Affected versions:
Nightly aarch64 70.0a1
Beta aarch64 v69.0b5
Release aarch64 v68.0

Affected platforms:
ARM64 - Windows 10

Steps to reproduce:

• Launch Firefox
• Go to any live streaming platform, such as twitch or youtube
• View any live stream that has 1080p resolution in settings
• Switch to 1080 resolution

Expected Firefox:

• The live streams should update the resolution and be played back without any issues.

Actual Result:

• The video will get stuck at a frame while the audio is still on-going.

Note:
Switching the resolution to a lower scale will fix this.
On Chrome live streams and videos work properly with 1080 resolution or higher
Normal videos can also stutter if higher resolutions are selected than the native one.

Here is an example of a normal video with 1080p 60fps that is constantly getting stuck frames and audio on-going:
http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_60fps_normal.mp4

Nils, any thoughts on who should take a look at this? I marked it P2 for now.

Reproducible on latest Nightly 73 on the same devices, marking the other version affected as well.

Reproducible on latest Nightly 74 on the same ARM YOGA laptop.

This is h.264 being decoded in software on these machines, could it be that this bit rate is simply too much for these low-powered machines to keep up?

Clearing this NI after 2 years.