diff --git a/demo/src/main/java/com/otaliastudios/transcoder/demo/TranscoderActivity.java b/demo/src/main/java/com/otaliastudios/transcoder/demo/TranscoderActivity.java
index 478fd41e..40b7f995 100644
--- a/demo/src/main/java/com/otaliastudios/transcoder/demo/TranscoderActivity.java
+++ b/demo/src/main/java/com/otaliastudios/transcoder/demo/TranscoderActivity.java
@@ -3,10 +3,12 @@
 import android.annotation.SuppressLint;
 import android.content.ClipData;
 import android.content.Intent;
-import android.media.MediaMuxer;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.SystemClock;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.widget.EditText;
 import android.widget.ProgressBar;
 import android.widget.RadioGroup;
 import android.widget.TextView;
@@ -61,6 +63,8 @@ public class TranscoderActivity extends AppCompatActivity implements
 
     private ProgressBar mProgressView;
     private TextView mButtonView;
+    private EditText mTrimStartView;
+    private EditText mTrimEndView;
     private TextView mAudioReplaceView;
 
     private boolean mIsTranscoding;
@@ -74,6 +78,52 @@ public class TranscoderActivity extends AppCompatActivity implements
     private long mTranscodeStartTime;
     private TrackStrategy mTranscodeVideoStrategy;
     private TrackStrategy mTranscodeAudioStrategy;
+    private long mTrimStartUs = 0;
+    private long mTrimEndUs = 0;
+
+    private TextWatcher mTrimStartTextWatcher = new TextWatcher() {
+        @Override
+        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+        }
+
+        @Override
+        public void onTextChanged(CharSequence s, int start, int before, int count) {
+        }
+
+        @Override
+        public void afterTextChanged(Editable s) {
+            if (s.length() > 0) {
+                try {
+                    mTrimStartUs = Long.valueOf(s.toString()) * 1000000;
+                } catch (NumberFormatException e) {
+                    mTrimStartUs = 0;
+                    LOG.w("Failed to read trimStart value.");
+                }
+            }
+        }
+    };
+    private TextWatcher mTrimEndTextWatcher = new TextWatcher() {
+        @Override
+        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+        }
+
+        @Override
+        public void onTextChanged(CharSequence s, int start, int before, int count) {
+        }
+
+        @Override
+        public void afterTextChanged(Editable s) {
+            if (s.length() > 0) {
+                try {
+                    mTrimEndUs = Long.valueOf(s.toString()) * 1000000;
+                } catch (NumberFormatException e) {
+                    mTrimEndUs = 0;
+                    LOG.w("Failed to read trimEnd value.");
+                }
+            }
+        }
+    };
+
 
     @SuppressLint("SetTextI18n")
     @Override
@@ -97,6 +147,8 @@ protected void onCreate(Bundle savedInstanceState) {
         mProgressView = findViewById(R.id.progress);
         mProgressView.setMax(PROGRESS_BAR_MAX);
 
+        mTrimStartView = findViewById(R.id.trim_start);
+        mTrimEndView = findViewById(R.id.trim_end);
         mAudioReplaceView = findViewById(R.id.replace_info);
 
         mAudioChannelsGroup = findViewById(R.id.channels);
@@ -113,6 +165,8 @@ protected void onCreate(Bundle savedInstanceState) {
         mVideoResolutionGroup.setOnCheckedChangeListener(this);
         mVideoAspectGroup.setOnCheckedChangeListener(this);
         mAudioSampleRateGroup.setOnCheckedChangeListener(this);
+        mTrimStartView.addTextChangedListener(mTrimStartTextWatcher);
+        mTrimEndView.addTextChangedListener(mTrimEndTextWatcher);
         syncParameters();
 
         mAudioReplaceGroup.setOnCheckedChangeListener((group, checkedId) -> {
@@ -257,13 +311,27 @@ private void transcode() {
         DataSink sink = new DefaultDataSink(mTranscodeOutputFile.getAbsolutePath());
         TranscoderOptions.Builder builder = Transcoder.into(sink);
         if (mAudioReplacementUri == null) {
-            if (mTranscodeInputUri1 != null) builder.addDataSource(this, mTranscodeInputUri1);
-            if (mTranscodeInputUri2 != null) builder.addDataSource(this, mTranscodeInputUri2);
-            if (mTranscodeInputUri3 != null) builder.addDataSource(this, mTranscodeInputUri3);
+            if (mTrimStartUs > 0 || mTrimEndUs > 0) {
+                if (mTranscodeInputUri1 != null) builder.addDataSource(this, mTranscodeInputUri1, mTrimStartUs, mTrimEndUs);
+                if (mTranscodeInputUri2 != null) builder.addDataSource(this, mTranscodeInputUri2, mTrimStartUs, mTrimEndUs);
+                if (mTranscodeInputUri3 != null) builder.addDataSource(this, mTranscodeInputUri3, mTrimStartUs, mTrimEndUs);
+            }
+            else {
+                if (mTranscodeInputUri1 != null) builder.addDataSource(this, mTranscodeInputUri1);
+                if (mTranscodeInputUri2 != null) builder.addDataSource(this, mTranscodeInputUri2);
+                if (mTranscodeInputUri3 != null) builder.addDataSource(this, mTranscodeInputUri3);
+            }
         } else {
-            if (mTranscodeInputUri1 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri1);
-            if (mTranscodeInputUri2 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri2);
-            if (mTranscodeInputUri3 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri3);
+            if (mTrimStartUs > 0 || mTrimEndUs > 0) {
+                if (mTranscodeInputUri1 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri1, mTrimStartUs, mTrimEndUs);
+                if (mTranscodeInputUri2 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri2, mTrimStartUs, mTrimEndUs);
+                if (mTranscodeInputUri3 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri3, mTrimStartUs, mTrimEndUs);
+            }
+            else {
+                if (mTranscodeInputUri1 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri1);
+                if (mTranscodeInputUri2 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri2);
+                if (mTranscodeInputUri3 != null) builder.addDataSource(TrackType.VIDEO, this, mTranscodeInputUri3);
+            }
             builder.addDataSource(TrackType.AUDIO, this, mAudioReplacementUri);
         }
         mTranscodeFuture = builder.setListener(this)
diff --git a/demo/src/main/res/layout/activity_transcoder.xml b/demo/src/main/res/layout/activity_transcoder.xml
index e142c221..9cbcafb7 100644
--- a/demo/src/main/res/layout/activity_transcoder.xml
+++ b/demo/src/main/res/layout/activity_transcoder.xml
@@ -285,6 +285,55 @@
                     android:layout_height="wrap_content" />
             </RadioGroup>
 
+            <!-- TRIM -->
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:padding="16dp"
+                android:text="Trim (seconds)" />
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="?attr/listPreferredItemHeightSmall"
+                android:gravity="center"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_marginEnd="8dp"
+                    android:text="Start:" />
+
+                <com.google.android.material.textfield.TextInputEditText
+                    android:id="@+id/trim_start"
+                    android:layout_width="wrap_content"
+                    android:layout_height="match_parent"
+                    android:inputType="number"
+                    android:maxLines="1"
+                    android:gravity="center_horizontal"
+                    android:minWidth="48dp"
+                    android:singleLine="true"
+                    android:text="0" />
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_marginStart="32dp"
+                    android:layout_marginEnd="8dp"
+                    android:text="End:" />
+
+                <com.google.android.material.textfield.TextInputEditText
+                    android:id="@+id/trim_end"
+                    android:layout_width="wrap_content"
+                    android:layout_height="match_parent"
+                    android:inputType="number"
+                    android:maxLines="1"
+                    android:gravity="center_horizontal"
+                    android:minWidth="48dp"
+                    android:singleLine="true"
+                    android:text="0" />
+            </LinearLayout>
+
             <!-- REPLACE AUDIO -->
             <TextView
                 android:padding="16dp"
diff --git a/lib/src/main/java/com/otaliastudios/transcoder/TranscoderOptions.java b/lib/src/main/java/com/otaliastudios/transcoder/TranscoderOptions.java
index 8ead0cfb..cd3a506f 100644
--- a/lib/src/main/java/com/otaliastudios/transcoder/TranscoderOptions.java
+++ b/lib/src/main/java/com/otaliastudios/transcoder/TranscoderOptions.java
@@ -13,6 +13,7 @@
 import com.otaliastudios.transcoder.source.DataSource;
 import com.otaliastudios.transcoder.source.FileDescriptorDataSource;
 import com.otaliastudios.transcoder.source.FilePathDataSource;
+import com.otaliastudios.transcoder.source.TrimDataSource;
 import com.otaliastudios.transcoder.source.UriDataSource;
 import com.otaliastudios.transcoder.strategy.DefaultAudioStrategy;
 import com.otaliastudios.transcoder.strategy.DefaultVideoStrategies;
@@ -174,12 +175,24 @@ public Builder addDataSource(@NonNull Context context, @NonNull Uri uri) {
             return addDataSource(new UriDataSource(context, uri));
         }
 
+        @NonNull
+        @SuppressWarnings({"unused", "UnusedReturnValue"})
+        public Builder addDataSource(@NonNull Context context, @NonNull Uri uri, long trimStartUs, long trimEndUs) {
+            return addDataSource(new TrimDataSource(new UriDataSource(context, uri), trimStartUs, trimEndUs));
+        }
+
         @NonNull
         @SuppressWarnings({"unused", "UnusedReturnValue"})
         public Builder addDataSource(@NonNull TrackType type, @NonNull Context context, @NonNull Uri uri) {
             return addDataSource(type, new UriDataSource(context, uri));
         }
 
+        @NonNull
+        @SuppressWarnings({"unused", "UnusedReturnValue"})
+        public Builder addDataSource(@NonNull TrackType type, @NonNull Context context, @NonNull Uri uri, long trimStartUs, long trimEndUs) {
+            return addDataSource(type, new TrimDataSource(new UriDataSource(context, uri), trimStartUs, trimEndUs));
+        }
+
         /**
          * Sets the audio output strategy. If absent, this defaults to
          * {@link com.otaliastudios.transcoder.strategy.DefaultAudioStrategy}.
diff --git a/lib/src/main/java/com/otaliastudios/transcoder/source/DataSource.java b/lib/src/main/java/com/otaliastudios/transcoder/source/DataSource.java
index e7eb3dd9..e8e3675e 100644
--- a/lib/src/main/java/com/otaliastudios/transcoder/source/DataSource.java
+++ b/lib/src/main/java/com/otaliastudios/transcoder/source/DataSource.java
@@ -54,6 +54,14 @@ public interface DataSource {
      */
     void selectTrack(@NonNull TrackType type);
 
+    /**
+     * Moves all selected tracks forward by the specified duration.
+     *
+     * @param durationUs requested duration
+     * @return the new presentation time in microseconds
+     */
+    long seekBy(long durationUs);
+
     /**
      * Returns true if we can read the given track at this point.
      * If true if returned, source should expect a {@link #readTrack(Chunk)} call.
diff --git a/lib/src/main/java/com/otaliastudios/transcoder/source/DefaultDataSource.java b/lib/src/main/java/com/otaliastudios/transcoder/source/DefaultDataSource.java
index e9140dca..396999e2 100644
--- a/lib/src/main/java/com/otaliastudios/transcoder/source/DefaultDataSource.java
+++ b/lib/src/main/java/com/otaliastudios/transcoder/source/DefaultDataSource.java
@@ -63,6 +63,22 @@ public void selectTrack(@NonNull TrackType type) {
         mExtractor.selectTrack(mIndex.require(type));
     }
 
+    @Override
+    public long seekBy(long durationUs) {
+        ensureExtractor();
+        final int trackCount = mExtractor.getTrackCount();
+        for (int i = 0; i < trackCount; i++) {
+            mExtractor.selectTrack(i);
+        }
+        long timestampUs = mExtractor.getSampleTime() + durationUs;
+        // Seeking once per track helps the extractor with Audio sampleTime issues
+        for (int i = 0; i < trackCount; i++) {
+            mExtractor.seekTo(timestampUs, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
+            timestampUs = mExtractor.getSampleTime();
+        }
+        return timestampUs;
+    }
+
     @Override
     public boolean isDrained() {
         ensureExtractor();
diff --git a/lib/src/main/java/com/otaliastudios/transcoder/source/TrimDataSource.java b/lib/src/main/java/com/otaliastudios/transcoder/source/TrimDataSource.java
new file mode 100644
index 00000000..f5fdc5e5
--- /dev/null
+++ b/lib/src/main/java/com/otaliastudios/transcoder/source/TrimDataSource.java
@@ -0,0 +1,115 @@
+package com.otaliastudios.transcoder.source;
+
+
+import android.media.MediaFormat;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.otaliastudios.transcoder.engine.TrackType;
+import com.otaliastudios.transcoder.internal.Logger;
+
+import org.jetbrains.annotations.Contract;
+
+/**
+ * A {@link DataSource} wrapper that trims source at both ends.
+ */
+public class TrimDataSource implements DataSource {
+    private static final String TAG = "TrimDataSource";
+    private static final Logger LOG = new Logger(TAG);
+    @NonNull
+    private DataSource source;
+    private long trimStartUs;
+    private long trimDurationUs;
+    private boolean didSeekTracks = false;
+
+    public TrimDataSource(@NonNull DataSource source, long trimStartUs, long trimEndUs) throws IllegalArgumentException {
+        if (trimStartUs < 0 || trimEndUs < 0) {
+            throw new IllegalArgumentException("Trim values cannot be negative.");
+        }
+        this.source = source;
+        this.trimStartUs = trimStartUs;
+        this.trimDurationUs = computeTrimDuration(source.getDurationUs(), trimStartUs, trimEndUs);
+    }
+
+    @Contract(pure = true)
+    private static long computeTrimDuration(long duration, long trimStart, long trimEnd) throws IllegalArgumentException {
+        if (trimStart + trimEnd > duration) {
+            throw new IllegalArgumentException("Trim values cannot be greater than media duration.");
+        }
+        return duration - trimStart - trimEnd;
+    }
+
+    @Override
+    public int getOrientation() {
+        return source.getOrientation();
+    }
+
+    @Nullable
+    @Override
+    public double[] getLocation() {
+        return source.getLocation();
+    }
+
+    @Override
+    public long getDurationUs() {
+        return trimDurationUs;
+    }
+
+    @Nullable
+    @Override
+    public MediaFormat getTrackFormat(@NonNull TrackType type) {
+        return source.getTrackFormat(type);
+    }
+
+    @Override
+    public void selectTrack(@NonNull TrackType type) {
+        source.selectTrack(type);
+    }
+
+    @Override
+    public long seekBy(long durationUs) {
+        return source.seekBy(durationUs);
+    }
+
+    @Override
+    public boolean canReadTrack(@NonNull TrackType type) {
+        if (!didSeekTracks) {
+            final long sampleTimeUs = seekBy(trimStartUs);
+            updateTrimValues(sampleTimeUs);
+            didSeekTracks = true;
+        }
+        return source.canReadTrack(type);
+    }
+
+    private void updateTrimValues(long timestampUs) {
+        trimDurationUs += trimStartUs - timestampUs;
+        trimStartUs = timestampUs;
+    }
+
+    @Override
+    public void readTrack(@NonNull Chunk chunk) {
+        source.readTrack(chunk);
+    }
+
+    @Override
+    public long getReadUs() {
+        return source.getReadUs();
+    }
+
+    @Override
+    public boolean isDrained() {
+        return source.isDrained() || getReadUs() >= getDurationUs();
+    }
+
+    @Override
+    public void releaseTrack(@NonNull TrackType type) {
+        source.releaseTrack(type);
+    }
+
+    @Override
+    public void rewind() {
+        didSeekTracks = false;
+        source.rewind();
+    }
+}