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 #include <vector> 16 17 #include "absl/types/optional.h" 18 #include "api/video/video_sink_interface.h" 19 #include "rtc_base/system/rtc_export.h" 20 21 namespace rtc { 22 23 // VideoSinkWants is used for notifying the source of properties a video frame 24 // should have when it is delivered to a certain sink. 25 struct RTC_EXPORT VideoSinkWants { 26 struct FrameSize { FrameSizeVideoSinkWants::FrameSize27 FrameSize(int width, int height) : width(width), height(height) {} 28 FrameSize(const FrameSize&) = default; 29 ~FrameSize() = default; 30 31 int width; 32 int height; 33 }; 34 35 VideoSinkWants(); 36 VideoSinkWants(const VideoSinkWants&); 37 ~VideoSinkWants(); 38 // Tells the source whether the sink wants frames with rotation applied. 39 // By default, any rotation must be applied by the sink. 40 bool rotation_applied = false; 41 42 // Tells the source that the sink only wants black frames. 43 bool black_frames = false; 44 45 // Tells the source the maximum number of pixels the sink wants. 46 int max_pixel_count = std::numeric_limits<int>::max(); 47 // Tells the source the desired number of pixels the sinks wants. This will 48 // typically be used when stepping the resolution up again when conditions 49 // have improved after an earlier downgrade. The source should select the 50 // closest resolution to this pixel count, but if max_pixel_count is set, it 51 // still sets the absolute upper bound. 52 absl::optional<int> target_pixel_count; 53 // Tells the source the maximum framerate the sink wants. 54 int max_framerate_fps = std::numeric_limits<int>::max(); 55 56 // Tells the source that the sink wants width and height of the video frames 57 // to be divisible by `resolution_alignment`. 58 // For example: With I420, this value would be a multiple of 2. 59 // Note that this field is unrelated to any horizontal or vertical stride 60 // requirements the encoder has on the incoming video frame buffers. 61 int resolution_alignment = 1; 62 63 // The resolutions that sink is configured to consume. If the sink is an 64 // encoder this is what the encoder is configured to encode. In singlecast we 65 // only encode one resolution, but in simulcast and SVC this can mean multiple 66 // resolutions per frame. 67 // 68 // The sink is always configured to consume a subset of the 69 // webrtc::VideoFrame's resolution. In the case of encoding, we usually encode 70 // at webrtc::VideoFrame's resolution but this may not always be the case due 71 // to scaleResolutionDownBy or turning off simulcast or SVC layers. 72 // 73 // For example, we may capture at 720p and due to adaptation (e.g. applying 74 // `max_pixel_count` constraints) create webrtc::VideoFrames of size 480p, but 75 // if we do scaleResolutionDownBy:2 then the only resolution we end up 76 // encoding is 240p. In this case we still need to provide webrtc::VideoFrames 77 // of size 480p but we can optimize internal buffers for 240p, avoiding 78 // downsampling to 480p if possible. 79 // 80 // Note that the `resolutions` can change while frames are in flight and 81 // should only be used as a hint when constructing the webrtc::VideoFrame. 82 std::vector<FrameSize> resolutions; 83 84 // This is the resolution requested by the user using RtpEncodingParameters. 85 absl::optional<FrameSize> requested_resolution; 86 87 // `active` : is (any) of the layers/sink(s) active. 88 bool is_active = true; 89 90 // This sub-struct contains information computed by VideoBroadcaster 91 // that aggregates several VideoSinkWants (and sends them to 92 // AdaptedVideoTrackSource). 93 struct Aggregates { 94 // `active_without_requested_resolution` is set by VideoBroadcaster 95 // when aggregating sink wants if there exists any sink (encoder) that is 96 // active but has not set the `requested_resolution`, i.e is relying on 97 // OnOutputFormatRequest to handle encode resolution. 98 bool any_active_without_requested_resolution = false; 99 }; 100 absl::optional<Aggregates> aggregates; 101 }; 102 103 inline bool operator==(const VideoSinkWants::FrameSize& a, 104 const VideoSinkWants::FrameSize& b) { 105 return a.width == b.width && a.height == b.height; 106 } 107 108 inline bool operator!=(const VideoSinkWants::FrameSize& a, 109 const VideoSinkWants::FrameSize& b) { 110 return !(a == b); 111 } 112 113 template <typename VideoFrameT> 114 class VideoSourceInterface { 115 public: 116 virtual ~VideoSourceInterface() = default; 117 118 virtual void AddOrUpdateSink(VideoSinkInterface<VideoFrameT>* sink, 119 const VideoSinkWants& wants) = 0; 120 // RemoveSink must guarantee that at the time the method returns, 121 // there is no current and no future calls to VideoSinkInterface::OnFrame. 122 virtual void RemoveSink(VideoSinkInterface<VideoFrameT>* sink) = 0; 123 124 // Request underlying source to capture a new frame. 125 // TODO(crbug/1255737): make pure virtual once downstream projects adapt. RequestRefreshFrame()126 virtual void RequestRefreshFrame() {} 127 }; 128 129 } // namespace rtc 130 #endif // API_VIDEO_VIDEO_SOURCE_INTERFACE_H_ 131