Cockpit-cpp/webrtcinterop/sdp_utils.cpp

#include "pch.h"
#include "../common/comm.h"
#include "sdp_utils.h"

#include "api/jsep_session_description.h"
#include "pc/session_description.h"
#include "pc/webrtc_sdp.h"



std::string SdpForceCodecs(const std::string& message,
	const std::string& audio_codec_name,
	const std::string& video_codec_name) {
	// Deserialize the SDP message
	webrtc::JsepSessionDescription jdesc(webrtc::SdpType::kOffer);
	webrtc::SdpParseError error;
	if (!webrtc::SdpDeserialize(message, &jdesc, &error)) {
		RTC_LOG(LS_WARNING)
			<< "Failed to deserialize SDP message to force codecs. Error line "
			<< error.line << ": " << error.description;
		return message;
	}

	// Remove codecs not wanted
	{
		// Loop over the session contents to find the audio and video ones
		const cricket::SessionDescription* const desc = jdesc.description();
		const cricket::ContentInfos& contents = desc->contents();
		for (auto&& content : contents) {
			cricket::MediaContentDescription* media_desc = (cricket::MediaContentDescription*)content.media_description();
			switch (media_desc->type()) {
			case cricket::MediaType::MEDIA_TYPE_AUDIO:
				// Only try modify the audio codecs if asked for
				if (!audio_codec_name.empty()) {
					 cricket::AudioContentDescription* const audio_desc =
						media_desc->as_audio();
					const std::vector<cricket::AudioCodec>& codecs =
						audio_desc->codecs();
					auto it = std::find_if(
						codecs.begin(), codecs.end(),
						[&audio_codec_name](const cricket::AudioCodec& codec) {
							return (codec.name == audio_codec_name);
						});
					if (it == codecs.end()) {
						break;
					}
					std::vector<cricket::AudioCodec> new_codecs;
					new_codecs.push_back(*it);
					audio_desc->set_codecs(new_codecs);
				}
				break;
			case cricket::MediaType::MEDIA_TYPE_VIDEO:
				// Only try modify the audio codecs if asked for
				if (!video_codec_name.empty()) {
					cricket::VideoContentDescription* const video_desc =
						media_desc->as_video();
					const std::vector<cricket::VideoCodec>& codecs =
						video_desc->codecs();
					auto it = std::find_if(
						codecs.begin(), codecs.end(),
						[&video_codec_name](const cricket::VideoCodec& codec) {
							return (codec.name == video_codec_name);
						});
					if (it == codecs.end()) {
						break;
					}
					std::vector<cricket::VideoCodec> new_codecs;
					new_codecs.push_back(*it);
					video_desc->set_codecs(new_codecs);
				}
				break;
			case cricket::MediaType::MEDIA_TYPE_DATA:
				continue;
			}
		}
	}

	// Re-serialize the SDP modified message
	return webrtc::SdpSerialize(jdesc);
}