Change precedence of ServiceDescription elements (#3923)

* Change precedence of ServiceDescription elements * Correct case for checking ServiceDescription applies to all clients
Dash-Industry-Forum · Apr 20, 2022 · 81e506f · 81e506f
1 parent 3d42188
commit 81e506f
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Showing 2 changed files with 47 additions and 18 deletions.
diff --git a/src/streaming/controllers/ServiceDescriptionController.js b/src/streaming/controllers/ServiceDescriptionController.js
@@ -98,27 +98,27 @@ function ServiceDescriptionController() {
             return;
         }
 
-        for (let i = 0; i < manifestInfo.serviceDescriptions.length; i++) {
-            const sd = manifestInfo.serviceDescriptions[i];
-
-            if (!sd.schemeIdUri || SUPPORTED_SCHEMES.includes(sd.schemeIdUri)) {
-
-                if (sd.latency && sd.latency.target > 0) {
-                    _applyServiceDescriptionLatency(sd);
-                }
+        const supportedServiceDescriptions = manifestInfo.serviceDescriptions.filter(sd => SUPPORTED_SCHEMES.includes(sd.schemeIdUri));
+        const allClientsServiceDescriptions = manifestInfo.serviceDescriptions.filter(sd => sd.schemeIdUri == null);
+        let sd = (supportedServiceDescriptions.length > 0) 
+            ? supportedServiceDescriptions[supportedServiceDescriptions.length - 1]
+            : allClientsServiceDescriptions[allClientsServiceDescriptions.length - 1];
+        if (!sd) return;
+
+        if (sd.latency && sd.latency.target > 0) {
+            _applyServiceDescriptionLatency(sd);
+        }
 
-                if (sd.playbackRate && sd.playbackRate.max > 1.0) {
-                    _applyServiceDescriptionPlaybackRate(sd);
-                }
+        if (sd.playbackRate && sd.playbackRate.max > 1.0) {
+            _applyServiceDescriptionPlaybackRate(sd);
+        }
 
-                if (sd.operatingQuality) {
-                    _applyServiceDescriptionOperatingQuality(sd);
-                }
+        if (sd.operatingQuality) {
+            _applyServiceDescriptionOperatingQuality(sd);
+        }
 
-                if (sd.operatingBandwidth) {
-                    _applyServiceDescriptionOperatingBandwidth(sd);
-                }
-            }
+        if (sd.operatingBandwidth) {
+            _applyServiceDescriptionOperatingBandwidth(sd);
         }
     }
 

diff --git a/test/unit/streaming.controllers.ServiceDescriptionController.js b/test/unit/streaming.controllers.ServiceDescriptionController.js
@@ -95,6 +95,35 @@ describe('ServiceDescriptionController', () => {
             expect(currentSettings.initialBitrate).to.be.empty;
         })
 
+        it('Should use supported scheme in preference of no provided schemeIdUri', () => {
+            dummyManifestInfo.serviceDescriptions.push({
+                latency: {
+                    target: 10000,
+                }
+            });
+            serviceDescriptionController.applyServiceDescription(dummyManifestInfo);
+            const currentSettings = serviceDescriptionController.getServiceDescriptionSettings();
+            expect(currentSettings.liveDelay).to.be.equal(5);
+        })
+
+        it('Should use ServiceDescription that appears last if multiple applicable ServiceDescriptions', () => {
+            // Also ensures only parameters from a single ServiceDescription element are used
+            dummyManifestInfo.serviceDescriptions.push({
+                schemeIdUri: 'urn:dvb:dash:lowlatency:scope:2019',
+                latency: {
+                    target: 10000,
+                }
+            });
+            serviceDescriptionController.applyServiceDescription(dummyManifestInfo);
+            const currentSettings = serviceDescriptionController.getServiceDescriptionSettings();
+            expect(currentSettings.liveDelay).to.be.equal(10);
+            expect(currentSettings.liveCatchup.maxDrift).to.be.NaN;
+            expect(currentSettings.liveCatchup.playbackRate).to.be.NaN;
+            expect(currentSettings.minBitrate).to.be.empty;
+            expect(currentSettings.maxBitrate).to.be.empty;
+            expect(currentSettings.initialBitrate).to.be.empty;
+        });
+
         it('Should not update the latency if target latency is equal to 0', () => {
             dummyManifestInfo.serviceDescriptions[0].latency.target = 0;
             delete dummyManifestInfo.serviceDescriptions[0].playbackRate;