Blue & Green frames in Studio14 ultimate

[Hadge]

Editing in Studio14 ultimate:

My clips are getting blue or green frames at start of clip,
and increasingly hard to get rid of.


Sometimes, trimming a frame from the clip works,
but then the unwanted frame crops up elsewhere.


What the heck is going on ?

[jagabo]

Open GOPs. Out of order storage in high compression codecs.

[Hadge]

Hi Jagabo,
Thanks for response, but I didnt understand it, unfortunately !



what are GOPs - how can I tell if they are open
& how do I close them ?


what is 'out of order storage' ( the video I am editing is MPEG2 )

[sanlyn]

what are GOPs

http://en.wikipedia.org/wiki/Group_of_pictures

[jagabo]

See Open and Close GOPs:
http://documentation.apple.com/en/compressor/usermanual/chapter_18_section_5.html

Out of order storage refers to the fact that the order of the compressed frames stored in the file is not the as the order in which they are to be displayed. That makes it more difficult for an editor to seek to random frames.

 1  2  3  4  5  6  7 --> Seven frames in order.
I1 B2 B3 P4 B5 B6 P7 --> How they're encoded and displayed.
I1 P4 B2 B3 P7 B5 B6 --> The order they're stored in the MPG file.

Since B2 and B3 can refer to either I1 or P4, both I1 and P4 must be decompressed before B2 and B3. So I1 and P4 appear before B2 an B3 in the MPG file. After the four frames have been decompressed they are displayed in the correct order.

[Hadge]

Wow,

I didnt realise it is so complicated !


So how can I overcome the problem, and eliminate the blue/green frames ?


Is there a difference in functions of blue VS green frames ?


ie: are they there for the same, or different reasons ?


Thanks for help guys, I am learning more & more