Windows下webrtc配置H264作为编解码器

注：本文假设webrtc源码已经下载完毕

1.编译

进入到webrtc/src目录下，重新编译webrtc源代码，让代码支持h264编解码

set DEPOT_TOOLS_WIN_TOOLCHAIN=0
set GYP_MSVS_VERSION=2019
set GYP_MSVS_OVERRIDE_PATH="/C/Program Files (x86)/Microsoft Visual Studio/2019/Community"
set GYP_GENERATORS=msvs-ninja,ninja
set WINDOWSSDKDIR="/C/Program Files (x86)/Windows Kits/10"
gn gen out/h264debug --args="is_debug=true target_cpu=\"x64\" use_openh264=true proprietary_codecs=true ffmpeg_branding=\"Chrome\"" --ide=vs2019

等待构建完成，即可demo即可支持open h264编解码。

2.媒体协商优先使用h264编码

打开webrtc/src/media/engine/internal_encoder_factory.cc，找到InternalEncoderFactory::SupportedFormats()函数

std::vector<SdpVideoFormat> InternalEncoderFactory::SupportedFormats() {
std::vector<SdpVideoFormat> supported_codecs;
supported_codecs.push_back(SdpVideoFormat(cricket::kVp8CodecName));
for (const webrtc::SdpVideoFormat& format : webrtc::SupportedVP9Codecs())
    supported_codecs.push_back(format);
for (const webrtc::SdpVideoFormat& format : webrtc::SupportedH264Codecs())
    supported_codecs.push_back(format);
if (kIsLibaomAv1EncoderSupported)
    supported_codecs.push_back(SdpVideoFormat(cricket::kAv1CodecName));
return supported_codecs;
}

改成：

std::vector<SdpVideoFormat> InternalEncoderFactory::SupportedFormats() {
std::vector<SdpVideoFormat> supported_codecs;
for (const webrtc::SdpVideoFormat& format : webrtc::SupportedH264Codecs())
    supported_codecs.push_back(format);
supported_codecs.push_back(SdpVideoFormat(cricket::kVp8CodecName));
for (const webrtc::SdpVideoFormat& format : webrtc::SupportedVP9Codecs())
    supported_codecs.push_back(format);
if (kIsLibaomAv1EncoderSupported)
    supported_codecs.push_back(SdpVideoFormat(cricket::kAv1CodecName));
return supported_codecs;
}

然后在编译运行，即可在协商时优先使用h264编解码器编解码。