156 lines
7.0 KiB
C++
156 lines
7.0 KiB
C++
/*
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* Copyright (c) 2010 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MEDIA_BASE_VIDEO_ADAPTER_H_
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#define MEDIA_BASE_VIDEO_ADAPTER_H_
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#include <stdint.h>
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#include <utility>
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#include "absl/types/optional.h"
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#include "api/video/video_source_interface.h"
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#include "common_video/framerate_controller.h"
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#include "media/base/video_common.h"
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#include "rtc_base/constructor_magic.h"
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#include "rtc_base/synchronization/mutex.h"
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#include "rtc_base/system/rtc_export.h"
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#include "rtc_base/thread_annotations.h"
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namespace cricket {
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// VideoAdapter adapts an input video frame to an output frame based on the
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// specified input and output formats. The adaptation includes dropping frames
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// to reduce frame rate and scaling frames.
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// VideoAdapter is thread safe.
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class RTC_EXPORT VideoAdapter {
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public:
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VideoAdapter();
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// The source requests output frames whose width and height are divisible
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// by `source_resolution_alignment`.
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explicit VideoAdapter(int source_resolution_alignment);
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virtual ~VideoAdapter();
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// Return the adapted resolution and cropping parameters given the
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// input resolution. The input frame should first be cropped, then
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// scaled to the final output resolution. Returns true if the frame
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// should be adapted, and false if it should be dropped.
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bool AdaptFrameResolution(int in_width,
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int in_height,
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int64_t in_timestamp_ns,
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int* cropped_width,
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int* cropped_height,
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int* out_width,
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int* out_height) RTC_LOCKS_EXCLUDED(mutex_);
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// DEPRECATED. Please use OnOutputFormatRequest below.
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// TODO(asapersson): Remove this once it is no longer used.
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// Requests the output frame size and frame interval from
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// `AdaptFrameResolution` to not be larger than `format`. Also, the input
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// frame size will be cropped to match the requested aspect ratio. The
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// requested aspect ratio is orientation agnostic and will be adjusted to
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// maintain the input orientation, so it doesn't matter if e.g. 1280x720 or
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// 720x1280 is requested.
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// Note: Should be called from the source only.
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void OnOutputFormatRequest(const absl::optional<VideoFormat>& format)
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RTC_LOCKS_EXCLUDED(mutex_);
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// Requests output frame size and frame interval from `AdaptFrameResolution`.
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// `target_aspect_ratio`: The input frame size will be cropped to match the
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// requested aspect ratio. The aspect ratio is orientation agnostic and will
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// be adjusted to maintain the input orientation (i.e. it doesn't matter if
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// e.g. <1280,720> or <720,1280> is requested).
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// `max_pixel_count`: The maximum output frame size.
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// `max_fps`: The maximum output framerate.
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// Note: Should be called from the source only.
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void OnOutputFormatRequest(
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const absl::optional<std::pair<int, int>>& target_aspect_ratio,
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const absl::optional<int>& max_pixel_count,
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const absl::optional<int>& max_fps) RTC_LOCKS_EXCLUDED(mutex_);
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// Same as above, but allows setting two different target aspect ratios
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// depending on incoming frame orientation. This gives more fine-grained
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// control and can e.g. be used to force landscape video to be cropped to
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// portrait video.
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void OnOutputFormatRequest(
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const absl::optional<std::pair<int, int>>& target_landscape_aspect_ratio,
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const absl::optional<int>& max_landscape_pixel_count,
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const absl::optional<std::pair<int, int>>& target_portrait_aspect_ratio,
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const absl::optional<int>& max_portrait_pixel_count,
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const absl::optional<int>& max_fps) RTC_LOCKS_EXCLUDED(mutex_);
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// Requests the output frame size from `AdaptFrameResolution` to have as close
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// as possible to `sink_wants.target_pixel_count` pixels (if set)
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// but no more than `sink_wants.max_pixel_count`.
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// `sink_wants.max_framerate_fps` is essentially analogous to
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// `sink_wants.max_pixel_count`, but for framerate rather than resolution.
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// Set `sink_wants.max_pixel_count` and/or `sink_wants.max_framerate_fps` to
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// std::numeric_limit<int>::max() if no upper limit is desired.
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// The sink resolution alignment requirement is given by
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// `sink_wants.resolution_alignment`.
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// Note: Should be called from the sink only.
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void OnSinkWants(const rtc::VideoSinkWants& sink_wants)
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RTC_LOCKS_EXCLUDED(mutex_);
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// Returns maximum image area, which shouldn't impose any adaptations.
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// Can return `numeric_limits<int>::max()` if no limit is set.
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int GetTargetPixels() const;
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// Returns current frame-rate limit.
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// Can return `numeric_limits<float>::infinity()` if no limit is set.
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float GetMaxFramerate() const;
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private:
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// Determine if frame should be dropped based on input fps and requested fps.
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bool DropFrame(int64_t in_timestamp_ns) RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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int frames_in_ RTC_GUARDED_BY(mutex_); // Number of input frames.
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int frames_out_ RTC_GUARDED_BY(mutex_); // Number of output frames.
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int frames_scaled_ RTC_GUARDED_BY(mutex_); // Number of frames scaled.
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int adaption_changes_
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RTC_GUARDED_BY(mutex_); // Number of changes in scale factor.
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int previous_width_ RTC_GUARDED_BY(mutex_); // Previous adapter output width.
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int previous_height_
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RTC_GUARDED_BY(mutex_); // Previous adapter output height.
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const bool variable_start_scale_factor_;
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// The fixed source resolution alignment requirement.
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const int source_resolution_alignment_;
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// The currently applied resolution alignment, as given by the requirements:
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// - the fixed `source_resolution_alignment_`; and
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// - the latest `sink_wants.resolution_alignment`.
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int resolution_alignment_ RTC_GUARDED_BY(mutex_);
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// Max number of pixels/fps requested via calls to OnOutputFormatRequest,
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// OnResolutionFramerateRequest respectively.
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// The adapted output format is the minimum of these.
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absl::optional<std::pair<int, int>> target_landscape_aspect_ratio_
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RTC_GUARDED_BY(mutex_);
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absl::optional<int> max_landscape_pixel_count_ RTC_GUARDED_BY(mutex_);
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absl::optional<std::pair<int, int>> target_portrait_aspect_ratio_
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RTC_GUARDED_BY(mutex_);
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absl::optional<int> max_portrait_pixel_count_ RTC_GUARDED_BY(mutex_);
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absl::optional<int> max_fps_ RTC_GUARDED_BY(mutex_);
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int resolution_request_target_pixel_count_ RTC_GUARDED_BY(mutex_);
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int resolution_request_max_pixel_count_ RTC_GUARDED_BY(mutex_);
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int max_framerate_request_ RTC_GUARDED_BY(mutex_);
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webrtc::FramerateController framerate_controller_ RTC_GUARDED_BY(mutex_);
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// The critical section to protect the above variables.
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mutable webrtc::Mutex mutex_;
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RTC_DISALLOW_COPY_AND_ASSIGN(VideoAdapter);
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};
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} // namespace cricket
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#endif // MEDIA_BASE_VIDEO_ADAPTER_H_
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