1.16. Stateless Codec Control Reference

The Stateless Codec control class is intended to support stateless decoder and encoders (i.e. hardware accelerators).

These drivers are typically supported by the Memory-to-memory Stateless Video Decoder Interface, and deal with parsed pixel formats such as V4L2_PIX_FMT_H264_SLICE.

1.16.1. Stateless Codec Control ID

V4L2_CID_CODEC_STATELESS_CLASS (class)

The Stateless Codec class descriptor.

V4L2_CID_STATELESS_H264_SPS (struct)

Specifies the sequence parameter set (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.1.1 “Sequence Parameter Set Data Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_sps
struct v4l2_ctrl_h264_sps

__u8

profile_idc

__u8

constraint_set_flags

See Sequence Parameter Set Constraints Set Flags

__u8

level_idc

__u8

seq_parameter_set_id

__u8

chroma_format_idc

__u8

bit_depth_luma_minus8

__u8

bit_depth_chroma_minus8

__u8

log2_max_frame_num_minus4

__u8

pic_order_cnt_type

__u8

log2_max_pic_order_cnt_lsb_minus4

__u8

max_num_ref_frames

__u8

num_ref_frames_in_pic_order_cnt_cycle

__s32

offset_for_ref_frame[255]

__s32

offset_for_non_ref_pic

__s32

offset_for_top_to_bottom_field

__u16

pic_width_in_mbs_minus1

__u16

pic_height_in_map_units_minus1

__u32

flags

See Sequence Parameter Set Flags

Sequence Parameter Set Constraints Set Flags

V4L2_H264_SPS_CONSTRAINT_SET0_FLAG

0x00000001

V4L2_H264_SPS_CONSTRAINT_SET1_FLAG

0x00000002

V4L2_H264_SPS_CONSTRAINT_SET2_FLAG

0x00000004

V4L2_H264_SPS_CONSTRAINT_SET3_FLAG

0x00000008

V4L2_H264_SPS_CONSTRAINT_SET4_FLAG

0x00000010

V4L2_H264_SPS_CONSTRAINT_SET5_FLAG

0x00000020

Sequence Parameter Set Flags

V4L2_H264_SPS_FLAG_SEPARATE_COLOUR_PLANE

0x00000001

V4L2_H264_SPS_FLAG_QPPRIME_Y_ZERO_TRANSFORM_BYPASS

0x00000002

V4L2_H264_SPS_FLAG_DELTA_PIC_ORDER_ALWAYS_ZERO

0x00000004

V4L2_H264_SPS_FLAG_GAPS_IN_FRAME_NUM_VALUE_ALLOWED

0x00000008

V4L2_H264_SPS_FLAG_FRAME_MBS_ONLY

0x00000010

V4L2_H264_SPS_FLAG_MB_ADAPTIVE_FRAME_FIELD

0x00000020

V4L2_H264_SPS_FLAG_DIRECT_8X8_INFERENCE

0x00000040

V4L2_CID_STATELESS_H264_PPS (struct)

Specifies the picture parameter set (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.2 “Picture Parameter Set RBSP Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_pps
struct v4l2_ctrl_h264_pps

__u8

pic_parameter_set_id

__u8

seq_parameter_set_id

__u8

num_slice_groups_minus1

__u8

num_ref_idx_l0_default_active_minus1

__u8

num_ref_idx_l1_default_active_minus1

__u8

weighted_bipred_idc

__s8

pic_init_qp_minus26

__s8

pic_init_qs_minus26

__s8

chroma_qp_index_offset

__s8

second_chroma_qp_index_offset

__u16

flags

See Picture Parameter Set Flags

Picture Parameter Set Flags

V4L2_H264_PPS_FLAG_ENTROPY_CODING_MODE

0x0001

V4L2_H264_PPS_FLAG_BOTTOM_FIELD_PIC_ORDER_IN_FRAME_PRESENT

0x0002

V4L2_H264_PPS_FLAG_WEIGHTED_PRED

0x0004

V4L2_H264_PPS_FLAG_DEBLOCKING_FILTER_CONTROL_PRESENT

0x0008

V4L2_H264_PPS_FLAG_CONSTRAINED_INTRA_PRED

0x0010

V4L2_H264_PPS_FLAG_REDUNDANT_PIC_CNT_PRESENT

0x0020

V4L2_H264_PPS_FLAG_TRANSFORM_8X8_MODE

0x0040

V4L2_H264_PPS_FLAG_SCALING_MATRIX_PRESENT

0x0080

V4L2_CID_STATELESS_H264_SCALING_MATRIX must be used for this picture.

V4L2_CID_STATELESS_H264_SCALING_MATRIX (struct)

Specifies the scaling matrix (as extracted from the bitstream) for the associated H264 slice data. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.2.1.1.1 “Scaling List Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_scaling_matrix
struct v4l2_ctrl_h264_scaling_matrix

__u8

scaling_list_4x4[6][16]

Scaling matrix after applying the inverse scanning process. Expected list order is Intra Y, Intra Cb, Intra Cr, Inter Y, Inter Cb, Inter Cr. The values on each scaling list are expected in raster scan order.

__u8

scaling_list_8x8[6][64]

Scaling matrix after applying the inverse scanning process. Expected list order is Intra Y, Inter Y, Intra Cb, Inter Cb, Intra Cr, Inter Cr. The values on each scaling list are expected in raster scan order.

V4L2_CID_STATELESS_H264_SLICE_PARAMS (struct)

Specifies the slice parameters (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.3 “Slice Header Semantics”. For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_slice_params
struct v4l2_ctrl_h264_slice_params

__u32

header_bit_size

Offset in bits to slice_data() from the beginning of this slice.

__u32

first_mb_in_slice

__u8

slice_type

__u8

colour_plane_id

__u8

redundant_pic_cnt

__u8

cabac_init_idc

__s8

slice_qp_delta

__s8

slice_qs_delta

__u8

disable_deblocking_filter_idc

__s8

slice_alpha_c0_offset_div2

__s8

slice_beta_offset_div2

__u8

num_ref_idx_l0_active_minus1

If num_ref_idx_active_override_flag is not set, this field must be set to the value of num_ref_idx_l0_default_active_minus1

__u8

num_ref_idx_l1_active_minus1

If num_ref_idx_active_override_flag is not set, this field must be set to the value of num_ref_idx_l1_default_active_minus1

__u8

reserved

Applications and drivers must set this to zero.

struct v4l2_h264_reference

ref_pic_list0[32]

Reference picture list after applying the per-slice modifications

struct v4l2_h264_reference

ref_pic_list1[32]

Reference picture list after applying the per-slice modifications

__u32

flags

See Slice Parameter Flags

Slice Parameter Set Flags

V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED

0x00000001

V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH

0x00000002

V4L2_CID_STATELESS_H264_PRED_WEIGHTS (struct)

Prediction weight table defined according to ITU-T Rec. H.264 Specification (04/2017 Edition), section 7.4.3.2 “Prediction Weight Table Semantics”. The prediction weight table must be passed by applications under the conditions explained in section 7.3.3 “Slice header syntax”.

type v4l2_ctrl_h264_pred_weights
struct v4l2_ctrl_h264_pred_weights

__u16

luma_log2_weight_denom

__u16

chroma_log2_weight_denom

struct v4l2_h264_weight_factors

weight_factors[2]

The weight factors at index 0 are the weight factors for the reference list 0, the one at index 1 for the reference list 1.

type v4l2_h264_weight_factors
struct v4l2_h264_weight_factors

__s16

luma_weight[32]

__s16

luma_offset[32]

__s16

chroma_weight[32][2]

__s16

chroma_offset[32][2]

Picture Reference

type v4l2_h264_reference
struct v4l2_h264_reference

__u8

fields

Specifies how the picture is referenced. See Reference Fields

__u8

index

Index into the v4l2_ctrl_h264_decode_params.dpb array.

Reference Fields

V4L2_H264_TOP_FIELD_REF

0x1

The top field in field pair is used for short-term reference.

V4L2_H264_BOTTOM_FIELD_REF

0x2

The bottom field in field pair is used for short-term reference.

V4L2_H264_FRAME_REF

0x3

The frame (or the top/bottom fields, if it’s a field pair) is used for short-term reference.

V4L2_CID_STATELESS_H264_DECODE_PARAMS (struct)

Specifies the decode parameters (as extracted from the bitstream) for the associated H264 slice data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for H264. The bitstream parameters are defined according to ITU-T Rec. H.264 Specification (04/2017 Edition). For further documentation, refer to the above specification, unless there is an explicit comment stating otherwise.

type v4l2_ctrl_h264_decode_params
struct v4l2_ctrl_h264_decode_params

struct v4l2_h264_dpb_entry

dpb[16]

__u16

nal_ref_idc

NAL reference ID value coming from the NAL Unit header

__u16

frame_num

__s32

top_field_order_cnt

Picture Order Count for the coded top field

__s32

bottom_field_order_cnt

Picture Order Count for the coded bottom field

__u16

idr_pic_id

__u16

pic_order_cnt_lsb

__s32

delta_pic_order_cnt_bottom

__s32

delta_pic_order_cnt0

__s32

delta_pic_order_cnt1

__u32

dec_ref_pic_marking_bit_size

Size in bits of the dec_ref_pic_marking() syntax element.

__u32

pic_order_cnt_bit_size

Combined size in bits of the picture order count related syntax elements: pic_order_cnt_lsb, delta_pic_order_cnt_bottom, delta_pic_order_cnt0, and delta_pic_order_cnt1.

__u32

slice_group_change_cycle

__u32

reserved

Applications and drivers must set this to zero.

__u32

flags

See Decode Parameters Flags

Decode Parameters Flags

V4L2_H264_DECODE_PARAM_FLAG_IDR_PIC

0x00000001

That picture is an IDR picture

V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC

0x00000002

V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD

0x00000004

type v4l2_h264_dpb_entry
struct v4l2_h264_dpb_entry

__u64

reference_ts

Timestamp of the V4L2 capture buffer to use as reference, used with B-coded and P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u32

pic_num

__u16

frame_num

__u8

fields

Specifies how the DPB entry is referenced. See Reference Fields

__u8

reserved[5]

Applications and drivers must set this to zero.

__s32

top_field_order_cnt

__s32

bottom_field_order_cnt

__u32

flags

See DPB Entry Flags

DPB Entries Flags

V4L2_H264_DPB_ENTRY_FLAG_VALID

0x00000001

The DPB entry is valid (non-empty) and should be considered.

V4L2_H264_DPB_ENTRY_FLAG_ACTIVE

0x00000002

The DPB entry is used for reference.

V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM

0x00000004

The DPB entry is used for long-term reference.

V4L2_H264_DPB_ENTRY_FLAG_FIELD

0x00000008

The DPB entry is a single field or a complementary field pair.

V4L2_CID_STATELESS_H264_DECODE_MODE (enum)

Specifies the decoding mode to use. Currently exposes slice-based and frame-based decoding but new modes might be added later on. This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE are required to set this control in order to specify the decoding mode that is expected for the buffer. Drivers may expose a single or multiple decoding modes, depending on what they can support.

type v4l2_stateless_h264_decode_mode

V4L2_STATELESS_H264_DECODE_MODE_SLICE_BASED

0

Decoding is done at the slice granularity. The OUTPUT buffer must contain a single slice. When this mode is selected, the V4L2_CID_STATELESS_H264_SLICE_PARAMS control shall be set. When multiple slices compose a frame, use of V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF flag is required.

V4L2_STATELESS_H264_DECODE_MODE_FRAME_BASED

1

Decoding is done at the frame granularity, The OUTPUT buffer must contain all slices needed to decode the frame. The OUTPUT buffer must also contain both fields. This mode will be supported by devices that parse the slice(s) header(s) in hardware. When this mode is selected, the V4L2_CID_STATELESS_H264_SLICE_PARAMS control shall not be set.

V4L2_CID_STATELESS_H264_START_CODE (enum)

Specifies the H264 slice start code expected for each slice. This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE are required to set this control in order to specify the start code that is expected for the buffer. Drivers may expose a single or multiple start codes, depending on what they can support.

type v4l2_stateless_h264_start_code

V4L2_STATELESS_H264_START_CODE_NONE

0

Selecting this value specifies that H264 slices are passed to the driver without any start code. The bitstream data should be according to ITU-T Rec. H.264 Specification (04/2017 Edition) 7.3.1 NAL unit syntax, hence contains emulation prevention bytes when required.

V4L2_STATELESS_H264_START_CODE_ANNEX_B

1

Selecting this value specifies that H264 slices are expected to be prefixed by Annex B start codes. According to ITU-T Rec. H.264 Specification (04/2017 Edition) valid start codes can be 3-bytes 0x000001 or 4-bytes 0x00000001.

V4L2_CID_STATELESS_FWHT_PARAMS (struct)

Specifies the FWHT (Fast Walsh Hadamard Transform) parameters (as extracted from the bitstream) for the associated FWHT data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for FWHT. This codec is specific to the vicodec test driver.

type v4l2_ctrl_fwht_params
struct v4l2_ctrl_fwht_params

__u64

backward_ref_ts

Timestamp of the V4L2 capture buffer to use as backward reference, used with P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u32

version

The version of the codec. Set to V4L2_FWHT_VERSION.

__u32

width

The width of the frame.

__u32

height

The height of the frame.

__u32

flags

The flags of the frame, see FWHT Flags.

__u32

colorspace

The colorspace of the frame, from enum v4l2_colorspace.

__u32

xfer_func

The transfer function, from enum v4l2_xfer_func.

__u32

ycbcr_enc

The Y’CbCr encoding, from enum v4l2_ycbcr_encoding.

__u32

quantization

The quantization range, from enum v4l2_quantization.

1.16.2. FWHT Flags

V4L2_FWHT_FL_IS_INTERLACED

0x00000001

Set if this is an interlaced format.

V4L2_FWHT_FL_IS_BOTTOM_FIRST

0x00000002

Set if this is a bottom-first (NTSC) interlaced format.

V4L2_FWHT_FL_IS_ALTERNATE

0x00000004

Set if each ‘frame’ contains just one field.

V4L2_FWHT_FL_IS_BOTTOM_FIELD

0x00000008

If V4L2_FWHT_FL_IS_ALTERNATE was set, then this is set if this ‘frame’ is the bottom field, else it is the top field.

V4L2_FWHT_FL_LUMA_IS_UNCOMPRESSED

0x00000010

Set if the Y’ (luma) plane is uncompressed.

V4L2_FWHT_FL_CB_IS_UNCOMPRESSED

0x00000020

Set if the Cb plane is uncompressed.

V4L2_FWHT_FL_CR_IS_UNCOMPRESSED

0x00000040

Set if the Cr plane is uncompressed.

V4L2_FWHT_FL_CHROMA_FULL_HEIGHT

0x00000080

Set if the chroma plane has the same height as the luma plane, else the chroma plane is half the height of the luma plane.

V4L2_FWHT_FL_CHROMA_FULL_WIDTH

0x00000100

Set if the chroma plane has the same width as the luma plane, else the chroma plane is half the width of the luma plane.

V4L2_FWHT_FL_ALPHA_IS_UNCOMPRESSED

0x00000200

Set if the alpha plane is uncompressed.

V4L2_FWHT_FL_I_FRAME

0x00000400

Set if this is an I-frame.

V4L2_FWHT_FL_COMPONENTS_NUM_MSK

0x00070000

The number of color components minus one.

V4L2_FWHT_FL_PIXENC_MSK

0x00180000

The mask for the pixel encoding.

V4L2_FWHT_FL_PIXENC_YUV

0x00080000

Set if the pixel encoding is YUV.

V4L2_FWHT_FL_PIXENC_RGB

0x00100000

Set if the pixel encoding is RGB.

V4L2_FWHT_FL_PIXENC_HSV

0x00180000

Set if the pixel encoding is HSV.

V4L2_CID_STATELESS_VP8_FRAME (struct)

Specifies the frame parameters for the associated VP8 parsed frame data. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for VP8. The bitstream parameters are defined according to VP8.

type v4l2_ctrl_vp8_frame
struct v4l2_ctrl_vp8_frame

struct v4l2_vp8_segment

segment

Structure with segment-based adjustments metadata.

struct v4l2_vp8_loop_filter

lf

Structure with loop filter level adjustments metadata.

struct v4l2_vp8_quantization

quant

Structure with VP8 dequantization indices metadata.

struct v4l2_vp8_entropy

entropy

Structure with VP8 entropy coder probabilities metadata.

struct v4l2_vp8_entropy_coder_state

coder_state

Structure with VP8 entropy coder state.

__u16

width

The width of the frame. Must be set for all frames.

__u16

height

The height of the frame. Must be set for all frames.

__u8

horizontal_scale

Horizontal scaling factor.

__u8

vertical_scaling factor

Vertical scale.

__u8

version

Bitstream version.

__u8

prob_skip_false

Indicates the probability that the macroblock is not skipped.

__u8

prob_intra

Indicates the probability that a macroblock is intra-predicted.

__u8

prob_last

Indicates the probability that the last reference frame is used for inter-prediction

__u8

prob_gf

Indicates the probability that the golden reference frame is used for inter-prediction

__u8

num_dct_parts

Number of DCT coefficients partitions. Must be one of: 1, 2, 4, or 8.

__u32

first_part_size

Size of the first partition, i.e. the control partition.

__u32

first_part_header_bits

Size in bits of the first partition header portion.

__u32

dct_part_sizes[8]

DCT coefficients sizes.

__u64

last_frame_ts

Timestamp for the V4L2 capture buffer to use as last reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

golden_frame_ts

Timestamp for the V4L2 capture buffer to use as last reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

alt_frame_ts

Timestamp for the V4L2 capture buffer to use as alternate reference frame, used with inter-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

flags

See Frame Flags

Frame Flags

V4L2_VP8_FRAME_FLAG_KEY_FRAME

0x01

Indicates if the frame is a key frame.

V4L2_VP8_FRAME_FLAG_EXPERIMENTAL

0x02

Experimental bitstream.

V4L2_VP8_FRAME_FLAG_SHOW_FRAME

0x04

Show frame flag, indicates if the frame is for display.

V4L2_VP8_FRAME_FLAG_MB_NO_SKIP_COEFF

0x08

Enable/disable skipping of macroblocks with no non-zero coefficients.

V4L2_VP8_FRAME_FLAG_SIGN_BIAS_GOLDEN

0x10

Sign of motion vectors when the golden frame is referenced.

V4L2_VP8_FRAME_FLAG_SIGN_BIAS_ALT

0x20

Sign of motion vectors when the alt frame is referenced.

type v4l2_vp8_entropy_coder_state
struct v4l2_vp8_entropy_coder_state

__u8

range

coder state value for “Range”

__u8

value

coder state value for “Value”-

__u8

bit_count

number of bits left.

__u8

padding

Applications and drivers must set this to zero.

type v4l2_vp8_segment
struct v4l2_vp8_segment

__s8

quant_update[4]

Signed quantizer value update.

__s8

lf_update[4]

Signed loop filter level value update.

__u8

segment_probs[3]

Segment probabilities.

__u8

padding

Applications and drivers must set this to zero.

__u32

flags

See Segment Flags

Segment Flags

V4L2_VP8_SEGMENT_FLAG_ENABLED

0x01

Enable/disable segment-based adjustments.

V4L2_VP8_SEGMENT_FLAG_UPDATE_MAP

0x02

Indicates if the macroblock segmentation map is updated in this frame.

V4L2_VP8_SEGMENT_FLAG_UPDATE_FEATURE_DATA

0x04

Indicates if the segment feature data is updated in this frame.

V4L2_VP8_SEGMENT_FLAG_DELTA_VALUE_MODE

0x08

If is set, the segment feature data mode is delta-value. If cleared, it’s absolute-value.

type v4l2_vp8_loop_filter
struct v4l2_vp8_loop_filter

__s8

ref_frm_delta[4]

Reference adjustment (signed) delta value.

__s8

mb_mode_delta[4]

Macroblock prediction mode adjustment (signed) delta value.

__u8

sharpness_level

Sharpness level

__u8

level

Filter level

__u16

padding

Applications and drivers must set this to zero.

__u32

flags

See Loop Filter Flags

Loop Filter Flags

V4L2_VP8_LF_ADJ_ENABLE

0x01

Enable/disable macroblock-level loop filter adjustment.

V4L2_VP8_LF_DELTA_UPDATE

0x02

Indicates if the delta values used in an adjustment are updated.

V4L2_VP8_LF_FILTER_TYPE_SIMPLE

0x04

If set, indicates the filter type is simple. If cleared, the filter type is normal.

type v4l2_vp8_quantization
struct v4l2_vp8_quantization

__u8

y_ac_qi

Luma AC coefficient table index.

__s8

y_dc_delta

Luma DC delta vaue.

__s8

y2_dc_delta

Y2 block DC delta value.

__s8

y2_ac_delta

Y2 block AC delta value.

__s8

uv_dc_delta

Chroma DC delta value.

__s8

uv_ac_delta

Chroma AC delta value.

__u16

padding

Applications and drivers must set this to zero.

type v4l2_vp8_entropy
struct v4l2_vp8_entropy

__u8

coeff_probs[4][8][3][11]

Coefficient update probabilities.

__u8

y_mode_probs[4]

Luma mode update probabilities.

__u8

uv_mode_probs[3]

Chroma mode update probabilities.

__u8

mv_probs[2][19]

MV decoding update probabilities.

__u8

padding[3]

Applications and drivers must set this to zero.

V4L2_CID_STATELESS_MPEG2_SEQUENCE (struct)

Specifies the sequence parameters (as extracted from the bitstream) for the associated MPEG-2 slice data. This includes fields matching the syntax elements from the sequence header and sequence extension parts of the bitstream as specified by ISO 13818-2.

type v4l2_ctrl_mpeg2_sequence
struct v4l2_ctrl_mpeg2_sequence

__u16

horizontal_size

The width of the displayable part of the frame’s luminance component.

__u16

vertical_size

The height of the displayable part of the frame’s luminance component.

__u32

vbv_buffer_size

Used to calculate the required size of the video buffering verifier, defined (in bits) as: 16 * 1024 * vbv_buffer_size.

__u16

profile_and_level_indication

The current profile and level indication as extracted from the bitstream.

__u8

chroma_format

The chrominance sub-sampling format (1: 4:2:0, 2: 4:2:2, 3: 4:4:4).

__u8

flags

See MPEG-2 Sequence Flags.

MPEG-2 Sequence Flags

V4L2_MPEG2_SEQ_FLAG_PROGRESSIVE

0x01

Indication that all the frames for the sequence are progressive instead of interlaced.

V4L2_CID_STATELESS_MPEG2_PICTURE (struct)

Specifies the picture parameters (as extracted from the bitstream) for the associated MPEG-2 slice data. This includes fields matching the syntax elements from the picture header and picture coding extension parts of the bitstream as specified by ISO 13818-2.

type v4l2_ctrl_mpeg2_picture
struct v4l2_ctrl_mpeg2_picture

__u64

backward_ref_ts

Timestamp of the V4L2 capture buffer to use as backward reference, used with B-coded and P-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

forward_ref_ts

Timestamp for the V4L2 capture buffer to use as forward reference, used with B-coded frames. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u32

flags

See MPEG-2 Picture Flags.

__u8

f_code[2][2]

Motion vector codes.

__u8

picture_coding_type

Picture coding type for the frame covered by the current slice (V4L2_MPEG2_PIC_CODING_TYPE_I, V4L2_MPEG2_PIC_CODING_TYPE_P or V4L2_MPEG2_PIC_CODING_TYPE_B).

__u8

picture_structure

Picture structure (1: interlaced top field, 2: interlaced bottom field, 3: progressive frame).

__u8

intra_dc_precision

Precision of Discrete Cosine transform (0: 8 bits precision, 1: 9 bits precision, 2: 10 bits precision, 3: 11 bits precision).

__u8

reserved[5]

Applications and drivers must set this to zero.

MPEG-2 Picture Flags

V4L2_MPEG2_PIC_FLAG_TOP_FIELD_FIRST

0x00000001

If set and it’s an interlaced stream, top field is output first.

V4L2_MPEG2_PIC_FLAG_FRAME_PRED_DCT

0x00000002

If set only frame-DCT and frame prediction are used.

V4L2_MPEG2_PIC_FLAG_CONCEALMENT_MV

0x00000004

If set motion vectors are coded for intra macroblocks.

V4L2_MPEG2_PIC_FLAG_Q_SCALE_TYPE

0x00000008

This flag affects the inverse quantization process.

V4L2_MPEG2_PIC_FLAG_INTRA_VLC

0x00000010

This flag affects the decoding of transform coefficient data.

V4L2_MPEG2_PIC_FLAG_ALT_SCAN

0x00000020

This flag affects the decoding of transform coefficient data.

V4L2_MPEG2_PIC_FLAG_REPEAT_FIRST

0x00000040

This flag affects the decoding process of progressive frames.

V4L2_MPEG2_PIC_FLAG_PROGRESSIVE

0x00000080

Indicates whether the current frame is progressive.

V4L2_CID_STATELESS_MPEG2_QUANTISATION (struct)

Specifies quantisation matrices, in zigzag scanning order, for the associated MPEG-2 slice data. This control is initialized by the kernel to the matrices default values. If a bitstream transmits a user-defined quantisation matrices load, applications are expected to use this control. Applications are also expected to set the control loading the default values, if the quantisation matrices need to be reset, for instance on a sequence header. This process is specified by section 6.3.7. “Quant matrix extension” of the specification.

type v4l2_ctrl_mpeg2_quantisation
struct v4l2_ctrl_mpeg2_quantisation

__u8

intra_quantiser_matrix[64]

The quantisation matrix coefficients for intra-coded frames, in zigzag scanning order. It is relevant for both luma and chroma components, although it can be superseded by the chroma-specific matrix for non-4:2:0 YUV formats.

__u8

non_intra_quantiser_matrix[64]

The quantisation matrix coefficients for non-intra-coded frames, in zigzag scanning order. It is relevant for both luma and chroma components, although it can be superseded by the chroma-specific matrix for non-4:2:0 YUV formats.

__u8

chroma_intra_quantiser_matrix[64]

The quantisation matrix coefficients for the chominance component of intra-coded frames, in zigzag scanning order. Only relevant for non-4:2:0 YUV formats.

__u8

chroma_non_intra_quantiser_matrix[64]

The quantisation matrix coefficients for the chrominance component of non-intra-coded frames, in zigzag scanning order. Only relevant for non-4:2:0 YUV formats.

V4L2_CID_STATELESS_VP9_COMPRESSED_HDR (struct)

Stores VP9 probabilities updates as parsed from the current compressed frame header. A value of zero in an array element means no update of the relevant probability. Motion vector-related updates contain a new value or zero. All other updates contain values translated with inv_map_table[] (see 6.3.5 in VP9).

type v4l2_ctrl_vp9_compressed_hdr
struct v4l2_ctrl_vp9_compressed_hdr

__u8

tx_mode

Specifies the TX mode. See TX Mode for more details.

__u8

tx8[2][1]

TX 8x8 probabilities delta.

__u8

tx16[2][2]

TX 16x16 probabilities delta.

__u8

tx32[2][3]

TX 32x32 probabilities delta.

__u8

coef[4][2][2][6][6][3]

Coefficient probabilities delta.

__u8

skip[3]

Skip probabilities delta.

__u8

inter_mode[7][3]

Inter prediction mode probabilities delta.

__u8

interp_filter[4][2]

Interpolation filter probabilities delta.

__u8

is_inter[4]

Is inter-block probabilities delta.

__u8

comp_mode[5]

Compound prediction mode probabilities delta.

__u8

single_ref[5][2]

Single reference probabilities delta.

__u8

comp_ref[5]

Compound reference probabilities delta.

__u8

y_mode[4][9]

Y prediction mode probabilities delta.

__u8

uv_mode[10][9]

UV prediction mode probabilities delta.

__u8

partition[16][3]

Partition probabilities delta.

__u8

mv.joint[3]

Motion vector joint probabilities delta.

__u8

mv.sign[2]

Motion vector sign probabilities delta.

__u8

mv.classes[2][10]

Motion vector class probabilities delta.

__u8

mv.class0_bit[2]

Motion vector class0 bit probabilities delta.

__u8

mv.bits[2][10]

Motion vector bits probabilities delta.

__u8

mv.class0_fr[2][2][3]

Motion vector class0 fractional bit probabilities delta.

__u8

mv.fr[2][3]

Motion vector fractional bit probabilities delta.

__u8

mv.class0_hp[2]

Motion vector class0 high precision fractional bit probabilities delta.

__u8

mv.hp[2]

Motion vector high precision fractional bit probabilities delta.

TX Mode

V4L2_VP9_TX_MODE_ONLY_4X4

0

Transform size is 4x4.

V4L2_VP9_TX_MODE_ALLOW_8X8

1

Transform size can be up to 8x8.

V4L2_VP9_TX_MODE_ALLOW_16X16

2

Transform size can be up to 16x16.

V4L2_VP9_TX_MODE_ALLOW_32X32

3

transform size can be up to 32x32.

V4L2_VP9_TX_MODE_SELECT

4

Bitstream contains the transform size for each block.

See section ‘7.3.1 Tx mode semantics’ of the VP9 specification for more details.

V4L2_CID_STATELESS_VP9_FRAME (struct)

Specifies the frame parameters for the associated VP9 frame decode request. This includes the necessary parameters for configuring a stateless hardware decoding pipeline for VP9. The bitstream parameters are defined according to VP9.

type v4l2_ctrl_vp9_frame
struct v4l2_ctrl_vp9_frame

struct v4l2_vp9_loop_filter

lf

Loop filter parameters. See struct v4l2_vp9_loop_filter for more details.

struct v4l2_vp9_quantization

quant

Quantization parameters. See v4l2_vp9_quantization for more details.

struct v4l2_vp9_segmentation

seg

Segmentation parameters. See v4l2_vp9_segmentation for more details.

__u32

flags

Combination of V4L2_VP9_FRAME_FLAG_* flags. See Frame Flags.

__u16

compressed_header_size

Compressed header size in bytes.

__u16

uncompressed_header_size

Uncompressed header size in bytes.

__u16

frame_width_minus_1

Add 1 to get the frame width expressed in pixels. See section 7.2.3 in VP9.

__u16

frame_height_minus_1

Add 1 to get the frame height expressed in pixels. See section 7.2.3 in VP9.

__u16

render_width_minus_1

Add 1 to get the expected render width expressed in pixels. This is not used during the decoding process but might be used by HW scalers to prepare a frame that’s ready for scanout. See section 7.2.4 in VP9.

__u16

render_height_minus_1

Add 1 to get the expected render height expressed in pixels. This is not used during the decoding process but might be used by HW scalers to prepare a frame that’s ready for scanout. See section 7.2.4 in VP9.

__u64

last_frame_ts

“last” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

golden_frame_ts

“golden” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u64

alt_frame_ts

“alt” reference buffer timestamp. The timestamp refers to the timestamp field in struct v4l2_buffer. Use the v4l2_timeval_to_ns() function to convert the struct timeval in struct v4l2_buffer to a __u64.

__u8

ref_frame_sign_bias

a bitfield specifying whether the sign bias is set for a given reference frame. See Reference Frame Sign Bias for more details.

__u8

reset_frame_context

specifies whether the frame context should be reset to default values. See Reset Frame Context for more details.

__u8

frame_context_idx

Frame context that should be used/updated.

__u8

profile

VP9 profile. Can be 0, 1, 2 or 3.

__u8

bit_depth

Component depth in bits. Can be 8, 10 or 12. Note that not all profiles support 10 and/or 12 bits depths.

__u8

interpolation_filter

Specifies the filter selection used for performing inter prediction. See Interpolation Filter for more details.

__u8

tile_cols_log2

Specifies the base 2 logarithm of the width of each tile (where the width is measured in units of 8x8 blocks). Shall be less than or equal to 6.

__u8

tile_rows_log2

Specifies the base 2 logarithm of the height of each tile (where the height is measured in units of 8x8 blocks).

__u8

reference_mode

Specifies the type of inter prediction to be used. See Reference Mode for more details.

__u8

reserved[7]

Applications and drivers must set this to zero.

Frame Flags

V4L2_VP9_FRAME_FLAG_KEY_FRAME

0x001

The frame is a key frame.

V4L2_VP9_FRAME_FLAG_SHOW_FRAME

0x002

The frame should be displayed.

V4L2_VP9_FRAME_FLAG_ERROR_RESILIENT

0x004

The decoding should be error resilient.

V4L2_VP9_FRAME_FLAG_INTRA_ONLY

0x008

The frame does not reference other frames.

V4L2_VP9_FRAME_FLAG_ALLOW_HIGH_PREC_MV

0x010

The frame can use high precision motion vectors.

V4L2_VP9_FRAME_FLAG_REFRESH_FRAME_CTX

0x020

Frame context should be updated after decoding.

V4L2_VP9_FRAME_FLAG_PARALLEL_DEC_MODE

0x040

Parallel decoding is used.

V4L2_VP9_FRAME_FLAG_X_SUBSAMPLING

0x080

Vertical subsampling is enabled.

V4L2_VP9_FRAME_FLAG_Y_SUBSAMPLING

0x100

Horizontal subsampling is enabled.

V4L2_VP9_FRAME_FLAG_COLOR_RANGE_FULL_SWING

0x200

The full UV range is used.

Reference Frame Sign Bias

V4L2_VP9_SIGN_BIAS_LAST

0x1

Sign bias is set for the last reference frame.

V4L2_VP9_SIGN_BIAS_GOLDEN

0x2

Sign bias is set for the golden reference frame.

V4L2_VP9_SIGN_BIAS_ALT

0x2

Sign bias is set for the alt reference frame.

Reset Frame Context

V4L2_VP9_RESET_FRAME_CTX_NONE

0

Do not reset any frame context.

V4L2_VP9_RESET_FRAME_CTX_SPEC

1

Reset the frame context pointed to by v4l2_ctrl_vp9_frame.frame_context_idx.

V4L2_VP9_RESET_FRAME_CTX_ALL

2

Reset all frame contexts.

See section ‘7.2 Uncompressed header semantics’ of the VP9 specification for more details.

Interpolation Filter

V4L2_VP9_INTERP_FILTER_EIGHTTAP

0

Eight tap filter.

V4L2_VP9_INTERP_FILTER_EIGHTTAP_SMOOTH

1

Eight tap smooth filter.

V4L2_VP9_INTERP_FILTER_EIGHTTAP_SHARP

2

Eeight tap sharp filter.

V4L2_VP9_INTERP_FILTER_BILINEAR

3

Bilinear filter.

V4L2_VP9_INTERP_FILTER_SWITCHABLE

4

Filter selection is signaled at the block level.

See section ‘7.2.7 Interpolation filter semantics’ of the VP9 specification for more details.

Reference Mode

V4L2_VP9_REFERENCE_MODE_SINGLE_REFERENCE

0

Indicates that all the inter blocks use only a single reference frame to generate motion compensated prediction.

V4L2_VP9_REFERENCE_MODE_COMPOUND_REFERENCE

1

Requires all the inter blocks to use compound mode. Single reference frame prediction is not allowed.

V4L2_VP9_REFERENCE_MODE_SELECT

2

Allows each individual inter block to select between single and compound prediction modes.

See section ‘7.3.6 Frame reference mode semantics’ of the VP9 specification for more details.

type v4l2_vp9_segmentation

Encodes the quantization parameters. See section ‘7.2.10 Segmentation params syntax’ of the VP9 specification for more details.

struct v4l2_vp9_segmentation

__u8

feature_data[8][4]

Data attached to each feature. Data entry is only valid if the feature is enabled. The array shall be indexed with segment number as the first dimension (0..7) and one of V4L2_VP9_SEG_* as the second dimension. See Segment Feature IDs.

__u8

feature_enabled[8]

Bitmask defining which features are enabled in each segment. The value for each segment is a combination of V4L2_VP9_SEGMENT_FEATURE_ENABLED(id) values where id is one of V4L2_VP9_SEG_*. See Segment Feature IDs.

__u8

tree_probs[7]

Specifies the probability values to be used when decoding a Segment-ID. See ‘5.15. Segmentation map’ section of VP9 for more details.

__u8

pred_probs[3]

Specifies the probability values to be used when decoding a Predicted-Segment-ID. See ‘6.4.14. Get segment id syntax’ section of VP9 for more details.

__u8

flags

Combination of V4L2_VP9_SEGMENTATION_FLAG_* flags. See Segmentation Flags.

__u8

reserved[5]

Applications and drivers must set this to zero.

Segment feature IDs

V4L2_VP9_SEG_LVL_ALT_Q

0

Quantizer segment feature.

V4L2_VP9_SEG_LVL_ALT_L

1

Loop filter segment feature.

V4L2_VP9_SEG_LVL_REF_FRAME

2

Reference frame segment feature.

V4L2_VP9_SEG_LVL_SKIP

3

Skip segment feature.

V4L2_VP9_SEG_LVL_MAX

4

Number of segment features.

Segmentation Flags

V4L2_VP9_SEGMENTATION_FLAG_ENABLED

0x01

Indicates that this frame makes use of the segmentation tool.

V4L2_VP9_SEGMENTATION_FLAG_UPDATE_MAP

0x02

Indicates that the segmentation map should be updated during the decoding of this frame.

V4L2_VP9_SEGMENTATION_FLAG_TEMPORAL_UPDATE

0x04

Indicates that the updates to the segmentation map are coded relative to the existing segmentation map.

V4L2_VP9_SEGMENTATION_FLAG_UPDATE_DATA

0x08

Indicates that new parameters are about to be specified for each segment.

V4L2_VP9_SEGMENTATION_FLAG_ABS_OR_DELTA_UPDATE

0x10

Indicates that the segmentation parameters represent the actual values to be used.

type v4l2_vp9_quantization

Encodes the quantization parameters. See section ‘7.2.9 Quantization params syntax’ of the VP9 specification for more details.

struct v4l2_vp9_quantization

__u8

base_q_idx

Indicates the base frame qindex.

__s8

delta_q_y_dc

Indicates the Y DC quantizer relative to base_q_idx.

__s8

delta_q_uv_dc

Indicates the UV DC quantizer relative to base_q_idx.

__s8

delta_q_uv_ac

Indicates the UV AC quantizer relative to base_q_idx.

__u8

reserved[4]

Applications and drivers must set this to zero.

type v4l2_vp9_loop_filter

This structure contains all loop filter related parameters. See sections ‘7.2.8 Loop filter semantics’ of the VP9 specification for more details.

struct v4l2_vp9_loop_filter

__s8

ref_deltas[4]

Contains the adjustment needed for the filter level based on the chosen reference frame.

__s8

mode_deltas[2]

Contains the adjustment needed for the filter level based on the chosen mode.

__u8

level

Indicates the loop filter strength.

__u8

sharpness

Indicates the sharpness level.

__u8

flags

Combination of V4L2_VP9_LOOP_FILTER_FLAG_* flags. See Loop Filter Flags.

__u8

reserved[7]

Applications and drivers must set this to zero.

Loop Filter Flags

V4L2_VP9_LOOP_FILTER_FLAG_DELTA_ENABLED

0x1

When set, the filter level depends on the mode and reference frame used to predict a block.

V4L2_VP9_LOOP_FILTER_FLAG_DELTA_UPDATE

0x2

When set, the bitstream contains additional syntax elements that specify which mode and reference frame deltas are to be updated.