Properly finalize EL writing when lengths differ

src/dovi/muxer.rs

@@ -257,6 +257,8 @@ impl IoProcessor for Muxer {
     }
 
     fn finalize(&mut self, parser: &HevcParser) -> Result<()> {
+        let mut error = None;
+
         let ordered_frames = parser.ordered_frames();
         let total_frames = ordered_frames.len();
 
@@ -283,20 +285,21 @@ impl IoProcessor for Muxer {
             // Write last BL frame
             self.write_bl_frame()?;
 
-            if self.el_handler.buffered_frames.len() == 1 {
-                // Maybe incomplete last frame
-                self.el_processor
-                    .parse_nalus(&mut self.el_reader, &mut self.el_handler)?;
-
-                // Write last EL frame
-                self.el_handler.write_next_frame()?;
-            } else if let Some(last_frame) = self.el_handler.buffered_frames.back() {
-                // Zero indexed
-                bail!(
-                    "Mismatched BL/EL frame count. Expected {} frames, got {} (or more) frames in EL",
+            // Finalize EL, maybe incomplete last frame
+            self.el_processor
+                .parse_nalus(&mut self.el_reader, &mut self.el_handler)?;
+
+            // Write last EL frame
+            self.el_handler.write_next_frame()?;
+
+            // There should be no more frames if the BL/EL have the same number
+            if let Some(last_frame) = self.el_handler.buffered_frames.back() {
+                // Do not bail here to avoid incomplete processing
+                error = Some(format!(
+                    "Mismatched BL/EL frame count. Expected {} frames, got {} (or more) frames in EL.\nThe EL will be trimmed to the BL length.",
                     total_frames,
                     last_frame.frame_number + 1
-                );
+                ));
             }
 
             // Write remaining EOS/EOB
@@ -316,7 +319,12 @@ impl IoProcessor for Muxer {
 
         self.progress_bar.finish_and_clear();
 
-        Ok(())
+        if let Some(err) = error {
+            // Should still error to have correct status code
+            bail!(err);
+        } else {
+            Ok(())
+        }
     }
 }
 

tests/hevc/mux.rs

@@ -199,3 +199,36 @@ fn edit_config() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn el_with_more_frames() -> Result<()> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let temp = assert_fs::TempDir::new().unwrap();
+
+    let input_bl = Path::new("assets/hevc_tests/regular_bl_start_code_4_shorter.hevc");
+    let input_el = Path::new("assets/hevc_tests/regular.hevc");
+
+    let output_file = temp.child("BL_EL_RPU.hevc");
+    let expected_bl_el_rpu =
+        Path::new("assets/hevc_tests/regular_start_code_4_shorter_trimmed_el.hevc");
+
+    let assert = cmd
+        .arg(SUBCOMMAND)
+        .arg("--bl")
+        .arg(input_bl)
+        .arg("--el")
+        .arg(input_el)
+        .arg("--output")
+        .arg(output_file.as_ref())
+        .assert();
+
+    assert.failure().stderr(predicate::str::contains(
+        "Error: Mismatched BL/EL frame count. Expected 258 frames, got 259 (or more) frames in EL",
+    ));
+
+    output_file
+        .assert(predicate::path::is_file())
+        .assert(predicate::path::eq_file(expected_bl_el_rpu));
+
+    Ok(())
+}