Le mardi 16 avril 2019 à 16:16 +0900, Tomasz Figa a écrit : > On Fri, Apr 12, 2019 at 12:57 AM Maxime Ripard > <maxime.ripard@xxxxxxxxxxx> wrote: > > Hi, > > > > On Fri, Apr 05, 2019 at 12:27:48PM -0400, Nicolas Dufresne wrote: > > > Le vendredi 05 avril 2019 à 17:15 +0200, Maxime Ripard a écrit : > > > > Hi Nicolas, > > > > > > > > On Thu, Apr 04, 2019 at 11:41:13AM -0400, Nicolas Dufresne wrote: > > > > > > > > + * - __u16 > > > > > > > > + - ``pic_width_in_mbs_minus1`` > > > > > > > > + - > > > > > > > > + * - __u16 > > > > > > > > + - ``pic_height_in_map_units_minus1`` > > > > > > > > + - > > > > > > > > > > > > > > We recently had some reflection with Alex that this is redundant with > > > > > > > the width and height in the OUTPUT format. It may also apply to some > > > > > > > other fields in these structs. I feel like they should be removed and > > > > > > > passed via corresponding generic V4L2 properties - format, selection, > > > > > > > etc. > > > > > > > > > > > > > > The same problem is also present in the MPEG2 controls. In fact, there > > > > > > > was a patch already which used some fields from the controls to > > > > > > > calculate the destination buffer strides, rather than bytesperline in > > > > > > > the format. > > > > > > > > > > > > > > Since we're in staging, it could be done with a follow-up patch, though. > > > > > > > > > > > > Just my two cents. I played with some codecs a while back. IIRC some > > > > > > specify a "codec" size in addition to the actual picture size, like > > > > > > when the encoder does padding to fit the requirements of the codec > > > > > > (spec). Is this needed anywhere? > > > > > > > > > > With state-less encoders, the headers, which contains the crop > > > > > information is created by userspace and for state less decoder, the > > > > > headers that contains this information is parsed by userspace. So I > > > > > believe that in theory, the accelerator does not strictly need to be > > > > > aware of the cropped dimensions. > > > > > > > > > > Another thing, is that there is not guarantied matches between e.g. > > > > > depth of the chrome/luma and the final image buffers. Some hardware may > > > > > have bandwidth limitation or internal converter and could possibly > > > > > decode 10bit data into 8bit buffers. > > > > > > > > > > A third reason why I would not try and encode this header information > > > > > is that there can be multiple PPS/SPS at the same time, and I think > > > > > it's confusing if the relevant information to differentiate them is > > > > > removed. > > > > > > > > Sorry if that sounds a bit dumb, but it's not really clear to me if > > > > you're arguing for the removal of the data as Tomasz suggests, or if > > > > you want to keep them. > > > > > > > > The first paragrah seems to advocate for the former, but the two > > > > others for the latter. > > > > > > I think the data should stay. As I said, there can be multiple SPS/PPS, > > > while there is only one format. That being said, how does SPS/PPS > > > activation works ? How do you tell the driver about all the SPS/PPS and > > > which one is being activated ? > > > > The current way of dealing with this is that the _SLICE_PARAMS control > > actually takes an array of SPS's. And same thing for PPS. > > > > There's no difference between activated and deactivated ones > > though. What is the use case for this? > > Uhm, there is only one format, but so there is only one active > SPS/PPS, isn't it? Yes, and the active one can only change on frame boundary. > An alternative would be to just make the OUTPUT format a function of > the currently set controls, so that it would always match the active > PPS/SPS, without the ability for the application to change it. > > I just want to avoid the case when the OUTPUT format can be set > randomly to something different than in the stream and also drivers > reading randomly the format-related information sometimes from the > controls and sometimes from the format state. Understood. > > Best regards, > Tomasz
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