Hi, On Thu 03 Oct 19, 22:44, Jernej Škrabec wrote: > Dne četrtek, 03. oktober 2019 ob 22:28:46 CEST je Paul Kocialkowski > napisal(a): > > Hi, > > > > On Thu 03 Oct 19, 07:16, Jernej Škrabec wrote: > > > Dne četrtek, 03. oktober 2019 ob 00:06:50 CEST je Paul Kocialkowski > > > > > > napisal(a): > > > > Hi, > > > > > > > > On Wed 02 Oct 19, 21:35, Jernej Skrabec wrote: > > > > > Reference index count in VE_H264_PPS should come from PPS control. > > > > > However, this is not really important, because reference index count > > > > > is > > > > > in our case always overridden by that from slice header. > > > > > > > > Thanks for the fixup! > > > > > > > > Our libva userspace and v4l2-request testing tool currently don't > > > > provide > > > > this, but I have a pending merge request adding it for the hantro so > > > > it's > > > > good to go. > > > > > > Actually, I think this is just cosmetic and it would work even if it would > > > be always 0. We always override this number in SHS2 register with > > > VE_H264_SHS2_NUM_REF_IDX_ACTIVE_OVRD flag and recently there was a patch > > > merged to clarify that value in slice parameters should be the one that's > > > set on default value if override flag is not set in bitstream: > > > https://git.linuxtv.org/media_tree.git/commit/? > > > id=187ef7c5c78153acdce8c8714e5918b1018c710b > > > > > > Well, we could always compare default and value in slice parameters, but I > > > really don't see the benefit of doing that extra work. > > > > Thanks for the detailed explanation! So I just realized that for HEVC, I > > didn't even include the default value in PPS and only went for the > > per-slice value. The HEVC hardware block apparently only needs the fields > > once at slice level, and by looking at the spec, only one of the two set of > > fields will be used. > > > > So perhaps we could do the same for H.264 and only have the set of fields > > once in the slice params, so that both codecs are consistent. Userspace can > > just check the flag to know whether it should put the PPS default or > > slice-specific value in the slice-specific control. > > > > What do you think? > > I think that there would be less confusion if only value in slice params would > exists. But since Philipp rather made clarification in documentation, maybe he > sees benefit having both values? Actually I just caught up with the discussion from thread: media: uapi: h264: Add num_ref_idx_active_override_flag which explains that we need to pass the default fields for hardware that parses the slice header itself and we need the non-default fields and flag for other cases. To cover the case of hardware that does slice header parsing, I guess it would also work to use the slice-specific values in place of the pps default values in the hardware register for that. But it feels quite confusing and a lot less straightforward than having all the fields and the override flag exposed. So I think I should fix HEVC support accordingly, just in case the same situation arises for HEVC. Cheers, Paul > Best regards, > Jernej > > > > > Cheers, > > > > Paul > > > > > Best regards, > > > Jernej > > > > > > > Acked-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx> > > > > > > > > Cheers, > > > > > > > > Paul > > > > > > > > > Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx> > > > > > --- > > > > > > > > > > drivers/staging/media/sunxi/cedrus/cedrus_h264.c | 8 ++------ > > > > > 1 file changed, 2 insertions(+), 6 deletions(-) > > > > > > > > > > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c > > > > > b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c index > > > > > bd848146eada..4a0e69855c7f 100644 > > > > > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c > > > > > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c > > > > > @@ -364,12 +364,8 @@ static void cedrus_set_params(struct cedrus_ctx > > > > > *ctx, > > > > > > > > > > // picture parameters > > > > > reg = 0; > > > > > > > > > > - /* > > > > > - * FIXME: the kernel headers are allowing the default value to > > > > > - * be passed, but the libva doesn't give us that. > > > > > - */ > > > > > - reg |= (slice->num_ref_idx_l0_active_minus1 & 0x1f) << 10; > > > > > - reg |= (slice->num_ref_idx_l1_active_minus1 & 0x1f) << 5; > > > > > + reg |= (pps->num_ref_idx_l0_default_active_minus1 & 0x1f) << 10; > > > > > + reg |= (pps->num_ref_idx_l1_default_active_minus1 & 0x1f) << 5; > > > > > > > > > > reg |= (pps->weighted_bipred_idc & 0x3) << 2; > > > > > if (pps->flags & V4L2_H264_PPS_FLAG_ENTROPY_CODING_MODE) > > > > > > > > > > reg |= VE_H264_PPS_ENTROPY_CODING_MODE; > > > > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com
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