A failed decode does not identify one cause by itself. Check the file or camera state first, then inspect the symbol’s focus, contrast, boundaries, damage, perspective, and format support.
Use a JPG, PNG, WebP, or SVG file within the size limit, or confirm that the camera stream is active and permitted.
Check whether the current scanner manifest declares the barcode symbology you are trying to read.
Look for blur, glare, shadows, low contrast, compression artifacts, missing edges, or excessive perspective.
Change distance, angle, lighting, orientation, or camera, or capture a sharper image and use the image scanner.
The decoder must distinguish individual bars, spaces, modules, and finder patterns. Motion blur, missed focus, aggressive resizing, or heavy compression can merge neighboring elements.
Try: Steady the device, let autofocus settle, move to a distance where the symbol is sharp, or capture a higher-quality image without digital zoom.
Reflections can erase dark modules, while shadows can fill light spaces. Glossy packaging and screens are common sources of uneven contrast.
Try: Move the light source, tilt the item slightly, reduce screen brightness, or use diffuse light from more than one direction.
Faded ink, thermal-print gaps, textured materials, colored backgrounds, or insufficient module size can reduce the distinction the decoder needs.
Try: Use the original label or source file, improve lighting, increase print scale, or reprint according to the specification required by the receiving system.
Tears, scratches, folds, stickers, and cropped edges can remove encoded data or orientation patterns. Error correction may help some 2D formats, but recovery depends on the format, settings, and damaged location.
Try: Flatten the label, remove removable obstructions without damaging it, capture another side or copy, or enter the printed number manually when the format provides one.
Barcode formats define clear space around the symbol. The required amount varies by symbology and scale, so a fixed margin is not correct for every barcode.
Try: Include more blank background around every edge and remove nearby text or graphics from the crop.
A steep camera angle or curved package can distort bars and modules unevenly.
Try: Face the symbol more directly, flatten flexible packaging, or take several images from moderate angles.
A high-resolution photo can still fail when the barcode occupies only a small part of the image.
Try: Move closer while maintaining focus, crop around the symbol without removing its quiet zone, or use a higher-resolution source.
The decoder may handle rotation, but blur, perspective, and partial cropping can make a rotated symbol harder to interpret.
Try: Use the rotate controls in the image scanner and compare several orientations.
| Problem | What it means | What to do |
|---|---|---|
| Unsupported image | The image scanner accepts JPG, PNG, WebP, and SVG files up to 10 MB. | Convert the source to a supported type, reduce its file size, and try again. |
| Unsupported symbology | The visible symbol is not declared in the current decoder manifest. | Review the barcode types comparison and use a decoder that supports the required format. |
| Camera denied or unavailable | The browser cannot obtain a usable camera stream. | Allow site permission, close other camera applications, reconnect the device, or use an uploaded photo. |
| No result after processing | The engine completed without finding a supported readable symbol. | Do not assume the number. Improve the capture or use another trusted source for manual entry. |
Manual entry is not a substitute for decoding