1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
package downloader
import (
"io/ioutil"
"os"
"os/exec"
"strconv"
"sync"
"time"
"github.com/mammothbane/thulani-go/wav"
)
// downloader handles a download for a particular song.
type downloader struct {
Url string
StartTime time.Duration
Duration time.Duration
EndTime time.Duration
once sync.Once
done chan struct{}
pb chan *wavBundle
info videoInfo
}
const clipTime = 10 * time.Second
const preloadCount = 5
func newDownload(url string, startTime, dur time.Duration) (*downloader, error) {
vInfo, err := info(url)
if err != nil {
return nil, err
}
if dur == 0 {
dur = vInfo.Duration - startTime
}
dl := &downloader{
Url: url,
StartTime: startTime,
Duration: dur,
EndTime: startTime + dur,
done: make(chan struct{}, 1),
pb: make(chan *wavBundle, preloadCount),
info: *vInfo,
}
go dl.schedule()
return dl, nil
}
func (d *downloader) Stop() {
d.once.Do(func() {
close(d.done)
})
}
func (d *downloader) Start() (<-chan []byte, <-chan struct{}) {
out := make(chan []byte, 1024)
done := make(chan struct{}, 1)
go func() {
defer close(done)
defer close(out)
for wavB := range d.pb {
wavB.wav.Start(out)
select {
case <-d.done:
wavB.wav.Stop()
wavB.cleanup()
case <-wavB.wav.Done:
break
}
}
}()
return out, done
}
func (d *downloader) schedule() {
defer close(d.pb)
for i := 0; ; i++ {
clipStart := time.Duration(i)*clipTime + d.StartTime
clipEnd := time.Duration(i+1)*clipTime + d.StartTime
if clipStart >= d.EndTime {
return
}
dur := clipTime
if clipEnd > d.EndTime {
dur = d.EndTime - clipStart
}
wavb, err := d.downloadSegment(clipStart, dur)
if err != nil {
log.Errorf("error setting up download: %q", err)
return
}
d.pb <- wavb
}
}
func (d *downloader) downloadSegment(startTime, duration time.Duration) (*wavBundle, error) {
startSecond := int(startTime.Seconds())
args := []string{
"-ss", strconv.Itoa(startSecond),
"-i", d.info.Url.String(),
"-c:a", "pcm_s16le",
"-f", "wav",
"-ar", "48000",
"-ac", "2",
"-vn", "-y",
}
dur := int(duration.Seconds())
if dur > 0 && startTime+duration < d.info.Duration {
args = append(args, "-t", strconv.Itoa(dur))
}
file, err := ioutil.TempFile("", "thulani_")
if err != nil {
return nil, err
}
clearTemp := func() {
if err := file.Close(); err != nil {
log.Errorf("error closing temp file: %q", err)
}
if err := os.Remove(file.Name()); err != nil {
log.Errorf("unable to remove temp file: %q", err)
}
}
args = append(args, file.Name())
dl := exec.Command(`ffmpeg`, args...)
b, err := dl.CombinedOutput()
if err != nil {
clearTemp()
log.Errorf("ffmpeg failed: \n%v", string(b))
return nil, err
}
wv, err := wav.New(file.Name())
if err != nil {
clearTemp()
return nil, err
}
return &wavBundle{wav: wv, cleanup: clearTemp}, err
}
|
