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1 /*
2  *  Copyright (c) 2012 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 "common_video/video_render_frames.h"
12 
13 #include <type_traits>
14 #include <utility>
15 
16 #include "rtc_base/checks.h"
17 #include "rtc_base/logging.h"
18 #include "rtc_base/time_utils.h"
19 #include "system_wrappers/include/metrics.h"
20 
21 namespace webrtc {
22 namespace {
23 // Don't render frames with timestamp older than 500ms from now.
24 const int kOldRenderTimestampMS = 500;
25 // Don't render frames with timestamp more than 10s into the future.
26 const int kFutureRenderTimestampMS = 10000;
27 
28 const uint32_t kEventMaxWaitTimeMs = 200;
29 const uint32_t kMinRenderDelayMs = 10;
30 const uint32_t kMaxRenderDelayMs = 500;
31 const size_t kMaxIncomingFramesBeforeLogged = 100;
32 
EnsureValidRenderDelay(uint32_t render_delay)33 uint32_t EnsureValidRenderDelay(uint32_t render_delay) {
34   return (render_delay < kMinRenderDelayMs || render_delay > kMaxRenderDelayMs)
35              ? kMinRenderDelayMs
36              : render_delay;
37 }
38 }  // namespace
39 
VideoRenderFrames(uint32_t render_delay_ms)40 VideoRenderFrames::VideoRenderFrames(uint32_t render_delay_ms)
41     : render_delay_ms_(EnsureValidRenderDelay(render_delay_ms)) {}
42 
~VideoRenderFrames()43 VideoRenderFrames::~VideoRenderFrames() {
44   frames_dropped_ += incoming_frames_.size();
45   RTC_HISTOGRAM_COUNTS_1000("WebRTC.Video.DroppedFrames.RenderQueue",
46                             frames_dropped_);
47   RTC_LOG(LS_INFO) << "WebRTC.Video.DroppedFrames.RenderQueue "
48                    << frames_dropped_;
49 }
50 
AddFrame(VideoFrame && new_frame)51 int32_t VideoRenderFrames::AddFrame(VideoFrame&& new_frame) {
52   const int64_t time_now = rtc::TimeMillis();
53 
54   // Drop old frames only when there are other frames in the queue, otherwise, a
55   // really slow system never renders any frames.
56   if (!incoming_frames_.empty() &&
57       new_frame.render_time_ms() + kOldRenderTimestampMS < time_now) {
58     RTC_LOG(LS_WARNING) << "Too old frame, timestamp=" << new_frame.timestamp();
59     ++frames_dropped_;
60     return -1;
61   }
62 
63   if (new_frame.render_time_ms() > time_now + kFutureRenderTimestampMS) {
64     RTC_LOG(LS_WARNING) << "Frame too long into the future, timestamp="
65                         << new_frame.timestamp();
66     ++frames_dropped_;
67     return -1;
68   }
69 
70   if (new_frame.render_time_ms() < last_render_time_ms_) {
71     RTC_LOG(LS_WARNING) << "Frame scheduled out of order, render_time="
72                         << new_frame.render_time_ms()
73                         << ", latest=" << last_render_time_ms_;
74     // For more details, see bug:
75     // https://bugs.chromium.org/p/webrtc/issues/detail?id=7253
76     ++frames_dropped_;
77     return -1;
78   }
79 
80   last_render_time_ms_ = new_frame.render_time_ms();
81   incoming_frames_.emplace_back(std::move(new_frame));
82 
83   if (incoming_frames_.size() > kMaxIncomingFramesBeforeLogged) {
84     RTC_LOG(LS_WARNING) << "Stored incoming frames: "
85                         << incoming_frames_.size();
86   }
87   return static_cast<int32_t>(incoming_frames_.size());
88 }
89 
FrameToRender()90 absl::optional<VideoFrame> VideoRenderFrames::FrameToRender() {
91   absl::optional<VideoFrame> render_frame;
92   // Get the newest frame that can be released for rendering.
93   while (!incoming_frames_.empty() && TimeToNextFrameRelease() <= 0) {
94     if (render_frame) {
95       ++frames_dropped_;
96     }
97     render_frame = std::move(incoming_frames_.front());
98     incoming_frames_.pop_front();
99   }
100   return render_frame;
101 }
102 
TimeToNextFrameRelease()103 uint32_t VideoRenderFrames::TimeToNextFrameRelease() {
104   if (incoming_frames_.empty()) {
105     return kEventMaxWaitTimeMs;
106   }
107   const int64_t time_to_release = incoming_frames_.front().render_time_ms() -
108                                   render_delay_ms_ - rtc::TimeMillis();
109   return time_to_release < 0 ? 0u : static_cast<uint32_t>(time_to_release);
110 }
111 
HasPendingFrames() const112 bool VideoRenderFrames::HasPendingFrames() const {
113   return !incoming_frames_.empty();
114 }
115 
116 }  // namespace webrtc
117