Add SPS parser and AVC/HVC conf encoders

2023-08-14 11:55:08 +03:00
parent 3a40515a90
commit de6bb33f01
12 changed files with 302 additions and 599 deletions
@@ -0,0 +1,164 @@
+package avc
+
+import "github.com/AlexxIT/go2rtc/pkg/bits"
+
+// http://www.itu.int/rec/T-REC-H.264
+// https://webrtc.googlesource.com/src/+/refs/heads/main/common_video/h264/sps_parser.cc
+
+//goland:noinspection GoSnakeCaseUsage
+type SPS struct {
+	profile_idc uint8
+	profile_iop uint8
+	level_idc   uint8
+
+	seq_parameter_set_id uint32
+
+	chroma_format_idc                    uint32
+	separate_colour_plane_flag           byte
+	bit_depth_luma_minus8                uint32
+	bit_depth_chroma_minus8              uint32
+	qpprime_y_zero_transform_bypass_flag byte
+	seq_scaling_matrix_present_flag      byte
+
+	log2_max_frame_num_minus4             uint32
+	pic_order_cnt_type                    uint32
+	log2_max_pic_order_cnt_lsb_minus4     uint32
+	delta_pic_order_always_zero_flag      byte
+	offset_for_non_ref_pic                int32
+	offset_for_top_to_bottom_field        int32
+	num_ref_frames_in_pic_order_cnt_cycle uint32
+	num_ref_frames                        uint32
+	gaps_in_frame_num_value_allowed_flag  byte
+
+	pic_width_in_mbs_minus_1        uint32
+	pic_height_in_map_units_minus_1 uint32
+	frame_mbs_only_flag             byte
+	mb_adaptive_frame_field_flag    byte
+	direct_8x8_inference_flag       byte
+
+	frame_cropping_flag      byte
+	frame_crop_left_offset   uint32
+	frame_crop_right_offset  uint32
+	frame_crop_top_offset    uint32
+	frame_crop_bottom_offset uint32
+
+	vui_parameters_present_flag    byte
+	aspect_ratio_info_present_flag byte
+	aspect_ratio_idc               uint32
+	sar_width                      uint32
+	sar_height                     uint32
+}
+
+func DecodeSPS(sps []byte) *SPS {
+	r := bits.NewReader(sps)
+
+	hdr := r.ReadByte()
+	if hdr&0x1F != 7 {
+		return nil
+	}
+
+	s := &SPS{
+		profile_idc:          r.ReadByte(),
+		profile_iop:          r.ReadByte(),
+		level_idc:            r.ReadByte(),
+		seq_parameter_set_id: r.ReadUEGolomb(),
+	}
+
+	switch s.profile_idc {
+	case 100, 110, 122, 244, 44, 83, 86, 118, 128, 138, 139, 134, 135:
+		n := byte(8)
+
+		s.chroma_format_idc = r.ReadUEGolomb()
+		if s.chroma_format_idc == 3 {
+			s.separate_colour_plane_flag = r.ReadBit()
+			n = 12
+		}
+
+		s.bit_depth_luma_minus8 = r.ReadUEGolomb()
+		s.bit_depth_chroma_minus8 = r.ReadUEGolomb()
+		s.qpprime_y_zero_transform_bypass_flag = r.ReadBit()
+
+		s.seq_scaling_matrix_present_flag = r.ReadBit()
+		if s.seq_scaling_matrix_present_flag != 0 {
+			for i := byte(0); i < n; i++ {
+				ssl := r.ReadBit() // seq_scaling_list_present_flag[i]
+				if ssl != 0 {
+					return nil // not implemented
+				}
+			}
+		}
+	}
+
+	s.log2_max_frame_num_minus4 = r.ReadUEGolomb()
+
+	s.pic_order_cnt_type = r.ReadUEGolomb()
+	switch s.pic_order_cnt_type {
+	case 0:
+		s.log2_max_pic_order_cnt_lsb_minus4 = r.ReadUEGolomb()
+	case 1:
+		s.delta_pic_order_always_zero_flag = r.ReadBit()
+		s.offset_for_non_ref_pic = r.ReadSEGolomb()
+		s.offset_for_top_to_bottom_field = r.ReadSEGolomb()
+
+		s.num_ref_frames_in_pic_order_cnt_cycle = r.ReadUEGolomb()
+		for i := uint32(0); i < s.num_ref_frames_in_pic_order_cnt_cycle; i++ {
+			_ = r.ReadSEGolomb() // offset_for_ref_frame[i]
+		}
+	}
+
+	s.num_ref_frames = r.ReadUEGolomb()
+	s.gaps_in_frame_num_value_allowed_flag = r.ReadBit()
+
+	s.pic_width_in_mbs_minus_1 = r.ReadUEGolomb()
+	s.pic_height_in_map_units_minus_1 = r.ReadUEGolomb()
+
+	s.frame_mbs_only_flag = r.ReadBit()
+	if s.frame_mbs_only_flag == 0 {
+		s.mb_adaptive_frame_field_flag = r.ReadBit()
+	}
+
+	s.direct_8x8_inference_flag = r.ReadBit()
+
+	s.frame_cropping_flag = r.ReadBit()
+	if s.frame_cropping_flag != 0 {
+		s.frame_crop_left_offset = r.ReadUEGolomb()
+		s.frame_crop_right_offset = r.ReadUEGolomb()
+		s.frame_crop_top_offset = r.ReadUEGolomb()
+		s.frame_crop_bottom_offset = r.ReadUEGolomb()
+	}
+
+	s.vui_parameters_present_flag = r.ReadBit()
+	if s.vui_parameters_present_flag != 0 {
+		s.aspect_ratio_info_present_flag = r.ReadBit()
+		if s.aspect_ratio_info_present_flag != 0 {
+			s.aspect_ratio_idc = r.ReadBits(8)
+			if s.aspect_ratio_idc == 255 {
+				s.sar_width = r.ReadBits(16)
+				s.sar_height = r.ReadBits(16)
+			}
+		}
+
+		//...
+	}
+
+	if r.EOF {
+		return nil
+	}
+
+	return s
+}
+
+func (s *SPS) Width() uint16 {
+	width := 16 * (s.pic_width_in_mbs_minus_1 + 1)
+	crop := 2 * (s.frame_crop_left_offset + s.frame_crop_right_offset)
+	return uint16(width - crop)
+}
+
+func (s *SPS) Heigth() uint16 {
+	height := 16 * (s.pic_height_in_map_units_minus_1 + 1)
+	crop := 2 * (s.frame_crop_top_offset + s.frame_crop_bottom_offset)
+	if s.frame_mbs_only_flag == 0 {
+		height *= 2
+	}
+	return uint16(height - crop)
+}