webrtc/api/mediaconstraintsinterface.h

/*
 *  Copyright 2013 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.
 */

// This file contains the interface for MediaConstraints, corresponding to
// the definition at
// http://www.w3.org/TR/mediacapture-streams/#mediastreamconstraints and also
// used in WebRTC: http://dev.w3.org/2011/webrtc/editor/webrtc.html#constraints.

#ifndef WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_
#define WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_

#include <string>
#include <vector>

namespace webrtc {

// MediaConstraintsInterface
// Interface used for passing arguments about media constraints
// to the MediaStream and PeerConnection implementation.
class MediaConstraintsInterface {
 public:
  struct Constraint {
    Constraint() {}
    Constraint(const std::string& key, const std::string value)
        : key(key), value(value) {
    }
    std::string key;
    std::string value;
  };

  class Constraints : public std::vector<Constraint> {
   public:
    bool FindFirst(const std::string& key, std::string* value) const;
  };

  virtual const Constraints& GetMandatory() const = 0;
  virtual const Constraints& GetOptional() const = 0;

  // Constraint keys used by a local video source.
  // Specified by draft-alvestrand-constraints-resolution-00b
  static const char kMinAspectRatio[];  // minAspectRatio
  static const char kMaxAspectRatio[];  // maxAspectRatio
  static const char kMaxWidth[];  // maxWidth
  static const char kMinWidth[];  // minWidth
  static const char kMaxHeight[];  // maxHeight
  static const char kMinHeight[];  // minHeight
  static const char kMaxFrameRate[];  // maxFrameRate
  static const char kMinFrameRate[];  // minFrameRate

  // Constraint keys used by a local audio source.
  static const char kEchoCancellation[];  // echoCancellation

  // These keys are google specific.
  static const char kGoogEchoCancellation[];  // googEchoCancellation

  static const char kExtendedFilterEchoCancellation[];  // googEchoCancellation2
  static const char kDAEchoCancellation[];  // googDAEchoCancellation
  static const char kAutoGainControl[];  // googAutoGainControl
  static const char kExperimentalAutoGainControl[];  // googAutoGainControl2
  static const char kNoiseSuppression[];  // googNoiseSuppression
  static const char kExperimentalNoiseSuppression[];  // googNoiseSuppression2
  static const char kHighpassFilter[];  // googHighpassFilter
  static const char kTypingNoiseDetection[];  // googTypingNoiseDetection
  static const char kAudioMirroring[];  // googAudioMirroring

  // Google-specific constraint keys for a local video source
  static const char kNoiseReduction[];  // googNoiseReduction

  // Constraint keys for CreateOffer / CreateAnswer
  // Specified by the W3C PeerConnection spec
  static const char kOfferToReceiveVideo[];  // OfferToReceiveVideo
  static const char kOfferToReceiveAudio[];  // OfferToReceiveAudio
  static const char kVoiceActivityDetection[];  // VoiceActivityDetection
  static const char kIceRestart[];  // IceRestart
  // These keys are google specific.
  static const char kUseRtpMux[];  // googUseRtpMUX

  // Constraints values.
  static const char kValueTrue[];  // true
  static const char kValueFalse[];  // false

  // PeerConnection constraint keys.
  // Temporary pseudo-constraints used to enable DTLS-SRTP
  static const char kEnableDtlsSrtp[];  // Enable DTLS-SRTP
  // Temporary pseudo-constraints used to enable DataChannels
  static const char kEnableRtpDataChannels[];  // Enable RTP DataChannels
  // Google-specific constraint keys.
  // Temporary pseudo-constraint for enabling DSCP through JS.
  static const char kEnableDscp[];  // googDscp
  // Constraint to enable IPv6 through JS.
  static const char kEnableIPv6[];  // googIPv6
  // Temporary constraint to enable suspend below min bitrate feature.
  static const char kEnableVideoSuspendBelowMinBitrate[];
      // googSuspendBelowMinBitrate
  // Constraint to enable combined audio+video bandwidth estimation.
  static const char kCombinedAudioVideoBwe[];  // googCombinedAudioVideoBwe
  static const char kScreencastMinBitrate[];  // googScreencastMinBitrate
  static const char kCpuOveruseDetection[];  // googCpuOveruseDetection
  static const char kPayloadPadding[];  // googPayloadPadding

  // The prefix of internal-only constraints whose JS set values should be
  // stripped by Chrome before passed down to Libjingle.
  static const char kInternalConstraintPrefix[];

 protected:
  // Dtor protected as objects shouldn't be deleted via this interface
  virtual ~MediaConstraintsInterface() {}
};

bool FindConstraint(const MediaConstraintsInterface* constraints,
                    const std::string& key, bool* value,
                    size_t* mandatory_constraints);

}  // namespace webrtc

#endif  // WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_