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1 /*
2  *  Copyright (c) 2016 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 API_VIDEO_VIDEO_SOURCE_INTERFACE_H_
12 #define API_VIDEO_VIDEO_SOURCE_INTERFACE_H_
13 
14 #include <limits>
15 
16 #include "absl/types/optional.h"
17 #include "api/video/video_sink_interface.h"
18 #include "rtc_base/system/rtc_export.h"
19 
20 namespace rtc {
21 
22 // VideoSinkWants is used for notifying the source of properties a video frame
23 // should have when it is delivered to a certain sink.
24 struct RTC_EXPORT VideoSinkWants {
25   VideoSinkWants();
26   VideoSinkWants(const VideoSinkWants&);
27   ~VideoSinkWants();
28   // Tells the source whether the sink wants frames with rotation applied.
29   // By default, any rotation must be applied by the sink.
30   bool rotation_applied = false;
31 
32   // Tells the source that the sink only wants black frames.
33   bool black_frames = false;
34 
35   // Tells the source the maximum number of pixels the sink wants.
36   int max_pixel_count = std::numeric_limits<int>::max();
37   // Tells the source the desired number of pixels the sinks wants. This will
38   // typically be used when stepping the resolution up again when conditions
39   // have improved after an earlier downgrade. The source should select the
40   // closest resolution to this pixel count, but if max_pixel_count is set, it
41   // still sets the absolute upper bound.
42   absl::optional<int> target_pixel_count;
43   // Tells the source the maximum framerate the sink wants.
44   int max_framerate_fps = std::numeric_limits<int>::max();
45 
46   // Tells the source that the sink wants width and height of the video frames
47   // to be divisible by |resolution_alignment|.
48   // For example: With I420, this value would be a multiple of 2.
49   // Note that this field is unrelated to any horizontal or vertical stride
50   // requirements the encoder has on the incoming video frame buffers.
51   int resolution_alignment = 1;
52 };
53 
54 template <typename VideoFrameT>
55 class VideoSourceInterface {
56  public:
57   virtual ~VideoSourceInterface() = default;
58 
59   virtual void AddOrUpdateSink(VideoSinkInterface<VideoFrameT>* sink,
60                                const VideoSinkWants& wants) = 0;
61   // RemoveSink must guarantee that at the time the method returns,
62   // there is no current and no future calls to VideoSinkInterface::OnFrame.
63   virtual void RemoveSink(VideoSinkInterface<VideoFrameT>* sink) = 0;
64 };
65 
66 }  // namespace rtc
67 #endif  // API_VIDEO_VIDEO_SOURCE_INTERFACE_H_
68