How to Use the 'zbarcam' Command (with Examples)

The zbarcam command is a versatile tool designed to scan and decode barcodes and QR codes from a video device on Linux systems. It is part of the ZBar suite, which is a set of software programs capable of reading barcodes from various sources, including video and image files. The zbarcam functionality is particularly aligned with real-time scanning needs, leveraging video capture devices such as webcams to detect and decode the data encoded in barcodes swiftly and efficiently.

Use Case 1: Continuously Read Barcodes and Print Them to stdout

Code:

zbarcam

Motivation:

This use case is beneficial for scenarios where ongoing barcode scanning is needed, such as in inventory systems, retail checkouts, or library lending stations. The ability to continuously read and immediately display barcode data ensures seamless operation without frequent manual interventions.

Explanation:

• zbarcam: Initiates the barcode scanning from the default video input device. No additional options are specified here, which means that each barcode detected will be displayed on the terminal’s standard output (stdout) as it’s scanned. This provides a straightforward, real-time feed of scanned data.

Example Output:

QR-Code:http://example.com
EAN-13:9781234567897
CODE-128:A123456B

Use Case 2: Disable Output Video Window While Scanning

Code:

zbarcam --nodisplay

Motivation:

In certain environments, displaying the video feed while scanning may be unnecessary or distracting. For example, backend systems where only the decoded data matter or resource-constrained systems where performance needs to be optimized by not rendering video content.

Explanation:

• --nodisplay: This option disables the display of the video window. The scanning operation continues in the background, and only the decoded barcode data is presented. This mode is efficient for conserving system resources by not engaging the graphical output processes.

Example Output:

QR-Code:http://example.com
EAN-13:9781234567897
CODE-128:A123456B

Use Case 3: Print Barcodes Without Type Information

Code:

zbarcam --raw

Motivation:

When the focus is solely on the content of the barcode without concern for the type of barcode being scanned, this mode proves useful. Such scenarios could involve data logging systems where only the encoded information is needed for further processing, stripping away unnecessary details like type annotations.

Explanation:

• --raw: Instructs zbarcam to output only the raw decoded data, omitting the type information prefixes. This concise output can be particularly helpful when processing scanned data through scripts or other software that expects only the essential payload.

Example Output:

http://example.com
9781234567897
A123456B

Use Case 4: Define Capture Device

Code:

zbarcam /dev/video_device

Motivation:

This use case is crucial for systems with multiple video input devices. Specifying the capture device allows users to direct the barcode scanning process to the correct input source, which is particularly important for setups with various webcams or external cameras attached.

Explanation:

• /dev/video_device: Represents the specific video input device file. Linux system devices like cameras are often listed under /dev/. Here, the user needs to replace /dev/video_device with the appropriate path to the desired video input device (e.g., /dev/video0).

Example Output:

QR-Code:http://example.com
EAN-13:9781234567897
CODE-128:A123456B

Conclusion

The zbarcam command is a powerful utility for decoding barcodes via video inputs in real-time, with various options to customize its behavior based on user needs. Whether it’s for performance improvement, minimalistic output, or choosing specific hardware devices, zbarcam provides flexible configurations to suit different application scenarios. Understanding these options enables users to integrate barcode scanning capabilities seamlessly into their workflows.