INTER4V ?? What is that ?

[ookzDVD]

Sorry for asking this in forum,
but I really don't have idea about that,

so hope some developers could give me just
a little introduction.... is it could
improve the quality or even could increase
the encoding speed ?

Thank you.

[Koepi]

INTER4V is a mode for storing motion data of a macroblock.

I'll explain it simple, thus introducing a small error, but I don't see the need for explaining every single detail :P

Usually, you have just have a macroblock of 16x16 pixels.
You can store it as INTRA (key-block), INTER (motion-block).
If you choose a search-precision >4 (mode 5 & 6), you enable the inter4v mode.

INTRA stores the whole block as "texture" with zero movement.
INTER stores 1 motion vector for the 16x16 block.
INTER4V breaks down the 16x16 MB into 4 8x8 blocks and stores 1 motionvector for each subblock (4V like 4 vectors).

If you choose motion search precision >4 you won't get a file with all MBs stored as 4 vectors, this would take up a LOT of space.

So this is just an addition, and the codec decides to use inter4v for a (some) MB if the overall frame gets smaller through this.

I hope this helps.

Regars,
Koepi

[ookzDVD]

@Koepi,

Thank you for the explaination.