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/*
* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef MODULES_RTP_RTCP_SOURCE_RTP_DEPENDENCY_DESCRIPTOR_WRITER_H_
#define MODULES_RTP_RTCP_SOURCE_RTP_DEPENDENCY_DESCRIPTOR_WRITER_H_
#include <bitset>
#include <cstddef>
#include <cstdint>
#include <vector>
#include "api/array_view.h"
#include "api/transport/rtp/dependency_descriptor.h"
#include "rtc_base/bit_buffer.h"
namespace webrtc {
class RtpDependencyDescriptorWriter {
public:
// Assumes `structure` and `descriptor` are valid and
// `descriptor` matches the `structure`.
RtpDependencyDescriptorWriter(rtc::ArrayView<uint8_t> data,
const FrameDependencyStructure& structure,
std::bitset<32> active_chains,
const DependencyDescriptor& descriptor);
// Serializes DependencyDescriptor rtp header extension.
// Returns false if `data` is too small to serialize the `descriptor`.
bool Write();
// Returns minimum number of bits needed to serialize descriptor with respect
// to the `structure`. Returns 0 if `descriptor` can't be serialized.
int ValueSizeBits() const;
private:
// Used both as pointer to the template and as index in the templates vector.
using TemplateIterator = std::vector<FrameDependencyTemplate>::const_iterator;
struct TemplateMatch {
TemplateIterator template_position;
bool need_custom_dtis;
bool need_custom_fdiffs;
bool need_custom_chains;
// Size in bits to store frame-specific details, i.e.
// excluding mandatory fields and template dependency structure.
int extra_size_bits;
};
int StructureSizeBits() const;
TemplateMatch CalculateMatch(TemplateIterator frame_template) const;
void FindBestTemplate();
bool ShouldWriteActiveDecodeTargetsBitmask() const;
bool HasExtendedFields() const;
uint64_t TemplateId() const;
void WriteBits(uint64_t val, size_t bit_count);
void WriteNonSymmetric(uint32_t value, uint32_t num_values);
// Functions to read template dependency structure.
void WriteTemplateDependencyStructure();
void WriteTemplateLayers();
void WriteTemplateDtis();
void WriteTemplateFdiffs();
void WriteTemplateChains();
void WriteResolutions();
// Function to read details for the current frame.
void WriteMandatoryFields();
void WriteExtendedFields();
void WriteFrameDependencyDefinition();
void WriteFrameDtis();
void WriteFrameFdiffs();
void WriteFrameChains();
bool build_failed_ = false;
const DependencyDescriptor& descriptor_;
const FrameDependencyStructure& structure_;
std::bitset<32> active_chains_;
rtc::BitBufferWriter bit_writer_;
TemplateMatch best_template_;
};
} // namespace webrtc
#endif // MODULES_RTP_RTCP_SOURCE_RTP_DEPENDENCY_DESCRIPTOR_WRITER_H_
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