3 ms·
Not really. Some RAWs from some cameras do compress, but not others. (Not sure why; maybe it's already pre-compressed.) As an example, I tried just compressing
by mehrdadn 7y ago
Not really. Some RAWs from some cameras do compress, but not others. (Not sure why; maybe it's already pre-compressed.) As an example, I tried just compressing a random 30MB RAW from my camera (just a photo of jeans, nothing particularly unusual) with 7z on Ultra compression, and it saved—guess what—a whopping 2.2% of its size.
- pletnes 7y agoThe RAW format is probably using e.g zlib for compression internally. You can check by calculating how many bytes in total a truly raw image is: 12-16 bits (1.5-2 byte) per pixel.
- remcob 7y ago7z is a generic lossless compressor. These algorithms tend to specialize in exact repeating patterns in sequences. Good for english prose, but images tend to have non-exact patterns in two dimension. A dedicated algorithm like FLIF will be much better at picking those up. I would expect an order of magnitude difference in performance between 7z and FLIF. For the curious: the way these non-exact pattern compressors work is by subtracting out the predicted pattern and then storing the remaining signal, which will be smaller numbers and therefore take less bits to store.
- ChrisLomont 7y agoWhat is your camera? Multiply your sensor size by the bit depth, and I suspect you’ll have more than 30mb. Also image compressors like FLIF vastly outperform general compressors on images.
- mpais 7y agoSome RAW formats are pre-compressed, usually with very simple (hence fast) algorithms, and some aren't even lossless (Sony ARW). It's often possible to further compress them with specialized tools. Disclosure: I'm the author of PackRAW, a tool that does exactly that (https://encode.su/threads/2762-PackRAW https://encode.su/threads/2762-PackRAW)