[Libva] (H264) Reference Picture selection

[Yuan, Feng]

Hi,

>>> I have a scheme where the decoder ack's received frames - With this
>>> information I could resync without an IDR by carefully selecting the
>>> reference frame(s).
>
>> Will you please describe your idea in detail?
>
>>> long term references would typically be employed as well, but it
>>> seems ref-pic-marking was removed may'13?
>
>> Why do you hope to use the long-term reference? As you know, the
>> current encoding is based on hardware-acceleration. When more the
>> reference frames can be selected, the driver will be more complex and
>> then the encoding speed is also affected.
>
>It's for implementing Cisco's clearpath technology
>(http://www.cisco.com/c/dam/en/us/td/docs/telepresence/endpoint/softwa
>re/clearpath/clearpath_whitepaper.pdf)
>Basically one would  periodically mark a P frame as long term reference, in
>case of packet loss one can thus refer to this one instead of restarting the
>stream with an idr.
>
>
>I'm not too concerned about the encoding speed as long as it's above
>realtime (60fps 1920x1080)

Maybe it's more convenient If libva can have a switch for slice_header made between driver and app. Then some specially cases(ref-reorder, long-term-ref) may let app to manage slice-header.