Re: [avtext] Frame marking & VP9 SVC

[Sergio Garcia Murillo <[e-mail]>]

On 05/07/2017 23:19, Bernard Aboba wrote:
> Sergio said:
>
> "So the question is they can be mapped 1-to-1 to the frame marking I 
> and B bits. If so, just adding that to the draft that the I and B bits 
> on the frame marking extension must be filled with the values of the 
> vp9 P and U bits ( I=!P , B=U), would work."
>
> [BA] It's not obvious to me that the P or U bits can be inferred from 
> existing framemarking bits including the I and B bits.

I agree, it is far from obvious.. :)

The point is that there is no easy way of calculating the B bit on frame 
marking for VP9 (you would need to process the SS to calculate it as you 
have done in the examples, but that info is not provided by the encoder 
neither present on the desc header), so the only close-enough info would 
be the U bit. If we "redefine" it's meaning for VP9 it could work.

Regarding the P bit, in prev draft the information was per layer-frame, 
now with the renaming, it is per picture. Not sure if it is a typo, or 
it has changed it's meaning, but if so, that would be exactly the 
inverse of the I bit.

Best regards
Sergio