On Thu, Sep 5, 2019 at 11:17 PM Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx> wrote: > > Le jeudi 05 septembre 2019 à 12:39 +0200, Philipp Zabel a écrit : > > On Thu, 2019-09-05 at 19:31 +0900, Tomasz Figa wrote: > > > On Thu, Sep 5, 2019 at 7:15 PM Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote: > > > > This flag tells the kernel whether the slice header contained the > > > > num_ref_idx_l[01]_active_minus1 syntax elements, or whether the > > > > num_ref_idx_l[01]_default_active_minus1 from PPS should be used > > > > instead. > > > > > > > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > > > --- > > > > Documentation/media/uapi/v4l/ext-ctrls-codec.rst | 3 +++ > > > > include/media/h264-ctrls.h | 1 + > > > > 2 files changed, 4 insertions(+) > > > > > > > > diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > index bc5dd8e76567..451a5b0f2a35 100644 > > > > --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > @@ -1860,6 +1860,9 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - > > > > * - ``V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH`` > > > > - 0x00000008 > > > > - > > > > + * - ``V4L2_H264_SLICE_FLAG_NUM_REF_IDX_ACTIVE_OVERRIDE > > > > + - 0x00000010 > > > > + - Corresponds to the num_ref_idx_active_override_flag syntax element. > > > > > > > > > > As far as I remember, the idea was for the userspace to always put the > > > right num_ref_idx in the slice_params and the drivers always use that. > > > Was there any problem with that? > > > > I don't think so, at least for currently known hardware. > > > > In that case we should drop the unused > > num_ref_idx_l[01]_default_active_minus1 fields from struct > > v4l2_ctrl_h264_pps and document that userspace should fill > > the defaults into v4l2_ctrl_h264_slice_params themselves if > > num_ref_idx_active_override_flag wasn't set. > > It might have been added in a previous effort to allow reconstructing > the bitstream from the structures. Wouldn't one still be able to reconstruct a valid (but not exact) stream without that flag, given the assumption above? Best regards, Tomasz
