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IVA codec reload time

ranchu
Guru 20755 points

Hello,

I would like to ask what is the estimate time it takes for IVA codec engine to unload and then load with a new codec? I assume it is the same for encoder and decoder.

Regards,

Ran

  • 0
    TI__Guru 59700 points

    The number measured in DVR RDK on 816x under real system load is around 25 - 35 micro seconds.i,e around 7000 - 10,000 M3 cycles with M3 running at 280 Mhz. This is for code and data reload case (Change in codec type as well as codec instance) . Note that this number depends on your instantaneous DDR load . In DVR RDK we use processN APIs where the frames from different channels (same codec type ) are grouped together and submitted to IVA HD. This greatly reduces the overhead of codec switching.

  • 0 in reply to Badri Narayanan
    Guru 20755 points

    Hi Badri,

    Is context switching something that can be tolerated, or does it damage the codec performance in most cases and should be prevented ?

    Thank you,

    Ran

  • 0 in reply to ranchu
    TI__Guru 59700 points

    Application should try to minimize context switching by assigning a proper channel to IVA map but this is _not_ something that should be avoided at all costs.Minimizing the number of channel switch is something that the application can easily tune if performance is a bottleneck .There are generally different concerns driving the channel map assignment at application level which are more important than minimizing context switch.For example in hybrid DVR usecases , the requirement is the encode fps should never be affected by decode channels and it is acceptable is decode is not realtime (reduces fps). So encodes and decodes are assigned to different IVA_HDs  (2 IVA_HDs to encode and single IVA_HD to all decode channels).