<d p="51.593,5,25,16711680,1408852480,0,7fa769b4,576008622">怒求 up 自己配音！</d><d p="10.286,1,25,16777215,1408852600,0,a3af4d0d,576011065">顏藝？</d><d p="12.65,1,25,16777215,1408852761,0,24570b5a,576014281">我的女神！</d><d p="19.033,1,25,16777215,1408852789,0,cb20d1c7,576014847">前！??！</d><d p="66.991,1,25,16777215,1408852886,0,a78e484d,576016806">已擼</d>

以上表第一條彈幕為例。很明顯的，p屬性開始的浮點(diǎn)數(shù)，與播放時(shí)一比對(duì)，就能知道，表示的是彈幕應(yīng)該出現(xiàn)的播放時(shí)間。隨后的1和25先不管；16777215，目測(cè)應(yīng)該是顏色（因?yàn)樵撝当硎緸槭M(jìn)制是FFFFFF）；1408852480，在彈幕中是遞增的，感覺應(yīng)該是個(gè)unix時(shí)間，用這個(gè)數(shù)（d），求：d/86400/365.2425+1970，結(jié)果約為2014.6?？磥?lái)確實(shí)是unix時(shí)間。估計(jì)是創(chuàng)建彈幕的時(shí)間。0，不知道，抓取了很多視頻的彈幕，這個(gè)位置都是0，暫且不管它。7fa769b4，估計(jì)是創(chuàng)建者的ID，因?yàn)橥粁ml文件會(huì)出現(xiàn)多次，而且看起來(lái)是十六進(jìn)制數(shù)，恰好有些hash函數(shù)就是返回4字節(jié)整數(shù)。576008622，也是遞增的，不用猜也知道，這個(gè)肯定就是彈幕的ID了。

<d/sp="([/d/.]+),([145]),(/d+),(/d+),/d+,/d+,/w+,/d+">([^<>]+?)</d>

// 將bilibili的xml彈幕文件轉(zhuǎn)換為ass字幕文件。// xml文件中，彈幕的格式如下：// <d p="32.066,1,25,16777215,1409046965,0,017d3f58,579516441">地板好評(píng)</d>// p的屬性為時(shí)間、彈幕類型、字體大小、字體顏色、創(chuàng)建時(shí)間、？、創(chuàng)建者ID、彈幕ID。// p的屬性中，后4項(xiàng)對(duì)ass字幕無(wú)用，舍棄。被<d>和</d>包圍的是彈幕文本。// 只處理右往左、上現(xiàn)隱、下現(xiàn)隱三種類型的普通彈幕。package main import (  "fmt"  "io"  "io/ioutil"  "math"  "os"  "regexp"  "sort"  "strconv"  "strings") // ass文件的頭部const header = `[Script Info]ScriptType: v4.00+Collisions: NormalplayResX: 640playResY: 360 [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, EncodingStyle: Default, Microsoft YaHei, 28, &H00FFFFFF, &H00FFFFFF, &H00000000, &H00000000, 0, 0, 0, 0, 100, 100, 0.00, 0.00, 1, 1, 0, 2, 10, 10, 10, 0 [Events]Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text` // 正則匹配獲取彈幕原始信息var line = regexp.MustCompile(`<d/sp="([/d/.]+),([145]),(/d+),(/d+),/d+,/d+,/w+,/d+">([^<>]+?)</d>`) // 用來(lái)保管彈幕的信息type Danmu struct {  text string  time float64  kind byte  size int  color int} // 使[]Danmu實(shí)現(xiàn)sort.Interface接口，以便排序type Danmus []Danmu func (d Danmus) Len() int {  return len(d)}func (d Danmus) Less(i, j int) bool {  return d[i].time < d[j].time}func (d Danmus) Swap(i, j int) {  d[i], d[j] = d[j], d[i]} // 將正則匹配到的數(shù)據(jù)填寫入Danmu類型里func fill(d *Danmu, s [][]byte) {  d.time, _ = strconv.ParseFloat(string(s[1]), 64)  d.kind = s[2][0] - '0'  d.size, _ = strconv.Atoi(string(s[3]))  bgr, _ := strconv.Atoi(string(s[4]))  d.color = ((bgr >> 16) & 255) | (bgr & (255 << 8)) | ((bgr & 255) << 16)  d.text = string(s[5])} // 返回文本的長(zhǎng)度，假設(shè)ascii字符都是0.5個(gè)字長(zhǎng)，其余都是1個(gè)字長(zhǎng)func length(s string) float64 {  l := 0.0  for _, r := range s {    if r < 127 {      l += 0.5    } else {      l += 1    }  }  return l} // 生成時(shí)間點(diǎn)的ass格式表示：`0:00:00.00`func timespot(f float64) string {  h, f := math.Modf(f / 3600)  m, f := math.Modf(f * 60)  return fmt.Sprintf("%d:%02d:%05.2f", int(h), int(m), f*60)} // 讀取文件并獲取其中的彈幕func open(name string) ([]Danmu, error) {  data, err := ioutil.ReadFile(name)  if err != nil {    return nil, err  }  dan := line.FindAllSubmatch(data, -1)  ans := make([]Danmu, len(dan))  for i := len(dan) - 1; i >= 0; i-- {    fill(&ans[i], dan[i])  }  return ans, nil} // 將彈幕排布并寫入w，采用的簡(jiǎn)單的固定移速、最小重疊排布算法func save(w io.Writer, dans []Danmu) {  p1 := make([]float64, 36)  p2 := make([]float64, 36)  p3 := make([]float64, 36)  t := 0  max := func(x []float64) float64 {    i := x[0]    for _, j := range x[1:] {      if i < j {        i = j      }    }    return i  }  set := func(x []float64, f float64) {    for i, _ := range x {      x[i] = f    }  }  find := func(p []float64, f float64, i, d int) int {    i = (i/d + 1) * d % 36    m, k := f+10000, 0    for j := 0; j < 36; j += d {      t := (i + j) % 36      if n := max(p[t : t+d]); n <= f {        k = t        break      } else if m > n {        k = t        m = n      }    }    return k  }  for _, dan := range dans {    s, l := "", length(dan.text)    if l == 0 {      continue    }    switch {    case dan.size < 25:      dan.size, l, s = 2, l*18, "http://fs18"    case dan.size == 25:      dan.size, l = 3, l*28    case dan.size > 25:      dan.size, l, s = 4, l*38, "http://fs38"    }    if dan.color != 0x00FFFFFF {      s += fmt.Sprintf("http://c&H%06X", dan.color)    }    switch dan.kind {    case 1: // 右往左      t := find(p1, dan.time, t, dan.size)      set(p1[t:t+dan.size], dan.time+8)      h := (t+dan.size)*10 - 1      s += fmt.Sprintf("http://move(%d,%d,%d,%d)", 640+int(l/2), h, -int(l/2), h)      fmt.Fprintf(w, "Dialogue: 1,%s,%s,Default,,0000,0000,0000,,{%s}%s/n",        timespot(dan.time+0),        timespot(dan.time+8), s, dan.text)    case 4: // 下現(xiàn)隱      j := find(p2, dan.time, 35, dan.size)      set(p2[j:j+dan.size], dan.time+4)      s += fmt.Sprintf("http://pos(%d,%d)", 320, (36-j)*10-1)      fmt.Fprintf(w, "Dialogue: 2,%s,%s,Default,,0000,0000,0000,,{%s}%s/n",        timespot(dan.time+0),        timespot(dan.time+4), s, dan.text)    case 5: // 上現(xiàn)隱      j := find(p3, dan.time, 35, dan.size)      set(p3[j:j+dan.size], dan.time+4)      s += fmt.Sprintf("http://pos(%d,%d)", 320, (j+dan.size)*10-1)      fmt.Fprintf(w, "Dialogue: 3,%s,%s,Default,,0000,0000,0000,,{%s}%s/n",        timespot(dan.time+0),        timespot(dan.time+4), s, dan.text)    }  }} // 主函數(shù)，實(shí)現(xiàn)了命令行func main() {  if len(os.Args) <= 1 {    os.Exit(0)  }  for _, name := range os.Args[1:] {    dans, err := open(name)    if err != nil {      os.Exit(1)    }    if n := strings.LastIndex(name, "."); n != -1 {      name = name[:n]    }    name += ".ass"    file, err := os.Create(name)    if err != nil {      os.Exit(2)    }    file.WriteString(header)    sort.Sort(Danmus(dans))    save(file, dans)    file.Close()  }}