openvidu-server+clients: add new forcedVideoCodecResolved session property

Fill a new SessionProperties member "forcedVideoCodecResolved" to
contain the resolved value of "forcedVideoCodec", once the new
MEDIA_SERVER_PREFERRED has been taken into account and translated into
the appropriate option for each media server.

The logic to decide how to translate MEDIA_SERVER_PREFERRED into a
concrete forcedVideoCodec value is placed once in the REST entry point
of session creation (SessionRestController.java). Afterwards,
SessionProperties is just used as a simple storage for all session
features, and serialized / passed around between server and client.

openvidu-java-client/src/main/java/io/openvidu/java/client/Session.java

@@ -662,16 +662,17 @@ public class Session {
 				this.sessionId = responseJson.get("id").getAsString();
 				this.createdAt = responseJson.get("createdAt").getAsLong();
 
-				// forcedVideoCodec and allowTranscoding values are configured in OpenVidu
+				// Values that get filled by OpenVidu Server from its global or per-session configuration
-				// Server via configuration or session
 				VideoCodec forcedVideoCodec = VideoCodec.valueOf(responseJson.get("forcedVideoCodec").getAsString());
+				VideoCodec forcedVideoCodecResolved = VideoCodec
+						.valueOf(responseJson.get("forcedVideoCodecResolved").getAsString());
 				Boolean allowTranscoding = responseJson.get("allowTranscoding").getAsBoolean();
 
-				SessionProperties responseProperties = new SessionProperties.Builder()
+				SessionProperties responseProperties = new SessionProperties.Builder().mediaMode(properties.mediaMode())
-						.customSessionId(properties.customSessionId()).mediaMode(properties.mediaMode())
 						.recordingMode(properties.recordingMode())
 						.defaultRecordingProperties(properties.defaultRecordingProperties())
-						.mediaNode(properties.mediaNode()).forcedVideoCodec(forcedVideoCodec)
+						.customSessionId(properties.customSessionId()).mediaNode(properties.mediaNode())
+						.forcedVideoCodec(forcedVideoCodec).forcedVideoCodecResolved(forcedVideoCodecResolved)
 						.allowTranscoding(allowTranscoding).build();
 
 				this.properties = responseProperties;
@@ -719,6 +720,9 @@ public class Session {
 		if (json.has("forcedVideoCodec")) {
 			builder.forcedVideoCodec(VideoCodec.valueOf(json.get("forcedVideoCodec").getAsString()));
 		}
+		if (json.has("forcedVideoCodecResolved")) {
+			builder.forcedVideoCodecResolved(VideoCodec.valueOf(json.get("forcedVideoCodecResolved").getAsString()));
+		}
 		if (json.has("allowTranscoding")) {
 			builder.allowTranscoding(json.get("allowTranscoding").getAsBoolean());
 		}

openvidu-java-client/src/main/java/io/openvidu/java/client/SessionProperties.java

@@ -30,6 +30,7 @@ public class SessionProperties {
 	private String customSessionId;
 	private String mediaNode;
 	private VideoCodec forcedVideoCodec;
+	private VideoCodec forcedVideoCodecResolved;
 	private Boolean allowTranscoding;
 
 	/**
@@ -43,6 +44,7 @@ public class SessionProperties {
 		private String customSessionId = "";
 		private String mediaNode;
 		private VideoCodec forcedVideoCodec = VideoCodec.MEDIA_SERVER_PREFERRED;
+		private VideoCodec forcedVideoCodecResolved = VideoCodec.NONE;
 		private Boolean allowTranscoding = false;
 
 		/**
@@ -51,7 +53,8 @@ public class SessionProperties {
 		 */
 		public SessionProperties build() {
 			return new SessionProperties(this.mediaMode, this.recordingMode, this.defaultRecordingProperties,
-					this.customSessionId, this.mediaNode, this.forcedVideoCodec, this.allowTranscoding);
+					this.customSessionId, this.mediaNode, this.forcedVideoCodec, this.forcedVideoCodecResolved,
+					this.allowTranscoding);
 		}
 
 		/**
@@ -126,14 +129,25 @@ public class SessionProperties {
 		 * If defined here, this parameter has prevalence over
 		 * OPENVIDU_STREAMS_FORCED_VIDEO_CODEC.
 		 *
-		 * Default is {@link VideoCodec#VP8} for Kurento, and
+		 * Default is {@link VideoCodec#MEDIA_SERVER_PREFERRED}.
-		 * {@link VideoCodec#NONE} for mediasoup.
 		 */
 		public SessionProperties.Builder forcedVideoCodec(VideoCodec forcedVideoCodec) {
 			this.forcedVideoCodec = forcedVideoCodec;
 			return this;
 		}
 
+		/**
+		 * Actual video codec that will be forcibly used for this session.
+		 * This is the same as <code>forcedVideoCodec</code>, except when its
+		 * value is {@link VideoCodec#MEDIA_SERVER_PREFERRED}: in that case,
+		 * OpenVidu Server will fill this property with a resolved value,
+		 * depending on what is the configured media server.
+		 */
+		public SessionProperties.Builder forcedVideoCodecResolved(VideoCodec forcedVideoCodec) {
+			this.forcedVideoCodecResolved = forcedVideoCodec;
+			return this;
+		}
+
 		/**
 		 * Call this method to define if you want to allow transcoding in the media
 		 * server or not when {@link #forcedVideoCodec(VideoCodec)} is not compatible
@@ -159,13 +173,14 @@ public class SessionProperties {
 
 	private SessionProperties(MediaMode mediaMode, RecordingMode recordingMode,
 			RecordingProperties defaultRecordingProperties, String customSessionId, String mediaNode,
-			VideoCodec forcedVideoCodec, Boolean allowTranscoding) {
+			VideoCodec forcedVideoCodec, VideoCodec forcedVideoCodecResolved, Boolean allowTranscoding) {
 		this.mediaMode = mediaMode;
 		this.recordingMode = recordingMode;
 		this.defaultRecordingProperties = defaultRecordingProperties;
 		this.customSessionId = customSessionId;
 		this.mediaNode = mediaNode;
 		this.forcedVideoCodec = forcedVideoCodec;
+		this.forcedVideoCodecResolved = forcedVideoCodecResolved;
 		this.allowTranscoding = allowTranscoding;
 	}
 
@@ -222,12 +237,24 @@ public class SessionProperties {
 	}
 
 	/**
-	 * Defines which video codec is being forced to be used in the browser/client
+	 * Defines which video codec is being forced to be used in the browser/client.
+	 * This is the raw value that was configured. It might get resolved into a
+	 * different one for actual usage in the server.
 	 */
 	public VideoCodec forcedVideoCodec() {
 		return this.forcedVideoCodec;
 	}
 
+	/**
+	 * Defines which video codec is being forced to be used in the browser/client.
+	 * This is the resolved value, for actual usage in the server.
+	 *
+	 * @hidden
+	 */
+	public VideoCodec forcedVideoCodecResolved() {
+		return this.forcedVideoCodecResolved;
+	}
+
 	/**
 	 * Defines if transcoding is allowed or not when {@link #forcedVideoCodec} is
 	 * not a compatible codec with the browser/client.
@@ -238,20 +265,23 @@ public class SessionProperties {
 
 	public JsonObject toJson() {
 		JsonObject json = new JsonObject();
-		json.addProperty("mediaMode", mediaMode().name());
+		json.addProperty("mediaMode", this.mediaMode.name());
-		json.addProperty("recordingMode", recordingMode().name());
+		json.addProperty("recordingMode", this.recordingMode.name());
-		json.addProperty("customSessionId", customSessionId());
+		json.add("defaultRecordingProperties", this.defaultRecordingProperties.toJson());
-		json.add("defaultRecordingProperties", defaultRecordingProperties.toJson());
+		json.addProperty("customSessionId", this.customSessionId);
-		if (mediaNode() != null && !mediaNode().isEmpty()) {
+		if (this.mediaNode != null && !this.mediaNode.isEmpty()) {
 			JsonObject mediaNodeJson = new JsonObject();
-			mediaNodeJson.addProperty("id", mediaNode());
+			mediaNodeJson.addProperty("id", this.mediaNode);
 			json.add("mediaNode", mediaNodeJson);
 		}
-		if (forcedVideoCodec() != null) {
+		if (this.forcedVideoCodec != null) {
-			json.addProperty("forcedVideoCodec", forcedVideoCodec().name());
+			json.addProperty("forcedVideoCodec", this.forcedVideoCodec.name());
 		}
-		if (isTranscodingAllowed() != null) {
+		if (this.forcedVideoCodecResolved != null) {
-			json.addProperty("allowTranscoding", isTranscodingAllowed());
+			json.addProperty("forcedVideoCodecResolved", this.forcedVideoCodecResolved.name());
+		}
+		if (this.allowTranscoding != null) {
+			json.addProperty("allowTranscoding", this.allowTranscoding);
 		}
 		return json;
 	}

openvidu-node-client/src/Session.ts

@@ -490,6 +490,7 @@ export class Session {
                         this.properties.defaultRecordingProperties = res.data.defaultRecordingProperties;
                         this.properties.mediaNode = res.data.mediaNode;
                         this.properties.forcedVideoCodec = res.data.forcedVideoCodec;
+                        this.properties.forcedVideoCodecResolved = res.data.forcedVideoCodecResolved;
                         this.properties.allowTranscoding = res.data.allowTranscoding;
                         this.sanitizeDefaultSessionProperties(this.properties);
                         resolve(this.sessionId);
@@ -533,6 +534,7 @@ export class Session {
             recordingMode: json.recordingMode,
             defaultRecordingProperties: json.defaultRecordingProperties,
             forcedVideoCodec: json.forcedVideoCodec,
+            forcedVideoCodecResolved: json.forcedVideoCodecResolved,
             allowTranscoding: json.allowTranscoding
         };
         this.sanitizeDefaultSessionProperties(this.properties);
@@ -548,6 +550,9 @@ export class Session {
         if (json.forcedVideoCodec == null) {
             delete this.properties.forcedVideoCodec;
         }
+        if (json.forcedVideoCodecResolved == null) {
+            delete this.properties.forcedVideoCodecResolved;
+        }
         if (json.allowTranscoding == null) {
             delete this.properties.allowTranscoding;
         }
@@ -655,9 +660,12 @@ export class Session {
         props.mediaMode = (props.mediaMode != null) ? props.mediaMode : MediaMode.ROUTED;
         props.recordingMode = (props.recordingMode != null) ? props.recordingMode : RecordingMode.MANUAL;
         props.customSessionId = (props.customSessionId != null) ? props.customSessionId : '';
-        props.mediaNode = (props.mediaNode != null) ? props.mediaNode : undefined;
+
-        props.forcedVideoCodec = props.forcedVideoCodec;
+        // Remove null values: either set, or undefined
-        props.allowTranscoding = props.allowTranscoding;
+        props.mediaNode = props.mediaNode ?? undefined;
+        props.forcedVideoCodec = props.forcedVideoCodec ?? undefined;
+        props.forcedVideoCodecResolved = props.forcedVideoCodecResolved ?? undefined;
+        props.allowTranscoding = props.allowTranscoding ?? undefined;
 
         if (!props.defaultRecordingProperties) {
             props.defaultRecordingProperties = {};

openvidu-node-client/src/SessionProperties.ts

@@ -78,11 +78,21 @@ export interface SessionProperties {
      * If defined here, this parameter has prevalence over
      * OPENVIDU_STREAMS_FORCED_VIDEO_CODEC.
      *
-     * Default is [[VideoCodec.VP8]] for Kurento, and
+     * Default is [[VideoCodec.MEDIA_SERVER_PREFERRED]].
-     * [[VideoCodec.NONE]] for mediasoup.
      */
     forcedVideoCodec?: VideoCodec;
 
+    /**
+     * Actual video codec that will be forcibly used for this session.
+     * This is the same as <code>forcedVideoCodec</code>, except when its value
+     * is [[VideoCodec.MEDIA_SERVER_PREFERRED]]: in that case, OpenVidu Server
+     * will fill this property with a resolved value, depending on what is the
+     * configured media server.
+     *
+     * @hidden
+     */
+     forcedVideoCodecResolved?: VideoCodec;
+
     /**
      * It defines if you want to allow transcoding in the media server or not
      * when [[forcedVideoCodec]] is not compatible with the browser/client.

openvidu-server/src/main/java/io/openvidu/server/kurento/core/KurentoSessionManager.java

@@ -380,7 +380,7 @@ public class KurentoSessionManager extends SessionManager {
 		KurentoParticipant kParticipant = (KurentoParticipant) participant;
 		KurentoSession kSession = kParticipant.getSession();
 		boolean isTranscodingAllowed = kSession.getSessionProperties().isTranscodingAllowed();
-		VideoCodec forcedVideoCodec = kSession.getSessionProperties().forcedVideoCodec();
+		VideoCodec forcedVideoCodec = kSession.getSessionProperties().forcedVideoCodecResolved();
 
 		final String streamId = kParticipant.generateStreamId(kurentoOptions);
 
@@ -392,22 +392,6 @@ public class KurentoSessionManager extends SessionManager {
 			log.warn("AllowTranscoding has no effect if the Media Server is not Kurento");
 		}
 
-		// Set appropriate value for the ForcedVideoCodec feature.
-		if (forcedVideoCodec == VideoCodec.MEDIA_SERVER_PREFERRED) {
-			final MediaServer mediaServer = openviduConfig.getMediaServer();
-			switch (mediaServer) {
-				case mediasoup:
-					forcedVideoCodec = VideoCodec.NONE;
-					break;
-				case kurento:
-				default:
-					forcedVideoCodec = VideoCodec.VP8;
-					break;
-			}
-
-			log.info("Media Server: {}, selected ForcedVideoCodec value: {}", mediaServer, forcedVideoCodec);
-		}
-
 		// Modify sdp if forced codec is defined
 		if (forcedVideoCodec != VideoCodec.NONE && !participant.isIpcam()) {
 			kurentoOptions.sdpOffer = sdpMunging.forceCodec(kurentoOptions.sdpOffer, participant, true, false,
@@ -613,7 +597,7 @@ public class KurentoSessionManager extends SessionManager {
 				WebrtcDebugEventType.sdpOffer, sdpOffer));
 
 		boolean isTranscodingAllowed = session.getSessionProperties().isTranscodingAllowed();
-		VideoCodec forcedVideoCodec = session.getSessionProperties().forcedVideoCodec();
+		VideoCodec forcedVideoCodec = session.getSessionProperties().forcedVideoCodecResolved();
 
 		// Modify server's SDPOffer if forced codec is defined
 		if (forcedVideoCodec != VideoCodec.NONE && !participant.isIpcam()) {
@@ -679,7 +663,7 @@ public class KurentoSessionManager extends SessionManager {
 				// Client initiated negotiation. sdpString is the SDP Offer of the client
 
 				boolean isTranscodingAllowed = session.getSessionProperties().isTranscodingAllowed();
-				VideoCodec forcedVideoCodec = session.getSessionProperties().forcedVideoCodec();
+				VideoCodec forcedVideoCodec = session.getSessionProperties().forcedVideoCodecResolved();
 				String sdpOffer = sdpString;
 
 				// Modify sdp if forced codec is defined
@@ -1236,7 +1220,7 @@ public class KurentoSessionManager extends SessionManager {
 
 	private String mungeSdpOffer(Session kSession, Participant participant, String sdpOffer, boolean isPublisher) {
 		boolean isTranscodingAllowed = kSession.getSessionProperties().isTranscodingAllowed();
-		VideoCodec forcedVideoCodec = kSession.getSessionProperties().forcedVideoCodec();
+		VideoCodec forcedVideoCodec = kSession.getSessionProperties().forcedVideoCodecResolved();
 		// Modify sdp if forced codec is defined
 		if (forcedVideoCodec != VideoCodec.NONE && !participant.isIpcam()) {
 			return sdpMunging.forceCodec(sdpOffer, participant, isPublisher, true, isTranscodingAllowed,

openvidu-server/src/main/java/io/openvidu/server/rest/SessionRestController.java

@@ -726,20 +726,31 @@ public class SessionRestController {
 
 		if (params != null) {
 
+			// Obtain primitive values from the params map
 			String mediaModeString;
 			String recordingModeString;
-			String forcedVideoCodec;
+			String forcedVideoCodecStr;
 			Boolean allowTranscoding;
 			try {
 				mediaModeString = (String) params.get("mediaMode");
 				recordingModeString = (String) params.get("recordingMode");
 				customSessionId = (String) params.get("customSessionId");
-				forcedVideoCodec = (String) params.get("forcedVideoCodec");
+				forcedVideoCodecStr = (String) params.get("forcedVideoCodec");
 				allowTranscoding = (Boolean) params.get("allowTranscoding");
 			} catch (ClassCastException e) {
 				throw new Exception("Type error in some parameter: " + e.getMessage());
 			}
 
+			// Parse obtained values into actual types
+			VideoCodec forcedVideoCodec = null;
+			try {
+				forcedVideoCodec = VideoCodec.valueOf(forcedVideoCodecStr);
+			} catch (NullPointerException e) {
+				// Not an error: "forcedVideoCodec" was not provided in params.
+			} catch (IllegalArgumentException e) {
+				throw new Exception("Invalid value for parameter 'forcedVideoCodec': " + e.getMessage());
+			}
+
 			try {
 				// Safe parameter retrieval. Default values if not defined
 				if (recordingModeString != null) {
@@ -761,11 +772,25 @@ public class SessionRestController {
 					}
 					builder = builder.customSessionId(customSessionId);
 				}
-				if (forcedVideoCodec != null) {
+
-					builder = builder.forcedVideoCodec(VideoCodec.valueOf(forcedVideoCodec));
+				if (forcedVideoCodec == null) {
-				} else {
+					forcedVideoCodec = openviduConfig.getOpenviduForcedCodec();
-					builder = builder.forcedVideoCodec(openviduConfig.getOpenviduForcedCodec());
 				}
+				builder = builder.forcedVideoCodec(forcedVideoCodec);
+				if (forcedVideoCodec == VideoCodec.MEDIA_SERVER_PREFERRED) {
+					switch (openviduConfig.getMediaServer()) {
+					case mediasoup:
+						builder = builder.forcedVideoCodecResolved(VideoCodec.NONE);
+						break;
+					case kurento:
+					default:
+						builder = builder.forcedVideoCodecResolved(VideoCodec.VP8);
+						break;
+					}
+				} else {
+					builder = builder.forcedVideoCodecResolved(forcedVideoCodec);
+				}
+
 				if (allowTranscoding != null) {
 					builder = builder.allowTranscoding(allowTranscoding);
 				} else {

openvidu-server/src/main/java/io/openvidu/server/utils/SDPMunging.java

@@ -187,7 +187,7 @@ public class SDPMunging {
 				return mungedSdpOffer;
 			} else {
 				throw new OpenViduException(Code.FORCED_CODEC_NOT_FOUND_IN_SDPOFFER,
-						"Codec not supported by Media Server");
+						"Codec not supported by Media Server: " + forcedVideoCodec);
 			}
 
 		} catch (OpenViduException e) {