1. 增加配置持久化

2. 完善细节

internal/ffmpeg/executor.go

@@ -56,7 +56,7 @@ func (e *Executor) Run(args []string, totalDuration float64) (context.CancelFunc
 	}
 
 	progressCh := make(chan Progress, 16)
-	logCh := make(chan string, 64)
+	logCh := make(chan string, 512)
 	errCh := make(chan error, 1)
 
 	go func() {
@@ -134,6 +134,13 @@ func scanLinesOrCR(data []byte, atEOF bool) (advance int, token []byte, err erro
 	return 0, nil, nil
 }
 
+// escapeFilterPath escapes a file path for use inside ffmpeg filter arguments.
+func escapeFilterPath(path string) string {
+	s := strings.ReplaceAll(path, "\\", "/")
+	s = strings.ReplaceAll(s, ":", "\\:")
+	return s
+}
+
 func tailLines(s string, n int) string {
 	lines := strings.Split(s, "\n")
 	if len(lines) > n {
@@ -159,8 +166,10 @@ type EncodeSettings struct {
 
 // RemuxSettings contains remux parameters.
 type RemuxSettings struct {
-	OutputFormat string `json:"outputFormat"`
-	MapStreams   []int  `json:"mapStreams"`
+	OutputFormat string   `json:"outputFormat"`
+	MapStreams   []int    `json:"mapStreams"`
+	SubFiles     []string `json:"subFiles"`
+	AudioFiles   []string `json:"audioFiles"`
 }
 
 // SubtitleSettings contains subtitle burn-in parameters.
@@ -170,10 +179,12 @@ type SubtitleSettings struct {
 
 // SubTrack represents a subtitle track to burn.
 type SubTrack struct {
-	Source   string `json:"source"`
-	Index    int    `json:"index"`
-	FilePath string `json:"filePath"`
-	Language string `json:"language"`
+	Source    string `json:"source"`
+	Index     int    `json:"index"`
+	FilePath  string `json:"filePath"`
+	Language  string `json:"language"`
+	Alignment int    `json:"alignment"` // 2=bottom, 6=top, 10=middle; 0=unspecified
+	MarginV   int    `json:"marginV"`   // vertical margin in pixels
 }
 
 // BuildEncodeArgs builds ffmpeg arguments for re-encoding.
@@ -192,7 +203,8 @@ func BuildEncodeArgs(input string, output string, s EncodeSettings, hwAccel stri
 		args = append(args, "-c:v", s.VideoCodec)
 	}
 
-	if s.Preset != "" && strings.HasPrefix(s.VideoCodec, "libx") {
+	if s.Preset != "" {
+		// libx* uses named presets (fast, medium…), HW encoders use p1–p7
 		args = append(args, "-preset", s.Preset)
 	}
 
@@ -202,8 +214,16 @@ func BuildEncodeArgs(input string, output string, s EncodeSettings, hwAccel stri
 		args = append(args, "-b:v", s.VideoBitrate)
 	}
 
-	if s.Width > 0 && s.Height > 0 {
-		args = append(args, "-vf", fmt.Sprintf("scale=%d:%d", s.Width, s.Height))
+	if s.Width > 0 || s.Height > 0 {
+		w := fmt.Sprintf("%d", s.Width)
+		h := fmt.Sprintf("%d", s.Height)
+		if s.Width <= 0 {
+			w = "-1"
+		}
+		if s.Height <= 0 {
+			h = "-1"
+		}
+		args = append(args, "-vf", fmt.Sprintf("scale=%s:%s", w, h))
 	}
 	if s.FPS > 0 {
 		args = append(args, "-r", fmt.Sprintf("%.2f", s.FPS))
@@ -228,6 +248,21 @@ func BuildRemuxArgs(input string, output string, s RemuxSettings, hwAccel string
 		args = append(args, "-hwaccel", hwAccel)
 	}
 	args = append(args, "-i", input)
+
+	// Add external subtitle and audio files as additional inputs
+	extIdx := 1
+	for _, sf := range s.SubFiles {
+		if sf != "" {
+			args = append(args, "-i", sf)
+		}
+	}
+	for _, af := range s.AudioFiles {
+		if af != "" {
+			args = append(args, "-i", af)
+		}
+	}
+
+	// Map streams from main input
 	if len(s.MapStreams) > 0 {
 		for _, idx := range s.MapStreams {
 			args = append(args, "-map", fmt.Sprintf("0:%d", idx))
@@ -235,32 +270,57 @@ func BuildRemuxArgs(input string, output string, s RemuxSettings, hwAccel string
 	} else {
 		args = append(args, "-map", "0")
 	}
-	args = append(args, "-c", "copy")
-	if s.OutputFormat != "" {
-		args = append(args, "-f", s.OutputFormat)
+
+	// Map subtitle streams from external files
+	for range s.SubFiles {
+		args = append(args, "-map", fmt.Sprintf("%d:s", extIdx))
+		extIdx++
 	}
-	// (progress flags removed — ffmpeg outputs to stderr by default)
+	// Map audio streams from external files
+	for range s.AudioFiles {
+		args = append(args, "-map", fmt.Sprintf("%d:a", extIdx))
+		extIdx++
+	}
+
+	args = append(args, "-c", "copy")
+	// MP4 needs mov_text for embedded subtitles
+	if len(s.SubFiles) > 0 && s.OutputFormat == "mp4" {
+		args = append(args, "-c:s", "mov_text")
+	}
+	// Don't force -f; let ffmpeg determine format from output extension
 	args = append(args, output)
 	return args
 }
 
 // BuildSubtitleArgs builds ffmpeg arguments for subtitle burn-in.
+// NOTE: -hwaccel is deliberately excluded — the subtitles filter (libass)
+// requires CPU frames and hangs when fed GPU surfaces.
 func BuildSubtitleArgs(input string, output string, s SubtitleSettings, encode EncodeSettings, hwAccel string) []string {
 	args := []string{"-y"}
 
-	if hwAccel != "" {
-		args = append(args, "-hwaccel", hwAccel)
-	}
-
 	args = append(args, "-i", input)
 
 	var subFilters []string
 	for _, sub := range s.Subtitles {
-		if sub.Source == "external" && sub.FilePath != "" {
-			escaped := strings.ReplaceAll(sub.FilePath, "\\", "/")
-			escaped = strings.ReplaceAll(escaped, ":", "\\:")
-			subFilters = append(subFilters, fmt.Sprintf("subtitles='%s'", escaped))
+		// Internal subtitles are pre-extracted to temp files by runTask.
+		// We only handle external file paths here.
+		if sub.FilePath == "" {
+			continue
 		}
+		escaped := escapeFilterPath(sub.FilePath)
+		filter := fmt.Sprintf("subtitles='%s'", escaped)
+		// Append force_style for position control (works with ASS/SSA subtitles)
+		var styles []string
+		if sub.Alignment > 0 {
+			styles = append(styles, fmt.Sprintf("Alignment=%d", sub.Alignment))
+		}
+		if sub.MarginV > 0 {
+			styles = append(styles, fmt.Sprintf("MarginV=%d", sub.MarginV))
+		}
+		if len(styles) > 0 {
+			filter += fmt.Sprintf(":force_style='%s'", strings.Join(styles, ","))
+		}
+		subFilters = append(subFilters, filter)
 	}
 
 	if len(subFilters) > 0 {