Speed up video playback on Firefox with a click - no more choppy videos!

Problem

You wanted to catch a Flash video (on YouTube, Vimeo or other similar services), but suddenly the video starts getting stuck, its playback gets choppy and you're forced to reload the page or to give up because of your browser's poor performance. Sound familiar?

This may happen both because of Adobe Flash issues (i.e. an outdated or corrupt version) and because of some browser settings. Mozilla Firefox saves a snapshot of the video file each 15 seconds. This is helpful in case of a crash (as you can resume the video from where you left off) but it causes your browser to utilize more RAM memory than it should and that's the root of the problem. 

Solution

The quickest solution to this problem is to setup a higher time interval for the browser to save a snapshot, so Firefox will use less RAM memory and videos will be played smoothly.  To do this, you'll need to access Firefox advanced option by entering the following URL in your browser: about:config.

A pop-up message will warn that you could void your warranty by changing these settings (Fig.1). Click I'll be careful, I promise! and move on.

Fig. 1

You'll be shown Firefox advanced settings page (Fig. 2).

Fig. 2 (click to enlarge)

The page has a search engine to look for specific settings.

We'll need to locate the browser.sessionstore.interval item. This key determines the time interval at which Firefox will save a snapshot of the video. After finding this key through the search engine (Fig. 3) select it and double-click it.

Fig. 3 (Click to enlarge)

Fig. 4 (Click to enlarge)

You'll be shown a pop-up window where you can enter a new value for that key (Fig. 4) replacing the default (15000). Enter a higher value (for example 40000=40 seconds), click OK and restart Firefox.

You'll notice that your videos will play much more smoothly now. In case you should experience some problem after this change, you can revert it by accessing back about:config, locating the option you have changed and restoring the default value of the key.