support translator notes (scrcaps), emit ASS format instead of SRT

main.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 )
@@ -116,7 +117,7 @@ func performDownload(ctx context.Context, cfg *config, targetUrl string) error {
 		return err
 	}
 
-	err = ltc.WriteSRT(fh, float64(msecsDuration)/1000)
+	err = ltc.WriteSubtitle(fh, float64(msecsDuration)/1000)
 	fh.Close()
 	if err != nil {
 		return err

scrape.go

@@ -103,10 +103,6 @@ func (ltc *loadTupContent) Validate() error {
 		return fmt.Errorf("scrsecs/scrcaps length mismatch")
 	}
 
-	if !(len(ltc.Scrcaps) == 0 || (len(ltc.Scrcaps) == 1 && ltc.Scrcaps[0] == "")) {
-		return errors.New("unsupported use of strcaps")
-	}
-
 	if len(ltc.VideoID) == 0 {
 		return errors.New("unexpected blank video ID")
 	}

writesubs.go

@@ -3,10 +3,11 @@ package main
 import (
 	"fmt"
 	"io"
+	"sort"
 	"time"
 )
 
-func secs_to_srt_time(secs float64) string {
+func secs_to_ass_time(secs float64) string {
 	dur := time.Duration(secs) * time.Second
 
 	hh := int64(dur.Hours())
@@ -14,45 +15,92 @@ func secs_to_srt_time(secs float64) string {
 	ss := int64(dur.Seconds()) - (hh * 3600) - (mm * 60)
 	ms := int64(dur.Milliseconds()) - (hh * 3600000) - (mm * 60000) - (ss * 1000)
 
-	return fmt.Sprintf("%02d:%02d:%02d,%03d", hh, mm, ss, ms)
+	return fmt.Sprintf("%02d:%02d:%02d.%03d", hh, mm, ss, ms)
 }
 
-func (ltc *loadTupContent) WriteSRT(w io.Writer, totalVideoDurationSecs float64) error {
-	/*
+// WriteSubtitle streams the video subtitles to the supplied writer in ASS format.
+func (ltc *loadTupContent) WriteSubtitle(w io.Writer, totalVideoDurationSecs float64) error {
 
-		SRT file format (example from Wikipedia):
+	w.Write([]byte(`[Script Info]
+; Script generated by loadtup-dl
+ScriptType: v4.00+
+Collisions: Normal
+Timer: 100,0000
+Video Aspect Ratio: 0
  
-		1
-		00:02:17,440 --> 00:02:20,375
-		Senator, we're making
-		our final approach into Coruscant.
+[V4+ Styles]
+Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
+Style: Default, Arial,18,&H00FFFFFF,&H00FFFFFF,&H00000008,&H80000008,-1,0,0,0,100,100,0.00,0.00,1,1.00,2.00,2,30,30,30,0
+Style: TLNote, Arial,12,&H00FFFFFF,&H00FFFFFF,&H00000008,&H80000008,-1,0,0,0,100,100,0.00,0.00,1,1.00,2.00,2,30,30,30,0
 
-		2
-		00:02:20,476 --> 00:02:22,501
-		Very good, Lieutenant.
-	*/
+[Events]
+Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
+`))
+
+	type entry struct {
+		startTime float64
+		entry     string
+	}
+	entries := make([]entry, 0, len(ltc.Caps)+len(ltc.Scrcaps))
 
-	ctr := 1
 	for i := 0; i < len(ltc.Caps); i += 1 {
 		if ltc.Caps[i] == "" {
 			// Don't show anything
 			continue
 		}
 
-		start := secs_to_srt_time(ltc.Secs[i])
+		start := secs_to_ass_time(ltc.Secs[i])
 		var end string
 		if i < len(ltc.Caps)-1 {
-			end = secs_to_srt_time(ltc.Secs[i+1])
+			end = secs_to_ass_time(ltc.Secs[i+1])
 		} else {
 			// The final subtitle. Loadtup displays these for the entire
 			// remaining video duration
-			end = secs_to_srt_time(totalVideoDurationSecs)
+			end = secs_to_ass_time(totalVideoDurationSecs)
 		}
 
-		fmt.Fprintf(w, "%d\n%s --> %s\n%s\n\n",
-			ctr, start, end, ltc.Caps[i])
-		// We emitted a message, increase the counter
-		ctr += 1
+		// Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
+		entries = append(entries, entry{
+			startTime: ltc.Secs[i],
+			entry:     fmt.Sprintf("Dialogue: 0,%s,%s,Default,,0000,0000,0000,,{\\a2}%s\n", start, end, ltc.Caps[i]),
+		})
+
+	}
+
+	// Repeat for scrcaps, using top positioning and a different layer
+
+	for i := 0; i < len(ltc.Scrcaps); i += 1 {
+		if ltc.Caps[i] == "" {
+			// Don't show anything
+			continue
+		}
+
+		start := secs_to_ass_time(ltc.Scrsecs[i])
+		var end string
+		if i < len(ltc.Scrcaps)-1 {
+			end = secs_to_ass_time(ltc.Scrsecs[i+1])
+		} else {
+			// The final subtitle. Loadtup displays these for the entire
+			// remaining video duration
+			end = secs_to_ass_time(totalVideoDurationSecs)
+		}
+
+		// Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
+		entries = append(entries, entry{
+			startTime: ltc.Scrsecs[i],
+			entry:     fmt.Sprintf("Dialogue: 1,%s,%s,TLNote,,0000,0000,0000,,{\\a6}%s\n", start, end, ltc.Scrcaps[i]),
+		})
+	}
+
+	// Sort all the entries by their start time, to mingle TL note entries
+	// properly with the other subtitles
+	sort.SliceStable(entries, func(i, j int) bool {
+		return entries[i].startTime < entries[j].startTime
+	})
+
+	// Emit all to writer
+	for _, e := range entries {
+		w.Write([]byte(e.entry))
 	}
 
 	return nil