64 lines
2.1 KiB
C++
64 lines
2.1 KiB
C++
// Copyright 2014 Google LLC. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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#define MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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#include <stdint.h>
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#include <vector>
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namespace shaka {
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class BandwidthEstimator {
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public:
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BandwidthEstimator();
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~BandwidthEstimator();
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/// @param size is the size of the block in bytes. Should be positive.
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/// @param duration is the length in seconds. Should be positive.
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void AddBlock(uint64_t size_in_bytes, double duration);
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/// @return The estimate bandwidth, in bits per second, calculated from the
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/// sum of the sizes of every block, divided by the sum of durations
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/// of every block, of the number of blocks specified in the
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/// constructor. The value is rounded up to the nearest integer.
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uint64_t Estimate() const;
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/// @return The max bandwidth, in bits per second, of the number of blocks
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/// specified in the constructor. The value is rounded up to the
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/// nearest integer. Note that small blocks w.r.t.
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/// |target_block_duration| are not counted.
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uint64_t Max() const;
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private:
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BandwidthEstimator(const BandwidthEstimator&) = delete;
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BandwidthEstimator& operator=(const BandwidthEstimator&) = delete;
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struct Block {
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uint64_t size_in_bits;
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double duration;
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};
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// Return the average block duration of the blocks in |initial_blocks_|.
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double GetAverageBlockDuration() const;
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// Return the bitrate of the block. Note that a bitrate of 0 is returned if
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// the block duration is less than 50% of target block duration.
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uint64_t GetBitrate(const Block& block, double target_block_duration) const;
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std::vector<Block> initial_blocks_;
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// Target block duration will be estimated from the average duration of the
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// initial blocks.
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double target_block_duration_ = 0;
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uint64_t total_size_in_bits_ = 0;
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double total_duration_ = 0;
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uint64_t max_bitrate_ = 0;
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};
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} // namespace shaka
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#endif // MPD_BASE_BANDWIDTH_ESTIMATOR_H_
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