bframes number

[Kandor]

I have a question about bframes in xvid.
you can choose to have more than 1 in a row. but what is the effect? because I have tried with like up to 9 in a row and it looks exactly the same for me as with only 1 in a row.
the only diffrence is the size is smaller with 9 in a row (to my eyes) .

so if it is not a bad thing to use many for my eyes can I use like 100 in a row? or is there any other downside than picture quality if I use many?
someone please explain this for me.
sorry if this has been asked before but I didnt find anything very relative to my question that answers it 100%.

but anyway

Best Regards

Kandor

[Teegedeck]

The numbers you can set only determin a maximum. XviD decides dynamically whether to insert a B-frame (B-frames don't always give better results than P-frames) or not. When there's a lot of motion, you probably will have only 1 B-frame before another P-frame, when there's not much moving there might be 5 in a row or something. So, if you don't notice much of a difference, XviD's B-frame-decision seems to work pretty well. :) Actually it only means that the video you've encoded doesn't seem to allow too many B-frames in a row.

Because from others' (including mine) experience, sometimes even 4 B-frames are too many and make for a visible degradation of quality; and it doesn't help compressibility that much to set the limit higher.

[Kandor]

thank you very much. I use quant 2 all the way and I have only tried xvid with lord of the rings so far. so thats why I havent noticed anything. it is very clean source and maybe thats why.
but now I know how it works so I can experiment a little and see what happens.

but thank you once more.

Kandor