Add rid and allow subscribe a stream constrained by rid. (open-webrtc-toolkit#205)

Author: jianjunz

talk/owt/sdk/base/objc/OWTMediaFormat.mm

@@ -109,7 +109,7 @@ - (OWTAudioCodecParameters*)codec {
 }
 @end
 @implementation OWTVideoPublicationSettings
-@dynamic codec, resolution, frameRate, bitrate, keyframeInterval;
+@dynamic codec, resolution, frameRate, bitrate, keyframeInterval, rid;
 - (instancetype)initWithNativeVideoPublicationSettings:
     (const owt::base::VideoPublicationSettings &)nativeSettings {
   if (self = [super init]) {
@@ -134,7 +134,11 @@ -(NSUInteger)bitrate{
 -(NSUInteger)keyframeInterval{
   return _nativeSettings.keyframe_interval;
 }
+- (NSString*)rid {
+  return [NSString stringForStdString:_nativeSettings.rid];
+}
 @end
+
 @implementation OWTAudioSubscriptionCapabilities
 @dynamic codecs;
 - (instancetype)initWithNativeAudioSubscriptionCapabilities:

talk/owt/sdk/conference/objc/OWTConferenceSubscription.mm

@@ -180,6 +180,7 @@ @implementation OWTConferenceVideoSubscriptionConstraints
   constrains->frameRate = _frameRate;
   constrains->bitrateMultiplier = _bitrateMultiplier;
   constrains->keyFrameInterval = _keyFrameInterval;
+  constrains->rid = [NSString stdStringForString:_rid];
   return constrains;
 }
 @end

talk/owt/sdk/include/objc/OWT/OWTConferenceSubscription.h

@@ -54,6 +54,7 @@ RTC_OBJC_EXPORT
 @property(nonatomic, assign) BOOL disabled;
 @property(nonatomic, strong) NSArray<OWTAudioCodecParameters*>* codecs;
 @end
+
 RTC_OBJC_EXPORT
 /// Constraints for subscribing a remote stream.
 @interface OWTConferenceVideoSubscriptionConstraints : NSObject
@@ -63,7 +64,10 @@ RTC_OBJC_EXPORT
 @property(nonatomic, assign) double bitrateMultiplier;
 @property(nonatomic, assign) NSUInteger keyFrameInterval;
 @property(nonatomic, strong) NSArray<OWTVideoCodecParameters*>* codecs;
+/// Restriction identifier to identify the RTP Streams within an RTP session. When rid is specified, other constraints will be ignored.
+@property(nonatomic, strong) NSString* rid;
 @end
+
 RTC_OBJC_EXPORT
 @interface OWTConferenceSubscribeOptions : NSObject
 - (instancetype)initWithAudio:(OWTConferenceAudioSubscriptionConstraints*)audio

talk/owt/sdk/include/objc/OWT/OWTMediaFormat.h

@@ -84,6 +84,7 @@ RTC_OBJC_EXPORT
 @property(nonatomic, assign) CGFloat frameRate;
 @property(nonatomic, assign) NSUInteger bitrate;
 @property(nonatomic, assign) NSUInteger keyframeInterval;
+@property(nonatomic, strong) NSString* rid;
 @end
 /// The settings of a publication.
 RTC_OBJC_EXPORT