Using the Video API | StereoLabs

The ZED API provides low-level access to the camera hardware and video features, facilitating camera control and high-quality video recording and streaming.

Camera Configuration

To configure the camera, create a Camera object and specify your InitParameters. Initial parameters let you adjust camera resolution, FPS, depth sensing parameters and more. These parameters can only be set before opening the camera and cannot be changed while the camera is in use.

InitParameters contains a default configuration.

1 // Create a ZED camera object
2 Camera zed;
3 
4 // Set configuration parameters
5 InitParameters init_params;
6 init_params.camera_resolution = RESOLUTION::HD1080;
7 init_params.camera_fps = 30;
8 
9 // Open the camera
10 ERROR_CODE err = zed.open(init_params);
11 if (err != SUCCESS)
12     exit(-1);

Camera settings such as exposure, white balance and others can be manually set at runtime using setCameraSettings().

1 // Set exposure in manual mode at 50% of camera framerate
2 zed.setCameraSettings(VIDEO_SETTINGS::EXPOSURE, 50);
3 // Set white balance to 4600K
4 zed.setCameraSettings(VIDEO_SETTINGS::WHITE_BALANCE, 4600);
5 // Reset to auto exposure
6 zed.setCameraSettings(VIDEO_SETTINGS::EXPOSURE, -1);

To see the list of available video modes and settings, read Camera Controls.

Image Capture

To capture images from the ZED, specify your RuntimeParameters and call grab() to grab a new frame and retrieveImage() to retrieve the grabbed frame. retrieveImage() lets you select between different views such as left, right, unrectified and grayscale images.

1 sl::Mat image;
2 if (zed.grab() == ERROR_CODE::SUCCESS) {
3     // A new image is available if grab() returns SUCCESS
4     zed.retrieveImage(image, VIEW::LEFT); // Retrieve the left image
5 }

Video Recording

The ZED SDK uses StereoLabs’ SVO format to store videos along with additional metadata such as timestamps and sensor data.

To record SVO files, you need to enable the Recording module with enableRecording(). Specify an output file name (eg: output.svo) and SVO_COMPRESSION_MODE, then save each grabbed frame using record(). SVO lets you record video and associated metadata (timestamp, IMU data and more if available).

1 // Create a ZED camera object
2 Camera zed;
3 
4 // Enable recording with the filename specified in argument
5 String output_path(argv[1]);
6 RecordingParameters recordingParameters;
7 recordingParameters.compression_mode = SVO_COMPRESSION_MODE::H264;
8 recordingParameters.video_filename = output_path;
9 err = zed.enableRecording(recordingParameters);
10 
11 while (!exit_app) {
12     // Each new frame is added to the SVO file
13     zed.grab();
14 }
15 // Disable recording
16 zed.disableRecording();

Video Playback

To play SVO files, simply add the file path as an argument in setFromSVOFile(). When loading SVO files, the ZED API will behave as if a ZED was connected and a live feed was available. Every module of the ZED API will be available: depth, tracking, spatial mapping and more. When an SVO file is read entirely, END_OF_SVOFILE_REACHED error code is returned.

1 // Create a ZED camera object
2 Camera zed;
3 
4 // Set SVO path for playback
5 String input_path(argv[1]);
6 InitParameters init_parameters;
7 init_parameters.input.setFromSVOFile(input_path);
8 
9 // Open the ZED
10 ERROR_CODE err = zed.open(init_parameters);
11 
12 sl::Mat svo_image;
13 while (!exit_app) {
14     if (zed.grab(ref runtimeParameters) == ERROR_CODE::SUCCESS) {
15         // Read side by side frames stored in the SVO
16         zed.retrieveImage(svo_image, VIEW::SIDE_BY_SIDE);
17         // Get frame count      
18         int svo_position = zed.getSVOPosition();
19     }
20     else if (zed.grab() == ERROR_CODE::END_OF_SVOFILE_REACHED) {
21         std::cout << "SVO end has been reached. Looping back to first frame" << std::endl;
22         zed.setSVOPosition(0);
23     }
24 }

Local Streaming

To learn how to stream stereo video on the local network using the ZED SDK, read Local Streaming section.

Code Examples

Get started with stereo video capture, recording and streaming using the following code samples on GitHub: