272 lines
9.2 KiB
C++
272 lines
9.2 KiB
C++
/*
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* Copyright (c) 2004 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 MEDIA_BASE_CODEC_H_
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#define MEDIA_BASE_CODEC_H_
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#include <cstddef>
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#include <optional>
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#include <string>
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#include <vector>
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#include "absl/container/inlined_vector.h"
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#include "absl/strings/str_format.h"
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#include "absl/strings/string_view.h"
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#include "api/audio_codecs/audio_format.h"
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#include "api/rtp_parameters.h"
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#include "api/video_codecs/scalability_mode.h"
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#include "api/video_codecs/sdp_video_format.h"
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#include "media/base/media_constants.h"
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#include "rtc_base/system/rtc_export.h"
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namespace cricket {
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class FeedbackParam {
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public:
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FeedbackParam() = default;
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FeedbackParam(absl::string_view id, const std::string& param)
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: id_(id), param_(param) {}
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explicit FeedbackParam(absl::string_view id)
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: id_(id), param_(kParamValueEmpty) {}
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bool operator==(const FeedbackParam& other) const;
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bool operator!=(const FeedbackParam& c) const { return !(*this == c); }
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const std::string& id() const { return id_; }
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const std::string& param() const { return param_; }
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private:
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std::string id_; // e.g. "nack", "ccm"
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std::string param_; // e.g. "", "rpsi", "fir"
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};
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class FeedbackParams {
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public:
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FeedbackParams();
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~FeedbackParams();
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bool operator==(const FeedbackParams& other) const;
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bool operator!=(const FeedbackParams& c) const { return !(*this == c); }
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bool Has(const FeedbackParam& param) const;
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void Add(const FeedbackParam& param);
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bool Remove(const FeedbackParam& param);
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void Intersect(const FeedbackParams& from);
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const std::vector<FeedbackParam>& params() const { return params_; }
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private:
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bool HasDuplicateEntries() const;
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std::vector<FeedbackParam> params_;
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};
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struct RTC_EXPORT Codec {
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enum class Type {
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kAudio,
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kVideo,
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};
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enum class ResiliencyType {
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kNone,
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kRed,
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kUlpfec,
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kFlexfec,
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kRtx,
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};
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// Value of "id" if it's not explicitly set. Exposed for tests.
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static const int kIdNotSet = -1;
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Type type;
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int id;
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std::string name;
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int clockrate;
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// Audio only
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// Can be used to override the target bitrate in the encoder.
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// TODO(orphis): Remove in favor of alternative APIs
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int bitrate;
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size_t channels;
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// Video only
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std::optional<std::string> packetization;
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absl::InlinedVector<webrtc::ScalabilityMode, webrtc::kScalabilityModeCount>
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scalability_modes;
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// H.265 only
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std::optional<std::string> tx_mode;
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// Non key-value parameters such as the telephone-event "0‐15" are
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// represented using an empty string as key, i.e. {"": "0-15"}.
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// The equivalent of fmtp in SDP.
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webrtc::CodecParameterMap params;
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// The equivalent of rtcp-fb in SDP.
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FeedbackParams feedback_params;
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Codec(const Codec& c);
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Codec(Codec&& c);
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virtual ~Codec();
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// Indicates if this codec is compatible with the specified codec by
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// checking the assigned id and profile values for the relevant video codecs.
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// The rules for this comparison, in particular the parameters are
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// codec-specific as described in RFC 3264 6.1:
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// https://www.rfc-editor.org/rfc/rfc3264#section-6.1
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// For H.264, packetization modes will be compared.
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// If H.265 is enabled, TxModes will be compared.
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// H.264 (and H.265, if enabled) levels are not compared.
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// In all other cases, parameters do not need to match.
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// This is used in SDP offer/answer codec matching.
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bool Matches(const Codec& codec) const;
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// This is an exact match similar to what is described in
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// https://w3c.github.io/webrtc-pc/#dfn-codec-match
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// with two differences:
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// - rtx which is included in capabilities without the apt parameter
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// so number of channels, clock rate or the equality of the parameters
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// are not compared.
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// - parameters is compared element-wise, not as a string comparison.
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// This method should only be used to compare input on our end to something we
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// generated, done e.g. by setCodecPreferences or setParameters.
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bool MatchesRtpCodec(const webrtc::RtpCodec& capability) const;
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// Find the parameter for `name` and write the value to `out`.
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bool GetParam(const std::string& name, std::string* out) const;
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bool GetParam(const std::string& name, int* out) const;
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void SetParam(const std::string& name, const std::string& value);
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void SetParam(const std::string& name, int value);
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// It is safe to input a non-existent parameter.
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// Returns true if the parameter existed, false if it did not exist.
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bool RemoveParam(const std::string& name);
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bool HasFeedbackParam(const FeedbackParam& param) const;
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void AddFeedbackParam(const FeedbackParam& param);
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// Filter `this` feedbacks params such that only those shared by both `this`
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// and `other` are kept.
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void IntersectFeedbackParams(const Codec& other);
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virtual webrtc::RtpCodecParameters ToCodecParameters() const;
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// The codec represent an actual media codec, and not a resiliency codec.
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bool IsMediaCodec() const;
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// The codec represent a resiliency codec such as RED, RTX or FEC variants.
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bool IsResiliencyCodec() const;
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ResiliencyType GetResiliencyType() const;
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// Validates a VideoCodec's payload type, dimensions and bitrates etc. If they
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// don't make sense (such as max < min bitrate), and error is logged and
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// ValidateCodecFormat returns false.
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bool ValidateCodecFormat() const;
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std::string ToString() const;
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Codec& operator=(const Codec& c);
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Codec& operator=(Codec&& c);
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bool operator==(const Codec& c) const;
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bool operator!=(const Codec& c) const { return !(*this == c); }
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template <typename Sink>
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friend void AbslStringify(Sink& sink, const Codec& c) {
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absl::Format(&sink, "[%d:", c.id);
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switch (c.type) {
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case Codec::Type::kAudio:
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sink.Append("audio/");
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break;
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case Codec::Type::kVideo:
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sink.Append("video/");
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}
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absl::Format(&sink, "%s/%d/%d", c.name, c.clockrate, c.channels);
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for (auto param : c.params) {
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sink.Append(";");
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sink.Append(param.first);
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sink.Append("=");
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sink.Append(param.second);
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}
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sink.Append("]");
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}
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protected:
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// Creates an empty codec.
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explicit Codec(Type type);
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// Creates a codec with the given parameters.
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Codec(Type type, int id, const std::string& name, int clockrate);
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Codec(Type type,
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int id,
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const std::string& name,
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int clockrate,
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size_t channels);
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explicit Codec(const webrtc::SdpAudioFormat& c);
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explicit Codec(const webrtc::SdpVideoFormat& c);
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friend Codec CreateAudioCodec(int id,
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const std::string& name,
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int clockrate,
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size_t channels);
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friend Codec CreateAudioCodec(const webrtc::SdpAudioFormat& c);
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friend Codec CreateAudioRtxCodec(int rtx_payload_type,
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int associated_payload_type);
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friend Codec CreateVideoCodec(int id, const std::string& name);
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friend Codec CreateVideoCodec(const webrtc::SdpVideoFormat& c);
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friend Codec CreateVideoRtxCodec(int rtx_payload_type,
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int associated_payload_type);
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};
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// TODO(webrtc:15214): Compatibility names, to be migrated away and removed.
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using VideoCodec [[deprecated]] = Codec;
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using AudioCodec [[deprecated]] = Codec;
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using VideoCodecs [[deprecated]] = std::vector<Codec>;
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using AudioCodecs [[deprecated]] = std::vector<Codec>;
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using Codecs = std::vector<Codec>;
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Codec CreateAudioCodec(int id,
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const std::string& name,
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int clockrate,
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size_t channels);
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Codec CreateAudioCodec(const webrtc::SdpAudioFormat& c);
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Codec CreateAudioRtxCodec(int rtx_payload_type, int associated_payload_type);
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Codec CreateVideoCodec(const std::string& name);
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Codec CreateVideoCodec(int id, const std::string& name);
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Codec CreateVideoCodec(const webrtc::SdpVideoFormat& c);
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Codec CreateVideoCodec(int id, const webrtc::SdpVideoFormat& c);
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Codec CreateVideoRtxCodec(int rtx_payload_type, int associated_payload_type);
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// Get the codec setting associated with `payload_type`. If there
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// is no codec associated with that payload type it returns nullptr.
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const Codec* FindCodecById(const std::vector<Codec>& codecs, int payload_type);
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bool HasLntf(const Codec& codec);
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bool HasNack(const Codec& codec);
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bool HasRemb(const Codec& codec);
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bool HasRrtr(const Codec& codec);
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// Returns the first codec in `supported_codecs` that matches `codec`, or
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// nullptr if no codec matches.
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const Codec* FindMatchingVideoCodec(const std::vector<Codec>& supported_codecs,
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const Codec& codec);
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// Returns all codecs in `supported_codecs` that matches `codec`.
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std::vector<const Codec*> FindAllMatchingCodecs(
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const std::vector<Codec>& supported_codecs,
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const Codec& codec);
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RTC_EXPORT void AddH264ConstrainedBaselineProfileToSupportedFormats(
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std::vector<webrtc::SdpVideoFormat>* supported_formats);
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} // namespace cricket
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#endif // MEDIA_BASE_CODEC_H_
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