diff --git a/src/test/java/com/ddf/vodsystem/services/media/StreamActionsServiceTest.java b/src/test/java/com/ddf/vodsystem/services/media/StreamActionsServiceTest.java
index cb0d563..0d9e02c 100644
--- a/src/test/java/com/ddf/vodsystem/services/media/StreamActionsServiceTest.java
+++ b/src/test/java/com/ddf/vodsystem/services/media/StreamActionsServiceTest.java
@@ -45,6 +45,23 @@ class StreamActionsServiceTest {
         Files.createFile(tempDir.resolve(name));
     }
 
+    /**
+     * Stubs the two-arg {@link CommandRunner#run} so the head re-encode pass
+     * actually writes a non-empty file at its output path — {@code encodeHead}
+     * verifies its output exists and is non-empty before continuing. The concat
+     * pass (no {@code mpegts} muxer) is left untouched. Returns {@code output}
+     * for both invocations.
+     */
+    private void stubRunnerProducingHead(CommandOutput output) throws IOException, InterruptedException {
+        when(commandRunner.run(anyList(), any())).thenAnswer(inv -> {
+            List<String> cmd = inv.getArgument(0);
+            if (cmd.contains("mpegts")) {
+                Files.writeString(Path.of(cmd.get(cmd.size() - 1)), "x");
+            }
+            return output;
+        });
+    }
+
     // ---------------------------------------------------------------
     // getSegmentsInRange: missing / invalid directories
     // ---------------------------------------------------------------
@@ -279,23 +296,25 @@ class StreamActionsServiceTest {
         ProgressTracker progress = new ProgressTracker();
         CommandOutput commandOutput = new CommandOutput();
 
-        when(commandRunner.run(anyList())).thenReturn(commandOutput);
-        when(commandRunner.run(anyList(), any())).thenReturn(commandOutput);
+        stubRunnerProducingHead(commandOutput);
 
         var future = service.saveSection(List.of(segmentA, segmentB), 5.0f, 12.0f, output, progress);
 
         assertThat(future.get()).isSameAs(commandOutput);
         assertThat(progress.isComplete()).isTrue();
 
+        // saveSection issues two ffmpeg passes: the head re-encode (trims the
+        // first segment via -ss) followed by the stream-copy concat (-t/-c copy).
         @SuppressWarnings("unchecked")
         ArgumentCaptor<List<String>> captor = ArgumentCaptor.forClass(List.class);
-        Mockito.verify(commandRunner).run(captor.capture(), any());
-        List<String> command = captor.getValue();
+        Mockito.verify(commandRunner, Mockito.times(2)).run(captor.capture(), any());
+        List<String> headCommand = captor.getAllValues().get(0);
+        List<String> concatCommand = captor.getAllValues().get(1);
 
-        assertThat(command).containsSequence("-ss", "5.0");
-        assertThat(command).containsSequence("-t", "12.0");
-        assertThat(command).containsSequence("-c", "copy");
-        assertThat(command).endsWith(output.toAbsolutePath().toString());
+        assertThat(headCommand).containsSequence("-ss", "5.0");
+        assertThat(concatCommand).containsSequence("-t", "12.0");
+        assertThat(concatCommand).containsSequence("-c", "copy");
+        assertThat(concatCommand).endsWith(output.toAbsolutePath().toString());
     }
 
     @Test
@@ -303,7 +322,7 @@ class StreamActionsServiceTest {
         Path output = Path.of("/tmp/out/clip.mp4");
         ProgressTracker progress = new ProgressTracker();
 
-        when(commandRunner.run(anyList())).thenReturn(new CommandOutput());
+        // The head re-encode is the first ffmpeg pass; its failure must surface.
         when(commandRunner.run(anyList(), any())).thenThrow(new IOException("ffmpeg boom"));
 
         var future = service.saveSection(List.of(Path.of("/tmp/a.ts")), 0f, 10f, output, progress);
@@ -328,9 +347,12 @@ class StreamActionsServiceTest {
     }
 
     @Test
-    void saveSection_nullOutputFile_completesExceptionally() throws IOException {
+    void saveSection_nullOutputFile_completesExceptionally() throws Exception {
         ProgressTracker progress = new ProgressTracker();
 
+        // Let the head pass succeed so execution reaches the null output file.
+        stubRunnerProducingHead(new CommandOutput());
+
         var future = service.saveSection(List.of(Path.of("/tmp/a.ts")), 0f, 10f, null, progress);
 
         assertThatThrownBy(future::get)