mediasoup-sys 0.2.2

#define MS_CLASS "RTC::RtpParameters"
// #define MS_LOG_DEV_LEVEL 3

#include "Logger.hpp"
#include "MediaSoupErrors.hpp"
#include "RTC/RtpDictionaries.hpp"
#include <unordered_set>

namespace RTC
{
	/* Class variables. */

	// clang-format off
	std::unordered_map<std::string, RtpParameters::Type> RtpParameters::string2Type =
	{
		{ "none",      RtpParameters::Type::NONE      },
		{ "simple",    RtpParameters::Type::SIMPLE    },
		{ "simulcast", RtpParameters::Type::SIMULCAST },
		{ "svc",       RtpParameters::Type::SVC       },
		{ "pipe",      RtpParameters::Type::PIPE      }
	};
	std::map<RtpParameters::Type, std::string> RtpParameters::type2String =
	{
		{ RtpParameters::Type::NONE,      "none"      },
		{ RtpParameters::Type::SIMPLE,    "simple"    },
		{ RtpParameters::Type::SIMULCAST, "simulcast" },
		{ RtpParameters::Type::SVC,       "svc"       },
		{ RtpParameters::Type::PIPE,      "pipe"      }
	};
	// clang-format on

	/* Class methods. */

	RtpParameters::Type RtpParameters::GetType(const RtpParameters& rtpParameters)
	{
		MS_TRACE();

		if (rtpParameters.encodings.size() == 1)
		{
			auto& encoding = rtpParameters.encodings[0];

			if (encoding.spatialLayers > 1 || encoding.temporalLayers > 1)
				return RtpParameters::Type::SVC;
			else
				return RtpParameters::Type::SIMPLE;
		}
		else if (rtpParameters.encodings.size() > 1)
		{
			return RtpParameters::Type::SIMULCAST;
		}

		return RtpParameters::Type::NONE;
	}

	RtpParameters::Type RtpParameters::GetType(std::string& str)
	{
		MS_TRACE();

		auto it = RtpParameters::string2Type.find(str);

		if (it == RtpParameters::string2Type.end())
			MS_THROW_TYPE_ERROR("invalid RtpParameters type [type:%s]", str.c_str());

		return it->second;
	}

	RtpParameters::Type RtpParameters::GetType(std::string&& str)
	{
		MS_TRACE();

		auto it = RtpParameters::string2Type.find(str);

		if (it == RtpParameters::string2Type.end())
			MS_THROW_TYPE_ERROR("invalid RtpParameters type [type:%s]", str.c_str());

		return it->second;
	}

	std::string& RtpParameters::GetTypeString(RtpParameters::Type type)
	{
		MS_TRACE();

		return RtpParameters::type2String.at(type);
	}

	/* Instance methods. */

	RtpParameters::RtpParameters(json& data)
	{
		MS_TRACE();

		if (!data.is_object())
			MS_THROW_TYPE_ERROR("data is not an object");

		auto jsonMidIt              = data.find("mid");
		auto jsonCodecsIt           = data.find("codecs");
		auto jsonEncodingsIt        = data.find("encodings");
		auto jsonHeaderExtensionsIt = data.find("headerExtensions");
		auto jsonRtcpIt             = data.find("rtcp");

		// mid is optional.
		if (jsonMidIt != data.end() && jsonMidIt->is_string())
		{
			this->mid = jsonMidIt->get<std::string>();

			if (this->mid.empty())
				MS_THROW_TYPE_ERROR("empty mid");
		}

		// codecs is mandatory.
		if (jsonCodecsIt == data.end() || !jsonCodecsIt->is_array())
			MS_THROW_TYPE_ERROR("missing codecs");

		this->codecs.reserve(jsonCodecsIt->size());

		for (auto& entry : *jsonCodecsIt)
		{
			// This may throw due the constructor of RTC::RtpCodecParameters.
			this->codecs.emplace_back(entry);
		}

		if (this->codecs.empty())
			MS_THROW_TYPE_ERROR("empty codecs");

		// encodings is mandatory.
		if (jsonEncodingsIt == data.end() || !jsonEncodingsIt->is_array())
			MS_THROW_TYPE_ERROR("missing encodings");

		this->encodings.reserve(jsonEncodingsIt->size());

		for (auto& entry : *jsonEncodingsIt)
		{
			// This may throw due the constructor of RTC::RtpEncodingParameters.
			this->encodings.emplace_back(entry);
		}

		if (this->encodings.empty())
			MS_THROW_TYPE_ERROR("empty encodings");

		// headerExtensions is optional.
		if (jsonHeaderExtensionsIt != data.end() && jsonHeaderExtensionsIt->is_array())
		{
			this->headerExtensions.reserve(jsonHeaderExtensionsIt->size());

			for (auto& entry : *jsonHeaderExtensionsIt)
			{
				// This may throw due the constructor of RTC::RtpHeaderExtensionParameters.
				this->headerExtensions.emplace_back(entry);
			}
		}

		// rtcp is optional.
		if (jsonRtcpIt != data.end() && jsonRtcpIt->is_object())
		{
			// This may throw.
			this->rtcp    = RTC::RtcpParameters(*jsonRtcpIt);
			this->hasRtcp = true;
		}

		// Validate RTP parameters.
		ValidateCodecs();
		ValidateEncodings();
	}

	void RtpParameters::FillJson(json& jsonObject) const
	{
		MS_TRACE();

		// Add mid.
		if (!this->mid.empty())
			jsonObject["mid"] = this->mid;

		// Add codecs.
		jsonObject["codecs"] = json::array();
		auto jsonCodecsIt    = jsonObject.find("codecs");

		for (size_t i{ 0 }; i < this->codecs.size(); ++i)
		{
			jsonCodecsIt->emplace_back(json::value_t::object);

			auto& jsonEntry = (*jsonCodecsIt)[i];
			auto& codec     = this->codecs[i];

			codec.FillJson(jsonEntry);
		}

		// Add encodings.
		jsonObject["encodings"] = json::array();
		auto jsonEncodingsIt    = jsonObject.find("encodings");

		for (size_t i{ 0 }; i < this->encodings.size(); ++i)
		{
			jsonEncodingsIt->emplace_back(json::value_t::object);

			auto& jsonEntry = (*jsonEncodingsIt)[i];
			auto& encoding  = this->encodings[i];

			encoding.FillJson(jsonEntry);
		}

		// Add headerExtensions.
		jsonObject["headerExtensions"] = json::array();
		auto jsonHeaderExtensionsIt    = jsonObject.find("headerExtensions");

		for (size_t i{ 0 }; i < this->headerExtensions.size(); ++i)
		{
			jsonHeaderExtensionsIt->emplace_back(json::value_t::object);

			auto& jsonEntry       = (*jsonHeaderExtensionsIt)[i];
			auto& headerExtension = this->headerExtensions[i];

			headerExtension.FillJson(jsonEntry);
		}

		// Add rtcp.
		if (this->hasRtcp)
			this->rtcp.FillJson(jsonObject["rtcp"]);
		else
			jsonObject["rtcp"] = json::object();
	}

	const RTC::RtpCodecParameters* RtpParameters::GetCodecForEncoding(RtpEncodingParameters& encoding) const
	{
		MS_TRACE();

		uint8_t payloadType = encoding.codecPayloadType;
		auto it             = this->codecs.begin();

		for (; it != this->codecs.end(); ++it)
		{
			auto& codec = *it;

			if (codec.payloadType == payloadType)
				return std::addressof(codec);
		}

		// This should never happen.
		if (it == this->codecs.end())
			MS_ABORT("no valid codec payload type for the given encoding");

		return nullptr;
	}

	const RTC::RtpCodecParameters* RtpParameters::GetRtxCodecForEncoding(RtpEncodingParameters& encoding) const
	{
		MS_TRACE();

		static const std::string AptString{ "apt" };

		uint8_t payloadType = encoding.codecPayloadType;

		for (const auto& codec : this->codecs)
		{
			if (codec.mimeType.IsFeatureCodec() && codec.parameters.GetInteger(AptString) == payloadType)
			{
				return std::addressof(codec);
			}
		}

		return nullptr;
	}

	void RtpParameters::ValidateCodecs()
	{
		MS_TRACE();

		static const std::string AptString{ "apt" };

		std::unordered_set<uint8_t> payloadTypes;

		for (auto& codec : this->codecs)
		{
			if (payloadTypes.find(codec.payloadType) != payloadTypes.end())
				MS_THROW_TYPE_ERROR("duplicated payloadType");

			payloadTypes.insert(codec.payloadType);

			switch (codec.mimeType.subtype)
			{
				// A RTX codec must have 'apt' parameter pointing to a non RTX codec.
				case RTC::RtpCodecMimeType::Subtype::RTX:
				{
					// NOTE: RtpCodecParameters already asserted that there is apt parameter.
					int32_t apt = codec.parameters.GetInteger(AptString);
					auto it     = this->codecs.begin();

					for (; it != this->codecs.end(); ++it)
					{
						auto codec = *it;

						if (static_cast<int32_t>(codec.payloadType) == apt)
						{
							if (codec.mimeType.subtype == RTC::RtpCodecMimeType::Subtype::RTX)
								MS_THROW_TYPE_ERROR("apt in RTX codec points to a RTX codec");
							else if (codec.mimeType.subtype == RTC::RtpCodecMimeType::Subtype::ULPFEC)
								MS_THROW_TYPE_ERROR("apt in RTX codec points to a ULPFEC codec");
							else if (codec.mimeType.subtype == RTC::RtpCodecMimeType::Subtype::FLEXFEC)
								MS_THROW_TYPE_ERROR("apt in RTX codec points to a FLEXFEC codec");
							else
								break;
						}
					}

					if (it == this->codecs.end())
						MS_THROW_TYPE_ERROR("apt in RTX codec points to a non existing codec");

					break;
				}

				default:;
			}
		}
	}

	void RtpParameters::ValidateEncodings()
	{
		uint8_t firstMediaPayloadType{ 0 };

		{
			auto it = this->codecs.begin();

			for (; it != this->codecs.end(); ++it)
			{
				auto& codec = *it;

				// Must be a media codec.
				if (codec.mimeType.IsMediaCodec())
				{
					firstMediaPayloadType = codec.payloadType;

					break;
				}
			}

			if (it == this->codecs.end())
				MS_THROW_TYPE_ERROR("no media codecs found");
		}

		// Iterate all the encodings, set the first payloadType in all of them with
		// codecPayloadType unset, and check that others point to a media codec.
		//
		// Also, don't allow multiple SVC spatial layers into an encoding if there
		// are more than one encoding (simulcast).
		for (auto& encoding : this->encodings)
		{
			if (encoding.spatialLayers > 1 && this->encodings.size() > 1)
			{
				MS_THROW_TYPE_ERROR(
				  "cannot use both simulcast and encodings with multiple SVC spatial layers");
			}

			if (!encoding.hasCodecPayloadType)
			{
				encoding.codecPayloadType    = firstMediaPayloadType;
				encoding.hasCodecPayloadType = true;
			}
			else
			{
				auto it = this->codecs.begin();

				for (; it != this->codecs.end(); ++it)
				{
					auto codec = *it;

					if (codec.payloadType == encoding.codecPayloadType)
					{
						// Must be a media codec.
						if (codec.mimeType.IsMediaCodec())
							break;

						MS_THROW_TYPE_ERROR("invalid codecPayloadType");
					}
				}

				if (it == this->codecs.end())
					MS_THROW_TYPE_ERROR("unknown codecPayloadType");
			}
		}
	}
} // namespace RTC