srs/trunk/3rdparty/srs-bench/vendor/github.com/yapingcat/gomedia/codec

USAGE

1. 如何解析sps/pps/vps 以解析sps为例

   
   //sps原始数据,不带start code(0x00000001)
   var rawsps []byte = []byte{0x67,....}
   
   //step1 创建BitStream
   bs := codec.NewBitStream(rawsps)
   
   //step2 解析sps
   sps := &SPS{}
   sps.Decode(bs)
   
   

2. 获取视频宽高 以h264为例子

   //sps原始数据,以startcode开头(0x00000001)
   var rawsps []byte = []byte{0x00,0x00,0x00,0x01,0x67,.....}
   w, h := codec.GetH264Resolution(rawsps)
   

3. 生成Extradata 以h264为例子

   
   //多个sps原始数据,以startcode开头(0x00000001)
   var spss [][]byte = [][]byte{
       []byte{0x00,0x00,0x00,0x01,0x67,...},
       []byte{0x00,0x00,0x00,0x01,0x67,...},
       ....
   }
   
    //多个pps原始数据,以startcode开头(0x00000001)
   var ppss [][]byte = [][]byte{
       []byte{0x00,0x00,0x00,0x01,0x68,...},
       []byte{0x00,0x00,0x00,0x01,0x68,...},
       ....
   }
   extranData := codec.CreateH264AVCCExtradata(spss,ppss)
   

4. Extradata转为Annex-B格式的sps,pps 以h264为例子

   
   //一般从flv/mp4格式中获取 extraData
   //解析出来多个sps,pps, 且sps pps 都以startcode开头
   spss,ppss := codec.CovertExtradata(extraData)
   

5. 生成H265 extrandata

   // H265的extra data 生成过程稍微复杂一些
   //创建一个 HEVCRecordConfiguration 对象
   
   hvcc := codec.NewHEVCRecordConfiguration()
   
   //对每一个 sps/pps/vps,调用相应的UpdateSPS,UpdatePPS,UpdateVPS接口
   hvcc.UpdateSPS(sps)
   hvcc.UpdatePPS(pps)
   hvcc.UpdateVPS(vps)
   
   //调用Encode接口生成
   extran := hvcc.Encode()
   

6. 获取对应的sps id/vps id/pps id

   //以h264为例子，有四个接口
   //sps 以startcode 开头
   codec.GetSPSIdWithStartCode(sps)
   
   //sps2 不以startcode 开头
   codec.GetSPSId(sps2)
   
   //pps 以startcode 开头
   codec.GetPPSIdWithStartCode(pps)
   
   //pps2 不以startcode 开头
   codec.GetPPSId(pps2)