134 lines
4.7 KiB
C++
134 lines
4.7 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef API_AUDIO_CODECS_AUDIO_FORMAT_H_
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#define API_AUDIO_CODECS_AUDIO_FORMAT_H_
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#include <stddef.h>
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#include <map>
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#include <string>
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#include "absl/strings/string_view.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/system/rtc_export.h"
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namespace webrtc {
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// SDP specification for a single audio codec.
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struct RTC_EXPORT SdpAudioFormat {
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using Parameters = std::map<std::string, std::string>;
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SdpAudioFormat(const SdpAudioFormat&);
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SdpAudioFormat(SdpAudioFormat&&);
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SdpAudioFormat(absl::string_view name, int clockrate_hz, size_t num_channels);
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SdpAudioFormat(absl::string_view name,
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int clockrate_hz,
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size_t num_channels,
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const Parameters& param);
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SdpAudioFormat(absl::string_view name,
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int clockrate_hz,
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size_t num_channels,
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Parameters&& param);
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~SdpAudioFormat();
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// Returns true if this format is compatible with |o|. In SDP terminology:
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// would it represent the same codec between an offer and an answer? As
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// opposed to operator==, this method disregards codec parameters.
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bool Matches(const SdpAudioFormat& o) const;
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SdpAudioFormat& operator=(const SdpAudioFormat&);
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SdpAudioFormat& operator=(SdpAudioFormat&&);
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friend bool operator==(const SdpAudioFormat& a, const SdpAudioFormat& b);
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friend bool operator!=(const SdpAudioFormat& a, const SdpAudioFormat& b) {
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return !(a == b);
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}
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std::string name;
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int clockrate_hz;
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size_t num_channels;
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Parameters parameters;
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};
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// Information about how an audio format is treated by the codec implementation.
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// Contains basic information, such as sample rate and number of channels, which
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// isn't uniformly presented by SDP. Also contains flags indicating support for
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// integrating with other parts of WebRTC, like external VAD and comfort noise
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// level calculation.
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//
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// To avoid API breakage, and make the code clearer, AudioCodecInfo should not
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// be directly initializable with any flags indicating optional support. If it
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// were, these initializers would break any time a new flag was added. It's also
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// more difficult to understand:
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// AudioCodecInfo info{16000, 1, 32000, true, false, false, true, true};
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// than
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// AudioCodecInfo info(16000, 1, 32000);
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// info.allow_comfort_noise = true;
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// info.future_flag_b = true;
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// info.future_flag_c = true;
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struct AudioCodecInfo {
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AudioCodecInfo(int sample_rate_hz, size_t num_channels, int bitrate_bps);
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AudioCodecInfo(int sample_rate_hz,
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size_t num_channels,
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int default_bitrate_bps,
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int min_bitrate_bps,
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int max_bitrate_bps);
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AudioCodecInfo(const AudioCodecInfo& b) = default;
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~AudioCodecInfo() = default;
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bool operator==(const AudioCodecInfo& b) const {
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return sample_rate_hz == b.sample_rate_hz &&
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num_channels == b.num_channels &&
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default_bitrate_bps == b.default_bitrate_bps &&
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min_bitrate_bps == b.min_bitrate_bps &&
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max_bitrate_bps == b.max_bitrate_bps &&
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allow_comfort_noise == b.allow_comfort_noise &&
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supports_network_adaption == b.supports_network_adaption;
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}
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bool operator!=(const AudioCodecInfo& b) const { return !(*this == b); }
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bool HasFixedBitrate() const {
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RTC_DCHECK_GE(min_bitrate_bps, 0);
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RTC_DCHECK_LE(min_bitrate_bps, default_bitrate_bps);
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RTC_DCHECK_GE(max_bitrate_bps, default_bitrate_bps);
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return min_bitrate_bps == max_bitrate_bps;
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}
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int sample_rate_hz;
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size_t num_channels;
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int default_bitrate_bps;
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int min_bitrate_bps;
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int max_bitrate_bps;
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bool allow_comfort_noise = true; // This codec can be used with an external
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// comfort noise generator.
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bool supports_network_adaption = false; // This codec can adapt to varying
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// network conditions.
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};
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// AudioCodecSpec ties an audio format to specific information about the codec
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// and its implementation.
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struct AudioCodecSpec {
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bool operator==(const AudioCodecSpec& b) const {
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return format == b.format && info == b.info;
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}
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bool operator!=(const AudioCodecSpec& b) const { return !(*this == b); }
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SdpAudioFormat format;
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AudioCodecInfo info;
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};
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} // namespace webrtc
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#endif // API_AUDIO_CODECS_AUDIO_FORMAT_H_
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