revid,stream/flv: add back initial header write

revid/revid.go

@@ -289,7 +289,10 @@ func (r *Revid) reset(config Config) error {
 		r.encoder = mts.NewEncoder(&r.packer, float64(r.config.FrameRate))
 	case Flv:
 		r.config.Logger.Log(logger.Info, pkg+"using FLV packetisation")
-		r.encoder = flv.NewEncoder(&r.packer, true, true, int(r.config.FrameRate))
+		r.encoder, err = flv.NewEncoder(&r.packer, true, true, int(r.config.FrameRate))
+		if err != nil {
+			r.config.Logger.Log(logger.Fatal, pkg+"failed to open FLV encoder", err.Error())
+		}
 	}
 
 	return nil

rtmp/rtmp_test.go

@@ -180,7 +180,10 @@ func TestFromFrame(t *testing.T) {
 	// ToDo: fix this. Although we can encode the file and YouTube
 	// doesn't complain, YouTube doesn't play it (even when we
 	// send 1 minute's worth).
-	flvEncoder := flv.NewEncoder(s, true, true, 25)
+	flvEncoder, err := flv.NewEncoder(s, true, true, 25)
+	if err != nil {
+		t.Fatalf("failed to create encoder: %v", err)
+	}
 	for i := 0; i < 25; i++ {
 		err := flvEncoder.Encode(b)
 		if err != nil {
@@ -219,7 +222,10 @@ func TestFromFile(t *testing.T) {
 	defer f.Close()
 
 	// Pass RTMP session, true for audio, true for video, and 25 FPS
-	flvEncoder := flv.NewEncoder(s, true, true, 25)
+	flvEncoder, err := flv.NewEncoder(s, true, true, 25)
+	if err != nil {
+		t.Fatalf("failed to create encoder: %v", err)
+	}
 	err = lex.H264(flvEncoder, f, time.Second/time.Duration(25))
 	if err != nil {
 		t.Errorf("Lexing and encoding failed with error: %v", err)

stream/flv/encoder.go

@@ -66,13 +66,18 @@ type Encoder struct {
 }
 
 // NewEncoder retuns a new FLV encoder.
-func NewEncoder(dst io.Writer, audio, video bool, fps int) *Encoder {
-	return &Encoder{
+func NewEncoder(dst io.Writer, audio, video bool, fps int) (*Encoder, error) {
+	e := Encoder{
 		dst:   dst,
 		fps:   fps,
 		audio: audio,
 		video: video,
 	}
+	_, err := dst.Write(e.HeaderBytes())
+	if err != nil {
+		return nil, err
+	}
+	return &e, err
 }
 
 // HeaderBytes returns the a