example of creating webm from webp

[LazarenkoA]

I have frames (webp files) I want to create a webm video out of them can I do it using your code?

[LazarenkoA]

or from image.Image

[at-wat]

Creating WebM video from images basically requires:

1. parse images
2. encode images to a video by VP8 or VP9 codec
3. store encoded video as WebM

This package handles 3, and you need to write 1 and 2.

[LazarenkoA]

to convert image to webp i use github.com/chai2010/webp but when i start to write frames to video, the video then doesn't play.

I can show the code if you want

[LazarenkoA]

it turned out to convert to vp8 (I used another converter), the video is played on the front (via WebRTC), how to use your package to get the video, I can't figure out. I would like an example that periodically takes an array of bytes and writes them to a file

[at-wat]

You can check https://github.com/pion/example-webrtc-applications/tree/master/save-to-webm if encoding part is done

[LazarenkoA]

I was guided by this example, but since PushVP8 does not accept an array of bytes, I call it like this

w.PushVP8(&rtp.Packet{Payload: data	})

where data is an array of bytes, but on the line
sample := s.videoBuilder.Pop() sample is always equal to nil

func newWebmSaver() *webmSaver {
	return &webmSaver{
		videoBuilder: samplebuilder.New(10, &codecs.VP8Packet{}, 90000),
	}
}
func (s *webmSaver) InitWriter(width, height int) webm.BlockWriteCloser {
	w, err := os.OpenFile("/Users/20128315/Documents/GIT/screenRecorder/test.webm", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		panic(err)
	}

	ws, err := webm.NewSimpleBlockWriter(w,
		[]webm.TrackEntry{
			{
				Name:            "Video",
				TrackNumber:     2,
				TrackUID:        67890,
				CodecID:         "V_VP8",
				TrackType:       1,
				DefaultDuration: 33333333,
				Video: &webm.Video{
					PixelWidth:  uint64(width),
					PixelHeight: uint64(height),
				},
			},
		})
	if err != nil {
		panic(err)
	}
	fmt.Printf("WebM saver has started with video width=%d, height=%d\n", width, height)

	return ws[0]
}
func (s *webmSaver) Close() {
	fmt.Printf("Finalizing webm...\n")
	if s.videoWriter != nil {
		if err := s.videoWriter.Close(); err != nil {
			panic(err)
		}
	}
}
func (s *webmSaver) PushVP8(rtpPacket *rtp.Packet) {
	s.videoBuilder.Push(rtpPacket)

	for {
		sample := s.videoBuilder.Pop()
		if sample == nil {
			return
		}
		// Read VP8 header.
		videoKeyframe := (sample.Data[0]&0x1 == 0)
		if videoKeyframe {
			// Keyframe has frame information.
			raw := uint(sample.Data[6]) | uint(sample.Data[7])<<8 | uint(sample.Data[8])<<16 | uint(sample.Data[9])<<24
			width := int(raw & 0x3FFF)
			height := int((raw >> 16) & 0x3FFF)

			if s.videoWriter == nil {
				// Initialize WebM saver using received frame size.
				s.InitWriter(width, height)
			}
		}
		if s.videoWriter != nil {
			s.videoTimestamp += sample.Duration
			if _, err := s.videoWriter.Write(videoKeyframe, int64(s.videoTimestamp/time.Millisecond), sample.Data); err != nil {
				panic(err)
			}
		}
	}
}

[at-wat]

samplebuilder.SampleBuilder is a class to reconstruct frames from partitioned RTP packets, and it requires RTP sequence number and timestamp.
As you already have frames without partitioning, you need to unuse SampleBuilder.

[LazarenkoA]

full story:
a stream of bytes comes from one application (screen agent) to the screen server. Task of the screen server is to send them to the front via webrtc and write them to a file (so that you can view it later), but this does not work with writing to a file, tell me, can your package be used to solve this problem?