Capture streaming video

Streaming video can be recorded with Miqus Video/Video+/Hybrid cameras and the Oqus 2c color video camera. When using streaming video, compressed video data is sent to QTM during the capture, allowing for long video captures.

In-camera MJPEG compression

The functionality to stream MJPEG compressed video is available on most Qualisys camera models, except the older Oqus camera models. In this mode, the image will be compressed in the camera before it is sent to QTM. This will reduce the amount of data that is sent so that you can measure video for an unlimited amount of time.

The available capture rates are lower than those for uncompressed video since the camera has to process the image. For example, on the Oqus 2c video camera at 1920*1080 the video capture rate is limited to 24 Hz. There are multiple high-speed sensor modes available on the 2c and 5+ series. These can be used if you want to have a higher capture rate, but want to keep the Full FOV at a reduced resolution, see chapter Sensor mode and Qualisys video sensor specifications (in-camera MJPEG).

The in-camera MJPEG compression is selected with the Video compression option, either on the Camera settings sidebar or on the Cameras page in the Project options dialog, see chapter Camera settings sidebar and Video compression. The in-camera MJPEG compression is default when it is available. Miqus Video cameras always uses in-camera MJPEG compression, so it is not available as an option.

You can specify the quality of the MJPEG codec on the Cameras page. The default quality is 50, you can increase it if you want higher quality but then the file will be larger.

The video file will be saved with MJPEG compression. Therefore, the computer needs to have codec that can read it to play the file. Mostly, Windows computers can play videos compressed with MJPEG codec without having to install a specific codec.

Streaming Video settings

The settings of streaming video cameras (Miqus Video, Miqus Video Plus and Oqus 2c) are available under the Streaming Video settings in the Camera settings sidebar. The Camera settings sidebar allows to adjust basic settings, see chapter Camera settings sidebar. Advanced video settings are available on the Cameras page in the Project options, see chapter Video settings.

The following steps show how you can change the settings for streaming video cameras.

  1. Choose the video capture rate. The buttons show a selection of common video capture rates. Integer divisions or multiples of the current marker capture rate are indicated bold. Note that the maximum frequency, as well as the frequency values of the buttons, may change depending on the selected resolution and aspect ratio (steps 2 and 3).

  2. Choose the video image resolution. The buttons show standard image resolutions available on the Miqus Video. Note that the field of view (FOV) may change depending on the resolution setting.

  3. Choose the aspect ratio. The buttons show standard aspect ratios of 16:9, 4:3 and 1:1.

  4. Set the exposure.

    • When using Auto Exposure, you can set the Exposure Compensation to get a brighter or darker image. You can also select the area on which the auto exposure is based using the Auto Exposure Tool on the 2D view Toolbar (see 2D view toolbar).

    • When Auto Exposure is unchecked, you can manually set the exposure by setting the Exposure Time and selecting the Gain.

The file size of the recorded videos can become very large when using a high resolution and a high video capture frequency. If you need the video for documentation purposes, you can reduce the file size considerably by using a lower resolution and a lower capture frequency (e.g. 540p @25 Hz).

Maximum capture rate for streaming video

The maximum capture rate for streaming video cameras depends on the selected resolution and aspect ratio. The available capture frequency range for the current combination of settings is shown under Video settings on the Cameras page in Project options. The below Tables give an overview of the maximum frequency values for Miqus Video and Oqus 2c.

Miqus Video (VC+)

Maximum video capture frequency (in Hz) as a function of resolution and aspect ratio for Miqus VC+.

  16:9 4:3 1:1
1440p - 100 120
1080p 120 160 180
720p - 400 480
540p 440 480 480

Miqus Video (VC, VM)

Maximum video capture frequency (in Hz) as a function of resolution and aspect ratio for Miqus VC and VM.

  16:9 4:3 1:1
1080p 86 111 149
720p 180 237 292
540p 333 428 565
480p 416 550 714

Oqus 2c

Maximum video capture frequency (in Hz) as a function of resolution and aspect ratio for Oqus 2c.

  16:9 4:3 1:1
1080p 24 32 41
720p 53 68 86
540p 62 77 94
480p 77 95 116