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/*
* Copyright (c) 2017 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_VIDEO_CODECS_VIDEO_ENCODER_FACTORY_H_
#define API_VIDEO_CODECS_VIDEO_ENCODER_FACTORY_H_
#include <memory>
#include <string>
#include <vector>
#include "absl/types/optional.h"
#include "api/units/data_rate.h"
#include "api/video_codecs/sdp_video_format.h"
namespace webrtc {
class VideoEncoder;
// A factory that creates VideoEncoders.
// NOTE: This class is still under development and may change without notice.
class VideoEncoderFactory {
public:
// TODO(magjed): Try to get rid of this struct.
struct CodecInfo {
// |has_internal_source| is true if encoders created by this factory of the
// given codec will use internal camera sources, meaning that they don't
// require/expect frames to be delivered via webrtc::VideoEncoder::Encode.
// This flag is used as the internal_source parameter to
// webrtc::ViEExternalCodec::RegisterExternalSendCodec.
bool has_internal_source = false;
};
struct CodecSupport {
bool is_supported = false;
bool is_power_efficient = false;
};
// An injectable class that is continuously updated with encoding conditions
// and selects the best encoder given those conditions.
class EncoderSelectorInterface {
public:
virtual ~EncoderSelectorInterface() {}
// Informs the encoder selector about which encoder that is currently being
// used.
virtual void OnCurrentEncoder(const SdpVideoFormat& format) = 0;
// Called every time the available bitrate is updated. Should return a
// non-empty if an encoder switch should be performed.
virtual absl::optional<SdpVideoFormat> OnAvailableBitrate(
const DataRate& rate) = 0;
// Called if the currently used encoder reports itself as broken. Should
// return a non-empty if an encoder switch should be performed.
virtual absl::optional<SdpVideoFormat> OnEncoderBroken() = 0;
};
// Returns a list of supported video formats in order of preference, to use
// for signaling etc.
virtual std::vector<SdpVideoFormat> GetSupportedFormats() const = 0;
// Returns a list of supported video formats in order of preference, that can
// also be tagged with additional information to allow the VideoEncoderFactory
// to separate between different implementations when CreateVideoEncoder is
// called.
virtual std::vector<SdpVideoFormat> GetImplementations() const {
return GetSupportedFormats();
}
// Returns information about how this format will be encoded. The specified
// format must be one of the supported formats by this factory.
// TODO(magjed): Try to get rid of this method. Since is_hardware_accelerated
// is unused, only factories producing internal source encoders (in itself a
// deprecated feature) needs to override this method.
virtual CodecInfo QueryVideoEncoder(const SdpVideoFormat& format) const {
return CodecInfo();
}
// Query whether the specifed format is supported or not and if it will be
// power efficient, which is currently interpreted as if there is support for
// hardware acceleration.
// See https://w3c.github.io/webrtc-svc/#scalabilitymodes* for a specification
// of valid values for |scalability_mode|.
// NOTE: QueryCodecSupport is currently an experimental feature that is
// subject to change without notice.
virtual CodecSupport QueryCodecSupport(
const SdpVideoFormat& format,
absl::optional<std::string> scalability_mode) const {
// Default implementation, query for supported formats and check if the
// specified format is supported. Returns false if scalability_mode is
// specified.
CodecSupport codec_support;
if (!scalability_mode) {
codec_support.is_supported = format.IsCodecInList(GetSupportedFormats());
}
return codec_support;
}
// Creates a VideoEncoder for the specified format.
virtual std::unique_ptr<VideoEncoder> CreateVideoEncoder(
const SdpVideoFormat& format) = 0;
virtual std::unique_ptr<EncoderSelectorInterface> GetEncoderSelector() const {
return nullptr;
}
virtual ~VideoEncoderFactory() {}
};
} // namespace webrtc
#endif // API_VIDEO_CODECS_VIDEO_ENCODER_FACTORY_H_
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