only render the frames that are available
only render the frames that are available

This is in a pretty ugly state, as I haven't yet figured out the API semantics
I want SwfdecAudio to provide in the future yet, in particular the behavior of
"no more data available for rendering right now"

freedesktop-unofficial-mirror/swfdec__swfdec,mltframework/swfdec,mltframework/swfdec,freedesktop-unofficial-mirror/swfdec__swfdec,freedesktop-unofficial-mirror/swfdec__swfdec