1 /* 2 * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef API_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_ 12 #define API_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_ 13 14 #include <memory> 15 #include <vector> 16 17 #include "absl/types/optional.h" 18 #include "api/audio_codecs/audio_codec_pair_id.h" 19 #include "api/audio_codecs/audio_encoder.h" 20 #include "api/audio_codecs/audio_format.h" 21 #include "rtc_base/ref_count.h" 22 23 namespace webrtc { 24 25 // A factory that creates AudioEncoders. 26 class AudioEncoderFactory : public rtc::RefCountInterface { 27 public: 28 // Returns a prioritized list of audio codecs, to use for signaling etc. 29 virtual std::vector<AudioCodecSpec> GetSupportedEncoders() = 0; 30 31 // Returns information about how this format would be encoded, provided it's 32 // supported. More format and format variations may be supported than those 33 // returned by GetSupportedEncoders(). 34 virtual absl::optional<AudioCodecInfo> QueryAudioEncoder( 35 const SdpAudioFormat& format) = 0; 36 37 // Creates an AudioEncoder for the specified format. The encoder will tags its 38 // payloads with the specified payload type. The `codec_pair_id` argument is 39 // used to link encoders and decoders that talk to the same remote entity: if 40 // a AudioEncoderFactory::MakeAudioEncoder() and a 41 // AudioDecoderFactory::MakeAudioDecoder() call receive non-null IDs that 42 // compare equal, the factory implementations may assume that the encoder and 43 // decoder form a pair. (The intended use case for this is to set up 44 // communication between the AudioEncoder and AudioDecoder instances, which is 45 // needed for some codecs with built-in bandwidth adaptation.) 46 // 47 // Note: Implementations need to be robust against combinations other than 48 // one encoder, one decoder getting the same ID; such encoders must still 49 // work. 50 // 51 // TODO(ossu): Try to avoid audio encoders having to know their payload type. 52 virtual std::unique_ptr<AudioEncoder> MakeAudioEncoder( 53 int payload_type, 54 const SdpAudioFormat& format, 55 absl::optional<AudioCodecPairId> codec_pair_id) = 0; 56 }; 57 58 } // namespace webrtc 59 60 #endif // API_AUDIO_CODECS_AUDIO_ENCODER_FACTORY_H_ 61