fix: ctx cancellation

internal/downloader/downloader.go

@@ -24,6 +24,7 @@ import (
 
 const (
 	defaultClientTimeout = 30 * time.Second
+	vodSegmentTimeout    = 5 * time.Minute // Longer timeout for VOD segments which can be large
 	maxRedirects         = 5
 	playlistPollInterval = 2 * time.Second // Poll interval for livestreams
 )
@@ -193,37 +194,66 @@ func downloadPlaylist(ctx context.Context, client *http.Client, parsed *url.URL,
 	}
 
 	// For VOD (Video on Demand), use temp file and convert to MP4
+	// Create a context without deadline for VOD downloads to avoid premature cancellation
+	// Preserve cancellation from parent context but remove any deadline
+	vodCtx, vodCancel := context.WithCancel(context.Background())
+	defer vodCancel()
+
+	// If parent context is cancelled, cancel VOD context too
+	go func() {
+		<-ctx.Done()
+		vodCancel()
+	}()
+
+	// Create a client with longer timeout for VOD segments
+	vodClient := &http.Client{Timeout: vodSegmentTimeout}
+
 	tempTS, err := os.CreateTemp("", "sdl-*.ts")
 	if err != nil {
 		return fmt.Errorf("create temp file: %w", err)
 	}
 	tempPath := tempTS.Name()
-	defer func() {
-		tempTS.Close()
-		os.Remove(tempPath)
-	}()
+	defer os.Remove(tempPath)
 
 	segments := collectSegments(mediaPlaylist)
 	totalSegments := len(segments)
 	fmt.Fprintf(os.Stderr, "Downloading %d segments...\n", totalSegments)
 
 	for i, segment := range segments {
-		if err := downloadSegment(ctx, client, finalURL, segment, tempTS); err != nil {
+		if err := downloadSegment(vodCtx, vodClient, finalURL, segment, tempTS); err != nil {
+			tempTS.Close()
 			return fmt.Errorf("download segment %d: %w", i, err)
 		}
 		// Show progress: segment number, total, and percentage
 		progress := float64(i+1) / float64(totalSegments) * 100
 		fmt.Fprintf(os.Stderr, "\rProgress: %d/%d segments (%.1f%%)", i+1, totalSegments, progress)
+		os.Stderr.Sync() // Flush progress output
 	}
 	fmt.Fprintf(os.Stderr, "\n")
 
-	if _, err := tempTS.Seek(0, io.SeekStart); err != nil {
-		return fmt.Errorf("rewind temp file: %w", err)
+	// Flush and sync the file to ensure all data is written to disk
+	if err := tempTS.Sync(); err != nil {
+		tempTS.Close()
+		return fmt.Errorf("sync temp file: %w", err)
+	}
+
+	// Close the file before conversion
+	if err := tempTS.Close(); err != nil {
+		return fmt.Errorf("close temp file: %w", err)
+	}
+
+	// Verify the file exists and has content
+	stat, err := os.Stat(tempPath)
+	if err != nil {
+		return fmt.Errorf("stat temp file: %w", err)
+	}
+	if stat.Size() == 0 {
+		return fmt.Errorf("downloaded file is empty")
 	}
 
 	mp4Name := ensureMP4Extension(name)
-	fmt.Fprintf(os.Stderr, "Converting to MP4...\n")
-	if err := transmuxToMP4(ctx, tempPath, mp4Name); err != nil {
+	fmt.Fprintf(os.Stderr, "Converting to MP4 (%.2f MB)...\n", float64(stat.Size())/1024/1024)
+	if err := transmuxToMP4(vodCtx, tempPath, mp4Name); err != nil {
 		return err
 	}
 	fmt.Fprintf(os.Stderr, "Complete: %s\n", mp4Name)
@@ -642,14 +672,50 @@ func transmuxToMP4(ctx context.Context, tsPath, mp4Path string) error {
 		return fmt.Errorf("ensure output directory: %w", err)
 	}
 
-	cmd := exec.CommandContext(ctx, "ffmpeg", "-y", "-i", tsPath, "-c", "copy", "-movflags", "+faststart", mp4Path)
+	// Try with copy first (fastest), fall back to re-encoding if needed
+	// Use -fflags +genpts to generate presentation timestamps if missing
+	// Use -err_detect ignore_err to be more tolerant of minor errors
+	cmd := exec.CommandContext(ctx, "ffmpeg",
+		"-y",
+		"-fflags", "+genpts",
+		"-err_detect", "ignore_err",
+		"-i", tsPath,
+		"-c", "copy",
+		"-movflags", "+faststart",
+		mp4Path)
 	cmd.Stdout = io.Discard
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
 
 	if err := cmd.Run(); err != nil {
-		os.Remove(mp4Path)
+		// If copy fails, try with re-encoding as fallback
 		msg := strings.TrimSpace(stderr.String())
+		if strings.Contains(msg, "could not find corresponding") || strings.Contains(msg, "error reading header") {
+			// Try re-encoding instead of copy
+			fmt.Fprintf(os.Stderr, "Copy mode failed, trying re-encode...\n")
+			cmd2 := exec.CommandContext(ctx, "ffmpeg",
+				"-y",
+				"-fflags", "+genpts",
+				"-err_detect", "ignore_err",
+				"-i", tsPath,
+				"-c:v", "libx264",
+				"-c:a", "aac",
+				"-movflags", "+faststart",
+				mp4Path)
+			cmd2.Stdout = io.Discard
+			var stderr2 bytes.Buffer
+			cmd2.Stderr = &stderr2
+			if err2 := cmd2.Run(); err2 != nil {
+				os.Remove(mp4Path)
+				msg2 := strings.TrimSpace(stderr2.String())
+				if msg2 != "" {
+					return fmt.Errorf("ffmpeg (re-encode): %s", msg2)
+				}
+				return fmt.Errorf("ffmpeg (re-encode): %w", err2)
+			}
+			return nil
+		}
+		os.Remove(mp4Path)
 		if msg != "" {
 			return fmt.Errorf("ffmpeg: %s", msg)
 		}