Add framerate to VideoSinkWants and ability to signal on overuse

webrtc/media/base/videoadapter.h

 /*
  *  Copyright (c) 2010 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.
  */
 
 #ifndef WEBRTC_MEDIA_BASE_VIDEOADAPTER_H_
 #define WEBRTC_MEDIA_BASE_VIDEOADAPTER_H_
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/optional.h"
 #include "webrtc/media/base/videocommon.h"
 
 namespace cricket {
 
 // VideoAdapter adapts an input video frame to an output frame based on the
 // specified input and output formats. The adaptation includes dropping frames
 // to reduce frame rate and scaling frames.
 // VideoAdapter is thread safe.
 class VideoAdapter {
  public:
   VideoAdapter();
-  VideoAdapter(int required_resolution_alignment);
+  explicit VideoAdapter(int required_resolution_alignment);

[nisse-webrtc, 2017/03/08 08:08:54]

Not your change, but this argument deserves a comment.

[sprang_webrtc, 2017/03/09 13:19:34]

Done.

   virtual ~VideoAdapter();
 
   // Return the adapted resolution and cropping parameters given the
   // input resolution. The input frame should first be cropped, then
   // scaled to the final output resolution. Returns true if the frame
   // should be adapted, and false if it should be dropped.
   bool AdaptFrameResolution(int in_width,
                             int in_height,
                             int64_t in_timestamp_ns,
                             int* cropped_width,
                             int* cropped_height,
                             int* out_width,
                             int* out_height);
 
   // Requests the output frame size and frame interval from
   // |AdaptFrameResolution| to not be larger than |format|. Also, the input
   // frame size will be cropped to match the requested aspect ratio. The
   // requested aspect ratio is orientation agnostic and will be adjusted to
   // maintain the input orientation, so it doesn't matter if e.g. 1280x720 or
   // 720x1280 is requested.
   void OnOutputFormatRequest(const VideoFormat& format);
 
   // Requests the output frame size from |AdaptFrameResolution| to have as close
   // as possible to |target_pixel_count|, but no more than |max_pixel_count|
   // pixels. If |target_pixel_count| is not set, treat it as being equal to
   // |max_pixel_count|. If |max_pixel_count| is not set, treat is as being the
   // highest resolution available.
-  void OnResolutionRequest(const rtc::Optional<int>& target_pixel_count,
-                           const rtc::Optional<int>& max_pixel_count);
+  // |framerate_fps| is essentially analogous to |max_pixel_count|, but for
+  // framerate rather than resolution.
+  void OnResolutionFramerateRequest(
+      const rtc::Optional<int>& target_pixel_count,
+      const rtc::Optional<int>& max_pixel_count,
+      const rtc::Optional<int>& framerate_fps);
 
  private:
   // Determine if frame should be dropped based on input fps and requested fps.
   bool KeepFrame(int64_t in_timestamp_ns);
 
   int frames_in_;         // Number of input frames.
   int frames_out_;        // Number of output frames.
   int frames_scaled_;     // Number of frames scaled.
   int adaption_changes_;  // Number of changes in scale factor.
   int previous_width_;    // Previous adapter output width.
   int previous_height_;   // Previous adapter output height.
   // Resolution must be divisible by this factor.
   const int required_resolution_alignment_;
   // The target timestamp for the next frame based on requested format.
   rtc::Optional<int64_t> next_frame_timestamp_ns_ GUARDED_BY(critical_section_);
 
   // Max number of pixels requested via calls to OnOutputFormatRequest,
   // OnResolutionRequest respectively.
   // The adapted output format is the minimum of these.
   rtc::Optional<VideoFormat> requested_format_ GUARDED_BY(critical_section_);
   int resolution_request_target_pixel_count_ GUARDED_BY(critical_section_);
   int resolution_request_max_pixel_count_ GUARDED_BY(critical_section_);
+  int max_framerate_request_ GUARDED_BY(critical_section_);
 
   // The critical section to protect the above variables.
   rtc::CriticalSection critical_section_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(VideoAdapter);
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_VIDEOADAPTER_H_