1 /* 2 * Copyright (c) 2010 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 MEDIA_BASE_VIDEO_ADAPTER_H_ 12 #define MEDIA_BASE_VIDEO_ADAPTER_H_ 13 14 #include <stdint.h> 15 16 #include <string> 17 #include <utility> 18 19 #include "absl/types/optional.h" 20 #include "api/video/video_source_interface.h" 21 #include "common_video/framerate_controller.h" 22 #include "media/base/video_common.h" 23 #include "rtc_base/synchronization/mutex.h" 24 #include "rtc_base/system/rtc_export.h" 25 #include "rtc_base/thread_annotations.h" 26 27 namespace cricket { 28 29 // VideoAdapter adapts an input video frame to an output frame based on the 30 // specified input and output formats. The adaptation includes dropping frames 31 // to reduce frame rate and scaling frames. 32 // VideoAdapter is thread safe. 33 class RTC_EXPORT VideoAdapter { 34 public: 35 VideoAdapter(); 36 // The source requests output frames whose width and height are divisible 37 // by `source_resolution_alignment`. 38 explicit VideoAdapter(int source_resolution_alignment); 39 virtual ~VideoAdapter(); 40 41 VideoAdapter(const VideoAdapter&) = delete; 42 VideoAdapter& operator=(const VideoAdapter&) = delete; 43 44 // Return the adapted resolution and cropping parameters given the 45 // input resolution. The input frame should first be cropped, then 46 // scaled to the final output resolution. Returns true if the frame 47 // should be adapted, and false if it should be dropped. 48 bool AdaptFrameResolution(int in_width, 49 int in_height, 50 int64_t in_timestamp_ns, 51 int* cropped_width, 52 int* cropped_height, 53 int* out_width, 54 int* out_height) RTC_LOCKS_EXCLUDED(mutex_); 55 56 // DEPRECATED. Please use OnOutputFormatRequest below. 57 // TODO(asapersson): Remove this once it is no longer used. 58 // Requests the output frame size and frame interval from 59 // `AdaptFrameResolution` to not be larger than `format`. Also, the input 60 // frame size will be cropped to match the requested aspect ratio. The 61 // requested aspect ratio is orientation agnostic and will be adjusted to 62 // maintain the input orientation, so it doesn't matter if e.g. 1280x720 or 63 // 720x1280 is requested. 64 // Note: Should be called from the source only. 65 void OnOutputFormatRequest(const absl::optional<VideoFormat>& format) 66 RTC_LOCKS_EXCLUDED(mutex_); 67 68 // Requests output frame size and frame interval from `AdaptFrameResolution`. 69 // `target_aspect_ratio`: The input frame size will be cropped to match the 70 // requested aspect ratio. The aspect ratio is orientation agnostic and will 71 // be adjusted to maintain the input orientation (i.e. it doesn't matter if 72 // e.g. <1280,720> or <720,1280> is requested). 73 // `max_pixel_count`: The maximum output frame size. 74 // `max_fps`: The maximum output framerate. 75 // Note: Should be called from the source only. 76 void OnOutputFormatRequest( 77 const absl::optional<std::pair<int, int>>& target_aspect_ratio, 78 const absl::optional<int>& max_pixel_count, 79 const absl::optional<int>& max_fps) RTC_LOCKS_EXCLUDED(mutex_); 80 81 // Same as above, but allows setting two different target aspect ratios 82 // depending on incoming frame orientation. This gives more fine-grained 83 // control and can e.g. be used to force landscape video to be cropped to 84 // portrait video. 85 void OnOutputFormatRequest( 86 const absl::optional<std::pair<int, int>>& target_landscape_aspect_ratio, 87 const absl::optional<int>& max_landscape_pixel_count, 88 const absl::optional<std::pair<int, int>>& target_portrait_aspect_ratio, 89 const absl::optional<int>& max_portrait_pixel_count, 90 const absl::optional<int>& max_fps) RTC_LOCKS_EXCLUDED(mutex_); 91 92 // Requests the output frame size from `AdaptFrameResolution` to have as close 93 // as possible to `sink_wants.target_pixel_count` pixels (if set) 94 // but no more than `sink_wants.max_pixel_count`. 95 // `sink_wants.max_framerate_fps` is essentially analogous to 96 // `sink_wants.max_pixel_count`, but for framerate rather than resolution. 97 // Set `sink_wants.max_pixel_count` and/or `sink_wants.max_framerate_fps` to 98 // std::numeric_limit<int>::max() if no upper limit is desired. 99 // The sink resolution alignment requirement is given by 100 // `sink_wants.resolution_alignment`. 101 // Note: Should be called from the sink only. 102 void OnSinkWants(const rtc::VideoSinkWants& sink_wants) 103 RTC_LOCKS_EXCLUDED(mutex_); 104 105 // Returns maximum image area, which shouldn't impose any adaptations. 106 // Can return `numeric_limits<int>::max()` if no limit is set. 107 int GetTargetPixels() const; 108 109 // Returns current frame-rate limit. 110 // Can return `numeric_limits<float>::infinity()` if no limit is set. 111 float GetMaxFramerate() const; 112 113 private: 114 // Determine if frame should be dropped based on input fps and requested fps. 115 bool DropFrame(int64_t in_timestamp_ns) RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_); 116 117 int frames_in_ RTC_GUARDED_BY(mutex_); // Number of input frames. 118 int frames_out_ RTC_GUARDED_BY(mutex_); // Number of output frames. 119 int frames_scaled_ RTC_GUARDED_BY(mutex_); // Number of frames scaled. 120 int adaption_changes_ 121 RTC_GUARDED_BY(mutex_); // Number of changes in scale factor. 122 int previous_width_ RTC_GUARDED_BY(mutex_); // Previous adapter output width. 123 int previous_height_ 124 RTC_GUARDED_BY(mutex_); // Previous adapter output height. 125 const bool variable_start_scale_factor_; 126 127 // The fixed source resolution alignment requirement. 128 const int source_resolution_alignment_; 129 // The currently applied resolution alignment, as given by the requirements: 130 // - the fixed `source_resolution_alignment_`; and 131 // - the latest `sink_wants.resolution_alignment`. 132 int resolution_alignment_ RTC_GUARDED_BY(mutex_); 133 134 // Max number of pixels/fps requested via calls to OnOutputFormatRequest, 135 // OnResolutionFramerateRequest respectively. 136 // The adapted output format is the minimum of these. 137 struct OutputFormatRequest { 138 absl::optional<std::pair<int, int>> target_landscape_aspect_ratio; 139 absl::optional<int> max_landscape_pixel_count; 140 absl::optional<std::pair<int, int>> target_portrait_aspect_ratio; 141 absl::optional<int> max_portrait_pixel_count; 142 absl::optional<int> max_fps; 143 144 // For logging. 145 std::string ToString() const; 146 }; 147 148 OutputFormatRequest output_format_request_ RTC_GUARDED_BY(mutex_); 149 int resolution_request_target_pixel_count_ RTC_GUARDED_BY(mutex_); 150 int resolution_request_max_pixel_count_ RTC_GUARDED_BY(mutex_); 151 int max_framerate_request_ RTC_GUARDED_BY(mutex_); 152 153 // Stashed OutputFormatRequest that is used to save value of 154 // OnOutputFormatRequest in case all active encoders are using 155 // requested_resolution. I.e when all active encoders are using 156 // requested_resolution, the call to OnOutputFormatRequest is ignored 157 // and the value from requested_resolution is used instead (to scale/crop 158 // frame). This allows for an application to only use 159 // RtpEncodingParameters::request_resolution and get the same behavior as if 160 // it had used VideoAdapter::OnOutputFormatRequest. 161 absl::optional<OutputFormatRequest> stashed_output_format_request_ 162 RTC_GUARDED_BY(mutex_); 163 164 webrtc::FramerateController framerate_controller_ RTC_GUARDED_BY(mutex_); 165 166 // The critical section to protect the above variables. 167 mutable webrtc::Mutex mutex_; 168 }; 169 170 } // namespace cricket 171 172 #endif // MEDIA_BASE_VIDEO_ADAPTER_H_ 173