Unexpected droppedVideoFrames while using a-videosphere

Description:

• A-Frame Version: 1.3.0
• Platform / Device: Intel Mac OS X 10_14_4, Chrome/108.0.0.0
• Reproducible Code Snippet or URL:

let quality = document.querySelector('a-videosphere').object3D.children[0].material.map.image.getVideoPlaybackQuality();
decoded = quality.totalVideoFrames;  // 657
dropped = quality.droppedVideoFrames; // 646

Actually, the frames are decoded successfully and the playback is not stalled. Since droppedVideoFrames are defined as the frames that are typically dropped either before or after decoding when it's determined that it will not be possible to draw them to the screen at the correct time, maybe it is reasonable that there are so many droppedVideoFrames due to partial render of the 360 video.

I wonder if there is any way to measure the dropped frames in panorama video when using a-videosphere?

Start by reproducing the reported getVideoPlaybackQuality() measurements from the a-videosphere snippet in the issue on the listed Chrome and macOS environment. Compare droppedVideoFrames with the visible 360-video playback and determine whether A-Frame exposes a meaningful panorama-specific measurement; document the result and any supported approach.