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1 /*
2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "modules/video_coding/codec_timer.h"
12 
13 #include <cstdint>
14 
15 namespace webrtc {
16 
17 namespace {
18 
19 // The first kIgnoredSampleCount samples will be ignored.
20 const int kIgnoredSampleCount = 5;
21 // Return the |kPercentile| value in RequiredDecodeTimeMs().
22 const float kPercentile = 0.95f;
23 // The window size in ms.
24 const int64_t kTimeLimitMs = 10000;
25 
26 }  // anonymous namespace
27 
VCMCodecTimer()28 VCMCodecTimer::VCMCodecTimer()
29     : ignored_sample_count_(0), filter_(kPercentile) {}
30 VCMCodecTimer::~VCMCodecTimer() = default;
31 
AddTiming(int64_t decode_time_ms,int64_t now_ms)32 void VCMCodecTimer::AddTiming(int64_t decode_time_ms, int64_t now_ms) {
33   // Ignore the first |kIgnoredSampleCount| samples.
34   if (ignored_sample_count_ < kIgnoredSampleCount) {
35     ++ignored_sample_count_;
36     return;
37   }
38 
39   // Insert new decode time value.
40   filter_.Insert(decode_time_ms);
41   history_.emplace(decode_time_ms, now_ms);
42 
43   // Pop old decode time values.
44   while (!history_.empty() &&
45          now_ms - history_.front().sample_time_ms > kTimeLimitMs) {
46     filter_.Erase(history_.front().decode_time_ms);
47     history_.pop();
48   }
49 }
50 
51 // Get the 95th percentile observed decode time within a time window.
RequiredDecodeTimeMs() const52 int64_t VCMCodecTimer::RequiredDecodeTimeMs() const {
53   return filter_.GetPercentileValue();
54 }
55 
Sample(int64_t decode_time_ms,int64_t sample_time_ms)56 VCMCodecTimer::Sample::Sample(int64_t decode_time_ms, int64_t sample_time_ms)
57     : decode_time_ms(decode_time_ms), sample_time_ms(sample_time_ms) {}
58 
59 }  // namespace webrtc
60