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codec/h264/h264dec/sps.go: commented fields of syntax structures
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@ -63,48 +63,155 @@ var (
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// SPS describes a sequence parameter set as defined by section 7.3.2.1.1 in
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// the Specifications.
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// For semantics see section 7.4.2.1. Comments for fields are excerpts from
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// section 7.4.2.1.
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type SPS struct {
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Profile uint8
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// pofile_idx and level_idc indicate the profile and level to which the
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// coded video sequence conforms.
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Profile, LevelIDC uint8
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// The constraint_setx_flag flags specify the constraints defined in A.2 for
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// which this stream conforms.
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Constraint0 bool
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Constraint1 bool
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Constraint2 bool
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Constraint3 bool
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Constraint4 bool
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Constraint5 bool
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LevelIDC uint8
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// seq_parameter_set_id identifies this sequence parameter set, and can then
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// be reference by the picture parameter set. The seq_parameter_set_id is
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// in the range of 0 to 30 inclusive.
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SPSID uint64
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// chroma_format_idc specifies the chroma sampling relative to the luma
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// sampling as specified in caluse 6.2. Range of chroma_format_idc is in
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// from 0 to 3 inclusive.
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ChromaFormatIDC uint64
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// separate_color_plane_flag if true specifies that the three components of
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// the 4:4:4 chroma formta are coded separately.
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SeparateColorPlaneFlag bool
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// bit_depth_luma_minus8 specifies the luma array sample bit depth and the
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// luma quantisation parameter range offset QpBdOffset_y (eq 7-3 and 7-4).
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BitDepthLumaMinus8 uint64
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// bit_depth_luma_minus8 specifies the chroma array sample bit depth and the
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// chroma quantisation parameter range offset QpBdOffset_c (eq 7-3 and 7-4).
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BitDepthChromaMinus8 uint64
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// qpprime_y_zero_transform_bypass_flag equal to 1 specifies that, when QP′ Y
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// is equal to 0, a transform bypass operation for the transform coefficient
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// decoding process and picture construction process prior to deblocking
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// filter process as specified in clause 8.5 shall be applied.
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QPPrimeYZeroTransformBypassFlag bool
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// seq_scaling_matrix_present_flag equal to 1 specifies that
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// seq_scaling_list_present_flag[ i ] are present. When 0 they are not present
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// and the sequence-level scaling lists specified by Flat_4x4_16 and
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// Flat_8x8_16 shall be inferred.
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SeqScalingMatrixPresentFlag bool
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// seq_scaling_lit_present_flag[i] specifics whether the syntax structure for
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// scaling list i is present. If 1 then present, otherwise not, and scaling
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// list for i is inferred as per rule set A in table 7-2.
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SeqScalingListPresentFlag []bool
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// The 4x4 sequence scaling lists for each i.
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ScalingList4x4 [][]uint64
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// Flag to indicate for a 4x4 scaling list, if we use the default.
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UseDefaultScalingMatrix4x4Flag []bool
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// The 8x8 sequence scaling lists for each i.
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ScalingList8x8 [][]uint64
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// Flag to indicate for a 8x8 scaling list, if we use the default.
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UseDefaultScalingMatrix8x8Flag []bool
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// log2_max_frame_num_minus4 allows for derivation of MaxFrameNum using eq 7-10.
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Log2MaxFrameNumMinus4 uint64
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// pic_order_cnt_type specifiess the method to decode picture order count.
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PicOrderCountType uint64
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// log2_max_pic_order_cnt_lsb_minus4 allows for the dreivation of
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// MaxPicOrderCntLsb using eq 7-11.
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Log2MaxPicOrderCntLSBMin4 uint64
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// delta_pic_order_always_zero_flag if true indicates delta_pic_order_cnt[0]
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// and delta_pic_order_cnt[1].
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DeltaPicOrderAlwaysZeroFlag bool
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// offset_for_non_ref_pic is used to calculate the picture order count of a
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// non-reference picture as specified in clause 8.2.1.
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OffsetForNonRefPic int64
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// offset_for_top_to_bottom_field is used to calculate the picture order count
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// of a bottom field as specified in clause 8.2.1.
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OffsetForTopToBottomField int64
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// num_ref_frames_in_pic_order_cnt_cycle is used in the decoding process for
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// picture order count as specified in clause 8.2.1.
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NumRefFramesInPicOrderCntCycle uint64
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// offset_for_ref_frame[ i ] is an element of a list of
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// num_ref_frames_in_pic_order_cnt_cycle values used in the decoding process
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// for picture order count as specified in clause 8.2.1.
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OffsetForRefFrameList []int
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// max_num_ref_frames specifies the max number of short-term and long-term
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// reference frames, complementary reference field pairs, and non-paired
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// reference fields that may be used by the decoding process for inter prediction.
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MaxNumRefFrames uint64
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// gaps_in_frame_num_value_allowed_flag specifies the allowed values of
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// frame_num as specified in clause 7.4.3 and the decoding process in case of
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// an inferred gap between values of frame_num as specified in clause 8.2.5.2.
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GapsInFrameNumValueAllowed bool
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// pic_width_in_mbs_minus1 plus 1 specifies the width of each decode picutre
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// in units of macroblocks. See eq 7-13.
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PicWidthInMBSMinus1 uint64
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// pic_height_in_map_units_minus1 plus 1 specifies the height in slice group
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// map units of a decoded frame or field. See eq 7-16.
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PicHeightInMapUnitsMinus1 uint64
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// frame_mbs_only_flag if 0 coded pictures of the coded video sequence may be
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// coded fields or coded frames. If 1 every coded picture of the coded video
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// sequence is a coded frame containing only frame macroblocks.
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FrameMBSOnlyFlag bool
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// mb_adaptive_frame_field_flag if 0 specifies no switching between
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// frame and field macroblocks within a picture. If 1 specifies the possible
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// use of switching between frame and field macroblocks within frames.
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MBAdaptiveFrameFieldFlag bool
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// direct_8x8_inference_flag specifies the method used in the derivation
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// process for luma motion vectors for B_Skip, B_Direct_16x16 and B_Direct_8x8
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// as specified in clause 8.4.1.2.
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Direct8x8InferenceFlag bool
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// frame_cropping_flag if 1 then frame cropping offset parameters are next in
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// the sequence parameter set. If 0 they are not.
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FrameCroppingFlag bool
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// frame_crop_left_offset, frame_crop_right_offset, frame_crop_top_offset,
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// frame_crop_bottom_offset specify the samples of the pictures in the coded
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// video sequence that are output from the decoding process, in terms of a
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// rectangular region specified in frame coordinates for output.
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FrameCropLeftOffset uint64
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FrameCropRightOffset uint64
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FrameCropTopOffset uint64
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FrameCropBottomOffset uint64
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// vui_parameters_present_flag if 1 the vui_parameters() syntax structure is
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// present, otherwise it is not.
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VUIParametersPresentFlag bool
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// The vui_parameters() syntax structure specified in appendix E.
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VUIParameters *VUIParameters
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}
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@ -225,40 +332,157 @@ func NewSPS(rbsp []byte, showPacket bool) (*SPS, error) {
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// SPS describes a sequence parameter set as defined by section E.1.1 in the
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// Specifications.
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// Semantics for fields are define in section E.2.1. Comments on fields are
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// excerpts from the this section.
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type VUIParameters struct {
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// aspect_ratio_info_present_flag if 1 then aspect_ratio_idc is present,
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// otherwsise is not.
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AspectRatioInfoPresentFlag bool
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// aspect_ratio_idc specifies the value of sample aspect ratio of the luma samples.
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AspectRatioIDC uint8
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// sar_width indicates the horizontal size of the sample aspect ratio (in
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// arbitrary units).
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SARWidth uint32
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// sar_height indicates the vertical size of the sample aspect ratio (in the
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// same arbitrary units as sar_width).
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SARHeight uint32
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// overscan_info_present_flag if 1 then overscan_appropriate_flag is present,
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// otherwise if 0, then the display method for the video signal is unspecified.
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OverscanInfoPresentFlag bool
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// overscan_appropriate_flag if 1 then the cropped decoded pictures output
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// are suitable for display using overscan, othersise if 0, then the cropped
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// decoded pictures output should not be displayed using overscan.
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OverscanAppropriateFlag bool
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// video_signal_type_present_flag equal to 1 specifies that video_format,
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// video_full_range_flag and colour_description_present_flag are present,
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// otherwise if 0, then they are not present.
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VideoSignalTypePresentFlag bool
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// video_format indicates the representation of the pictures as specified in
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// Table E-2, before being coded in accordance with this Recommendation |
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// International Standard.
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VideoFormat uint8
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// video_full_range_flag indicates the black level and range of the luma and
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// chroma signals as derived from E′_Y, E′_PB, and E′_PR or E′_R, E′_G,
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// and E′_B real-valued component signals.
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VideoFullRangeFlag bool
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// colour_description_present_flag if 1 specifies that colour_primaries,
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// transfer_characteristics and matrix_coefficients are present, otherwise if
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// 0 then they are not present.
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ColorDescriptionPresentFlag bool
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// colour_primaries indicates the chromaticity coordinates of the source
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// primaries as specified in Table E-3 in terms of the CIE 1931 definition of
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// x and y as specified by ISO 11664-1.
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ColorPrimaries uint8
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// transfer_characteristics either indicates the reference opto-electronic
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// transfer characteristic function of the source picture, or indicates the
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// inverse of the reference electro-optical transfer characteristic function.
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TransferCharacteristics uint8
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// matrix_coefficients describes the matrix coefficients used in deriving luma
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// and chroma signals from the green, blue, and red, or Y, Z, and X primaries,
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// as specified in Table E-5.
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MatrixCoefficients uint8
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// chroma_loc_info_present_flag if 1 specifies that chroma_sample_loc_type_top_field
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// and chroma_sample_loc_type_bottom_field are present, otherwise if 0,
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// they are not present.
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ChromaLocInfoPresentFlag bool
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ChromaSampleLocTypeTopField uint64
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ChromaSampleLocTypeBottomField uint64
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// chroma_sample_loc_type_top_field and chroma_sample_loc_type_bottom_field
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// specify the location of chroma samples.
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ChromaSampleLocTypeTopField, ChromaSampleLocTypeBottomField uint64
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// timing_info_present_flag if 1 specifies that num_units_in_tick, time_scale
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// and fixed_frame_rate_flag are present in the bitstream, otherwise if 0,
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// they are not present.
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TimingInfoPresentFlag bool
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// num_units_in_tick is the number of time units of a clock operating at the
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// frequency time_scale Hz that corresponds to one increment (called a clock
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// tick) of a clock tick counter.
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NumUnitsInTick uint32
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// time_scale is the number of time units that pass in one second.
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TimeScale uint32
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// fixed_frame_rate_flag if 1 indicates that the temporal distance
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// between the HRD output times of any two consecutive pictures in output
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// order is constrained as follows. fixed_frame_rate_flag equal to 0 indicates
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// that no such constraints apply to the temporal distance between the HRD
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// output times of any two consecutive pictures in output order.
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FixedFrameRateFlag bool
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// nal_hrd_parameters_present_flag if 1 then NAL HRD parameters (pertaining to
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// Type II bitstream conformance) are present, otherwise if 0, then they
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// are not present.
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NALHRDParametersPresentFlag bool
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// The nal_hrd_parameters() syntax structure as specified in section E.1.2.
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NALHRDParameters *HRDParameters
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// vcl_hrd_parameters_present_flag if 1 specifies that VCL HRD parameters
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// (pertaining to all bitstream conformance) are present, otherwise if 0, then
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// they are not present.
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VCLHRDParametersPresentFlag bool
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// The vcl_nal_hrd_parameters() syntax structure as specified in section E.1.2.
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VCLHRDParameters *HRDParameters
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// low_delay_hrd_flag specifies the HRD operational mode as specified in Annex C.
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LowDelayHRDFlag bool
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// pic_struct_present_flag if 1 then picture timing SEI messages (clause D.2.3)
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// are present that include the pic_struct syntax element, otherwise if 0, then
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// not present.
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PicStructPresentFlag bool
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// bitstream_restriction_flag if 1, then the following coded video sequence
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// bitstream restriction parameters are present, otherwise if 0, then they are
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// not present.
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BitstreamRestrictionFlag bool
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// motion_vectors_over_pic_boundaries_flag if 0 then no sample outside the
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// picture boundaries and no sample at a fractional sample position for which
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// the sample value is derived using one or more samples outside the picture
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// boundaries is used for inter prediction of any sample, otherwise if 1,
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// indicates that one or more samples outside picture boundaries may be used
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// in inter prediction.
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MotionVectorsOverPicBoundariesFlag bool
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// max_bytes_per_pic_denom indicates a number of bytes not exceeded by the sum
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// of the sizes of the VCL NAL units associated with any coded picture in the
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// coded video sequence.
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MaxBytesPerPicDenom uint64
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// max_bits_per_mb_denom indicates an upper bound for the number of coded bits
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// of macroblock_layer() data for any macroblock in any picture of the coded
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// video sequence.
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MaxBitsPerMBDenom uint64
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Log2MaxMVLengthHorizontal uint64
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Log2MaxMVLengthVertical uint64
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// log2_max_mv_length_horizontal and log2_max_mv_length_vertical indicate the
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// maximum absolute value of a decoded horizontal and vertical motion vector
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// component, respectively, in 1⁄4 luma sample units, for all pictures in the
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// coded video sequence.
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Log2MaxMVLengthHorizontal, Log2MaxMVLengthVertical uint64
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// max_num_reorder_frames indicates an upper bound for the number of frames
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// buffers, in the decoded picture buffer (DPB), that are required for storing
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// frames, complementary field pairs, and non-paired fields before output.
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MaxNumReorderFrames uint64
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// max_dec_frame_buffering specifies the required size of the HRD decoded
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// picture buffer (DPB) in units of frame buffers.
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MaxDecFrameBuffering uint64
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}
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@ -357,16 +581,51 @@ func NewVUIParameters(br *bits.BitReader) (*VUIParameters, error) {
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// HRDParameters describes hypothetical reference decoder parameters as defined
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// by section E.1.2 in the specifications.
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// Field semantics are defined in section E.2.2. Comments on fields are excerpts
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// from section E.2.2.
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type HRDParameters struct {
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// cpb_cnt_minus1 plus 1 specifies the number of alternative CPB specifications
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// in the bitstream.
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CPBCntMinus1 uint64
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// bit_rate_scale (together with bit_rate_value_minus1[ SchedSelIdx ])
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// specifies the maximum input bit rate of the SchedSelIdx-th CPB.
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BitRateScale uint8
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// cpb_size_scale (together with cpb_size_value_minus1[ SchedSelIdx ])
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// specifies the CPB size of the SchedSelIdx-th CPB.
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CPBSizeScale uint8
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// bit_rate_value_minus1[ SchedSelIdx ] (together with bit_rate_scale)
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//specifies the maximum input bit rate for the SchedSelIdx-th CPB.
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BitRateValueMinus1 []uint64
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// cpb_size_value_minus1[ SchedSelIdx ] is used together with cpb_size_scale
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// to specify the SchedSelIdx-th CPB size.
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CPBSizeValueMinus1 []uint64
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// cbr_flag[ SchedSelIdx ] equal to 0 specifies that to decode this bitstream
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// by the HRD using the SchedSelIdx-th CPB specification, the hypothetical
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// stream delivery scheduler (HSS) operates in an intermittent bit rate mode,
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// otherwise if 1 specifies that the HSS operates in a constant bit rate mode.
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CBRFlag []bool
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// initial_cpb_removal_delay_length_minus1 specifies the length in bits of the
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// initial_cpb_removal_delay[ SchedSelIdx ] and
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// initial_cpb_removal_delay_offset[ SchedSelIdx ] syntax elements of the
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// buffering period SEI message.
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InitialCPBRemovalDelayLenMinus1 uint8
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// cpb_removal_delay_length_minus1 specifies the length in bits of the
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// cpb_removal_delay syntax element.
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CPBRemovalDelayLenMinus1 uint8
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// dpb_output_delay_length_minus1 specifies the length in bits of the
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// dpb_output_delay syntax element.
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DPBOutputDelayLenMinus1 uint8
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// time_offset_length greater than 0 specifies the length in bits of the
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// time_offset syntax element.
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TimeOffsetLen uint8
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}
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