在之前两篇对于SkeyeRTMPClient扩大反对HEVC(H.265)解决方案的文章中，咱们曾经实现了对H265的反对，本文次要论述将H26和H265反对兼容起来，实现不同视频编码格局的自适应兼容适配。
1. 依据CodecId判断数据编码类型
依据视频编码ID判断视频编码类型，如果视频编码ID==FlvCodeId_Hevc（12）,则判断视频编码格局为H265，反之则为H264（因为目前咱们只反对这两种编码格局的视频推送），如下代码所示：
parser_VideoTag *video_tag = (parser_VideoTag*)(buf+parser_offset); FlvCodeId video_code_id = (FlvCodeId)(video_tag->code_id&0x0f); if (video_code_id == FlvCodeId_Hevc) { av_frame.u32AVFrameFlag = SKEYE_SDK_VIDEO_CODEC_H265;// HEVC; } else { av_frame.u32AVFrameFlag = SKEYE_SDK_VIDEO_CODEC_H264;// 默认h264, 其余类型是否须要判断?!; }2. 数据帧头部判断
依据FLV/RTMP扩大反对H265规范，反对HEVC的VideoTagHeader定义如下图所示：
即 当CodecID == 12时，AVCPacketType为HEVCPacketType：
- 如果HEVCPacketType为0，示意HEVCVIDEOPACKET中寄存的是HEVC sequence header；
- 如果HEVCPacketType为1，示意HEVCVIDEOPACKET中寄存的是HEVC NALU；
- 如果HEVCPacketType为2，示意HEVCVIDEPACKET中寄存的是HEVC end of sequence，即HEVCDecoderConfigurationRecord；
而当CodecID == 7时，AVCPacketType为AVCPacketType：
- 如果AVCPacketType为0，示意HEVCVIDEOPACKET中寄存的是AVC sequence header；
- 如果AVCPacketType为1，示意HEVCVIDEOPACKET中寄存的是AVC NALU；
- 如果AVCPacketType为2，示意HEVCVIDEPACKET中寄存的是AVC end of sequence，即AVCDecoderConfigurationRecord；
SkeyeRTMPClient对sequence header的解析函数如下代码段所示：
int ParserVideoSequencePacket(FlvCodeId video_code_id, char *buf,int len){ int parser_offset = 0; char *parser_config = buf; if (video_code_id == FlvCodeId_Hevc) { if(len <= sizeof(Parser_HEVCDecoderConfigurationRecord)) { return -1001; } ......’ //Parser HEVCDecoderConfigurationRecord ...... rtmpclient_h265_decode_sps((unsigned char *)sps_buf_, sps_len_, width_, height_); } else { if(len <= sizeof(parser_AVCDecoderHeader)) { return -1001; } ......’ //Parser HEVCDecoderHeader ...... rtmpclient_h264_decode_sps((unsigned char *)sps_buf_, sps_len_, width_, height_); } return 0;}3. 视频数据体帧数据nalu类型判断
依据FLV/RTMP扩大反对协定规范，反对H265的VideoTagBody定义如下, 扩大后的VideoTagBody如下图所示(红色字体为HEVC新增内容)：：
当CodecID为12时，VideoTagBody中寄存的就是HEVC视频帧内容。
SkeyeRTMPClient视频帧nalu解析如下代码所示：
int ParserOneVideoNalu(SkeyeRTMPClient_AV_Frame& av_frame,char *buf,int len,char* processbuf){ if(processbuf == NULL || buf == NULL || len == 0) { return -3001; } if(sps_len_ == 0 || pps_len_ == 0) { printf("do not get sequence head yet\n"); return -3002; } int parse_offset = 0; int nalu_len = 0; int nalu_type = 0; int processlen = 0; while(parse_offset < len - 4) { nalu_len = ntohl(*(int*)(buf + parse_offset)); parse_offset += 4; //如果视频帧编码类型为H265 if(av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265) { nalu_type = (buf[parse_offset] >> 1) & 0x3F; if(nalu_type == e_H265_NAL_UNIT_VPS) { ASSERT_PARSER(nalu_len,MAX_VPS_LEN); memcpy(vps_buf_,buf + parse_offset,nalu_len); vps_len_ = nalu_len; parse_offset += nalu_len; continue; } }else{ nalu_type = buf[parse_offset]&0x1F; } //H265 以及 H264的SPS头解析兼容 if((av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265&&nalu_type ==e_H265_NAL_UNIT_SPS) || av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H264&&nalu_type == e_H264_Frame_Type_Sps) { ASSERT_PARSER(nalu_len,MAX_PPS_LEN); memcpy(sps_buf_,buf + parse_offset,nalu_len); sps_len_ = nalu_len; parse_offset += nalu_len; if(width_ == 0 && sps_len_ > 0) { if(av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265) rtmpclient_h265_decode_sps((unsigned char *)sps_buf_, sps_len_, width_, height_); else rtmpclient_h264_decode_sps((unsigned char *)sps_buf_, sps_len_, width_, height_); } continue; } //H265 以及 H264的PPS头解析兼容 else if((av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265&&nalu_type ==e_H265_NAL_UNIT_PPS) || av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H264&&nalu_type == e_H264_Frame_Type_Pps) { memcpy(pps_buf_,buf + parse_offset,nalu_len); pps_len_ = nalu_len; parse_offset += nalu_len; continue; } //H265 以及 H264的I帧解析兼容 else if((av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265&&nalu_type >=e_H265_NAL_UNIT_SLICE_BLA&&nalu_type <=e_H265_NAL_UNIT_SLICE_CRA ) || av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H264&&nalu_type == e_H264_Frame_Type_Idr) { if(av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265) { memcpy(processbuf + processlen,nalu_head_,4); processlen += 4; memcpy(processbuf + processlen,vps_buf_,vps_len_); processlen += vps_len_; } ....... //拷贝SPS和PPS以及Idr nalu ...... av_frame.u32VFrameType = SKEYE_SDK_VIDEO_FRAME_I; continue ; } //H265 以及 H264的P帧解析兼容 else if((av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H265&&nalu_type >=e_H265_NAL_UNIT_SLICE_TRAIL_R&&nalu_type <=e_H265_NAL_UNIT_SLICE_TFD ) || av_frame.u32AVFrameFlag == SKEYE_SDK_VIDEO_CODEC_H264&&nalu_type == e_H264_Frame_Type_Slice) { memcpy(processbuf + processlen,nalu_head_,4); processlen += 4; memcpy(processbuf + processlen,buf + parse_offset,nalu_len); processlen += nalu_len; parse_offset += nalu_len; av_frame.u32VFrameType = SKEYE_SDK_VIDEO_FRAME_P; continue ; } else { parse_offset += nalu_len; continue; } } av_frame.pBuffer = (uint8_t *)processbuf; av_frame.u32AVFrameLen = processlen; return 0;}至此，SkeyeRTMPClient对H264和H265的兼容适配就实现了，咱们能够通过SkeyeRTMPClient拉取任意编码格局为H264或者H265的RTMP进行拉流，均能获得残缺的视频帧数据进行解码和播放。