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// Copyright 2021 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_BITRATE_H_
#define MEDIA_BASE_BITRATE_H_
#include <stdint.h>
#include <string>
#include "media/base/media_export.h"
namespace media {
class MEDIA_EXPORT Bitrate {
public:
// Indicates whether constant bitrate (CBR) or variable bitrate (VBR) should
// be used for encoding.
enum class Mode { kConstant, kVariable };
// Required by Mojo for serialization and de-serialization. Creates an
// invalid constant bitrate with |target_| and |peak_| set to 0u. Prefer
// to use the Bitrate::ConstantBitrate() method.
constexpr Bitrate() = default;
constexpr Bitrate(const Bitrate& other) = default;
constexpr Bitrate& operator=(const Bitrate& other) = default;
// Do not use int or uint64_t variations of these. If you have a signed
// or 64-bit value you want to use as input, you must explicitly convert to
// uint32_t before calling. This is intended to prevent implicit and unsafe
// type conversion.
static constexpr Bitrate ConstantBitrate(uint32_t target_bitrate) {
return Bitrate(Mode::kConstant, target_bitrate, 0);
}
static Bitrate VariableBitrate(uint32_t target_bitrate,
uint32_t peak_bitrate);
// Deleted variants: you must SAFELY convert to uint32_t before calling.
// See base/numerics/safe_conversions.h for functions to safely convert
// between types.
static Bitrate ConstantBitrate(int target_bitrate) = delete;
static Bitrate VariableBitrate(int target_bitrate, int peak_bitrate) = delete;
static Bitrate VariableBitrate(int target_bitrate,
uint32_t peak_bitrate) = delete;
static Bitrate VariableBitrate(uint32_t target_bitrate,
int peak_bitrate) = delete;
static Bitrate ConstantBitrate(uint64_t target_bitrate) = delete;
static Bitrate VariableBitrate(uint64_t target_bitrate,
uint64_t peak_bitrate) = delete;
static Bitrate VariableBitrate(uint64_t target_bitrate,
uint32_t peak_bitrate) = delete;
static Bitrate VariableBitrate(uint32_t target_bitrate,
uint64_t peak_bitrate) = delete;
bool operator==(const Bitrate& right) const;
bool operator!=(const Bitrate& right) const;
// Accessor for |mode_|.
constexpr Mode mode() const { return mode_; }
// Accessor for |target_|.
constexpr uint32_t target() const { return target_; }
// Accessor for |peak_|. Returns 0 if |mode_| is
// Mode::kConstantBitrate.
uint32_t peak() const;
std::string ToString() const;
private:
constexpr Bitrate(Mode mode, uint32_t target_bitrate, uint32_t peak_bitrate)
: mode_(mode), target_(target_bitrate), peak_(peak_bitrate) {}
// These member variables cannot be const (despite the intent that we do not
// change them after creation) because we must have an assignment operator for
// Mojo, and const member variables are incompatible with an assignment
// operator.
// The bitrate mode.
Mode mode_ = Mode::kConstant;
// Target bitrate for the stream in bits per second.
uint32_t target_ = 0u;
// For use with Mode::kVariable. Peak bitrate in bits per second.
uint32_t peak_ = 0u;
};
} // namespace media
#endif // MEDIA_BASE_BITRATE_H_
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