I looked into this while looking into https://bugs.chromium.org/p/chromium/issues/detail?id=893056. It seems that this problem is independent of surfaces, and I believe that somewhere along the way of creating the PiP window, we aren't correctly communicating the opacity. I don't really know much about how the PiP window is set up, so I'll defer this bug mlamouri@, but feel free to bounce it back onto me. 

Thanks for your feedback CJ!
I was able to reproduce without MediaStream.

If <video> is not visible, PiP window is black. In a non-MediaStream video, there is a play button in the PiP black window which allows user to start playback. In a MediaStream video, there is none. It means web developer has to call `video.play()` manually to start playback and video shows up in PiP window.


I'm not sure how to fix it. WDYT Mounir? 

From mlamouri@ in an email, pasted here to keep track of all the info.

"I believe the issue comes from FrameDeliver which seems to be suspended when the page becomes hidden. I think I added in the VFS a flag to always submit frames and weirdly, we may want to do the same thing here and have another flag that will tell FrameDeliver to never suspend while we are in Picture-in-Picture."

So, from what I can tell, in the case that I'm testing (PiPing the MediaStream video in https://beaufortfrancois.github.io/sandbox/media/picture-in-picture-playground), no frames are being suspended, but the background is still black.

It could be that there are two different issues happening here. When I was tracking down this issue, it seemed to be a problem with PiP specific code, not at the mediaplayer level.

So the reason why the background is always black is because of this line
https://cs.chromium.org/chromium/src/chrome/browser/ui/views/overlay/overlay_window_views.cc?rcl=4667a219b729a7e3cb1dc6b31d3f5ca024715dd9&l=269

I don't understand fully what we would want it to be. I can pass opacity information through, and that solves the issue I'm looking at, but I'm not too sure what you all are trying to solve/would want things to look like.

*fully understand

This happens to be a side effect of using <video autplay muted>: they end up being paused when not visible which leads to this.

I've added steps to reproduce in the description.

Please re-open as I can reproduce without "muted". 

I think I've found the issue. See https://chromium-review.googlesource.com/c/chromium/src/+/1299003

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0c7cd64aec528b8355ed040fe502ffc8c7dee33c

commit 0c7cd64aec528b8355ed040fe502ffc8c7dee33c
Author: François Beaufort <beaufort.francois@gmail.com>
Date: Thu Oct 25 21:45:36 2018

Always show mediastream video if Picture-in-Picture

This CL makes sure that a mediastream video always get painted if it is
in Picture-in-Picture.

Bug:  893062 
Change-Id: I0bf5fbe744a98155135dcade83e6ba7646d2f6b3
Reviewed-on: https://chromium-review.googlesource.com/c/1299003
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602865}
[modify] https://crrev.com/0c7cd64aec528b8355ed040fe502ffc8c7dee33c/content/renderer/media/stream/webmediaplayer_ms.cc
[modify] https://crrev.com/0c7cd64aec528b8355ed040fe502ffc8c7dee33c/content/renderer/media/stream/webmediaplayer_ms.h

This bug requires manual review: M71 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), kbleicher@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Tried checking the issue on latest chrome version 72.0.3592.0 using Mac 10.13.1 with the below mentioned steps.
1. Launched Chrome
2. Navigated to https://beaufortfrancois.github.io/sandbox/media/picture-in-picture-get-user-media.html
3. Clicked on "Toggle Picture-in-Picture" button
4. Then clicked on "Toggle video visibility" button
In step 3 after clicking "Toggle Picture-in-Picture" button, Still observing the black screen. Attaching the screen cast of the same for reference.

@François Beaufort: Could you please have a look at the screen cast and let us know if we have missed anything while testing the issue. And requesting you to help us in verifying the fix.

Thanks!

Deleted: 893062.mp4 1.8 MB

	893062.mp4 1.8 MB View Download

 fbeaufort@, PTAL comment #17 and verify the bug on latest canary, also pls provide merge justification. Thank you.

Picture-in-Picture window (in the corner) is not black anymore. So we're good. Thanks for testing  vamshi.kommuri!

govind@, we're aiming to experiment with Picture-in-Picture for MediaStreams in Beta M71. The intent is to be able to use a finch experiment.

Thank you  fbeaufort@.

Approving merge to M71 branch 3578 based on comment #19. Pls merge  before 3:00 PM PT, Monday so we can pick it up for next week Beta release. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f8d863a28d55d9369058e31a8715b554867f3836

commit f8d863a28d55d9369058e31a8715b554867f3836
Author: François Beaufort <beaufort.francois@gmail.com>
Date: Sat Oct 27 06:31:30 2018

Always show mediastream video if Picture-in-Picture

This CL makes sure that a mediastream video always get painted if it is
in Picture-in-Picture.

Bug:  893062 
Change-Id: I0bf5fbe744a98155135dcade83e6ba7646d2f6b3
Reviewed-on: https://chromium-review.googlesource.com/c/1299003
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#602865}(cherry picked from commit 0c7cd64aec528b8355ed040fe502ffc8c7dee33c)
Reviewed-on: https://chromium-review.googlesource.com/c/1303335
Reviewed-by: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/branch-heads/3578@{#358}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
[modify] https://crrev.com/f8d863a28d55d9369058e31a8715b554867f3836/content/renderer/media/stream/webmediaplayer_ms.cc
[modify] https://crrev.com/f8d863a28d55d9369058e31a8715b554867f3836/content/renderer/media/stream/webmediaplayer_ms.h

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/f8d863a28d55d9369058e31a8715b554867f3836

Commit: f8d863a28d55d9369058e31a8715b554867f3836
Author: beaufort.francois@gmail.com
Commiter: beaufort.francois@gmail.com
Date: 2018-10-27 06:31:30 +0000 UTC

Always show mediastream video if Picture-in-Picture

This CL makes sure that a mediastream video always get painted if it is
in Picture-in-Picture.

Bug:  893062 
Change-Id: I0bf5fbe744a98155135dcade83e6ba7646d2f6b3
Reviewed-on: https://chromium-review.googlesource.com/c/1299003
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#602865}(cherry picked from commit 0c7cd64aec528b8355ed040fe502ffc8c7dee33c)
Reviewed-on: https://chromium-review.googlesource.com/c/1303335
Reviewed-by: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/branch-heads/3578@{#358}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}

Able to reproduce the issue on chrome version# 71.0.3578.20(Build without fix)
Verified the fix on Mac 10.12.6 and Windows-10 on Chrome version #71.0.3578.30 as per the comment#0
Attaching screen cast for reference.
Observed "video in PIP window continued playing"
Hence, the fix is working as expected.
Adding the verified label.

Thanks!

Deleted: 893062.mp4 1007 KB

	893062.mp4 1007 KB View Download