Noticed that PiP window closes while watching video popped out from Air Mozilla.

Steps to reproduce:

1. Watch video - example "Virtu-All Hands 2020 - Desktop All Hands"
2. Pop out video

What happens:

After a few minutes, the PiP window closes. The video continues playing in the parent tab.

Expected result:

PiP window does not close.

I see errors in the developer console:

Media resource blob:https://onlinexperiences.com/417a3ba3-538d-4c84-8437-63b961980b71 could not be decoded. Server.nxp
error 3016 
Object { detail: {…}, bubbles: false, cancelable: false, defaultPrevented: false, timeStamp: 569497, type: "error", isTrusted: false, currentTarget: {…}, target: {…}, a: false }
MediaPlayer.js:1:16459
This error message will be blank when privacy.resistFingerprinting = true.  If it is really necessary, please add it to the whitelist in MediaError::GetMessage: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004) - virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<58>::DoDecode(mozilla::MediaRawData *, uint8_t *, int, bool *, MediaDataDecoder::DecodedData &): avcodec_send_packet error: -1094995529 shaka-player.compiled.js:510:333
Media resource blob:https://onlinexperiences.com/417a3ba3-538d-4c84-8437-63b961980b71 could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004)
Details: virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<58>::DoDecode(mozilla::MediaRawData *, uint8_t *, int, bool *, MediaDataDecoder::DecodedData &): avcodec_send_packet error: -1094995529 Server.nxp

Please disable widget.wayland-dmabuf-vaapi.enabled and widget.wayland-dmabuf-video-textures.enabled. If it doesn't come back, we can likely close this as dupe of bug 1643855. I assume the pip window closes in case of an "the video file is corrupt" error message (or its MSE equivalent).

I could reproduce this with YouTube. The PIP window was closed. (YouTube tries to fall back to the next lower video quality as often as possible. If it fails at the lowest quality, it shows even an error message instead of the video.)

Medien-Ressource blob:https://www.youtube.com/2e5446fc-f18f-4326-b766-5f282e315fd3 konnte nicht dekodiert werden, Fehler: Error Code: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004)
Details: virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<58>::DoDecode(mozilla::MediaRawData *, uint8_t *, int, bool *, MediaDataDecoder::DecodedData &): avcodec_send_packet error: -1094995529