Reland of Add ability to scale to arbitrary factors

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);
   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,
@@ skipping 18 matching lines @@
  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_max_pixel_count_ GUARDED_BY(critical_section_);
-  int resolution_request_max_pixel_count_step_up_ GUARDED_BY(critical_section_);
+  bool step_up_ 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_