Deprecation warning

Please note that this is outdated documentation for an older release of the Scandit Barcode Scanner SDK.

We are deprecating the 5.x API on all platforms (except Linux). Release 5.19 in April 2021 will be our final. Applications running 5.x will continue to work, and we will continue to release critical bug fixes and security patches only, for one year. We encourage you to migrate to 6.x and take advantage of our latest / advanced features and improved performance.

You'll find the updated documentation at: Data Capture SDK Documentation for Android

CommandLineBarcodeScannerCameraSample.c

Detecting Barcodes in a Camera Image Stream

This example uses the Scandit SDK to detect barcodes in frames from a camera.

This demo is currently limited to GNU/Linux systems with a Video4Linux 2 camera.

Low-End Devices

On slow hardware platforms like the Raspberry 2, 3 or Zero we recommend the following change to the sample: Set the define LOW_END_DEVICE_CONFIGURATION to 1 and run the sample with a resolution of 640x480.

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
// Please insert your app key here:
#define SCANDIT_SDK_LICENSE_KEY "-- INSERT YOUR LICENSE KEY HERE --"
// Please insert the desired default camera resolution here:
#define DEFAULT_RESOLUTION_WIDTH 1280
#define DEFAULT_RESOLUTION_HEIGHT 720
// Set this define to 1 of you run the demo on a device with slow hardware or no GPU support
// such as a Raspberry Pi Zero.
// It disables barcode search and only scans codes in the center image area.
#define LOW_END_DEVICE_CONFIGURATION 0
static volatile ScBool process_frames;
static void catch_exit(int signo) {
printf("SIGINT received.\n");
process_frames = SC_FALSE;
}
static void print_all_discrete_resolutions(const ScCamera *cam) {
printf("This camera uses discrete resolutions:\n");
ScSize resolution_array[20];
ScFramerate framerate_array[10];
const int32_t resolution_count = sc_camera_query_supported_resolutions(cam, &resolution_array[0], 20);
for (int32_t i = 0; i < resolution_count; i++) {
const int32_t framerate_count = sc_camera_query_supported_framerates(cam, resolution_array[i], framerate_array, 10);
for (int32_t j = 0; j < framerate_count; j++) {
const float fps = sc_framerate_get_fps(&framerate_array[j]);
printf("\t%u:%u @ %.2f FPS\n", resolution_array[i].width, resolution_array[i].height, fps);
}
}
}
int main(int argc, const char *argv[]) {
// Handle ctrl+c events.
if (signal(SIGINT, catch_exit) == SIG_ERR) {
printf("Could not set up signal handler.\n");
return -1;
}
// Create the camera object.
ScCamera *camera = NULL;
if (argc > 1) {
// Setup the camera from a device path. E.g. /dev/video1
// We use 4 image buffers.
camera = sc_camera_new_from_path(argv[1], 4);
} else {
// When no parameters are given, the camera is automatically detected.
camera = sc_camera_new();
}
if (camera == NULL) {
printf("No camera available.\n");
return -1;
}
uint32_t resolution_width = DEFAULT_RESOLUTION_WIDTH;
uint32_t resolution_height = DEFAULT_RESOLUTION_HEIGHT;
// Read the desired resolution form the command line.
if (argc == 4) {
resolution_width = atoi(argv[2]);
resolution_height = atoi(argv[3]);
}
// Get the supported resolutions and check
// if the desired resolution is supported.
ScBool supported = SC_FALSE;
const uint32_t resolutions_size = 30;
ScSize resolutions[resolutions_size];
int32_t resolutions_found;
switch (resm) {
print_all_discrete_resolutions(camera);
// The camera supports a small set of predefined resolutions
resolutions_found = sc_camera_query_supported_resolutions(camera, &resolutions[0], resolutions_size);
if (!resolutions_found) {
printf("There was an error getting the discrete resolution capabilities of the camera.\n");
return -1;
}
for (int i = 0; i < resolutions_found; i++) {
if (resolutions[i].width == resolution_width &&
resolutions[i].height == resolution_height) {
supported = SC_TRUE;
break;
}
}
break;
// The camera supports a wide range of resolutions that are
// generated step-wise. Refer to documentation for further
// explanation.
printf("There was an error getting the stepwise resolution capabilities of the camera.\n");
return -1;
}
printf("This camera uses step-wise resolutions:\n");
printf("\tx: %u:%u:%u\n", swres.min_width, swres.step_width, swres.max_width);
printf("\ty: %u:%u:%u\n", swres.min_height, swres.step_height, swres.max_height);
if (swres.min_width <= resolution_width &&
resolution_width <= swres.max_width &&
swres.min_height <= resolution_height &&
resolution_height <= swres.max_height &&
resolution_width % swres.step_width == 0 &&
resolution_height % swres.step_height == 0) {
supported = SC_TRUE;
}
break;
default:
printf("Could not get camera resolution mode.\n");
return -1;
}
// Set the resolution
if (!supported) {
printf("%dx%d is not supported by this camera.\nPlease specify a supported resolution on the command line or in the source code.\n", resolution_width, resolution_height);
return -1;
}
ScSize desired_resolution;
desired_resolution.width = resolution_width;
desired_resolution.height = resolution_height;
if (!sc_camera_request_resolution(camera, desired_resolution)) {
printf("Setting resolution failed.\n");
return -1;
}
// Start streaming.
if (!sc_camera_start_stream(camera)) {
printf("Start the camera failed.\n");
return -1;
}
// Create a recognition context. Files created by the recognition context and the
// attached scanners will be written to this directory. In production environment,
// it should be replaced with writable path which does not get removed between reboots
sc_recognition_context_new(SCANDIT_SDK_LICENSE_KEY, "/tmp", NULL);
if (context == NULL) {
printf("Could not initialize context.\n");
return -1;
}
// Create barcode scanner with EAN13/UPCA and QR code scanning enabled.
// The default preset is optimized for real-time frame processing using a
// camera.
if (settings == NULL) {
return -1;
}
// We want to scan at most one code per frame.
// We define the center area of the image to be the most likely location for a 1d barcode.
ScRectangleF code_location = { .position.x = 0.f, .position.y = 0.4f,
.size.width = 1.0f, .size.height = 0.2f };
// We keep the area for 2d codes to the default (whole image).
#if LOW_END_DEVICE_CONFIGURATION
// Scan at the code location area exclusively.
// This disables full image search to speed up procesing.
#else
// Search in the full image but occasionally check the code loaction too.
#endif
// Only keep codes for one frame and do not accumulate anything.
// Our camera has no auto-focus.
// Codes are most likely oriented from left to right.
// Create a barcode scanner for our context and settings.
if (scanner == NULL) {
return -1;
}
// The scanner is setup asynchronous.
// We could wait here using sc_barcode_scanner_wait_for_setup_completed if needed.
// Access the barcode scanner session. It collects all the results.
// Signal a new frame sequence to the context.
// Create an image description that is reused for every frame.
process_frames = SC_TRUE;
while (process_frames) {
// Get the latest camera frame data and description.
const uint8_t *image_data = sc_camera_get_frame(camera, image_descr);
if (image_data == NULL) {
printf("Frame access failed. Exiting.\n");
break;
}
// Process the frame.
ScProcessFrameResult result = sc_recognition_context_process_frame(context, image_descr, image_data);
printf("Processing frame failed with error %d: '%s'\n", result.status,
}
// Get the results. If there is a barcode, print it!
int code_count = sc_barcode_array_get_size(new_codes);
for (int i = 0; i < code_count; i++) {
const ScBarcode * code = sc_barcode_array_get_item_at(new_codes, i);
printf("Barcode found: '%s'\n", data.str);
}
// Signal the camera that we are done reading the image buffer.
sc_camera_enqueue_frame_data(camera, image_data);
// Cleanup the memory we used.
}
// Signal to the context that the frame sequence is finished.
// Cleanup all objects.
}