Add 'SkipNextFrame' to the FrameGeneratorInterface.

Also fix PRESUBMIT.py following https://webrtc-review.googlesource.com/c/src/+/358160.

Change-Id: I00682209607a184448255cf5ad8fd213fda7f4af
Bug: b/355120692
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/358320
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#42711}

PRESUBMIT.py

@@ -650,8 +650,8 @@ def CheckGnGen(input_api, output_api):
     with _AddToPath(
             input_api.os_path.join(input_api.PresubmitLocalPath(),
                                    'tools_webrtc', 'presubmit_checks_lib')):
-        from build_helpers import RunGnCheck
-    errors = RunGnCheck(input_api.change.RepositoryRoot())[:5]
+        from build_helpers import run_gn_check
+    errors = run_gn_check(input_api.change.RepositoryRoot())[:5]
     if errors:
         return [
             output_api.PresubmitPromptWarning(

api/test/frame_generator_interface.h

@@ -44,6 +44,9 @@ class FrameGeneratorInterface {
   // Returns VideoFrameBuffer and area where most of update was done to set them
   // on the VideoFrame object.
   virtual VideoFrameData NextFrame() = 0;
+  // Skips the next frame in case it doesn't need to be encoded.
+  // Default implementation is to call NextFrame and ignore the returned value.
+  virtual void SkipNextFrame() { NextFrame(); }
 
   // Change the capture resolution.
   virtual void ChangeResolution(size_t width, size_t height) = 0;

test/frame_generator_capturer.cc

@@ -92,15 +92,15 @@ bool FrameGeneratorCapturer::Init() {
 void FrameGeneratorCapturer::InsertFrame() {
   MutexLock lock(&lock_);
   if (sending_) {
-    FrameGeneratorInterface::VideoFrameData frame_data =
-        frame_generator_->NextFrame();
     // TODO(srte): Use more advanced frame rate control to allow arbitrary
     // fractions.
     int decimation =
         std::round(static_cast<double>(source_fps_) / target_capture_fps_);
     for (int i = 1; i < decimation; ++i)
-      frame_data = frame_generator_->NextFrame();
+      frame_generator_->SkipNextFrame();
 
+    FrameGeneratorInterface::VideoFrameData frame_data =
+        frame_generator_->NextFrame();
     VideoFrame frame = VideoFrame::Builder()
                            .set_video_frame_buffer(frame_data.buffer)
                            .set_rotation(fake_rotation_)

test/testsupport/ivf_video_frame_generator.cc

@@ -120,6 +120,21 @@ FrameGeneratorInterface::VideoFrameData IvfVideoFrameGenerator::NextFrame() {
   return VideoFrameData(buffer, next_frame_->update_rect());
 }
 
+void IvfVideoFrameGenerator::SkipNextFrame() {
+  MutexLock lock(&lock_);
+  next_frame_decoded_.Reset();
+  RTC_CHECK(file_reader_);
+  if (!file_reader_->HasMoreFrames()) {
+    file_reader_->Reset();
+  }
+  absl::optional<EncodedImage> image = file_reader_->NextFrame();
+  RTC_CHECK(image);
+  // Last parameter is undocumented and there is no usage of it found.
+  // Frame has to be decoded in case it is a key frame.
+  RTC_CHECK_EQ(WEBRTC_VIDEO_CODEC_OK,
+               video_decoder_->Decode(*image, /*render_time_ms=*/0));
+}
+
 void IvfVideoFrameGenerator::ChangeResolution(size_t width, size_t height) {
   MutexLock lock(&lock_);
   width_ = width;

test/testsupport/ivf_video_frame_generator.h

@@ -36,6 +36,7 @@ class IvfVideoFrameGenerator : public FrameGeneratorInterface {
   ~IvfVideoFrameGenerator() override;
 
   VideoFrameData NextFrame() override;
+  void SkipNextFrame() override;
   void ChangeResolution(size_t width, size_t height) override;
   Resolution GetResolution() const override;
 

test/testsupport/y4m_frame_generator.cc

@@ -74,6 +74,10 @@ Y4mFrameGenerator::VideoFrameData Y4mFrameGenerator::NextFrame() {
   return VideoFrameData(scaled_buffer, update_rect);
 }
 
+void Y4mFrameGenerator::SkipNextFrame() {
+  frame_reader_->PullFrame();
+}
+
 void Y4mFrameGenerator::ChangeResolution(size_t width, size_t height) {
   width_ = width;
   height_ = height;

test/testsupport/y4m_frame_generator.h

@@ -45,6 +45,8 @@ class Y4mFrameGenerator : public FrameGeneratorInterface {
 
   VideoFrameData NextFrame() override;
 
+  void SkipNextFrame() override;
+
   void ChangeResolution(size_t width, size_t height) override;
 
   Resolution GetResolution() const override;