Reply #17: Flash video is a bear

[charlie]

and it gets worse with every new iteration. I'm one who thinks the problem is largely with Flash itself. It's prone to memory leaks. Its customizability compounds the problem of performance -- its feature set and GUI for videos can be manipulated by website developers and some are better at it than others. YouTube is good at Flash optimization (it's Google, they're great at that sort of thing), compared to the likes of Vimeo, Break, 5minute, etc.

Unfortunately, I can't help with fixing intrinsic Flash video problems, but there are 3 things that have made my Firefox experience immeasurably better.

First, if you're using extensions, find out if any of them conflict with video performance. You can do this a couple of ways. One is to use the Add-ons menu under Tools to disable all extensions, then restart Firefox. The other is to create a new profile: Close Firefox, then... Start --> Run --> Cmd --> Enter "firefox.exe -profilemanager" (without the quotes). Use the prompts to make another profile and start that. Either way, use Firefox sans extensions for a good while, visiting a lot of video sites, and see if there is improvement. If there is, re-enable (or reinstall) extensions one by one with video testing inbetween, beginning with the ones you think you need the most. If any of them affect performance, they're the ones to dump.

Second, you can increase the size of Firefox's video cache.

Type "about:config" in the URL bar. Click through the warning. Right-click anywhere on the page that comes up and from the submenu, click "New", then "Integer". Type "browser.cache.memory.capacity" (no quotes) in the dialog that pops up and click OK. Enter a number in KBs in the next dialog. 80000 is often suggested as sufficient. I use 100000. Close and restart Firefox. Again, surf for a while and see if it made a difference.

Third. With this one, you'll have to make a choice to lose something to gain something. It is, however, the modification that had the largest effect for me.

Firefox comes with a crash recovery feature. To do this, it polls all open webpages every 10 seconds. So if it crashes, the state of the pages it restores are as close as possible to the ones you had open. It's good, but it can also get CPU intensive. Have enough pages open or surf long enough for Firefox's memory usage to bloom, and it'll start to interfere with Flash video playback. If the stuttering you see happens with metronomic regularity, this is probably the big culprit.

You can set Firefox to poll less frequently. The trade-off is, of course, that if it crashes, the restored session can be much older than 10 seconds before it went blooey.

Type "about:config" in the URL bar. Click the warning. Type "browser.sessionstore.interval" in the filter box to find and isolate the line you need to change. The line will have a default value of 10000. Right-click the line and select Modify. Change it to something longer, in milliseconds. I use 300000, which is 5 minutes. Close Firefox and restart.

Bonus tip: Consider using a Flash blocker, such as NoScript or FlashBlock. Cutting the number of instances of Flash running concurrently goes a way toward taking a load off your CPU.