The Downmixer wasn't updating its output format correctly, so it was
prone to outputting the wrong format for a while, which could confuse
the output device and produce garbage output.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>
Check for paused processing state in various places, so that startup
playback works properly, and resume playback at seek offset works
properly and doesn't hang the player.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>
