Datamatrix uses ECC200 almost always. In practice, especially for phone-reader applications, the limiting factor for data transmission is not the symbology choi

Datamatrix uses ECC200 almost always. In practice, especially for phone-reader applications, the limiting factor for data transmission is not the symbology choice (datamatrix/QR) but limitations from the camera. That said dense 2D barcodes read by dedicated imagers in controlled lighting scenarios, as far as I've seen, are always datamatrix. Not sure if that's merely historical or if there's a technical reason for that.