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/*
* Copyright 2020 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef API_FRAME_TRANSFORMER_INTERFACE_H_
#define API_FRAME_TRANSFORMER_INTERFACE_H_
#include <cstdint>
#include <memory>
#include <string>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "api/ref_count.h"
#include "api/scoped_refptr.h"
#include "api/units/timestamp.h"
#include "api/video/video_frame_metadata.h"
#include "rtc_base/system/rtc_export.h"
namespace webrtc {
// Owns the frame payload data.
class TransformableFrameInterface {
public:
// Only a known list of internal implementations of transformable frames are
// permitted to allow internal downcasting. This is enforced via the
// internally-constructable Passkey.
// TODO: bugs.webrtc.org/339815768 - Remove this passkey once the
// downcasts are removed.
class Passkey;
RTC_EXPORT explicit TransformableFrameInterface(Passkey);
TransformableFrameInterface(TransformableFrameInterface&&) = default;
TransformableFrameInterface& operator=(TransformableFrameInterface&&) =
default;
virtual ~TransformableFrameInterface() = default;
// Returns the frame payload data. The data is valid until the next non-const
// method call.
virtual rtc::ArrayView<const uint8_t> GetData() const = 0;
// Copies `data` into the owned frame payload data.
virtual void SetData(rtc::ArrayView<const uint8_t> data) = 0;
virtual uint8_t GetPayloadType() const = 0;
virtual uint32_t GetSsrc() const = 0;
virtual uint32_t GetTimestamp() const = 0;
virtual void SetRTPTimestamp(uint32_t timestamp) = 0;
// is implemented everywhere.
virtual absl::optional<Timestamp> GetCaptureTimeIdentifier() const {
return absl::nullopt;
}
enum class Direction {
kUnknown,
kReceiver,
kSender,
};
// TODO(crbug.com/1250638): Remove this distinction between receiver and
// sender frames to allow received frames to be directly re-transmitted on
// other PeerConnectionss.
virtual Direction GetDirection() const { return Direction::kUnknown; }
virtual std::string GetMimeType() const = 0;
};
class TransformableVideoFrameInterface : public TransformableFrameInterface {
public:
RTC_EXPORT explicit TransformableVideoFrameInterface(Passkey passkey);
virtual ~TransformableVideoFrameInterface() = default;
virtual bool IsKeyFrame() const = 0;
virtual const std::string& GetRid() const = 0;
virtual VideoFrameMetadata Metadata() const = 0;
virtual void SetMetadata(const VideoFrameMetadata&) = 0;
};
// Extends the TransformableFrameInterface to expose audio-specific information.
class TransformableAudioFrameInterface : public TransformableFrameInterface {
public:
RTC_EXPORT explicit TransformableAudioFrameInterface(Passkey passkey);
virtual ~TransformableAudioFrameInterface() = default;
virtual rtc::ArrayView<const uint32_t> GetContributingSources() const = 0;
virtual const absl::optional<uint16_t> SequenceNumber() const = 0;
virtual absl::optional<uint64_t> AbsoluteCaptureTimestamp() const = 0;
enum class FrameType { kEmptyFrame, kAudioFrameSpeech, kAudioFrameCN };
// TODO(crbug.com/1456628): Change this to pure virtual after it
// is implemented everywhere.
virtual FrameType Type() const { return FrameType::kEmptyFrame; }
// Audio level in -dBov. Values range from 0 to 127, representing 0 to -127
// dBov. 127 represents digital silence. Only present on remote frames if
// the audio level header extension was included.
virtual absl::optional<uint8_t> AudioLevel() const = 0;
// Timestamp at which the packet has been first seen on the network interface.
// Only defined for received audio packet.
virtual absl::optional<Timestamp> ReceiveTime() const = 0;
};
// Objects implement this interface to be notified with the transformed frame.
class TransformedFrameCallback : public RefCountInterface {
public:
virtual void OnTransformedFrame(
std::unique_ptr<TransformableFrameInterface> frame) = 0;
// Request to no longer be called on each frame, instead having frames be
// sent directly to OnTransformedFrame without additional work.
// TODO(crbug.com/1502781): Make pure virtual once all mocks have
// implementations.
virtual void StartShortCircuiting() {}
protected:
~TransformedFrameCallback() override = default;
};
// Transforms encoded frames. The transformed frame is sent in a callback using
// the TransformedFrameCallback interface (see above).
class FrameTransformerInterface : public RefCountInterface {
public:
// Transforms `frame` using the implementing class' processing logic.
virtual void Transform(
std::unique_ptr<TransformableFrameInterface> transformable_frame) = 0;
virtual void RegisterTransformedFrameCallback(
rtc::scoped_refptr<TransformedFrameCallback>) {}
virtual void RegisterTransformedFrameSinkCallback(
rtc::scoped_refptr<TransformedFrameCallback>,
uint32_t ssrc) {}
virtual void UnregisterTransformedFrameCallback() {}
virtual void UnregisterTransformedFrameSinkCallback(uint32_t ssrc) {}
protected:
~FrameTransformerInterface() override = default;
};
// An interface implemented by classes that can host a transform.
// Currently this is implemented by the RTCRtpSender and RTCRtpReceiver.
class FrameTransformerHost {
public:
virtual ~FrameTransformerHost() {}
virtual void SetFrameTransformer(
rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) = 0;
// TODO: bugs.webrtc.org/15929 - To be added:
// virtual AddIncomingMediaType(RtpCodec codec) = 0;
// virtual AddOutgoingMediaType(RtpCodec codec) = 0;
};
//------------------------------------------------------------------------------
// Implementation details follow
//------------------------------------------------------------------------------
class TransformableFrameInterface::Passkey {
public:
~Passkey() = default;
private:
// Explicit list of allowed internal implmentations of
// TransformableFrameInterface.
friend class TransformableOutgoingAudioFrame;
friend class TransformableIncomingAudioFrame;
friend class TransformableVideoSenderFrame;
friend class TransformableVideoReceiverFrame;
friend class MockTransformableFrame;
friend class MockTransformableAudioFrame;
friend class MockTransformableVideoFrame;
Passkey() = default;
};
} // namespace webrtc
#endif // API_FRAME_TRANSFORMER_INTERFACE_H_