Fix shift in buffer size calculation which resulted in too large allocs.

Fixes issue 426.
Check allocation of the conversion buffer
Update QuickSync decoder
qsdecoder: temporirarly activate timestamp manager

This fixes a few issues with unset timestamps which cause the driver to
"invent" timestamps.
Update ffmpeg
Separate ATRAC series from Real Audio

ATRAC is not a Real format, although its older versions are at
times seen muxed in Real files.
Add support for ATRAC3+