Question

Consider a DASH system for which there are N video versions (at N different rates and qualities) and N audio versions (at N different rates and qualities). Suppose we want to allow the player to choose at any time any of the N video versions and any of the N audio versions. a. If we create files so that the audio is mixed in with the video, so server sends only one media stream at given time, how many files will the server need to store (each a different URL)? b. If the server instead sends the audio and video streams separately and has the client synchronize the streams, how many files will the server need to store?

Answer 1

Answer: a) N² files. b) 2N files.

Explanation:

If an user can choose freely both the video and the audio quality, if they are stored separately, but the user can download any mix of them as a single file, the server must store one audio version for each video version, so it will need to store NxN = N² files.

If, instead, the server can send the audio and video streams separately, so the user can choose one of the N videos available, and one of the N audio versions, the server will need to store only N video files + N audio audio files, i.e. , 2 N files.