Add a YouTube DASH manifest parser to make live DASH manifests usable

This is a hacky solution, a better one should be investigated and used.

Author: AudricV

app/src/main/java/org/schabi/newpipe/player/helper/YoutubeDashLiveManifestParser.java

@@ -0,0 +1,68 @@
+package org.schabi.newpipe.player.helper;
+
+import android.net.Uri;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.google.android.exoplayer2.source.dash.manifest.DashManifest;
+import com.google.android.exoplayer2.source.dash.manifest.DashManifestParser;
+import com.google.android.exoplayer2.source.dash.manifest.Period;
+import com.google.android.exoplayer2.source.dash.manifest.ProgramInformation;
+import com.google.android.exoplayer2.source.dash.manifest.ServiceDescriptionElement;
+import com.google.android.exoplayer2.source.dash.manifest.UtcTimingElement;
+
+import java.util.List;
+
+/**
+ * A {@link DashManifestParser} fixing YouTube DASH manifests to allow starting playback from the
+ * newest period available instead of the earliest one in some cases.
+ *
+ * <p>
+ * It changes the {@code availabilityStartTime} passed to a custom value doing the workaround.
+ * A better approach to fix the issue should be investigated and used in the future.
+ * </p>
+ */
+public class YoutubeDashLiveManifestParser extends DashManifestParser {
+
+    // Result of Util.parseXsDateTime("1970-01-01T00:00:00Z")
+    private static final long AVAILABILITY_START_TIME_TO_USE = 0;
+
+    // There is no computation made with the availabilityStartTime value in the
+    // parseMediaPresentationDescription method itself, so we can just override methods called in
+    // this method using the workaround value
+    // Overriding parsePeriod does not seem to be needed
+
+    @SuppressWarnings("checkstyle:ParameterNumber")
+    @NonNull
+    @Override
+    protected DashManifest buildMediaPresentationDescription(
+            final long availabilityStartTime,
+            final long durationMs,
+            final long minBufferTimeMs,
+            final boolean dynamic,
+            final long minUpdateTimeMs,
+            final long timeShiftBufferDepthMs,
+            final long suggestedPresentationDelayMs,
+            final long publishTimeMs,
+            @Nullable final ProgramInformation programInformation,
+            @Nullable final UtcTimingElement utcTiming,
+            @Nullable final ServiceDescriptionElement serviceDescription,
+            @Nullable final Uri location,
+            @NonNull final List<Period> periods) {
+        return super.buildMediaPresentationDescription(
+                AVAILABILITY_START_TIME_TO_USE,
+                durationMs,
+                minBufferTimeMs,
+                dynamic,
+                minUpdateTimeMs,
+                timeShiftBufferDepthMs,
+                suggestedPresentationDelayMs,
+                publishTimeMs,
+                programInformation,
+                utcTiming,
+                serviceDescription,
+                location,
+                periods);
+    }
+}