Re: [PATCH v6 3/5] media: v4l: Add definitions for the HEVC slice controls

From: Paul Kocialkowski
Date: Thu Jul 25 2019 - 14:06:12 EST


Hi Hans and thanks for the review!

On Mon 22 Jul 19, 16:40, Hans Verkuil wrote:
> On 6/14/19 4:38 PM, Paul Kocialkowski wrote:
> > This introduces the required definitions for HEVC decoding support with
> > stateless VPUs. The controls associated to the HEVC slice format provide
> > the required meta-data for decoding slices extracted from the bitstream.
> >
> > They are not exported to the public V4L2 API since reworking this API
> > will be needed for covering various use-cases and new hardware.
> >
> > The interface comes with the following limitations:
> > * No custom quantization matrices (scaling lists);
> > * Support for a single temporal layer only;
> > * No slice entry point offsets support;
> > * No conformance window support;
> > * No VUI parameters support;
> > * No support for SPS extensions: range, multilayer, 3d, scc, 4 bits;
> > * No support for PPS extensions: range, multilayer, 3d, scc, 4 bits.
> >
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> > ---
> > Documentation/media/uapi/v4l/biblio.rst | 9 +
> > .../media/uapi/v4l/ext-ctrls-codec.rst | 474 +++++++++++++++++-
> > .../media/uapi/v4l/vidioc-queryctrl.rst | 18 +
> > .../media/videodev2.h.rst.exceptions | 3 +
> > drivers/media/v4l2-core/v4l2-ctrls.c | 103 ++++
> > drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> > include/media/hevc-ctrls.h | 197 ++++++++
> > include/media/v4l2-ctrls.h | 7 +
> > 8 files changed, 809 insertions(+), 3 deletions(-)
> > create mode 100644 include/media/hevc-ctrls.h
> >
>
> <snip>
>
> > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> > new file mode 100644
> > index 000000000000..f10f57625142
> > --- /dev/null
> > +++ b/include/media/hevc-ctrls.h
> > @@ -0,0 +1,197 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * These are the HEVC state controls for use with stateless HEVC
> > + * codec drivers.
> > + *
> > + * It turns out that these structs are not stable yet and will undergo
> > + * more changes. So keep them private until they are stable and ready to
> > + * become part of the official public API.
> > + */
> > +
> > +#ifndef _HEVC_CTRLS_H_
> > +#define _HEVC_CTRLS_H_
> > +
> > +#include <linux/videodev2.h>
> > +
> > +/* The pixel format isn't stable at the moment and will likely be renamed. */
> > +#define V4L2_PIX_FMT_HEVC_SLICE v4l2_fourcc('S', '2', '6', '5') /* HEVC parsed slices */
> > +
> > +#define V4L2_CID_MPEG_VIDEO_HEVC_SPS (V4L2_CID_MPEG_BASE + 1008)
> > +#define V4L2_CID_MPEG_VIDEO_HEVC_PPS (V4L2_CID_MPEG_BASE + 1009)
> > +#define V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS (V4L2_CID_MPEG_BASE + 1010)
> > +
> > +/* enum v4l2_ctrl_type type values */
> > +#define V4L2_CTRL_TYPE_HEVC_SPS 0x0120
> > +#define V4L2_CTRL_TYPE_HEVC_PPS 0x0121
> > +#define V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS 0x0122
> > +
> > +#define V4L2_HEVC_SLICE_TYPE_B 0
> > +#define V4L2_HEVC_SLICE_TYPE_P 1
> > +#define V4L2_HEVC_SLICE_TYPE_I 2
> > +
> > +#define V4L2_HEVC_SPS_FLAG_SEPARATE_COLOUR_PLANE (1 << 0)
> > +#define V4L2_HEVC_SPS_FLAG_SCALING_LIST_ENABLED (1 << 1)
> > +#define V4L2_HEVC_SPS_FLAG_AMP_ENABLED (1 << 2)
> > +#define V4L2_HEVC_SPS_FLAG_SAMPLE_ADAPTIVE_OFFSET (1 << 3)
> > +#define V4L2_HEVC_SPS_FLAG_PCM_ENABLED (1 << 4)
> > +#define V4L2_HEVC_SPS_FLAG_PCM_LOOP_FILTER_DISABLED (1 << 5)
> > +#define V4L2_HEVC_SPS_FLAG_LONG_TERM_REF_PICS_PRESENT (1 << 6)
> > +#define V4L2_HEVC_SPS_FLAG_SPS_TEMPORAL_MVP_ENABLED (1 << 7)
> > +#define V4L2_HEVC_SPS_FLAG_STRONG_INTRA_SMOOTHING_ENABLED (1 << 8)
> > +
> > +/* The controls are not stable at the moment and will likely be reworked. */
> > +struct v4l2_ctrl_hevc_sps {
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: Sequence parameter set */
> > + __u8 chroma_format_idc;
>
> There is a hole in the struct here. Can that be fixed?

Oh I had missed it. Let's move that u8 between num_long_term_ref_pics_sps and
flags (at the end) then.

> > + __u16 pic_width_in_luma_samples;
> > + __u16 pic_height_in_luma_samples;
> > + __u8 bit_depth_luma_minus8;
> > + __u8 bit_depth_chroma_minus8;
> > + __u8 log2_max_pic_order_cnt_lsb_minus4;
> > + __u8 sps_max_dec_pic_buffering_minus1;
> > + __u8 sps_max_num_reorder_pics;
> > + __u8 sps_max_latency_increase_plus1;
> > + __u8 log2_min_luma_coding_block_size_minus3;
> > + __u8 log2_diff_max_min_luma_coding_block_size;
> > + __u8 log2_min_luma_transform_block_size_minus2;
> > + __u8 log2_diff_max_min_luma_transform_block_size;
> > + __u8 max_transform_hierarchy_depth_inter;
> > + __u8 max_transform_hierarchy_depth_intra;
> > + __u8 pcm_sample_bit_depth_luma_minus1;
> > + __u8 pcm_sample_bit_depth_chroma_minus1;
> > + __u8 log2_min_pcm_luma_coding_block_size_minus3;
> > + __u8 log2_diff_max_min_pcm_luma_coding_block_size;
> > + __u8 num_short_term_ref_pic_sets;
> > + __u8 num_long_term_ref_pics_sps;
> > +
> > + __u64 flags;
> > +};
> > +
> > +#define V4L2_HEVC_PPS_FLAG_DEPENDENT_SLICE_SEGMENT (1 << 0)
> > +#define V4L2_HEVC_PPS_FLAG_OUTPUT_FLAG_PRESENT (1 << 1)
> > +#define V4L2_HEVC_PPS_FLAG_SIGN_DATA_HIDING_ENABLED (1 << 2)
> > +#define V4L2_HEVC_PPS_FLAG_CABAC_INIT_PRESENT (1 << 3)
> > +#define V4L2_HEVC_PPS_FLAG_CONSTRAINED_INTRA_PRED (1 << 4)
> > +#define V4L2_HEVC_PPS_FLAG_TRANSFORM_SKIP_ENABLED (1 << 5)
> > +#define V4L2_HEVC_PPS_FLAG_CU_QP_DELTA_ENABLED (1 << 6)
> > +#define V4L2_HEVC_PPS_FLAG_PPS_SLICE_CHROMA_QP_OFFSETS_PRESENT (1 << 7)
> > +#define V4L2_HEVC_PPS_FLAG_WEIGHTED_PRED (1 << 8)
> > +#define V4L2_HEVC_PPS_FLAG_WEIGHTED_BIPRED (1 << 9)
> > +#define V4L2_HEVC_PPS_FLAG_TRANSQUANT_BYPASS_ENABLED (1 << 10)
> > +#define V4L2_HEVC_PPS_FLAG_TILES_ENABLED (1 << 11)
> > +#define V4L2_HEVC_PPS_FLAG_ENTROPY_CODING_SYNC_ENABLED (1 << 12)
> > +#define V4L2_HEVC_PPS_FLAG_LOOP_FILTER_ACROSS_TILES_ENABLED (1 << 13)
> > +#define V4L2_HEVC_PPS_FLAG_PPS_LOOP_FILTER_ACROSS_SLICES_ENABLED (1 << 14)
> > +#define V4L2_HEVC_PPS_FLAG_DEBLOCKING_FILTER_OVERRIDE_ENABLED (1 << 15)
> > +#define V4L2_HEVC_PPS_FLAG_PPS_DISABLE_DEBLOCKING_FILTER (1 << 16)
> > +#define V4L2_HEVC_PPS_FLAG_LISTS_MODIFICATION_PRESENT (1 << 17)
> > +#define V4L2_HEVC_PPS_FLAG_SLICE_SEGMENT_HEADER_EXTENSION_PRESENT (1 << 18)
> > +
> > +struct v4l2_ctrl_hevc_pps {
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: Picture parameter set */
> > + __u8 num_extra_slice_header_bits;
> > + __s8 init_qp_minus26;
> > + __u8 diff_cu_qp_delta_depth;
> > + __s8 pps_cb_qp_offset;
> > + __s8 pps_cr_qp_offset;
> > + __u8 num_tile_columns_minus1;
> > + __u8 num_tile_rows_minus1;
> > + __u8 column_width_minus1[20];
> > + __u8 row_height_minus1[22];
> > + __s8 pps_beta_offset_div2;
> > + __s8 pps_tc_offset_div2;
> > + __u8 log2_parallel_merge_level_minus2;
> > +
> > + __u8 padding[4];
>
> General note regarding padding:
>
> 1) Padding fields should be zeroed in std_validate_hevc(), but it
> looks that already happens, right?

Yes, that should be taken care of already.

> 2) Padding fields should be documented like this:
>
> * - __u8
> - ``padding``
> - Applications and drivers must set this to zero.
>
> That doesn't happen, AFAICS.

Will do!

> > + __u64 flags;
> > +};
> > +
> > +#define V4L2_HEVC_DPB_ENTRY_RPS_ST_CURR_BEFORE 0x01
> > +#define V4L2_HEVC_DPB_ENTRY_RPS_ST_CURR_AFTER 0x02
> > +#define V4L2_HEVC_DPB_ENTRY_RPS_LT_CURR 0x03
> > +
> > +#define V4L2_HEVC_DPB_ENTRIES_NUM_MAX 16
> > +
> > +struct v4l2_hevc_dpb_entry {
> > + __u64 timestamp;
> > + __u8 rps;
> > + __u8 field_pic;
> > + __u16 pic_order_cnt[2];
> > + __u8 padding[2];
> > +};
> > +
> > +struct v4l2_hevc_pred_weight_table {
> > + __u8 luma_log2_weight_denom;
> > + __s8 delta_chroma_log2_weight_denom;
> > +
> > + __s8 delta_luma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __s8 luma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __s8 delta_chroma_weight_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2];
> > + __s8 chroma_offset_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2];
> > +
> > + __s8 delta_luma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __s8 luma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __s8 delta_chroma_weight_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2];
> > + __s8 chroma_offset_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX][2];
> > +
> > + __u8 padding[6];
> > +};
> > +
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_SAO_LUMA (1 << 0)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_SAO_CHROMA (1 << 1)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_TEMPORAL_MVP_ENABLED (1 << 2)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_MVD_L1_ZERO (1 << 3)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_CABAC_INIT (1 << 4)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_COLLOCATED_FROM_L0 (1 << 5)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_USE_INTEGER_MV (1 << 6)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_DEBLOCKING_FILTER_DISABLED (1 << 7)
> > +#define V4L2_HEVC_SLICE_PARAMS_FLAG_SLICE_LOOP_FILTER_ACROSS_SLICES_ENABLED (1 << 8)
> > +
> > +struct v4l2_ctrl_hevc_slice_params {
> > + __u32 bit_size;
> > + __u32 data_bit_offset;
> > +
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: NAL unit header */
> > + __u8 nal_unit_type;
> > + __u8 nuh_temporal_id_plus1;
> > +
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: General slice segment header */
> > + __u8 slice_type;
> > + __u8 colour_plane_id;
> > + __u16 slice_pic_order_cnt;
> > + __u8 num_ref_idx_l0_active_minus1;
> > + __u8 num_ref_idx_l1_active_minus1;
> > + __u8 collocated_ref_idx;
> > + __u8 five_minus_max_num_merge_cand;
> > + __s8 slice_qp_delta;
> > + __s8 slice_cb_qp_offset;
> > + __s8 slice_cr_qp_offset;
> > + __s8 slice_act_y_qp_offset;
> > + __s8 slice_act_cb_qp_offset;
> > + __s8 slice_act_cr_qp_offset;
> > + __s8 slice_beta_offset_div2;
> > + __s8 slice_tc_offset_div2;
> > +
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: Picture timing SEI message */
> > + __u8 pic_struct;
> > +
> > + __u8 padding_pre[13];
>
> Where does '13' come from? I expect values between 1 and 7, so 13 is weird.

Huh, I can't recall why I picked 13, but 5 should obviously do the work just as
well.

> I'm also not keen on having _pre and _post padding fields. Can that be
> avoided somehow?

Ah, this is because I had decided to keep the (64-bit-aligned) structs in the
middle of this structure, but it's probably best to have them at the end and
only have one padding field between (unaligned) individual fields and (aligned)
struct fields. Will fix in the next revision!

Cheers,

Paul

> > +
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: General slice segment header */
> > + struct v4l2_hevc_dpb_entry dpb[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __u8 num_active_dpb_entries;
> > + __u8 ref_idx_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > + __u8 ref_idx_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
> > +
> > + __u8 num_rps_poc_st_curr_before;
> > + __u8 num_rps_poc_st_curr_after;
> > + __u8 num_rps_poc_lt_curr;
> > +
> > + /* ISO/IEC 23008-2, ITU-T Rec. H.265: Weighted prediction parameter */
> > + struct v4l2_hevc_pred_weight_table pred_weight_table;
> > +
> > + __u8 padding_post[4];
> > + __u64 flags;
> > +};
> > +
> > +#endif
> > diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> > index b4433483af23..2fd477108e7a 100644
> > --- a/include/media/v4l2-ctrls.h
> > +++ b/include/media/v4l2-ctrls.h
> > @@ -20,6 +20,7 @@
> > #include <media/mpeg2-ctrls.h>
> > #include <media/fwht-ctrls.h>
> > #include <media/h264-ctrls.h>
> > +#include <media/hevc-ctrls.h>
> >
> > /* forward references */
> > struct file;
> > @@ -48,6 +49,9 @@ struct poll_table_struct;
> > * @p_h264_scaling_matrix: Pointer to a struct v4l2_ctrl_h264_scaling_matrix.
> > * @p_h264_slice_params: Pointer to a struct v4l2_ctrl_h264_slice_params.
> > * @p_h264_decode_params: Pointer to a struct v4l2_ctrl_h264_decode_params.
> > + * @p_hevc_sps: Pointer to an HEVC sequence parameter set structure.
> > + * @p_hevc_pps: Pointer to an HEVC picture parameter set structure.
> > + * @p_hevc_slice_params: Pointer to an HEVC slice parameters structure.
> > * @p: Pointer to a compound value.
> > */
> > union v4l2_ctrl_ptr {
> > @@ -65,6 +69,9 @@ union v4l2_ctrl_ptr {
> > struct v4l2_ctrl_h264_scaling_matrix *p_h264_scaling_matrix;
> > struct v4l2_ctrl_h264_slice_params *p_h264_slice_params;
> > struct v4l2_ctrl_h264_decode_params *p_h264_decode_params;
> > + struct v4l2_ctrl_hevc_sps *p_hevc_sps;
> > + struct v4l2_ctrl_hevc_pps *p_hevc_pps;
> > + struct v4l2_ctrl_hevc_slice_params *p_hevc_slice_params;
> > void *p;
> > };
> >
> >
>
> Regards,
>
> Hans

--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com