing. I found it just go to onPause(), not go to onStop(). So is that OK?

When the system is in multi window mode and home button is pressed system should either:

1) Invoke onPause() but isInMultiWindowMode() should return false;
2) Invoke onStop();

I vote for alternative 1. It is more consistent with existing lifecycle.

I still have this on android 7.0 with nexus 6p. when YouTube is open and a second app is started then YouTube goes black. it comes back when I change the size sightly.

YouTube Player API still not follows the guidelines and pauses video in multi-window mode.

Simply resize video as small as possible and it will work.

As you can see video plays withoit any problem :)