From 47b32594ee1fab67e4158ab6c50b1406d9b940f8 Mon Sep 17 00:00:00 2001
From: kimvde <kimvde@google.com>
Date: Mon, 30 Jan 2023 14:04:36 +0000
Subject: [PATCH] Add error message if track is added during transformation

PiperOrigin-RevId: 505670386
---
 .../android/exoplayer2/transformer/CompositeAssetLoader.java  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/CompositeAssetLoader.java b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/CompositeAssetLoader.java
index 34043b947a..efbacc2fc5 100644
--- a/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/CompositeAssetLoader.java
+++ b/library/transformer/src/main/java/com/google/android/exoplayer2/transformer/CompositeAssetLoader.java
@@ -153,7 +153,9 @@ import java.util.concurrent.atomic.AtomicLong;
       sampleConsumersByTrackType.put(trackType, sampleConsumer);
       return sampleConsumer;
     }
-    return checkStateNotNull(sampleConsumersByTrackType.get(trackType));
+    return checkStateNotNull(
+        sampleConsumersByTrackType.get(trackType),
+        "The preceding MediaItem does not contain any track of type " + trackType);
   }
 
   @Override