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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_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_
#define API_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_
#include <memory>
#include <vector>
#include "absl/types/optional.h"
#include "api/audio_codecs/audio_codec_pair_id.h"
#include "api/audio_codecs/audio_encoder.h"
#include "api/audio_codecs/audio_format.h"
#include "rtc_base/ref_count.h"
namespace webrtc {
// A factory that creates AudioEncoders.
class AudioEncoderFactory : public rtc::RefCountInterface {
public:
// Returns a prioritized list of audio codecs, to use for signaling etc.
virtual std::vector<AudioCodecSpec> GetSupportedEncoders() = 0;
// Returns information about how this format would be encoded, provided it's
// supported. More format and format variations may be supported than those
// returned by GetSupportedEncoders().
virtual absl::optional<AudioCodecInfo> QueryAudioEncoder(
const SdpAudioFormat& format) = 0;
// Creates an AudioEncoder for the specified format. The encoder will tags its
// payloads with the specified payload type. The `codec_pair_id` argument is
// used to link encoders and decoders that talk to the same remote entity: if
// a AudioEncoderFactory::MakeAudioEncoder() and a
// AudioDecoderFactory::MakeAudioDecoder() call receive non-null IDs that
// compare equal, the factory implementations may assume that the encoder and
// decoder form a pair. (The intended use case for this is to set up
// communication between the AudioEncoder and AudioDecoder instances, which is
// needed for some codecs with built-in bandwidth adaptation.)
//
// Returns null if the format isn't supported.
//
// Note: Implementations need to be robust against combinations other than
// one encoder, one decoder getting the same ID; such encoders must still
// work.
//
// TODO(ossu): Try to avoid audio encoders having to know their payload type.
virtual std::unique_ptr<AudioEncoder> MakeAudioEncoder(
int payload_type,
const SdpAudioFormat& format,
absl::optional<AudioCodecPairId> codec_pair_id) = 0;
};
} // namespace webrtc
#endif // API_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_
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