You Tube’d? Weird caching issue wrecks video playback?

First some good news.

By the time I got to the end of this troubleshooting I found a work-around for the problem and I can play any YouTube video I try, and even make them run full screen.

In the process of my research I also discovered Obama Girl. Not a bad discovery…

Now back to the disappointing surprise…

Something very strange is going on with YouTube playback.

Before I go any further, I did have Firefox crash previously (or did I terminate it because it froze? I can’t remember). Either way, it resulted in a “white” desktop. I hope that helps the Zonbu team. Now a brief description of the issue:

It’s not a performance issues, the frame rate and audio synch look great (even full screen). It’s some kind of strange caching issue.

Now I’ll preface this by saying I run the broadband ISP I’m attached to so I know the cache architecture intimately. It’s big and complex but it doesn’t cause this problem. At least not with any other Linux or Windows clients.. Read on to discover what is happening…

Ground hog day?

The first video I watch, on opening the browser and visiting YouTube, plays fine. When I click on a second video, FF loads the surrounding content, titles, sidebar, links etc. and appears to be loading the video. Then, to my shock and amazement it plays the exact same previous video. I can click on other random links and I’ll keep getting the same first video.

I tried center-clicking (to open the target in a new window) and sometimes that got me the proper video, sometimes I still got the original video. Strangely, about six videos later, instead of the correct sixth video, I got the second or third video I clicked on.

Some weird cache issues is going on, and its not the ISP cache.

Set Firefox to 0MB of cache

I immediately suspected the browser cache, so I looked in the preferences and set the default Zonbu Firefox cache size (100MB) down to 0MB. I restarted the browser and tried again. Same weirdness as before.

I’m not sure what else to try. I’ll try a reboot and see what happens…

Post Reboot – Everything is ok now?!

Looks like I found a real bug. Whatever caused the “white desktop” crash may or may not have contributed to the flash problem.

Happily, on a reboot, YouTube is working normally (note that my FF cache is still set to 0MB).

I’m going to turn the FF cache back on and see what happens.

Cache re-enabled and the problem is back

Drat. The firest video I clicked on (something about the Simpsons premiere) resulted in a replay of Cristina Aguileras (does anyone spell that right on the first try?) “Candyman” music video, which I had clicked on previously (prior to turning the cache back on).

I’ll restart FF and see what happens, with the cache back at 0 MB.

This looks like it might be nasty… I really should get paid for this work.

Cache back to 0MB and FF reset – everything ok

Well I’ve confirmed it. If you don’t set the cache to 0MB then you get very odd behavior with YouTube. Or at least I do.

I’ll look to others (or to Zonbu themselves) to confirm my findings.

Please comment if you have any first hand experience with this.

-Mr. Zonbu

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