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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_MODULES_VIDEO_PROCESSING_INCLUDE_VIDEO_PROCESSING_H_
     12 #define WEBRTC_MODULES_VIDEO_PROCESSING_INCLUDE_VIDEO_PROCESSING_H_
     13 
     14 #include "webrtc/modules/include/module_common_types.h"
     15 #include "webrtc/modules/video_processing/include/video_processing_defines.h"
     16 #include "webrtc/video_frame.h"
     17 
     18 // The module is largely intended to process video streams, except functionality
     19 // provided by static functions which operate independent of previous frames. It
     20 // is recommended, but not required that a unique instance be used for each
     21 // concurrently processed stream. Similarly, it is recommended to call Reset()
     22 // before switching to a new stream, but this is not absolutely required.
     23 //
     24 // The module provides basic thread safety by permitting only a single function
     25 // to execute concurrently.
     26 
     27 namespace webrtc {
     28 
     29 class VideoProcessing {
     30  public:
     31   struct FrameStats {
     32     uint32_t hist[256];  // Frame histogram.
     33     uint32_t mean;
     34     uint32_t sum;
     35     uint32_t num_pixels;
     36     uint32_t sub_sampling_factor;  // Sub-sampling factor, in powers of 2.
     37   };
     38 
     39   enum BrightnessWarning { kNoWarning, kDarkWarning, kBrightWarning };
     40 
     41   static VideoProcessing* Create();
     42   virtual ~VideoProcessing() {}
     43 
     44   // Retrieves statistics for the input frame. This function must be used to
     45   // prepare a FrameStats struct for use in certain VPM functions.
     46   static void GetFrameStats(const VideoFrame& frame, FrameStats* stats);
     47 
     48   // Checks the validity of a FrameStats struct. Currently, valid implies only
     49   // that is had changed from its initialized state.
     50   static bool ValidFrameStats(const FrameStats& stats);
     51 
     52   static void ClearFrameStats(FrameStats* stats);
     53 
     54   // Increases/decreases the luminance value. 'delta' can be in the range {}
     55   static void Brighten(int delta, VideoFrame* frame);
     56 
     57   // Detects and removes camera flicker from a video stream. Every frame from
     58   // the stream must be passed in. A frame will only be altered if flicker has
     59   // been detected. Has a fixed-point implementation.
     60   // Frame statistics provided by GetFrameStats(). On return the stats will
     61   // be reset to zero if the frame was altered. Call GetFrameStats() again
     62   // if the statistics for the altered frame are required.
     63   virtual int32_t Deflickering(VideoFrame* frame, FrameStats* stats) = 0;
     64 
     65   // Detects if a video frame is excessively bright or dark. Returns a
     66   // warning if this is the case. Multiple frames should be passed in before
     67   // expecting a warning. Has a floating-point implementation.
     68   virtual int32_t BrightnessDetection(const VideoFrame& frame,
     69                                       const FrameStats& stats) = 0;
     70 
     71   // The following functions refer to the pre-processor unit within VPM. The
     72   // pre-processor perfoms spatial/temporal decimation and content analysis on
     73   // the frames prior to encoding.
     74 
     75   // Enable/disable temporal decimation
     76   virtual void EnableTemporalDecimation(bool enable) = 0;
     77 
     78   virtual int32_t SetTargetResolution(uint32_t width,
     79                                       uint32_t height,
     80                                       uint32_t frame_rate) = 0;
     81 
     82   virtual void SetTargetFramerate(int frame_rate) = 0;
     83 
     84   virtual uint32_t GetDecimatedFrameRate() = 0;
     85   virtual uint32_t GetDecimatedWidth() const = 0;
     86   virtual uint32_t GetDecimatedHeight() const = 0;
     87 
     88   // Set the spatial resampling settings of the VPM according to
     89   // VideoFrameResampling.
     90   virtual void SetInputFrameResampleMode(
     91       VideoFrameResampling resampling_mode) = 0;
     92 
     93   virtual void EnableDenosing(bool enable) = 0;
     94   virtual const VideoFrame* PreprocessFrame(const VideoFrame& frame) = 0;
     95 
     96   virtual VideoContentMetrics* GetContentMetrics() const = 0;
     97   virtual void EnableContentAnalysis(bool enable) = 0;
     98 };
     99 
    100 }  // namespace webrtc
    101 
    102 #endif  // WEBRTC_MODULES_VIDEO_PROCESSING_INCLUDE_VIDEO_PROCESSING_H_
    103