Under what conditions will the browser cache <v

Question

Under what conditions will the browser cache files? Sometimes it does, sometimes it doesn't. If no one here knows, my next step will be to test the various file format, file size, and htaccess scenarios.

If you don't know, can you think of any other variables that you'd recommend testing?

Thanks in advance!

Answer 1

The following works to instruct the browser to cache the files. The last line was necessary to make the server deliver webm files with the correct header MIME type.

# Expires is set to a point we won't reach,
# Cache control will trigger first, 10 days after access
# 10 Days = 60s x 60m x 24hrs x 10days =  864,000
<FilesMatch "\.(webm|ogg|mp4)$">
Header set Expires "Mon, 27 Mar 2038 13:33:37 GMT"
Header set Cache-Control "max-age=864000"
</FilesMatch>
AddType video/webm .webm

Answer 2

The HTML5 spec is not strict about what a browser must do with caching video files - it just suggests what is "reasonable", so theoretically different browsers could have different behaviour.

Web developers can try to control video caching using the preload attribute on the <audio> or <video> element like this:

preload=none The user might not watch the video (i.e. better not to preload)

preload=metadata The user might watch the video (i.e. better to just download information about the video (size, duration, etc.))

preload=auto The user is likely to watch the video (i.e.probably a good idea to preload and cache the video)

As I said, the spec does not enforce this so browsers could ignore the preload values if they choose. One example could be if a browser detects a slow or unstable connection and therefore refuses to preload, although I don't know of any browsers that do this at present.

More information on the preload attribute is here: http://www.w3.org/TR/html5/video.html#attr-media-preload