Created attachment 287500 [details] [review]
dashdemux: improve bandwidth calculation

The current method used in dashdemux compute the overall bandwidth from the beginning of the stream download, so the more you go in time, the less you are likely to be able to react to a (big) bandwidth change.

The following patch uses a simple sliding window, where the download rate is computed for each fragment download. A simple average is made out of the N previous value to get the current bandwidth, so dashdemux is more likely to react to bandwidth changes.

This patch is a WIP and obviously need to be tweaked / completed (and more tested): so we don't end up switching representations all the time.

Maybe we can try to react quickly when the bandwidth goes down, and slightly recover when it goes up to preserve playback smoothness ?

Comments welcome :)