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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_STATS_COLLECTING_DECODER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_STATS_COLLECTING_DECODER_H_
#include "base/memory/raw_ptr.h"
#include "base/thread_annotations.h"
#include "base/time/time.h"
#include "third_party/blink/renderer/platform/peerconnection/stats_collector.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/webrtc/api/video_codecs/sdp_video_format.h"
#include "third_party/webrtc/api/video_codecs/video_decoder.h"
namespace blink {
// This class acts as a wrapper around the WebRTC video decoder that is used in
// Chrome.
//
// Its purpose is to collect decode performance statistics for the current video
// stream. The performance statistics is pushed to a local database through a
// callback and is later used to determine if a specific video configuration is
// considered to be smooth or not, see
// https://w3c.github.io/media-capabilities/. Smooth will be an optimistic
// prediction and data collection therefore only takes place if there's a single
// decoder active.
//
// It's assumed that Configure(), Decode(), and RegisterDecodeCompleteCallback()
// are called on the decode sequence. Decoded() may be called on either the
// decode sequecene or the media sequence depending on if the underlying decoder
// is a HW or SW decoder. However, the calls to Decoded() on these sequences are
// mutual exclusive. Release() may be called on any sequence as long as the
// decoding sequence has stopped.
class PLATFORM_EXPORT StatsCollectingDecoder
: private StatsCollector,
public webrtc::VideoDecoder,
private webrtc::DecodedImageCallback {
public:
// Creates a StatsCollectingDecoder object for the specified `format`.
// `decoder` specifies the underlying decoder that is wrapped and all calls to
// the methods of the webrtc::VideoDecoder interface are forwarded to
// `decoder`. The provided `stats_callback` will be called periodically to
// push the performance data that has been collected. The lifetime of
// `stats_callback` must outlive the lifetime of the StatsCollectingDecoder.
explicit StatsCollectingDecoder(const webrtc::SdpVideoFormat& format,
std::unique_ptr<webrtc::VideoDecoder> decoder,
StoreProcessingStatsCB stats_callback);
~StatsCollectingDecoder() override;
// Implementation of webrtc::VideoDecoder.
bool Configure(const Settings& settings) override;
int32_t Decode(const webrtc::EncodedImage& input_image,
bool missing_frames,
int64_t render_time_ms) override;
int32_t RegisterDecodeCompleteCallback(
DecodedImageCallback* callback) override;
int32_t Release() override;
DecoderInfo GetDecoderInfo() const override;
private:
// Implementation of webrtc::DecodedImageCallback.
int32_t Decoded(webrtc::VideoFrame& decodedImage) override;
void Decoded(webrtc::VideoFrame& decodedImage,
std::optional<int32_t> decode_time_ms,
std::optional<uint8_t> qp) override;
const std::unique_ptr<webrtc::VideoDecoder> decoder_;
raw_ptr<webrtc::DecodedImageCallback> decoded_callback_{nullptr};
// Lock for variables that are accessed in both Decode() and Decoded(). This
// is needed because Decode() and Decoded() may be called simultaneously on
// the decode sequence and the media sequence.
base::Lock lock_;
bool first_frame_decoded_{false};
// `number_of_new_keyframes_` is used to count the number of processed key
// frames, which is only known in Decode(). The value of this counter is
// continuously read out in the Decoded() callback.
size_t number_of_new_keyframes_ GUARDED_BY(lock_){0};
base::TimeTicks last_check_for_simultaneous_decoders_;
SEQUENCE_CHECKER(decoding_sequence_checker_);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_PEERCONNECTION_STATS_COLLECTING_DECODER_H_
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