Resolution is certainly a major factor in the scanning acuity. The browser scanning issue is somewhat paradoxical: getting a clear and high-resolution image of the barcode improves scan accuracy, but to achieve this, the camera needs to get so close to the barcode that the autofocus starts to freak out and blur the barcode. Since the browser scanner is using the browser camera API, there's no good mechanism to control the autofocus. It's enough to make you want to throw your phone in the garbage.

I’m confused why you’d need to deskew 1D barcode. 2D have the fiducials meant for image warp corrections. 1D is meant for a laser to sweep across at any odd angle up to diagonal across all the bars. Why not read the pixels in 1 horizontal row of the image and use an algorithm more like the laser does? You’re looking for alternating black/white with unknown period.

This is in fact how ZBar works, see zbar/scanner.c (source: I am the original author of the ZBar QR code support, and I was pretty envious of how easy 1D codes are, conceptually).