On 30/12/16 00:14, Zhao Yakui wrote: > On 12/30/2016 02:52 AM, Mark Thompson wrote: >> On 29/12/16 07:09, Zhao Yakui wrote: >>> On 12/29/2016 03:08 PM, Xiang, Haihao wrote: >>>> >>>>> On 12/29/2016 01:22 PM, Xiang, Haihao wrote: >>>>>> User can use VAEncMiscParameterRateControl to update bitrate, so we >>>>>> should ignore >>>>>> the bitrate in the sequence parameter if >>>>>> VAEncMiscParameterRateControl is present. >>>>> >>>>> This makes sense. The MiscRateControl mentions that it can override >>>>> the >>>>> bps setting in sequence parameter. >>>>> >>>>>> Hence it is not needed to reset brc if >>>>>> VAEncMiscParameterRateControl doesn't change >>>>>> the used bitrate. >>>>> >>>>> Does it still need to send the VAEncMiscParameterRateControl >>>>> parameter >>>>> if the bps is not changed for the new sequence? >>>> >>>> Yes if bits_per_second in the sequence parameter is not equal to the >>>> value for the previous Begin/Render/End sequence except bits_per_second >>>> in the sequence parameter is 0. >>>> >>> >>> OK. >>> It makes sense. >>> >>> This looks good to me. >> >> I'm not sure this behaviour is correct. Should not the most recently given >> bitrate value from the user, either from sequence parameters or RC >> parameters, be used? When is_new_sequence is set, the user will have >> provided a set of sequence parameters (because we are making an IDR frame), >> so the bitrate there is provided by the user and should override any >> previous RC parameters given before that frame (but not any on this one). >> >> That is, I think it should work like: > > Hi, Mark > > Thanks for patch review and nice consideration. > As we know, IDR frame can indicate that a new video sequence is started. > During the decoding, the previous frames before IDR are discarded and not > used. Maybe it will be better that the encoding parameter related with RC is > resent after a new sequence. That is to say: The bps in SPS is used for the > initialization for a new sequence. If the MiscRC is sent, it will override > the bps in SPS. If there is no RC, the bps in SPS will be used. > > In such case the user-space middleware only needs to follow the same > logic for every video sequence. Otherwise the different logic is considered > for each video sequence.
Hmm, yes. That would entail discarding the contents of encoder_context->misc_param[VAEncMiscParameterTypeRateControl] when new sequence parameters are provided? (In the same way that ROI parameters are discarded after every frame.) I think that's a much nicer answer than what I had, and is more consistent as well. Thanks, - Mark _______________________________________________ Libva mailing list Libva@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/libva
