On Wed, 05 Jun 2019 23:01:37 +0200 Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx> wrote: > Hi, > > Le mardi 04 juin 2019 à 10:31 -0400, Nicolas Dufresne a écrit : > > Le mardi 04 juin 2019 à 10:12 +0200, Thierry Reding a écrit : > > > On Mon, Jun 03, 2019 at 07:55:48PM -0400, Nicolas Dufresne wrote: > > > > Le lundi 03 juin 2019 à 23:48 +0200, Jernej Škrabec a écrit : > > > > > Dne ponedeljek, 03. junij 2019 ob 13:09:45 CEST je Boris Brezillon napisal(a): > > > > > > The driver only supports per-slice decoding, and in that mode > > > > > > decode_params->num_slices must be set to 1 and the slice_params array > > > > > > should contain only one element. > > > > > > > > > > What Cedrus actually needs to know is if this is first slice in frame or not. I > > > > > imagine it resets some stuff internally when first slice is processed. > > > > > > > > > > So if driver won't get all slices of one frame at once, it can't know if this > > > > > is first slice in frame or not. I guess we need additional flag for this. > > > > > > > > A first slice of a frame comes with a new timestamp, so you don't need > > > > a flag for that. > > > > > > But slices for the same frame will all have the same timestamp, so we > > > can't use the timestamp to tell the individual slices apart. > > > > > > I mentioned this in that other thread, but I think it'd be useful to > > > pass along the number of each of the slices. Drivers can use this in > > > order to conceal errors when corrupt slices are detected during the > > > decode operation. > > > > This is already passed as this is part of the slice header that we both > > pass and parse to structure. Each slice have it's first MB indicated > > (that standard to H264) and you can deduce the lost slice from that. > > > > > So if we also passed a slice index along with the offset of the slice in > > > the bitstream, that should give us enough information to achieve both. A > > > slice with index 0 is obviously going to be the first slice in a frame. > > > > We do this in per-frame mode only. The offset of the slice in the > > bitstream is always 0 in per-slice mode, since each v4l2 input buffer > > is a slice. > > I don't think we need a slice index either, we most likely already have > enough information to know where we're at regarding slices position. > > But how about allowing an arbitrary number of slices within frame > boundary in per-slice decoding mode? Yep, will send a v2 taking that case into consideration.
