Improve audio stream selection for video-only streams in the downloader

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -267,8 +267,8 @@ private void updateSecondaryStreams() {
             if (!videoStreams.get(i).isVideoOnly()) {
                 continue;
             }
-            final AudioStream audioStream = SecondaryStreamHelper
-                    .getAudioStreamFor(audioStreams.getStreamsList(), videoStreams.get(i));
+            final AudioStream audioStream = SecondaryStreamHelper.getAudioStreamFor(
+                    context, audioStreams.getStreamsList(), videoStreams.get(i));
 
             if (audioStream != null) {
                 secondaryStreams.append(i, new SecondaryStreamHelper<>(audioStreams, audioStream));

app/src/main/java/org/schabi/newpipe/util/ListHelper.java

@@ -46,10 +46,10 @@ public final class ListHelper {
             List.of(MediaFormat.MP3, MediaFormat.M4A, MediaFormat.WEBMA);
     // Use a Set for better performance
     private static final Set<String> HIGH_RESOLUTION_LIST = Set.of("1440p", "2160p");
-    // Audio track types in order of priotity. 0=lowest, n=highest
+    // Audio track types in order of priority. 0=lowest, n=highest
     private static final List<AudioTrackType> AUDIO_TRACK_TYPE_RANKING =
             List.of(AudioTrackType.DESCRIPTIVE, AudioTrackType.DUBBED, AudioTrackType.ORIGINAL);
-    // Audio track types in order of priotity when descriptive audio is preferred.
+    // Audio track types in order of priority when descriptive audio is preferred.
     private static final List<AudioTrackType> AUDIO_TRACK_TYPE_RANKING_DESCRIPTIVE =
             List.of(AudioTrackType.ORIGINAL, AudioTrackType.DUBBED, AudioTrackType.DESCRIPTIVE);
 
@@ -689,7 +689,7 @@ private static int compareVideoStreamResolution(@NonNull final String r1,
         }
     }
 
-    private static boolean isLimitingDataUsage(final Context context) {
+    static boolean isLimitingDataUsage(@NonNull final Context context) {
         return getResolutionLimit(context) != null;
     }
 
@@ -731,7 +731,7 @@ public static boolean isMeteredNetwork(@NonNull final Context context) {
     /**
      * Get a {@link Comparator} to compare {@link AudioStream}s by their format and bitrate.
      *
-     * <p>The prefered stream will be ordered last.</p>
+     * <p>The preferred stream will be ordered last.</p>
      *
      * @param context app context
      * @return Comparator
@@ -746,7 +746,7 @@ private static Comparator<AudioStream> getAudioFormatComparator(
     /**
      * Get a {@link Comparator} to compare {@link AudioStream}s by their format and bitrate.
      *
-     * <p>The prefered stream will be ordered last.</p>
+     * <p>The preferred stream will be ordered last.</p>
      *
      * @param defaultFormat  the default format to look for
      * @param limitDataUsage choose low bitrate audio stream
@@ -788,7 +788,7 @@ static Comparator<AudioStream> getAudioFormatComparator(
      * <li>Language is English</li>
      * </ol>
      *
-     * <p>The prefered track will be ordered last.</p>
+     * <p>The preferred track will be ordered last.</p>
      *
      * @param context App context
      * @return Comparator
@@ -825,7 +825,7 @@ private static Comparator<AudioStream> getAudioTrackComparator(
      * <li>Language is English</li>
      * </ol>
      *
-     * <p>The prefered track will be ordered last.</p>
+     * <p>The preferred track will be ordered last.</p>
      *
      * @param preferredLanguage      Preferred audio stream language
      * @param preferOriginalAudio    Get the original audio track regardless of its language

app/src/main/java/org/schabi/newpipe/util/SecondaryStreamHelper.java

@@ -1,5 +1,7 @@
 package org.schabi.newpipe.util;
 
+import android.content.Context;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
@@ -9,6 +11,7 @@
 import org.schabi.newpipe.extractor.stream.VideoStream;
 import org.schabi.newpipe.util.StreamItemAdapter.StreamInfoWrapper;
 
+import java.util.Comparator;
 import java.util.List;
 
 public class SecondaryStreamHelper<T extends Stream> {
@@ -25,14 +28,19 @@ public SecondaryStreamHelper(@NonNull final StreamInfoWrapper<T> streams,
     }
 
     /**
-     * Find the correct audio stream for the desired video stream.
+     * Finds an audio stream compatible with the provided video-only stream, so that the two streams
+     * can be combined in a single file by the downloader. If there are multiple available audio
+     * streams, chooses either the highest or the lowest quality one based on
+     * {@link ListHelper#isLimitingDataUsage(Context)}.
      *
+     * @param context      Android context
      * @param audioStreams list of audio streams
-     * @param videoStream  desired video ONLY stream
-     * @return selected audio stream or null if a candidate was not found
+     * @param videoStream  desired video-ONLY stream
+     * @return the selected audio stream or null if a candidate was not found
      */
     @Nullable
-    public static AudioStream getAudioStreamFor(@NonNull final List<AudioStream> audioStreams,
+    public static AudioStream getAudioStreamFor(@NonNull final Context context,
+                                                @NonNull final List<AudioStream> audioStreams,
                                                 @NonNull final VideoStream videoStream) {
         final MediaFormat mediaFormat = videoStream.getFormat();
         if (mediaFormat == null) {
@@ -41,33 +49,36 @@ public static AudioStream getAudioStreamFor(@NonNull final List<AudioStream> aud
 
         switch (mediaFormat) {
             case WEBM:
-            case MPEG_4:// ¿is mpeg-4 DASH?
+            case MPEG_4: // Is MPEG-4 DASH?
                 break;
             default:
                 return null;
         }
 
-        final boolean m4v = (mediaFormat == MediaFormat.MPEG_4);
+        final boolean m4v = mediaFormat == MediaFormat.MPEG_4;
+        final boolean isLimitingDataUsage = ListHelper.isLimitingDataUsage(context);
+
+        Comparator<AudioStream> comparator = ListHelper.getAudioFormatComparator(
+                m4v ? MediaFormat.M4A : MediaFormat.WEBMA, isLimitingDataUsage);
+        int preferredAudioStreamIndex = ListHelper.getAudioIndexByHighestRank(
+                audioStreams, comparator);
 
-        for (final AudioStream audio : audioStreams) {
-            if (audio.getFormat() == (m4v ? MediaFormat.M4A : MediaFormat.WEBMA)) {
-                return audio;
+        if (preferredAudioStreamIndex == -1) {
+            if (m4v) {
+                return null;
             }
-        }
 
-        if (m4v) {
-            return null;
-        }
+            comparator = ListHelper.getAudioFormatComparator(
+                    MediaFormat.WEBMA_OPUS, isLimitingDataUsage);
+            preferredAudioStreamIndex = ListHelper.getAudioIndexByHighestRank(
+                    audioStreams, comparator);
 
-        // retry, but this time in reverse order
-        for (int i = audioStreams.size() - 1; i >= 0; i--) {
-            final AudioStream audio = audioStreams.get(i);
-            if (audio.getFormat() == MediaFormat.WEBMA_OPUS) {
-                return audio;
+            if (preferredAudioStreamIndex == -1) {
+                return null;
             }
         }
 
-        return null;
+        return audioStreams.get(preferredAudioStreamIndex);
     }
 
     public T getStream() {