Motion-JPEG over HTTP

A toolset that allows to take video buffers using v4l2 and streams them over HTTP in Motion-JPEG. Designed to handle the resources efficiently.

Plug-in a web camera and run:

$ ./bin/mjpeg-over-http
Host................: 0.0.0.0
Port................: 8080
Authorization: Basic: disabled
Device..............: /dev/video0
Image size..........: 640x480

• Now you can access the video stream by openning http://127.0.0.1:8080/stream in a browser,
• or inserting html tag <img src="http://127.0.0.1:8080/stream" /> to your webpage.
• http://127.0.0.1:8080/snapshot could be used to get a snapshot from the camera.
• Some clients such as QuickTime or VLC also can be used to view the stream.

The solution consists of several separate tools:

Capture::v4l2

A wrapper of Video4Linux to simplify reading of video frames from a camera.

Currently supports only V4L2_BUF_TYPE_VIDEO_CAPTURE buffer type and V4L2_MEMORY_MMAP memory.

By default Motion-JPEG (V4L2_PIX_FMT_MJPEG) is used.

Useful when there is no GStreamer available but need to process video buffers.

Capture::v4l2 cap("/dev/video0");
if (!cap.start(1920, 1080))
  return;

auto frame = cap.read_frame();
if (frame) {
  FILE *fp = fopen("frame.jpg", "wb");
  fwrite(frame.data(), frame.size(), 1, fp);
  fclose(fp);
}

Capture::socket

Used to handle TCP/IP connections.

Capture::socket_listener s;
// Opens port for connections
if (!s.listen(hostname, port)))
  return;

// A thread to handle connections
Capture::socket_thread worker_thread;
worker_thread.start(
  [&](auto &batch) {
    for (auto &socket : batch)
      socket.write(response);
  });

while (!stop) {
  // Waits for new connection and pushes it to worker thread
  s.accept([&](auto socket) {
    worker_thread.push(std::move(socket));
  });
}

Capture::http_request is also useful to handle http requests:

  Capture::http_request http(socket);

  if (credentials != http.basic_authorization()) {
    socket.write(access_denied);
    return;
  }

  if (http.uri() == "/data") {
      if (!socket.write(data))
          return;
  }

Qt5Multimedia example

There is an example in examples/receiver that shows how to use Capture::mjpeg_stream to parse the video stream and render it to VideoOutput QML item, or QVideoWidget or QGraphicsVideoItem:

  QNetworkAccessManager qnam;
  auto reply = qnam.get(QNetworkRequest(QUrl("http://127.0.0.1:8080/stream")));
  Capture::mjpeg_stream stream([&](const unsigned char *data, size_t size) {
    QVideoFrame frame = QImage::fromData(data, size, "JPG");
    if (!videoOutput->videoSurface()->isActive()) {
      QVideoSurfaceFormat format(frame.size(), frame.pixelFormat());
      videoOutput->videoSurface()->start(format);
    }
    videoOutput->videoSurface()->present(frame);
  });

  QObject::connect(reply, &QIODevice::readyRead, [&]{
    auto d = reply->readAll();
    stream.read(d.constData(), d.size());
  });

Build

$ meson build --prefix=/path/to/install
$ ninja install -C build/