For each file type, I show one of the test images with 1 and 4 B/MB corruption applied to it.Īt low levels of corruption, 2 bytes in a 2 MB image and 4 bytes in a 4 MB image, visual artefact was limited to a partial horizontal line, which multiplied and became more prominent as corruption rose to 8 and 16 bytes respectively. All the corrupted images could be opened successfully, but a few lost all usable content. This wasn’t possible with raw or TIFF images though, whose minimum sizes were 4.7 and 6.1 MB respectively.Įven using very low rates of data corruption of 1-4 B/MB, most images suffered substantial damage, much of which would be difficult if not impossible to repair well. Wherever possible, I’ve used smaller image files of 1-2 MB, so that Vandal can produce 1-8 changed bytes in each image. I looked at images from a range of sources in five popular formats: TIFF, PNG, JPEG, HEIC (from an iPhone XR), and some different camera ‘raw’ formats. Vandal isn’t a model for any specific type of corruption, merely a tool for producing single byte changes of this type. Some ‘natural’ errors won’t involve single bytes like that, but might flip single bits others might change whole sectors at a time. It’s important to understand that doesn’t try to mimic any particular type of data corruption, but provides precise, evenly spread randomised changes to data at a byte level. This article describes some results from tests in which I’ve deliberately corrupted test images in different formats using my tool Vandal.
With many of us now using iOS devices to capture important images comes another question: should you store those in their original HEIC format, or convert them to something else?
Common practice for many is to store original ‘raw’ files for reference, and to keep another copy (perhaps fully processed) in a different format. Whether you just want to put important family photos into safe storage, or you’re more serious about your digital photography, you’ll want archived images to have the best possible chance of surviving for years.
#Corrupt photo reader as filetype archive#
One of the most common types of file to want to archive reliably is the digital image.
0 kommentar(er)
