Haxe Lib Datachannel

lib/datachannel/cpp/libdatachannel/include/rtc/dependencydescriptor.hpp

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+/**
+ * Copyright (c) 2024 Shigemasa Watanabe (Wandbox)
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef RTC_DEPENDENCY_DESCRIPTOR_H
+#define RTC_DEPENDENCY_DESCRIPTOR_H
+
+#include "common.hpp"
+
+#include <bitset>
+
+namespace rtc {
+
+struct BitWriter {
+	static BitWriter fromSizeBits(byte *buf, size_t offsetBits, size_t sizeBits);
+	static BitWriter fromNull();
+
+	size_t getWrittenBits() const;
+
+	bool write(uint64_t v, size_t bits);
+	// Write non-symmetric unsigned encoded integer
+	// ref: https://aomediacodec.github.io/av1-rtp-spec/#a82-syntax
+	bool writeNonSymmetric(uint64_t v, uint64_t n);
+
+private:
+	size_t writePartialByte(uint8_t *p, size_t offset, uint64_t v, size_t bits);
+
+private:
+	byte *mBuf = nullptr;
+	size_t mInitialOffset = 0;
+	size_t mOffset = 0;
+	size_t mSize = 0;
+};
+
+enum class DecodeTargetIndication {
+	NotPresent = 0,
+	Discardable = 1,
+	Switch = 2,
+	Required = 3,
+};
+
+struct RenderResolution {
+	int width = 0;
+	int height = 0;
+};
+
+struct FrameDependencyTemplate {
+	int spatialId = 0;
+	int temporalId = 0;
+	std::vector<DecodeTargetIndication> decodeTargetIndications;
+	std::vector<int> frameDiffs;
+	std::vector<int> chainDiffs;
+};
+
+struct FrameDependencyStructure {
+	int templateIdOffset = 0;
+	int decodeTargetCount = 0;
+	int chainCount = 0;
+	std::vector<int> decodeTargetProtectedBy;
+	std::vector<RenderResolution> resolutions;
+	std::vector<FrameDependencyTemplate> templates;
+};
+
+struct DependencyDescriptor {
+	bool startOfFrame = true;
+	bool endOfFrame = true;
+	int frameNumber = 0;
+	FrameDependencyTemplate dependencyTemplate;
+	std::optional<RenderResolution> resolution;
+	std::optional<uint32_t> activeDecodeTargetsBitmask;
+	bool structureAttached;
+};
+
+struct DependencyDescriptorContext {
+	DependencyDescriptor descriptor;
+	std::bitset<32> activeChains;
+	FrameDependencyStructure structure;
+};
+
+// Write dependency descriptor to RTP Header Extension
+// Dependency descriptor specification is here:
+// https://aomediacodec.github.io/av1-rtp-spec/#dependency-descriptor-rtp-header-extension
+class DependencyDescriptorWriter {
+public:
+	explicit DependencyDescriptorWriter(const DependencyDescriptorContext& context);
+	size_t getSizeBits() const;
+	size_t getSize() const;
+	void writeTo(byte *buf, size_t sizeBytes) const;
+
+private:
+	void doWriteTo(BitWriter &writer) const;
+	void writeBits(BitWriter &writer, uint64_t v, size_t bits) const;
+	void writeNonSymmetric(BitWriter &writer, uint64_t v, uint64_t n) const;
+
+private:
+	const FrameDependencyStructure &mStructure;
+	std::bitset<32> mActiveChains;
+	const DependencyDescriptor &mDescriptor;
+};
+
+} // namespace rtc
+
+#endif