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();
~VideoProcessing()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