github.com/cnotch/ipchub@v1.1.0/av/codec/h264/const.go (about)

     1  // Copyright (c) 2019,CAOHONGJU All rights reserved.
     2  // Use of this source code is governed by a MIT-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package h264
     6  
     7  /*
     8   * Table 7-1 – NAL unit type codes, syntax element categories, and NAL unit type classes in
     9   * T-REC-H.264-201704
    10   */
    11  // H264 NAL 单元类型
    12  const (
    13  	NalUnspecified     = 0
    14  	NalSlice           = 1  // 不分区非IDR图像的片
    15  	NalDpa             = 2  // 片分区A
    16  	NalDpb             = 3  // 片分区B
    17  	NalDpc             = 4  // 片分区C
    18  	NalIdrSlice        = 5  // IDR图像中的片（I帧）
    19  	NalSei             = 6  // 补充增强信息单元，sei playload可以使用户自定义数据， 那么我们就可以利用它来传输数据
    20  	NalSps             = 7  // 序列参数集
    21  	NalPps             = 8  // 图像参数集
    22  	NalAud             = 9  // 分界符
    23  	NalEndSequence     = 10 // 序列结束
    24  	NalEndStream       = 11 // 码流结束
    25  	NalFillerData      = 12 // 填充
    26  	NalSpsExt          = 13 //
    27  	NalPrefix          = 14
    28  	NalSubSps          = 15
    29  	NalDps             = 16
    30  	NalReserved17      = 17
    31  	NalReserved18      = 18
    32  	NalAuxiliarySlice  = 19
    33  	NalExtenSlice      = 20
    34  	NalDepthExtenSlice = 21
    35  	NalReserved22      = 22
    36  	NalReserved23      = 23
    37  	NalUnspecified24   = 24
    38  	NalUnspecified25   = 25
    39  	NalUnspecified26   = 26
    40  	NalUnspecified27   = 27
    41  	NalUnspecified28   = 28
    42  	NalUnspecified29   = 29
    43  	NalUnspecified30   = 30
    44  	NalUnspecified31   = 31
    45  
    46  	// NAL 在 RTP 包中的扩展
    47  	NalStapaInRtp  = 24 // 单一时间的组合包
    48  	NalStapbInRtp  = 25 // 单一时间的组合包
    49  	NalMtap16InRtp = 26 // 多个时间的组合包
    50  	NalMtap24InRtp = 27 // 多个时间的组合包
    51  	NalFuAInRtp    = 28 // 分片的单元
    52  	NalFuBInRtp    = 29 // 分片的单元
    53  
    54  	NalTypeBitmask = 0x1F
    55  )
    56  
    57  // Profile
    58  const (
    59  	ProfileConstrained = (1 << 9)  // 8+1; constraint_set1_flag
    60  	ProfileIntra       = (1 << 11) // 8+3; constraint_set3_flag
    61  
    62  	ProfileBaseline            = 66
    63  	ProfileConstrainedBaseline = (66 | ProfileConstrained)
    64  	ProfileMain                = 77
    65  	ProfileExtended            = 88
    66  	ProfileHigh                = 100
    67  	ProfileHigh10              = 110
    68  	ProfileHigh10Intra         = (110 | ProfileIntra)
    69  	ProfileMultiViewHigh       = 118
    70  	ProfileHigh422             = 122
    71  	ProfileHigh422Intra        = (122 | ProfileIntra)
    72  	ProfileStereoHigh          = 128
    73  	ProfileHigh444             = 144
    74  	ProfileHigh444Predictive   = 244
    75  	ProfileHigh444Intra        = (244 | ProfileIntra)
    76  	ProfileCAVLC444            = 44
    77  )
    78  
    79  // 参数集索引
    80  const (
    81  	ParameterSetSps = iota
    82  	ParameterSetPps
    83  )
    84  
    85  // 其他常量
    86  const (
    87  	// 7.4.2.1.1: seq_parameter_set_id is in [0, 31].
    88  	MaxSpsCount = 32
    89  	// 7.4.2.2: pic_parameter_set_id is in [0, 255].
    90  	MaxPpsCount = 256
    91  
    92  	// A.3: MaxDpbFrames is bounded above by 16.
    93  	MaxDpbFrames = 16
    94  	// 7.4.2.1.1: max_num_ref_frames is in [0, MaxDpbFrames], and
    95  	// each reference frame can have two fields.
    96  	MaxRefs = 2 * MaxDpbFrames
    97  
    98  	// 7.4.3.1: modification_of_pic_nums_idc is not equal to 3 at most
    99  	// num_ref_idx_lN_active_minus1 + 1 times (that is, once for each
   100  	// possible reference), then equal to 3 once.
   101  	MaxRplmCount = MaxRefs + 1
   102  
   103  	// 7.4.3.3: in the worst case, we begin with a full short-term
   104  	// reference picture list.  Each picture in turn is moved to the
   105  	// long-term list (type 3) and then discarded from there (type 2).
   106  	// Then, we set the length of the long-term list (type 4), mark
   107  	// the current picture as long-term (type 6) and terminate the
   108  	// process (type 0).
   109  	MaxMmcoCount = MaxRefs*2 + 3
   110  
   111  	// A.2.1, A.2.3: profiles supporting FMO constrain
   112  	// num_slice_groups_minus1 to be in [0, 7].
   113  	MaxSliceGroups = 8
   114  
   115  	// E.2.2: cpb_cnt_minus1 is in [0, 31].
   116  	MaxCpbCnt = 32
   117  
   118  	// A.3: in table A-1 the highest level allows a MaxFS of 139264.
   119  	MaxMbPicSize = 139264
   120  	// A.3.1, A.3.2: PicWidthInMbs and PicHeightInMbs are constrained
   121  	// to be not greater than sqrt(MaxFS * 8).  Hence height/width are
   122  	// bounded above by sqrt(139264 * 8) = 1055.5 macroblocks.
   123  	MaxMbWidth  = 1055
   124  	MaxMbHeight = 1055
   125  	MaxWidth    = MaxMbWidth * 16
   126  	MaxHeight   = MaxMbHeight * 16
   127  )