In a future CL, adaptation processing and stream encoder resource management will happen on different task queues. When this is the case, asynchronous tasks will be posted in both directions and some resources will have internal states used on multiple threads. This CL makes the Resource class reference counted in order to support posting tasks to a different threads without risk of use-after-free when a posted task is executed with a delay. This is preferred over WeakPtr strategies because WeakPtrs are single-threaded and preferred over raw pointer usage because the reference counted approach enables more compile-time and run-time assurance. This is also "future proof"; when resources can be injected through public APIs, ownership needs to be shared between libwebrtc and the application (e.g. Chrome). To reduce the risk of making mistakes in the future CL, sequence checkers and task queue DCHECKs are added as well as other DCHECKs to make sure things have been cleaned up before destruction, e.g: - Processor gets a sequence checker. It is entirely single-threaded. - Processor must not have any attached listeners or resources on destruction. - Resources must not have any listeners on destruction. - The Manager, EncodeUsageResource and QualityScalerResource DCHECKs they are running on the encoder queue. - TODOs are added illustrating where we want to add PostTasks in the future CL. Lastly, upon VideoStreamEncoder::Stop() we delete the ResourceAdaptationProcessor. Because the Processor is already used in posted tasks, some if statements are added to ensure the Processor is not used after destruction. Bug: webrtc:11542, webrtc:11520 Change-Id: Ibaa8a61d86d87a71f477d1075a117c28d9d2d285 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/174760 Commit-Queue: Henrik Boström <hbos@webrtc.org> Reviewed-by: Evan Shrubsole <eshr@google.com> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Cr-Commit-Position: refs/heads/master@{#31217}
73 lines
3.1 KiB
C++
73 lines
3.1 KiB
C++
/*
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* Copyright 2020 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 VIDEO_VIDEO_SOURCE_SINK_CONTROLLER_H_
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#define VIDEO_VIDEO_SOURCE_SINK_CONTROLLER_H_
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#include "absl/types/optional.h"
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#include "api/video/video_frame.h"
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#include "api/video/video_sink_interface.h"
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#include "api/video/video_source_interface.h"
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#include "call/adaptation/video_source_restrictions.h"
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#include "rtc_base/critical_section.h"
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namespace webrtc {
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// Responsible for configuring source/sink settings, i.e. performing
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// rtc::VideoSourceInterface<VideoFrame>::AddOrUpdateSink(). It does this by
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// storing settings internally which are converted to rtc::VideoSinkWants when
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// PushSourceSinkSettings() is performed.
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class VideoSourceSinkController {
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public:
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VideoSourceSinkController(rtc::VideoSinkInterface<VideoFrame>* sink,
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rtc::VideoSourceInterface<VideoFrame>* source);
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void SetSource(rtc::VideoSourceInterface<VideoFrame>* source);
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// Must be called in order for changes to settings to have an effect. This
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// allows you to modify multiple properties in a single push to the sink.
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void PushSourceSinkSettings();
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VideoSourceRestrictions restrictions() const;
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absl::optional<size_t> pixels_per_frame_upper_limit() const;
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absl::optional<double> frame_rate_upper_limit() const;
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bool rotation_applied() const;
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int resolution_alignment() const;
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// Updates the settings stored internally. In order for these settings to be
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// applied to the sink, PushSourceSinkSettings() must subsequently be called.
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void SetRestrictions(VideoSourceRestrictions restrictions);
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void SetPixelsPerFrameUpperLimit(
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absl::optional<size_t> pixels_per_frame_upper_limit);
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void SetFrameRateUpperLimit(absl::optional<double> frame_rate_upper_limit);
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void SetRotationApplied(bool rotation_applied);
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void SetResolutionAlignment(int resolution_alignment);
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private:
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rtc::VideoSinkWants CurrentSettingsToSinkWants() const
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RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
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mutable rtc::CriticalSection crit_;
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rtc::VideoSinkInterface<VideoFrame>* const sink_;
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rtc::VideoSourceInterface<VideoFrame>* source_ RTC_GUARDED_BY(&crit_);
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// Pixel and frame rate restrictions.
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VideoSourceRestrictions restrictions_ RTC_GUARDED_BY(&crit_);
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// Ensures that even if we are not restricted, the sink is never configured
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// above this limit. Example: We are not CPU limited (no |restrictions_|) but
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// our encoder is capped at 30 fps (= |frame_rate_upper_limit_|).
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absl::optional<size_t> pixels_per_frame_upper_limit_ RTC_GUARDED_BY(&crit_);
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absl::optional<double> frame_rate_upper_limit_ RTC_GUARDED_BY(&crit_);
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bool rotation_applied_ RTC_GUARDED_BY(&crit_) = false;
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int resolution_alignment_ RTC_GUARDED_BY(&crit_) = 1;
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};
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} // namespace webrtc
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#endif // VIDEO_VIDEO_SOURCE_SINK_CONTROLLER_H_
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