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/*
* Copyright (c) 2013 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 VIDEO_CONFIG_VIDEO_ENCODER_CONFIG_H_
#define VIDEO_CONFIG_VIDEO_ENCODER_CONFIG_H_
#include <stddef.h>
#include <string>
#include <vector>
#include "absl/types/optional.h"
#include "api/scoped_refptr.h"
#include "api/video/resolution.h"
#include "api/video_codecs/scalability_mode.h"
#include "api/video_codecs/sdp_video_format.h"
#include "api/video_codecs/video_codec.h"
#include "rtc_base/ref_count.h"
namespace webrtc {
// The `VideoStream` struct describes a simulcast layer, or "stream".
struct VideoStream {
VideoStream();
~VideoStream();
VideoStream(const VideoStream& other);
std::string ToString() const;
// Width/Height in pixels.
// This is the actual width and height used to configure encoder,
// which might be less than `requested_resolution` due to adaptation
// or due to the source providing smaller frames than requested.
size_t width;
size_t height;
// Frame rate in fps.
int max_framerate;
// Bitrate, in bps, for the stream.
int min_bitrate_bps;
int target_bitrate_bps;
int max_bitrate_bps;
// Scaling factor applied to the stream size.
// `width` and `height` values are already scaled down.
double scale_resolution_down_by;
// Maximum Quantization Parameter to use when encoding the stream.
int max_qp;
// Determines the number of temporal layers that the stream should be
// encoded with. This value should be greater than zero.
// TODO(brandtr): This class is used both for configuring the encoder
// (meaning that this field _must_ be set), and for signaling the app-level
// encoder settings (meaning that the field _may_ be set). We should separate
// this and remove this optional instead.
absl::optional<size_t> num_temporal_layers;
// The priority of this stream, to be used when allocating resources
// between multiple streams.
absl::optional<double> bitrate_priority;
absl::optional<ScalabilityMode> scalability_mode;
// If this stream is enabled by the user, or not.
bool active;
// An optional user supplied max_frame_resolution
// than can be set independently of (adapted) VideoSource.
// This value is set from RtpEncodingParameters::requested_resolution
// (i.e. used for signaling app-level settings).
//
// The actual encode resolution is in `width` and `height`,
// which can be lower than requested_resolution,
// e.g. if source only provides lower resolution or
// if resource adaptation is active.
absl::optional<Resolution> requested_resolution;
};
class VideoEncoderConfig {
public:
// These are reference counted to permit copying VideoEncoderConfig and be
// kept alive until all encoder_specific_settings go out of scope.
// TODO(kthelgason): Consider removing the need for copying VideoEncoderConfig
// and use absl::optional for encoder_specific_settings instead.
class EncoderSpecificSettings : public rtc::RefCountInterface {
public:
// TODO(pbos): Remove FillEncoderSpecificSettings as soon as VideoCodec is
// not in use and encoder implementations ask for codec-specific structs
// directly.
void FillEncoderSpecificSettings(VideoCodec* codec_struct) const;
virtual void FillVideoCodecVp8(VideoCodecVP8* vp8_settings) const;
virtual void FillVideoCodecVp9(VideoCodecVP9* vp9_settings) const;
virtual void FillVideoCodecAv1(VideoCodecAV1* av1_settings) const;
private:
~EncoderSpecificSettings() override {}
friend class VideoEncoderConfig;
};
class Vp8EncoderSpecificSettings : public EncoderSpecificSettings {
public:
explicit Vp8EncoderSpecificSettings(const VideoCodecVP8& specifics);
void FillVideoCodecVp8(VideoCodecVP8* vp8_settings) const override;
private:
VideoCodecVP8 specifics_;
};
class Vp9EncoderSpecificSettings : public EncoderSpecificSettings {
public:
explicit Vp9EncoderSpecificSettings(const VideoCodecVP9& specifics);
void FillVideoCodecVp9(VideoCodecVP9* vp9_settings) const override;
private:
VideoCodecVP9 specifics_;
};
class Av1EncoderSpecificSettings : public EncoderSpecificSettings {
public:
explicit Av1EncoderSpecificSettings(const VideoCodecAV1& specifics);
void FillVideoCodecAv1(VideoCodecAV1* av1_settings) const override;
private:
VideoCodecAV1 specifics_;
};
enum class ContentType {
kRealtimeVideo,
kScreen,
};
class VideoStreamFactoryInterface : public rtc::RefCountInterface {
public:
// An implementation should return a std::vector<VideoStream> with the
// wanted VideoStream settings for the given video resolution.
// The size of the vector may not be larger than
// `encoder_config.number_of_streams`.
virtual std::vector<VideoStream> CreateEncoderStreams(
int frame_width,
int frame_height,
const VideoEncoderConfig& encoder_config) = 0;
protected:
~VideoStreamFactoryInterface() override {}
};
VideoEncoderConfig& operator=(VideoEncoderConfig&&) = default;
VideoEncoderConfig& operator=(const VideoEncoderConfig&) = delete;
// Mostly used by tests. Avoid creating copies if you can.
VideoEncoderConfig Copy() const { return VideoEncoderConfig(*this); }
VideoEncoderConfig();
VideoEncoderConfig(VideoEncoderConfig&&);
~VideoEncoderConfig();
std::string ToString() const;
// TODO(bugs.webrtc.org/6883): Consolidate on one of these.
VideoCodecType codec_type;
SdpVideoFormat video_format;
// Note: This factory can be unset, and VideoStreamEncoder will
// then use the EncoderStreamFactory. The factory is only set by
// tests.
rtc::scoped_refptr<VideoStreamFactoryInterface> video_stream_factory;
std::vector<SpatialLayer> spatial_layers;
ContentType content_type;
bool frame_drop_enabled;
rtc::scoped_refptr<const EncoderSpecificSettings> encoder_specific_settings;
// Padding will be used up to this bitrate regardless of the bitrate produced
// by the encoder. Padding above what's actually produced by the encoder helps
// maintaining a higher bitrate estimate. Padding will however not be sent
// unless the estimated bandwidth indicates that the link can handle it.
int min_transmit_bitrate_bps;
int max_bitrate_bps;
// The bitrate priority used for all VideoStreams.
double bitrate_priority;
// The simulcast layer's configurations set by the application for this video
// sender. These are modified by the video_stream_factory before being passed
// down to lower layers for the video encoding.
// `simulcast_layers` is also used for configuring non-simulcast (when there
// is a single VideoStream).
// We have the same number of `simulcast_layers` as we have negotiated
// encodings, for example 3 are used in both simulcast and legacy kSVC.
std::vector<VideoStream> simulcast_layers;
// Max number of encoded VideoStreams to produce.
// This is the same as the number of encodings negotiated (i.e. SSRCs),
// whether or not those encodings are `active`, except for when legacy kSVC
// is used. In this case we have three SSRCs but `number_of_streams` is
// changed to 1 to tell lower layers to limit the number of streams.
size_t number_of_streams;
// Legacy Google conference mode flag for simulcast screenshare
bool legacy_conference_mode;
// Indicates whether quality scaling can be used or not.
bool is_quality_scaling_allowed;
// Maximum Quantization Parameter.
// This value is fed into EncoderStreamFactory that
// apply it to all simulcast layers/spatial layers.
int max_qp;
private:
// Access to the copy constructor is private to force use of the Copy()
// method for those exceptional cases where we do use it.
VideoEncoderConfig(const VideoEncoderConfig&);
};
} // namespace webrtc
#endif // VIDEO_CONFIG_VIDEO_ENCODER_CONFIG_H_
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