Use MediaCodec API for Android

[kairusds]

I think this is a better option than using ffmpeg just to reduce the overhead and improve performance as it actually uses the built-in low-level APIs.

I thought I'd just leave this suggestion here in case the development shifts focus on this specific os.

[bdach]

FFmpeg has the benefit of just-working on all platforms and not needing to go out of our way to support Android.

Gains would have to be demonstrably significant to even begin considering this.

[kairusds]

I'm not sure about the performance since I haven't really used the API in any real-world projects yet but it has the ability to encode videos from a Surface class which might be useful for turning replays into videos without the need for using screen recording software.

[bdach]

Recording replays into videos is out of scope of the project, sorry.

[tutacat]

FFMpeg/libavcodec supports MediaCodec already, you just need to select it as the hwaccel (decoder). Video currently causes too much latency to be used realistically.

[peppy]

cc @FreezyLemon for visibility