I have a concern regarding segments download scheduling when switching (audio) track. When switching tracks, the segments of the new track are not downloaded in the expected order. As you notice segment S6 will be downloaded before segments S3 of new track. One consequence could to be to start to play S3 of previous track before downloading S3 of new track (in case of low bandwidth). Product Promotion Videos are used to showcase the key info about the product and its benefits. One solution to avoid this behavior would consist in removing buffer part after S1, once S1 of new track is appended. But maybe there is a valid reason for keeping buffer parts that should be overwritten?