diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index a3f6c1ebfc..133f68195d 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -1,5 +1,12 @@
 # Release notes #
 
+### 2.10.5 ###
+
+* Add `allowAudioMixedChannelCountAdaptiveness` parameter to
+  `DefaultTrackSelector` to allow adaptive selections of audio tracks with
+  different channel counts
+  ([#6257](https://github.com/google/ExoPlayer/issues/6257)).
+
 ### 2.10.4 ###
 
 * Offline: Add `Scheduler` implementation that uses `WorkManager`.
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java b/library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java
index b8dd40f8bd..006c281ec7 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java
@@ -178,6 +178,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
     private boolean exceedAudioConstraintsIfNecessary;
     private boolean allowAudioMixedMimeTypeAdaptiveness;
     private boolean allowAudioMixedSampleRateAdaptiveness;
+    private boolean allowAudioMixedChannelCountAdaptiveness;
     // General
     private boolean forceLowestBitrate;
     private boolean forceHighestSupportedBitrate;
@@ -215,6 +216,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       exceedAudioConstraintsIfNecessary = initialValues.exceedAudioConstraintsIfNecessary;
       allowAudioMixedMimeTypeAdaptiveness = initialValues.allowAudioMixedMimeTypeAdaptiveness;
       allowAudioMixedSampleRateAdaptiveness = initialValues.allowAudioMixedSampleRateAdaptiveness;
+      allowAudioMixedChannelCountAdaptiveness =
+          initialValues.allowAudioMixedChannelCountAdaptiveness;
       // General
       forceLowestBitrate = initialValues.forceLowestBitrate;
       forceHighestSupportedBitrate = initialValues.forceHighestSupportedBitrate;
@@ -412,6 +415,17 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       return this;
     }
 
+    /**
+     * See {@link Parameters#allowAudioMixedChannelCountAdaptiveness}.
+     *
+     * @return This builder.
+     */
+    public ParametersBuilder setAllowAudioMixedChannelCountAdaptiveness(
+        boolean allowAudioMixedChannelCountAdaptiveness) {
+      this.allowAudioMixedChannelCountAdaptiveness = allowAudioMixedChannelCountAdaptiveness;
+      return this;
+    }
+
     // Text
 
     @Override
@@ -628,6 +642,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           exceedAudioConstraintsIfNecessary,
           allowAudioMixedMimeTypeAdaptiveness,
           allowAudioMixedSampleRateAdaptiveness,
+          allowAudioMixedChannelCountAdaptiveness,
           // Text
           preferredTextLanguage,
           selectUndeterminedTextLanguage,
@@ -749,6 +764,12 @@ public class DefaultTrackSelector extends MappingTrackSelector {
      * different sample rates may not be completely seamless. The default value is {@code false}.
      */
     public final boolean allowAudioMixedSampleRateAdaptiveness;
+    /**
+     * Whether to allow adaptive audio selections containing mixed channel counts. Adaptations
+     * between different channel counts may not be completely seamless. The default value is {@code
+     * false}.
+     */
+    public final boolean allowAudioMixedChannelCountAdaptiveness;
 
     // General
     /**
@@ -809,6 +830,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           /* exceedAudioConstraintsIfNecessary= */ true,
           /* allowAudioMixedMimeTypeAdaptiveness= */ false,
           /* allowAudioMixedSampleRateAdaptiveness= */ false,
+          /* allowAudioMixedChannelCountAdaptiveness= */ false,
           // Text
           TrackSelectionParameters.DEFAULT.preferredTextLanguage,
           TrackSelectionParameters.DEFAULT.selectUndeterminedTextLanguage,
@@ -841,6 +863,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
         boolean exceedAudioConstraintsIfNecessary,
         boolean allowAudioMixedMimeTypeAdaptiveness,
         boolean allowAudioMixedSampleRateAdaptiveness,
+        boolean allowAudioMixedChannelCountAdaptiveness,
         // Text
         @Nullable String preferredTextLanguage,
         boolean selectUndeterminedTextLanguage,
@@ -875,6 +898,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       this.exceedAudioConstraintsIfNecessary = exceedAudioConstraintsIfNecessary;
       this.allowAudioMixedMimeTypeAdaptiveness = allowAudioMixedMimeTypeAdaptiveness;
       this.allowAudioMixedSampleRateAdaptiveness = allowAudioMixedSampleRateAdaptiveness;
+      this.allowAudioMixedChannelCountAdaptiveness = allowAudioMixedChannelCountAdaptiveness;
       // General
       this.forceLowestBitrate = forceLowestBitrate;
       this.forceHighestSupportedBitrate = forceHighestSupportedBitrate;
@@ -908,6 +932,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       this.exceedAudioConstraintsIfNecessary = Util.readBoolean(in);
       this.allowAudioMixedMimeTypeAdaptiveness = Util.readBoolean(in);
       this.allowAudioMixedSampleRateAdaptiveness = Util.readBoolean(in);
+      this.allowAudioMixedChannelCountAdaptiveness = Util.readBoolean(in);
       // General
       this.forceLowestBitrate = Util.readBoolean(in);
       this.forceHighestSupportedBitrate = Util.readBoolean(in);
@@ -989,6 +1014,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           && exceedAudioConstraintsIfNecessary == other.exceedAudioConstraintsIfNecessary
           && allowAudioMixedMimeTypeAdaptiveness == other.allowAudioMixedMimeTypeAdaptiveness
           && allowAudioMixedSampleRateAdaptiveness == other.allowAudioMixedSampleRateAdaptiveness
+          && allowAudioMixedChannelCountAdaptiveness
+              == other.allowAudioMixedChannelCountAdaptiveness
           // General
           && forceLowestBitrate == other.forceLowestBitrate
           && forceHighestSupportedBitrate == other.forceHighestSupportedBitrate
@@ -1019,6 +1046,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       result = 31 * result + (exceedAudioConstraintsIfNecessary ? 1 : 0);
       result = 31 * result + (allowAudioMixedMimeTypeAdaptiveness ? 1 : 0);
       result = 31 * result + (allowAudioMixedSampleRateAdaptiveness ? 1 : 0);
+      result = 31 * result + (allowAudioMixedChannelCountAdaptiveness ? 1 : 0);
       // General
       result = 31 * result + (forceLowestBitrate ? 1 : 0);
       result = 31 * result + (forceHighestSupportedBitrate ? 1 : 0);
@@ -1055,6 +1083,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       Util.writeBoolean(dest, exceedAudioConstraintsIfNecessary);
       Util.writeBoolean(dest, allowAudioMixedMimeTypeAdaptiveness);
       Util.writeBoolean(dest, allowAudioMixedSampleRateAdaptiveness);
+      Util.writeBoolean(dest, allowAudioMixedChannelCountAdaptiveness);
       // General
       Util.writeBoolean(dest, forceLowestBitrate);
       Util.writeBoolean(dest, forceHighestSupportedBitrate);
@@ -1936,7 +1965,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
               formatSupports[selectedGroupIndex],
               params.maxAudioBitrate,
               params.allowAudioMixedMimeTypeAdaptiveness,
-              params.allowAudioMixedSampleRateAdaptiveness);
+              params.allowAudioMixedSampleRateAdaptiveness,
+              params.allowAudioMixedChannelCountAdaptiveness);
       if (adaptiveTracks.length > 0) {
         definition = new TrackSelection.Definition(selectedGroup, adaptiveTracks);
       }
@@ -1954,7 +1984,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       int[] formatSupport,
       int maxAudioBitrate,
       boolean allowMixedMimeTypeAdaptiveness,
-      boolean allowMixedSampleRateAdaptiveness) {
+      boolean allowMixedSampleRateAdaptiveness,
+      boolean allowAudioMixedChannelCountAdaptiveness) {
     int selectedConfigurationTrackCount = 0;
     AudioConfigurationTuple selectedConfiguration = null;
     HashSet<AudioConfigurationTuple> seenConfigurationTuples = new HashSet<>();
@@ -1971,7 +2002,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
                 configuration,
                 maxAudioBitrate,
                 allowMixedMimeTypeAdaptiveness,
-                allowMixedSampleRateAdaptiveness);
+                allowMixedSampleRateAdaptiveness,
+                allowAudioMixedChannelCountAdaptiveness);
         if (configurationCount > selectedConfigurationTrackCount) {
           selectedConfiguration = configuration;
           selectedConfigurationTrackCount = configurationCount;
@@ -1991,7 +2023,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
             selectedConfiguration,
             maxAudioBitrate,
             allowMixedMimeTypeAdaptiveness,
-            allowMixedSampleRateAdaptiveness)) {
+            allowMixedSampleRateAdaptiveness,
+            allowAudioMixedChannelCountAdaptiveness)) {
           adaptiveIndices[index++] = i;
         }
       }
@@ -2006,7 +2039,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       AudioConfigurationTuple configuration,
       int maxAudioBitrate,
       boolean allowMixedMimeTypeAdaptiveness,
-      boolean allowMixedSampleRateAdaptiveness) {
+      boolean allowMixedSampleRateAdaptiveness,
+      boolean allowAudioMixedChannelCountAdaptiveness) {
     int count = 0;
     for (int i = 0; i < group.length; i++) {
       if (isSupportedAdaptiveAudioTrack(
@@ -2015,7 +2049,8 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           configuration,
           maxAudioBitrate,
           allowMixedMimeTypeAdaptiveness,
-          allowMixedSampleRateAdaptiveness)) {
+          allowMixedSampleRateAdaptiveness,
+          allowAudioMixedChannelCountAdaptiveness)) {
         count++;
       }
     }
@@ -2028,11 +2063,13 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       AudioConfigurationTuple configuration,
       int maxAudioBitrate,
       boolean allowMixedMimeTypeAdaptiveness,
-      boolean allowMixedSampleRateAdaptiveness) {
+      boolean allowMixedSampleRateAdaptiveness,
+      boolean allowAudioMixedChannelCountAdaptiveness) {
     return isSupported(formatSupport, false)
         && (format.bitrate == Format.NO_VALUE || format.bitrate <= maxAudioBitrate)
-        && (format.channelCount != Format.NO_VALUE
-            && format.channelCount == configuration.channelCount)
+        && (allowAudioMixedChannelCountAdaptiveness
+            || (format.channelCount != Format.NO_VALUE
+                && format.channelCount == configuration.channelCount))
         && (allowMixedMimeTypeAdaptiveness
             || (format.sampleMimeType != null
                 && TextUtils.equals(format.sampleMimeType, configuration.mimeType)))
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelectorTest.java b/library/core/src/test/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelectorTest.java
index 224b2965ba..9941ae1098 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelectorTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelectorTest.java
@@ -143,6 +143,7 @@ public final class DefaultTrackSelectorTest {
             /* exceedAudioConstraintsIfNecessary= */ false,
             /* allowAudioMixedMimeTypeAdaptiveness= */ true,
             /* allowAudioMixedSampleRateAdaptiveness= */ false,
+            /* allowAudioMixedChannelCountAdaptiveness= */ true,
             // Text
             /* preferredTextLanguage= */ "de",
             /* selectUndeterminedTextLanguage= */ true,