HTML5 stutters

[kelvin-koolohm]

I use NoScript because I'm paranoid. I use the HTML5 playback on Youtube to avoid using Flash.
I leave Youtube, Ytimg, and Googlevideo disabled until I want to actually watch something on Youtube.
Even then, I only temporarily allow them.
Can someone explain to me why not enabling other Google sites would cause the following weird behavior:
I start a video with Youtube, Ytimg, and Googlevideo temporarily enabled.
EVERY time (no matter what video), after EXACTLY 25:21 (25 minutes, 21 seconds), the image update
stops and the sound becomes choppy. If I stop the playback and back the progress bar up a couple of
seconds and restart the video, it will play for another 25:21 and then I have to do the same thing again.
I have to continue doing this all the way through the video and if one of the multiples of 25:21 falls
just a couple of seconds short of the end of the video, I have to use the same procedure just to get
the video to finish.
Simply stopping the video and restarting it doesn't work. You actually have to back the progress bar
up a couple of seconds and then restart it.
Although I've only tried it twice, temporarily allowing every single Google site that pops up in the "allow"
menu seems to let the video play completely.
What Google script would stop video playback every 1521 seconds and why?

[barbaz]

I have a similar NoScript setup to you for Youtube and I've never seen this.

Can you please post a URL to a video where you experience the behavior?
Do you have Media Source Extensions enabled? (about:config > media.mediasource.* should all be set to true)
Does https://www.youtube.com/html5 show anything unsupported in your browser?

[kelvin-koolohm]

The Youtube HTML5 check page shows red exclamation marks for H.264 and MSE & H.264,
everything else is O.K.

My Win10 machine does not show the problem, only my WinXP, SP3 machine has it.

If you are a fan of steam railways and don't mind seeing the Scottish Highlands and north Wales,
you won't feel like you've wasted an hour and ten minutes on the following documentary.

For those volunteers who've given their time to improve Firefox and NoScript and who are hoping
it's appreciated, be sure to watch the last 15 minutes of this documentary to see how
volunteers literally gave up every free minute in the 1960's to dig 2 1/2 miles of new track
bed and hand-cut a 280 foot tunnel to rejuvenate a railroad that had been neglected for so
long that small trees were growing up through the tracks.
Since large parts of the scenery are shot from the helicopter following the documentary crew
on the train, be sure to watch this in full screen on the largest monitor that you have.

https://www.youtube.com/watch?v=8nSqU12oGsk

BTW, "content.googleapis" and "googletagservices" are the 2 google sites still disallowed.

Any further suggestions?

Thanks

[barbaz]

Sorry the delay. No stuttering here on that video either.

Can you please right-click the video, select "Stats for nerds" (in Youtube's context menu), wait for the stuttering to start, and post the information here?
(You might need to take a screenshot of it as it's hard to select and copy.)

For comparison, with some numbers partially obscured:

Code: Select all

Mime Type: video/webm; codecs="vp9"
DASH: yes (***/***)
Connection Speed: 2**** Kbps
Buffer Health: 355.0 s
Dropped Frames: 0/39***

Maybe it's an OS-specific issue?