Comment Re:The rotation was always pointless. (Score 2) 64
The data from image sensors is read in scanline order. The data arrives at the image processor in this fixed order, whether you hold the camera horizontally or vertically. Every computationally expensive step the processor needs to do to compress the image data into a JPG can be performed on the streaming data with a buffer that holds just a few scanlines. JPEG is a very old standard. Compression was (and still is) performed by an image processor with limited amounts of on-die RAM, because that stuff is expensive. The rest of the hardware is much slower than the hardware compression could make you believe. This is the domain of fixed-function DSPs. The data comes out of the image processor in that given order and is written to the file in that order, because rotating the image may not sound like much, but for the anemic CPU in a battery powered device it is much less costly and less battery consuming to just add a number that says turn image 0, 90, 180 or 270 degrees. And then you run jhead -autorot *.jpg on the data and there's no problem.
