[ExoPlayer] Using MergingDataSource

I'm using AndroidVideoCache v2.7.0 and ExoPlayer v2.4.1, I have no trouble playing & caching a **single** media, however, I can't find a way to cache two medias (audio & video) at the same time.

To get into the details, I'm retrieving the URLs of the audio and video medias separately, I tried to cache both medias at the same time but it would then throw an IllegalStateException when passing the URI to ExoPlayer. Removing the cache functionality, passing both URI to ExoPlayer with MergingMediaSource works well and no errors are thrown.

So i'm starting to guess AndroidVideoCache cannot cache two or more medias at the same time. I dived a bit into the code and noticed the library open a single socket bound to the local address per instance. Even if I tried to create 2 instances of HttpProxyCacheServer, it doesn't work aswell.

Inizia riproducendo il caso con due media con AndroidVideoCache v2.7.0 ed ExoPlayer v2.4.1, usando URL separate per audio e video con MergingMediaSource. Esamina HttpProxyCacheServer e la IllegalStateException segnalata, quindi determina se il caching simultaneo è supportato; il lavoro è completato quando il comportamento è stato corretto oppure la sua limitazione è stata stabilita chiaramente.

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