parse VTT

Author: martinlindhe

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2015-2018 Martin Lindhe
+Copyright (c) 2015-2019 Martin Lindhe
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -5,25 +5,21 @@
 
 This is a go library and command-line tools for handling .srt, .vtt and .ssa subtitles
 
-
-# Installation
+## Installation
 
 Windows and macOS binaries are available under [Releases](https://github.com/martinlindhe/subtitles/releases)
 
 Or install them directly from git:
 
-```
+```sh
 go get -u github.com/martinlindhe/subtitles/...
 ```
 
-
-
-# Sub-projects
+## Sub-projects
 
 - [subber](https://github.com/martinlindhe/subtitles/tree/master/cmd/subber) command line tool for subtitles
 
-
-# Library example - convert srt to vtt
+## Library example - convert srt to vtt
 
 ```go
 import "github.com/martinlindhe/subtitles"
@@ -47,8 +43,7 @@ res, _ := subtitles.NewFromSRT(in)
 fmt.Println(res.AsVTT())
 ```
 
-
-# Library example - download subtitles
+## Library example - download subtitles
 
 ```go
 f, _ := os.Open(fileName)
@@ -58,7 +53,6 @@ finder := subtitles.NewSubFinder(f, fileName, "en")
 text, err := finder.TheSubDb()
 ```
 
-
-# License
+## License
 
 Under [MIT](LICENSE)

parser.go

@@ -17,6 +17,8 @@ func Parse(b []byte) (Subtitle, error) {
 		return NewFromDCSub(s)
 	} else if looksLikeSRT(s) {
 		return NewFromSRT(s)
+	} else if looksLikeVTT(s) {
+		return NewFromVTT(s)
 	}
 	return Subtitle{}, fmt.Errorf("parse: unrecognized subtitle type")
 }
@@ -28,5 +30,5 @@ func LooksLikeTextSubtitle(filename string) bool {
 		log.Fatal(err)
 	}
 	s := ConvertToUTF8(data)
-	return looksLikeCCDBCapture(s) || looksLikeSSA(s) || looksLikeDCSub(s) || looksLikeSRT(s)
+	return looksLikeCCDBCapture(s) || looksLikeSSA(s) || looksLikeDCSub(s) || looksLikeSRT(s) || looksLikeVTT(s)
 }

srt.go

@@ -11,17 +11,15 @@ import (
 
 // Eol is the end of line characters to use when writing .srt data
 var eol = "\n"
+
 func init() {
 	if runtime.GOOS == "windows" {
 		eol = "\r\n"
 	}
 }
 
 func looksLikeSRT(s string) bool {
-	if strings.HasPrefix(s, "1\n") || strings.HasPrefix(s, "1\r\n") {
-		return true
-	}
-	return false
+	return strings.HasPrefix(s, "1\n") || strings.HasPrefix(s, "1\r\n")
 }
 
 // NewFromSRT parses a .srt text into Subtitle, assumes s is a clean utf8 string
@@ -36,7 +34,7 @@ func NewFromSRT(s string) (res Subtitle, err error) {
 			continue
 		}
 
-		_, err := strconv.Atoi(seq)
+		_, err = strconv.Atoi(seq)
 		if err != nil {
 			err = fmt.Errorf("srt: atoi error at line %d: %v", i, err)
 			break
@@ -52,7 +50,7 @@ func NewFromSRT(s string) (res Subtitle, err error) {
 
 		matches := r1.FindStringSubmatch(lines[i])
 		if len(matches) < 3 {
-			err = fmt.Errorf("srt: parse error at line %d (idx out of range)", i)
+			err = fmt.Errorf("srt: parse error at line %d (idx out of range) for input '%s'", i, lines[i])
 			break
 		}
 

vtt.go

@@ -1,13 +1,18 @@
 package subtitles
 
 import (
+	"fmt"
+	"regexp"
+	"strings"
 	"time"
 )
 
+var webVTTTag = "WEBVTT\n"
+
 // AsVTT renders the sub in WebVTT format
 // https://en.wikipedia.org/wiki/WebVTT
 func (subtitle *Subtitle) AsVTT() (res string) {
-	res = "WEBVTT\n\n"
+	res = webVTTTag + "\n"
 	for _, sub := range subtitle.Captions {
 		res += sub.AsVTT()
 	}
@@ -30,3 +35,75 @@ func TimeVTT(t time.Time) string {
 	}
 	return t.Format("15:04:05.000")
 }
+
+func looksLikeVTT(s string) bool {
+	return strings.HasPrefix(s, webVTTTag)
+}
+
+// NewFromVTT parses a .vtt text into Subtitle, assumes s is a clean utf8 string
+func NewFromVTT(s string) (res Subtitle, err error) {
+	idx := strings.Index(s, webVTTTag)
+	if idx == -1 {
+		return res, fmt.Errorf("not a vtt")
+	}
+	s = s[idx+len(webVTTTag):]
+
+	r1 := regexp.MustCompile("([0-9:.,]*) --> ([0-9:.,]*)")
+	lines := strings.Split(s, "\n")
+	outSeq := 1
+
+	for i := 0; i < len(lines); i++ {
+		seq := strings.Trim(lines[i], "\r ")
+		if seq == "" {
+			continue
+		}
+
+		var o Caption
+		o.Seq = outSeq
+
+		matches := r1.FindStringSubmatch(lines[i])
+		if len(matches) < 3 {
+			err = fmt.Errorf("vtt: parse error at line %d (idx out of range) for input '%s'", i, lines[i])
+			break
+		}
+
+		o.Start, err = parseTime(matches[1])
+		if err != nil {
+			err = fmt.Errorf("vtt: start error at line %d: %v", i, err)
+			break
+		}
+
+		o.End, err = parseTime(matches[2])
+		if err != nil {
+			err = fmt.Errorf("vtt: end error at line %d: %v", i, err)
+			break
+		}
+
+		i++
+		if i >= len(lines) {
+			break
+		}
+
+		textLine := 1
+		for {
+			line := strings.Trim(lines[i], "\r ")
+			if line == "" && textLine > 1 {
+				break
+			}
+			if line != "" {
+				o.Text = append(o.Text, line)
+			}
+			i++
+			if i >= len(lines) {
+				break
+			}
+			textLine++
+		}
+
+		if len(o.Text) > 0 {
+			res.Captions = append(res.Captions, o)
+			outSeq++
+		}
+	}
+	return
+}

vtt_test.go

@@ -7,6 +7,39 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestParseVTT(t *testing.T) {
+	txt := "WEBVTT\n" +
+		"\n" +
+		"00:00:00.000 --> 00:00:05.560\n" +
+		"I Vetenskapens värld: ett experiment\n" +
+		"jag aldrig kommer att glömma.\n" +
+		"\n" +
+		"00:00:10.840 --> 00:00:15.760\n" +
+		"Om en person får kämpa\n" +
+		"för att hålla sig vaken–\n"
+
+	res, err := NewFromVTT(txt)
+	assert.Equal(t, nil, err)
+
+	expected := Subtitle{
+		[]Caption{{
+			1,
+			makeTime(0, 0, 0, 0),
+			makeTime(0, 0, 5, 560),
+			[]string{
+				"I Vetenskapens värld: ett experiment",
+				"jag aldrig kommer att glömma.",
+			}}, {
+			2,
+			makeTime(0, 0, 10, 840),
+			makeTime(0, 0, 15, 760),
+			[]string{
+				"Om en person får kämpa",
+				"för att hålla sig vaken–",
+			}}}}
+	assert.Equal(t, expected, res)
+}
+
 func TestAsVTT(t *testing.T) {
 	expected := "WEBVTT\n" +
 		"\n" +
@@ -16,6 +49,8 @@ func TestAsVTT(t *testing.T) {
 		"01:09.630 --> 01:11.005\n" +
 		"No ninja!\n\n"
 
+	assert.Equal(t, true, looksLikeVTT(expected))
+
 	in := Subtitle{[]Caption{{
 		1,
 		makeTime(0, 0, 4, 630),