Fixes an error when playing a QuickTime video that has a mediaTime set
on its first edit. This was caused by mediaTime changes in:
ef184a6cef
Those changes buffered frames during initialization so that the keyframe
and other frames don't play instead of the intended start frame that
mediaTime specifies. My mistake was that decoding isn't allowed during
VideoDecoder::loadStream(); VideoDecoder::setDitheringPalette() requires
that no frames have been decoded yet, and at least Director and Mohawk
call that.
Now the initial mediaTime buffering is delayed until the first decode.
Fixes bug #13479 where certain Myst videos error.
Fixes the opening movie in the Director game Chop Suey.
sluicebox
69662ee9a4