2023-07-08-webrtc-shi-pin-bian-macodec-xuan-ze-guo-cheng

编码参数设置到WebRtcEngine模块里 WebRtcVideoChannel，会调用到这里：

bool WebRtcVideoChannel::GetChangedSendParameters(    const VideoSendParameters& params,    ChangedSendParameters* changed_params) const {  if (!ValidateCodecFormats(params.codecs) ||      !ValidateRtpExtensions(params.extensions, send_rtp_extensions_)) {    return false;  }  std::vector negotiated_codecs =      SelectSendVideoCodecs(MapCodecs(params.codecs));

`SelectSendVideoCodecs` 函数

std::vectorWebRtcVideoChannel::SelectSendVideoCodecs(    const std::vector& remote_mapped_codecs) const {  std::vector sdp_formats =      encoder_factory_ ? encoder_factory_->GetImplementations()                       : std::vector();

会调用`encoder_factory_->GetImplementations()` 函数，

std::vectorNebulaVideoEncoderFactory::GetSupportedFormats() const {  NSLog(@"yinyinyin NebulaVideoEncoderFactory::GetSupportedFormats ");  std::vector supported_formats;  for (RTC_OBJC_TYPE(RTCVideoCodecInfo) * supportedCodec in       [encoder_factory_ supportedCodecs]) {    SdpVideoFormat format = [supportedCodec nativeSdpVideoFormat];    supported_formats.push_back(format);  }  for (const webrtc::SdpVideoFormat &format : SupportedX264Codecs())    supported_formats.push_back(format);  return supported_formats;}

最终调用到 `RTCDefaultVideoEncoderFactory`的 `supportedCodecs`,里面是所有支持的视频编码能力集合，这里添加需H265支持

+ (NSArray *)supportedCodecs {  NSDictionary *constrainedHighParams = @{    @"profile-level-id" : kRTCMaxSupportedH264ProfileLevelConstrainedHigh,    @"level-asymmetry-allowed" : @"1",    @"packetization-mode" : @"1",  };  RTC_OBJC_TYPE(RTCVideoCodecInfo) *constrainedHighInfo =      [[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecH264Name                                                  parameters:constrainedHighParams];  NSDictionary *constrainedBaselineParams = @{    @"profile-level-id" : kRTCMaxSupportedH264ProfileLevelConstrainedBaseline,    @"level-asymmetry-allowed" : @"1",    @"packetization-mode" : @"1",  };  RTC_OBJC_TYPE(RTCVideoCodecInfo) *constrainedBaselineInfo =      [[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecH264Name                                                  parameters:constrainedBaselineParams];#if defined(WEBRTC_MAC)  NSDictionary *constrainedMainParams = @{    @"profile-level-id" : kRTCSupportedH264ProfileLevelConstrainedMain,    @"level-asymmetry-allowed" : @"1",    @"packetization-mode" : @"1",  };  RTC_OBJC_TYPE(RTCVideoCodecInfo) *constrainedMainInfo =      [[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecH264Name                                                  parameters:constrainedMainParams];#endif  RTC_OBJC_TYPE(RTCVideoCodecInfo) *vp8Info =      [[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecVp8Name];  NSMutableArray *result = [@[    constrainedHighInfo,    constrainedBaselineInfo,#if defined(WEBRTC_MAC)    constrainedMainInfo,#endif    vp8Info,  ] mutableCopy];  if ([RTC_OBJC_TYPE(RTCVideoEncoderVP9) isSupported]) {    [result        addObject:[[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecVp9Name]];  }#if defined(RTC_USE_LIBAOM_AV1_ENCODER)  [result addObject:[[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecAv1Name]];#endif    #ifdef WEBRTC_USE_H265  RTC_OBJC_TYPE(RTCVideoCodecInfo) *h265Info = [[RTC_OBJC_TYPE(RTCVideoCodecInfo) alloc] initWithName:kRTCVideoCodecH265Name];  [result addObject:h265Info];#endif  return result;}