improve examples (#708)

examples/client-record-pause/dummy_image.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"image"
+	"image/color"
+)
+
+var dummyImageCount = 0
+
+func createDummyImage() *image.RGBA {
+	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
+
+	var cl color.RGBA
+	switch dummyImageCount {
+	case 0:
+		cl = color.RGBA{255, 0, 0, 0}
+	case 1:
+		cl = color.RGBA{0, 255, 0, 0}
+	case 2:
+		cl = color.RGBA{0, 0, 255, 0}
+	}
+	dummyImageCount = (dummyImageCount + 1) % 3
+
+	for y := 0; y < img.Rect.Dy(); y++ {
+		for x := 0; x < img.Rect.Dx(); x++ {
+			img.SetRGBA(x, y, cl)
+		}
+	}
+
+	return img
+}

examples/client-record-pause/h264_encoder.go

@@ -86,6 +86,8 @@ func (d *h264Encoder) initialize() error {
 
 	res = C.av_frame_get_buffer(d.rgbaFrame, 0)
 	if res < 0 {
+		C.av_frame_free(&d.rgbaFrame)
+		C.avcodec_close(d.codecCtx)
 		return fmt.Errorf("av_frame_get_buffer() failed")
 	}
 
@@ -102,6 +104,9 @@ func (d *h264Encoder) initialize() error {
 
 	res = C.av_frame_get_buffer(d.yuv420Frame, 0)
 	if res < 0 {
+		C.av_frame_free(&d.yuv420Frame)
+		C.av_frame_free(&d.rgbaFrame)
+		C.avcodec_close(d.codecCtx)
 		return fmt.Errorf("av_frame_get_buffer() failed")
 	}
 
@@ -116,7 +121,6 @@ func (d *h264Encoder) initialize() error {
 
 	d.pkt = C.av_packet_alloc()
 	if d.pkt == nil {
-		C.av_packet_free(&d.pkt)
 		C.av_frame_free(&d.yuv420Frame)
 		C.av_frame_free(&d.rgbaFrame)
 		C.avcodec_close(d.codecCtx)

examples/client-record-pause/main.go

@@ -4,8 +4,6 @@ package main
 
 import (
 	"crypto/rand"
-	"image"
-	"image/color"
 	"log"
 	"time"
 
@@ -24,7 +22,7 @@ import (
 // 7. repeat
 
 // This example requires the FFmpeg libraries, that can be installed with this command:
-// apt install -y libavformat-dev libswscale-dev gcc pkg-config
+// apt install -y libavcodec-dev libswscale-dev gcc pkg-config
 
 func multiplyAndDivide(v, m, d int64) int64 {
 	secs := v / d
@@ -41,28 +39,6 @@ func randUint32() (uint32, error) {
 	return uint32(b[0])<<24 | uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3]), nil
 }
 
-func createDummyImage(i int) *image.RGBA {
-	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
-
-	var cl color.RGBA
-	switch i {
-	case 0:
-		cl = color.RGBA{255, 0, 0, 0}
-	case 1:
-		cl = color.RGBA{0, 255, 0, 0}
-	case 2:
-		cl = color.RGBA{0, 0, 255, 0}
-	}
-
-	for y := 0; y < img.Rect.Dy(); y++ {
-		for x := 0; x < img.Rect.Dx(); x++ {
-			img.SetRGBA(x, y, cl)
-		}
-	}
-
-	return img
-}
-
 func main() {
 	// create a stream description that contains a H264 format
 	forma := &format.H264{
@@ -114,16 +90,13 @@ func main() {
 		ticker := time.NewTicker(200 * time.Millisecond)
 		defer ticker.Stop()
 
-		i := 0
-
 		for range ticker.C {
-			// create a dummy image
-			img := createDummyImage(i)
-			i = (i + 1) % 3
-
 			// get current timestamp
 			pts := multiplyAndDivide(int64(time.Since(start)), int64(forma.ClockRate()), int64(time.Second))
 
+			// create a dummy image
+			img := createDummyImage()
+
 			// encode the image with H264
 			au, pts, err := h264enc.encode(img, pts)
 			if err != nil {
@@ -145,7 +118,7 @@ func main() {
 
 			// write RTP packets to the server
 			for _, pkt := range pkts {
-				pkt.Timestamp = uint32(int64(randomStart) + pts)
+				pkt.Timestamp += uint32(int64(randomStart) + pts)
 
 				err = c.WritePacketRTP(desc.Medias[0], pkt)
 				if err != nil {