diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/CeaUtil.java b/libraries/extractor/src/main/java/androidx/media3/extractor/CeaUtil.java
index 8421d44605..58b7c45d52 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/CeaUtil.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/CeaUtil.java
@@ -15,6 +15,8 @@
  */
 package androidx.media3.extractor;
 
+import static androidx.media3.common.util.Assertions.checkState;
+
 import androidx.media3.common.C;
 import androidx.media3.common.util.Log;
 import androidx.media3.common.util.ParsableByteArray;
@@ -104,14 +106,13 @@ public final class CeaUtil {
     for (TrackOutput output : outputs) {
       ccDataBuffer.setPosition(sampleStartPosition);
       output.sampleData(ccDataBuffer, sampleLength);
-      if (presentationTimeUs != C.TIME_UNSET) {
-        output.sampleMetadata(
-            presentationTimeUs,
-            C.BUFFER_FLAG_KEY_FRAME,
-            sampleLength,
-            /* offset= */ 0,
-            /* cryptoData= */ null);
-      }
+      checkState(presentationTimeUs != C.TIME_UNSET);
+      output.sampleMetadata(
+          presentationTimeUs,
+          C.BUFFER_FLAG_KEY_FRAME,
+          sampleLength,
+          /* offset= */ 0,
+          /* cryptoData= */ null);
     }
   }
 
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac3Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac3Reader.java
index e5ce22e44d..fe69bff1f0 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac3Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac3Reader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 import static java.lang.annotation.ElementType.TYPE_USE;
 
@@ -112,9 +113,7 @@ public final class Ac3Reader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -143,10 +142,10 @@ public final class Ac3Reader implements ElementaryStreamReader {
           output.sampleData(data, bytesToRead);
           bytesRead += bytesToRead;
           if (bytesRead == sampleSize) {
-            if (timeUs != C.TIME_UNSET) {
-              output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
-              timeUs += sampleDurationUs;
-            }
+            // packetStarted method must be called before reading samples.
+            checkState(timeUs != C.TIME_UNSET);
+            output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
+            timeUs += sampleDurationUs;
             state = STATE_FINDING_SYNC;
           }
           break;
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac4Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac4Reader.java
index 5947a29132..5c967d724f 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac4Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Ac4Reader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 import static java.lang.annotation.ElementType.TYPE_USE;
 
@@ -114,9 +115,7 @@ public final class Ac4Reader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -145,10 +144,10 @@ public final class Ac4Reader implements ElementaryStreamReader {
           output.sampleData(data, bytesToRead);
           bytesRead += bytesToRead;
           if (bytesRead == sampleSize) {
-            if (timeUs != C.TIME_UNSET) {
-              output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
-              timeUs += sampleDurationUs;
-            }
+            // packetStarted method must be called before reading samples.
+            checkState(timeUs != C.TIME_UNSET);
+            output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
+            timeUs += sampleDurationUs;
             state = STATE_FINDING_SYNC;
           }
           break;
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/AdtsReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/AdtsReader.java
index de80f047d6..836c46d5f9 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/AdtsReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/AdtsReader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 
 import androidx.annotation.Nullable;
@@ -155,9 +156,7 @@ public final class AdtsReader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -537,10 +536,10 @@ public final class AdtsReader implements ElementaryStreamReader {
     currentOutput.sampleData(data, bytesToRead);
     bytesRead += bytesToRead;
     if (bytesRead == sampleSize) {
-      if (timeUs != C.TIME_UNSET) {
-        currentOutput.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
-        timeUs += currentSampleDuration;
-      }
+      // packetStarted method must be called before reading samples.
+      checkState(timeUs != C.TIME_UNSET);
+      currentOutput.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
+      timeUs += currentSampleDuration;
       setFindingSampleState();
     }
   }
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DtsReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DtsReader.java
index c28faf501d..7dd515ce66 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DtsReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DtsReader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 
 import androidx.annotation.Nullable;
@@ -89,9 +90,7 @@ public final class DtsReader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -117,10 +116,10 @@ public final class DtsReader implements ElementaryStreamReader {
           output.sampleData(data, bytesToRead);
           bytesRead += bytesToRead;
           if (bytesRead == sampleSize) {
-            if (timeUs != C.TIME_UNSET) {
-              output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
-              timeUs += sampleDurationUs;
-            }
+            // packetStarted method must be called before consuming samples.
+            checkState(timeUs != C.TIME_UNSET);
+            output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
+            timeUs += sampleDurationUs;
             state = STATE_FINDING_SYNC;
           }
           break;
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DvbSubtitleReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DvbSubtitleReader.java
index 5de21926f7..02d111c855 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DvbSubtitleReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/DvbSubtitleReader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.extractor.ts.TsPayloadReader.FLAG_DATA_ALIGNMENT_INDICATOR;
 
 import androidx.media3.common.C;
@@ -79,9 +80,7 @@ public final class DvbSubtitleReader implements ElementaryStreamReader {
       return;
     }
     writingSample = true;
-    if (pesTimeUs != C.TIME_UNSET) {
-      sampleTimeUs = pesTimeUs;
-    }
+    sampleTimeUs = pesTimeUs;
     sampleBytesWritten = 0;
     bytesToCheck = 2;
   }
@@ -89,10 +88,10 @@ public final class DvbSubtitleReader implements ElementaryStreamReader {
   @Override
   public void packetFinished(boolean isEndOfInput) {
     if (writingSample) {
-      if (sampleTimeUs != C.TIME_UNSET) {
-        for (TrackOutput output : outputs) {
-          output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleBytesWritten, 0, null);
-        }
+      // packetStarted method must be called before reading sample.
+      checkState(sampleTimeUs != C.TIME_UNSET);
+      for (TrackOutput output : outputs) {
+        output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleBytesWritten, 0, null);
       }
       writingSample = false;
     }
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/ElementaryStreamReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/ElementaryStreamReader.java
index 3d60db839c..a6decc12a2 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/ElementaryStreamReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/ElementaryStreamReader.java
@@ -21,7 +21,20 @@ import androidx.media3.common.util.UnstableApi;
 import androidx.media3.extractor.ExtractorOutput;
 import androidx.media3.extractor.TrackOutput;
 
-/** Extracts individual samples from an elementary media stream, preserving original order. */
+/**
+ * Extracts individual samples from an elementary media stream, preserving original order.
+ *
+ * <p>The expected sequence of method calls is as follows:
+ *
+ * <ol>
+ *   <li>{@link #createTracks(ExtractorOutput, PesReader.TrackIdGenerator)} (once at initialization)
+ *   <li>{@link #seek()} (optional, to reset the state)
+ *   <li>{@link #packetStarted(long, int)} (to signal the start of a new packet)
+ *   <li>{@link #consume(ParsableByteArray)} (zero or more times, to provide packet data)
+ *   <li>{@link #packetFinished(boolean)} (to signal the end of the current packet)
+ *   <li>Repeat steps 3-5 for subsequent packets
+ * </ol>
+ */
 @UnstableApi
 public interface ElementaryStreamReader {
 
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H263Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H263Reader.java
index 302dd500e8..5c9d03eab9 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H263Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H263Reader.java
@@ -16,6 +16,7 @@
 package androidx.media3.extractor.ts;
 
 import static androidx.media3.common.util.Assertions.checkNotNull;
+import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.common.util.Assertions.checkStateNotNull;
 import static androidx.media3.common.util.Util.castNonNull;
 import static java.lang.annotation.ElementType.TYPE_USE;
@@ -130,9 +131,7 @@ public final class H263Reader implements ElementaryStreamReader {
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
     // TODO (Internal b/32267012): Consider using random access indicator.
-    if (pesTimeUs != C.TIME_UNSET) {
-      this.pesTimeUs = pesTimeUs;
-    }
+    this.pesTimeUs = pesTimeUs;
   }
 
   @Override
@@ -479,10 +478,9 @@ public final class H263Reader implements ElementaryStreamReader {
     }
 
     public void onDataEnd(long position, int bytesWrittenPastPosition, boolean hasOutputFormat) {
-      if (startCodeValue == START_CODE_VALUE_VOP
-          && hasOutputFormat
-          && readingSample
-          && sampleTimeUs != C.TIME_UNSET) {
+      // packetStarted method must be called before reading sample.
+      checkState(sampleTimeUs != C.TIME_UNSET);
+      if (startCodeValue == START_CODE_VALUE_VOP && hasOutputFormat && readingSample) {
         int size = (int) (position - samplePosition);
         @C.BufferFlags int flags = sampleIsKeyframe ? C.BUFFER_FLAG_KEY_FRAME : 0;
         output.sampleMetadata(
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H264Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H264Reader.java
index 07786a4ba5..4445af067a 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H264Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H264Reader.java
@@ -114,9 +114,7 @@ public final class H264Reader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      this.pesTimeUs = pesTimeUs;
-    }
+    this.pesTimeUs = pesTimeUs;
     randomAccessIndicator |= (flags & FLAG_RANDOM_ACCESS_INDICATOR) != 0;
   }
 
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H265Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H265Reader.java
index 040ed9fb9b..7d265852a6 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H265Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/H265Reader.java
@@ -117,9 +117,7 @@ public final class H265Reader implements ElementaryStreamReader {
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
     // TODO (Internal b/32267012): Consider using random access indicator.
-    if (pesTimeUs != C.TIME_UNSET) {
-      this.pesTimeUs = pesTimeUs;
-    }
+    this.pesTimeUs = pesTimeUs;
   }
 
   @Override
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Id3Reader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Id3Reader.java
index 3d903ffbba..002dd33657 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Id3Reader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/Id3Reader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static androidx.media3.extractor.metadata.id3.Id3Decoder.ID3_HEADER_LENGTH;
 import static androidx.media3.extractor.ts.TsPayloadReader.FLAG_DATA_ALIGNMENT_INDICATOR;
 import static java.lang.Math.min;
@@ -77,9 +78,7 @@ public final class Id3Reader implements ElementaryStreamReader {
       return;
     }
     writingSample = true;
-    if (pesTimeUs != C.TIME_UNSET) {
-      sampleTimeUs = pesTimeUs;
-    }
+    sampleTimeUs = pesTimeUs;
     sampleSize = 0;
     sampleBytesRead = 0;
   }
@@ -126,9 +125,9 @@ public final class Id3Reader implements ElementaryStreamReader {
     if (!writingSample || sampleSize == 0 || sampleBytesRead != sampleSize) {
       return;
     }
-    if (sampleTimeUs != C.TIME_UNSET) {
-      output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
-    }
+    // packetStarted method must be called before consuming samples.
+    checkState(sampleTimeUs != C.TIME_UNSET);
+    output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
     writingSample = false;
   }
 }
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/LatmReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/LatmReader.java
index d51c50dcca..59612473f0 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/LatmReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/LatmReader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 
 import androidx.annotation.Nullable;
@@ -101,9 +102,7 @@ public final class LatmReader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -314,10 +313,10 @@ public final class LatmReader implements ElementaryStreamReader {
       sampleDataBuffer.setPosition(0);
     }
     output.sampleData(sampleDataBuffer, muxLengthBytes);
-    if (timeUs != C.TIME_UNSET) {
-      output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, muxLengthBytes, 0, null);
-      timeUs += sampleDurationUs;
-    }
+    // packetStarted method must be called before consuming samples.
+    checkState(timeUs != C.TIME_UNSET);
+    output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, muxLengthBytes, 0, null);
+    timeUs += sampleDurationUs;
   }
 
   private void resetBufferForSize(int newSize) {
diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/MpegAudioReader.java b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/MpegAudioReader.java
index 550eae2906..c17f7a942f 100644
--- a/libraries/extractor/src/main/java/androidx/media3/extractor/ts/MpegAudioReader.java
+++ b/libraries/extractor/src/main/java/androidx/media3/extractor/ts/MpegAudioReader.java
@@ -15,6 +15,7 @@
  */
 package androidx.media3.extractor.ts;
 
+import static androidx.media3.common.util.Assertions.checkState;
 import static java.lang.Math.min;
 
 import androidx.annotation.Nullable;
@@ -92,9 +93,7 @@ public final class MpegAudioReader implements ElementaryStreamReader {
 
   @Override
   public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
-    if (pesTimeUs != C.TIME_UNSET) {
-      timeUs = pesTimeUs;
-    }
+    timeUs = pesTimeUs;
   }
 
   @Override
@@ -233,10 +232,10 @@ public final class MpegAudioReader implements ElementaryStreamReader {
       return;
     }
 
-    if (timeUs != C.TIME_UNSET) {
-      output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, frameSize, 0, null);
-      timeUs += frameDurationUs;
-    }
+    // packetStarted method must be called before consuming samples.
+    checkState(timeUs != C.TIME_UNSET);
+    output.sampleMetadata(timeUs, C.BUFFER_FLAG_KEY_FRAME, frameSize, 0, null);
+    timeUs += frameDurationUs;
     frameBytesRead = 0;
     state = STATE_FINDING_HEADER;
   }