text: /*
   *  Copyright (c) 2017 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 "src/internal/video_capturer.h"
  
  #include <algorithm>
  
  #include "api/scoped_refptr.h"
  #include "api/video/i420_buffer.h"
  #include "api/video/video_frame_buffer.h"
  #include "api/video/video_rotation.h"
  
  namespace webrtc {
  namespace internal {
  VideoCapturer::VideoCapturer() = default;
  VideoCapturer::~VideoCapturer() = default;
  
  void VideoCapturer::OnFrame(const VideoFrame& frame) {
    int cropped_width = 0;
    int cropped_height = 0;
    int out_width = 0;
    int out_height = 0;
  
    if (!video_adapter_.AdaptFrameResolution(
            frame.width(), frame.height(), frame.timestamp_us() * 1000,
            &cropped_width, &cropped_height, &out_width, &out_height)) {
      // Drop frame in order to respect frame rate constraint.
      return;
    }
  
    if (out_height != frame.height() || out_width != frame.width()) {
      // Video adapter has requested a down-scale. Allocate a new buffer and
      // return scaled version.
      rtc::scoped_refptr<I420Buffer> scaled_buffer =
          I420Buffer::Create(out_width, out_height);
      scaled_buffer->ScaleFrom(*frame.video_frame_buffer()->ToI420());
      broadcaster_.OnFrame(VideoFrame::Builder()
                               .set_video_frame_buffer(scaled_buffer)
                               .set_rotation(kVideoRotation_0)
                               .set_timestamp_us(frame.timestamp_us())
                               .set_id(frame.id())
                               .build());
    } else {
      // No adaptations needed, just return the frame as is.
      broadcaster_.OnFrame(frame);
    }
  }
  
  rtc::VideoSinkWants VideoCapturer::GetSinkWants() {
    return broadcaster_.wants();
  }
  
  void VideoCapturer::AddOrUpdateSink(rtc::VideoSinkInterface<VideoFrame>* sink,
                                      const rtc::VideoSinkWants& wants) {
    broadcaster_.AddOrUpdateSink(sink, wants);
    UpdateVideoAdapter();
  }
  
  void VideoCapturer::RemoveSink(rtc::VideoSinkInterface<VideoFrame>* sink) {
    broadcaster_.RemoveSink(sink);
    UpdateVideoAdapter();
  }
  
  void VideoCapturer::UpdateVideoAdapter() {
    rtc::VideoSinkWants wants = broadcaster_.wants();
  
    if (0 < wants.resolutions.size()) {
      auto size = wants.resolutions.at(0);
      std::pair<int, int> target_aspect_ratiot(size.width, size.height);
      video_adapter_.OnOutputFormatRequest(
          target_aspect_ratiot, wants.max_pixel_count, wants.max_framerate_fps);
    }
  }
  
  }  // namespace internal
  }  // namespace webrtc
  