Embedded video automatically plays once and then does not play when .pdf is in a loop.

Still keeps acting the same. Works one time and then just shows th black screen with the play button on the second loop. 

It sounds like the issue may be with how the video is being activated when the PDF loops back to that page. Since the video plays the first time but sometimes does not restart when the document returns to the page, I’d check the video’s Rich Media properties and its activation settings.

In Acrobat Pro, select the video with the Select Object tool and check the Launch/Activation settings. Also check whether the video is set to activate on Page Enter or Page Visible. You may also want to set it to disable when the page containing the video is closed, so the previous playback state is cleared before the page is entered again.

If it still happens, I’d test the same PDF with the video set to manual playback. If manual playback works every time, that would point more toward the page-loop/action setup rather than the video file itself.

​@different_Diamondcdce what type of video is being embedded in your PDF? Acrobat relies on system-level media frameworks to decode video. High-bitrate files or non-standard MP4 audio/video streams (like HEVC/H.265 or variable frame rates) can cause 15-second buffer timeouts. Use Handbrake to convert your video (it’s free for both Mac and PC) and it’s open source. For example, I tried to download a video from my Youtube channel: 

Of course, if I click on the next page, the video does stop. You can set it up where the video floats too. I tested with a video, and it continue to play for 3 minutes. Are you using the latest Acrobat?