add assert to detect invalid packet_timestamp_start/end (that is check that the previous fix was sufficient)
add assert to detect invalid packet_timestamp_start/end
(that is check that the previous fix was sufficient)


git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@11153 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg