fix: add diagnostic logging for audio pipeline in VideoStitch node

Audio from generateAudio was being silently dropped during video
stitching. Add [VideoStitch] checkpoint logs at each stage where
audio can be discarded: getConnectedInputs, prepareAudioAsync,
and codec detection. Surface codec failure as a visible progress
warning instead of only console.warn.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/hooks/useAudioMixing.ts

@@ -228,9 +228,8 @@ export async function prepareAudioAsync(
       duration: totalSamples / sampleRate,
     };
   } catch (error) {
-    const errorMessage = error instanceof Error ? error.message : 'Unknown error';
-    console.error('Audio mixing error:', error);
-    throw new Error(`Failed to process audio: ${errorMessage}`);
+    console.error('[VideoStitch] Audio preparation failed:', error instanceof Error ? error.message : error, error);
+    throw new Error(`Failed to process audio: ${error instanceof Error ? error.message : 'Unknown error'}`);
   }
 }
 

src/hooks/useStitchVideos.ts

@@ -243,7 +243,8 @@ export async function stitchVideosAsync(
       });
 
       if (!audioCodec) {
-        console.warn('No supported audio codec found, continuing without audio');
+        console.warn('[VideoStitch] No supported audio codec found, continuing without audio');
+        updateProgress('processing', 'Warning: no supported audio codec — audio skipped', 10);
       } else {
         updateProgress('processing', `Adding audio track (${audioCodec})...`, 10);
 

src/store/execution/videoProcessingExecutors.ts

@@ -55,6 +55,7 @@ export async function executeVideoStitch(ctx: NodeExecutionContext): Promise<voi
     // Prepare audio if connected
     let audioData = null;
     if (inputs.audio.length > 0 && inputs.audio[0]) {
+      console.log('[VideoStitch] Audio input detected, preparing audio...');
       const { prepareAudioAsync } = await import("@/hooks/useAudioMixing");
       const audioUrl = inputs.audio[0];
       const audioResponse = await fetch(audioUrl);
@@ -68,6 +69,14 @@ export async function executeVideoStitch(ctx: NodeExecutionContext): Promise<voi
         ? rawBlob
         : new Blob([rawBlob], { type: audioMime });
       audioData = await prepareAudioAsync(audioBlob, 0);
+      if (!audioData) {
+        console.warn('[VideoStitch] prepareAudioAsync returned null — audio will be skipped');
+      } else {
+        console.log('[VideoStitch] Audio prepared: %ds, %d channels, %dHz',
+          audioData.duration.toFixed(1), audioData.buffer.numberOfChannels, audioData.buffer.sampleRate);
+      }
+    } else {
+      console.log('[VideoStitch] No audio connected (inputs.audio.length=%d)', inputs.audio.length);
     }
 
     const { stitchVideosAsync } = await import("@/hooks/useStitchVideos");