1 files changed, 114 insertions, 0 deletions
diff --git a/third_party/libwebrtc/test/testsupport/fixed_fps_video_frame_writer_adapter.cc b/third_party/libwebrtc/test/testsupport/fixed_fps_video_frame_writer_adapter.cc
new file mode 100644
index 0000000000..531dade0e8
--- /dev/null
+++ b/third_party/libwebrtc/test/testsupport/fixed_fps_video_frame_writer_adapter.cc
@@ -0,0 +1,114 @@
+/*
+ *  Copyright (c) 2022 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.
+ */
+
+#include "test/testsupport/fixed_fps_video_frame_writer_adapter.h"
+
+#include <cmath>
+#include <utility>
+
+#include "absl/types/optional.h"
+#include "api/units/time_delta.h"
+#include "api/video/video_sink_interface.h"
+#include "rtc_base/checks.h"
+#include "test/testsupport/video_frame_writer.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+constexpr TimeDelta kOneSecond = TimeDelta::Seconds(1);
+
+}  // namespace
+
+FixedFpsVideoFrameWriterAdapter::FixedFpsVideoFrameWriterAdapter(
+    int fps,
+    Clock* clock,
+    std::unique_ptr<VideoFrameWriter> delegate)
+    : inter_frame_interval_(kOneSecond / fps),
+      clock_(clock),
+      delegate_(std::move(delegate)) {}
+
+FixedFpsVideoFrameWriterAdapter::~FixedFpsVideoFrameWriterAdapter() {
+  Close();
+}
+
+void FixedFpsVideoFrameWriterAdapter::Close() {
+  if (is_closed_) {
+    return;
+  }
+  is_closed_ = true;
+  if (!last_frame_.has_value()) {
+    return;
+  }
+  Timestamp now = Now();
+  RTC_CHECK(WriteMissedSlotsExceptLast(now));
+  RTC_CHECK(delegate_->WriteFrame(*last_frame_));
+  delegate_->Close();
+}
+
+bool FixedFpsVideoFrameWriterAdapter::WriteFrame(const VideoFrame& frame) {
+  RTC_CHECK(!is_closed_);
+  Timestamp now = Now();
+  if (!last_frame_.has_value()) {
+    RTC_CHECK(!last_frame_time_.IsFinite());
+    last_frame_ = frame;
+    last_frame_time_ = now;
+    return true;
+  }
+
+  RTC_CHECK(last_frame_time_.IsFinite());
+
+  if (last_frame_time_ > now) {
+    // New frame was recevied before expected time "slot" for current
+    // `last_frame_` came => just replace current `last_frame_` with
+    // received `frame`.
+    RTC_CHECK_LE(last_frame_time_ - now, inter_frame_interval_ / 2);
+    last_frame_ = frame;
+    return true;
+  }
+
+  if (!WriteMissedSlotsExceptLast(now)) {
+    return false;
+  }
+
+  if (now - last_frame_time_ < inter_frame_interval_ / 2) {
+    // New frame was received closer to the expected time "slot" for current
+    // `last_frame_` than to the next "slot" => just replace current
+    // `last_frame_` with received `frame`.
+    last_frame_ = frame;
+    return true;
+  }
+
+  if (!delegate_->WriteFrame(*last_frame_)) {
+    return false;
+  }
+  last_frame_ = frame;
+  last_frame_time_ = last_frame_time_ + inter_frame_interval_;
+  return true;
+}
+
+bool FixedFpsVideoFrameWriterAdapter::WriteMissedSlotsExceptLast(
+    Timestamp now) {
+  RTC_CHECK(last_frame_time_.IsFinite());
+  while (now - last_frame_time_ > inter_frame_interval_) {
+    if (!delegate_->WriteFrame(*last_frame_)) {
+      return false;
+    }
+    last_frame_time_ = last_frame_time_ + inter_frame_interval_;
+  }
+  return true;
+}
+
+Timestamp FixedFpsVideoFrameWriterAdapter::Now() const {
+  return clock_->CurrentTime();
+}
+
+}  // namespace test
+}  // namespace webrtc