streaming

commit 69e6191557711b6dd82b524cd204458310fea746
parent 77cd9c1576a8929f7aed8cc9f81a8efca01130fd
Author: Oliver Lowe <o@olowe.co>
Date:   Fri, 17 May 2024 13:01:20 +1000

m3u8: implement basic playlist encoding/writing

This is enough to encode the simplest playlist from
test-streams.mux.dev. Plays ok in VLC, QuickTime, ffplay(1).

Diffstat:
A
m3u8/write.go
 | 
24
++++++++++++++++++++++++
A
m3u8/write_test.go
 | 
34
++++++++++++++++++++++++++++++++++

2 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/m3u8/write.go b/m3u8/write.go
@@ -0,0 +1,24 @@
+package m3u8
+
+import (
+	"fmt"
+	"io"
+	"time"
+)
+
+func Encode(w io.Writer, p *Playlist) error {
+	fmt.Fprintln(w, "#EXTM3U")
+	fmt.Fprintf(w, "%s:%d\n", tagVersion, p.Version)
+	fmt.Fprintf(w, "%s:%s\n", tagPlaylistType, p.Type)
+	fmt.Fprintf(w, "%s:%d\n", tagTargetDuration, p.TargetDuration/time.Second)
+	for _, seg := range p.Segments {
+		us := seg.Duration / time.Microsecond
+		// we do .03f for the same precision as test-streams.mux.dev.
+		fmt.Fprintf(w, "%s:%.03f\n", tagSegmentDuration, float32(us)/1e6)
+		fmt.Fprintln(w, seg.URI)
+	}
+	if p.End {
+		fmt.Fprintln(w, tagEndList)
+	}
+	return nil
+}
diff --git a/m3u8/write_test.go b/m3u8/write_test.go
@@ -0,0 +1,34 @@
+package m3u8
+
+import (
+	"bufio"
+	"bytes"
+	"testing"
+	"time"
+)
+
+func TestEncodeSegDuration(t *testing.T) {
+	plist := &Playlist{
+		Version:  7,
+		Segments: []Segment{{Duration: 9967 * time.Millisecond}},
+	}
+	buf := &bytes.Buffer{}
+	if err := Encode(buf, plist); err != nil {
+		t.Fatal(err)
+	}
+	sc := bufio.NewScanner(buf)
+	var linenum = 1
+	var found bool
+	want := "#EXTINF:9.967"
+	for sc.Scan() {
+		t.Log(sc.Text())
+		if sc.Text() == want {
+			found = true
+			return
+		}
+		linenum++
+	}
+	if !found {
+		t.Errorf("no matching segment duration %s", want)
+	}
+}