b frames referencing i frames??

[Blue_MiSfit]

I was idle'y staring at my stats window today whilst encoding a movie, and happened to notice the following GOP sequence...

I
B
B
P
etc...

I was under the impression that B frames were always put in between P frames...

Is something fishy happening here, or am I just bothered about nothing?

thanks
~misfit

[Tommy Carrot]

B-frames can refer to I-frames, it's not like it's forbidden, just it's not wise to put it _before_ an I-frame, because there is a big chance that it's a scene-cut, and in that case the I-frame is completely different, so referring to it is highly inefficient. However, putting a b-frame after an i-frame (like in your example) can be done without any problems.

[Blue_MiSfit]

thanks for clearing that up.