15 Replies Latest reply on May 2, 2011 6:18 AM by Another Photographer


    LMCarter Level 1
      Why use dcraw sources in ACR?
        • 1. Re: dcraw?
          michael shaffer Level 1
          ... why indeed? I'm not sure I understand your question(?) Surely, you're not suggesting ACR uses the same demosaicing algorithm(?) Leastwise, DCRAW generated much worse results than ACR3 (for my Oly dSLR) when I compared raw developers some time ago.
          • 2. Re: dcraw?
            LMCarter Level 1
            On dcraw site it says Adobe uses their codes. Just wondering why? I would had thought Adobe would want to use their own techniques.
            • 3. Re: dcraw?
              Level 1
              Since Dave Coffin does certain decoding that might be "difficult" to do in a corporate environment, the decoding by Dave and released as open source can then be used by others, such as the team on Camera Raw. It should also be noted that Dave uses DNG for support for some cameras that dcraw doesn't decode and also gets the benefits of DNG's color tables.
              • 4. Re: dcraw?
                LMCarter Level 1
                I can understand the time saved using Coffins stuff, IMO it kind of sacrifices image quality, I really don't care for GIMP or dcraw even doing linear RAW conversions at a low level. But I have always revered Adobe as the King of vector and bitmap image processing over anyone else in the industry and now I feel a bit let down. Maybe I'm wrong here but this is a bit like been told that there is no Santa Claus when I was 8 years old. ;)
                • 5. Re: dcraw?
                  Level 1
                  >I can understand the time saved using Coffins stuff

                  You don't "get" what I said, and I can't say more...reread what I wrote and read between the lines. Also understand that what Camera Raw may "use" from dcraw would only be those parts that are "useful" to use and it would be doubtful if that has any direct impact on the image quality of Camera Raw/Lightroom (and don't overlook the fact that dcraw got a lot from DNG which is an open spec unlike dcraw's open source).

                  ...and no, there ain't no Santa Claus, so get over it...

                  • 6. Re: dcraw?
                    LMCarter Level 1
                    Ok Jeff, don't get your panties in a wad, I do respect your products. If I was Adobe I would get upset about Coffin posting Adobe as an open source user of dcraw. ;)
                    • 7. Re: dcraw?
                      MadManChan2000 Adobe Employee
                      There's no compromise in quality involved. For example, algorithms to perform various bit twiddling tricks, perform image decompression, and read linearization tables from raw files involve no quality compromises, as long as the implementations aren't buggy. Fortunately, it's pretty easy to tell when an image decompression algorithm is failing (big black window ... no image ... bad ...).

                      Not sure why you would think Adobe would be upset about being associated with open source stuff. A fair amount of the architecture of CR is already fully public in the form of the DNG SDK.
                      • 8. Re: dcraw?
                        LMCarter Level 1
                        I think it's just a misconception I have of Adobe being the Gods of image manipulations (maybe I'm still right). And that's a compliment. I've always thought of Adobe as the ones that have all the best ideas and the rest of the industry are a bunch of noobs or Adobe wannabees. I just have great respect for Adobe and I demand more from Adobe.
                        • 9. Re: dcraw?
                          Level 1
                          > (maybe I'm still right)

                          You're still right...
                          • 10. Re: dcraw?
                            LMCarter Level 1
                            :D cooool.
                            • 11. Re: dcraw?
                              Level 1
                              There are just as many things Adobe didn't come up with. HDR, Panorama
                              Stitching, I don't believe they came up with layers, channels, RGB, CMYK,
                              Spot Colors, RAW images, etc. etc. What Adobe did do was popularize a lot of
                              it and in many cases made it more usable and accessible to the common
                              person. It is one thing to come up with the technology it is another to make
                              it easy to use and available to the masses. Frankly, I think Adobe is smart
                              going for the later in most cases it means they have the greatest impact.
                              • 12. Re: dcraw?
                                I have a hunch a lot of people are looking at this from the point of view of R&D, when in fact it's probably a question of intellectual property or licensing. I think it was pretty clear from Jeff's "hint" that there is some kind of legal restriction (not an engineering difficulty) stopping Adobe from directly coding some algorithm that's useful to ACR. By using the code from dcraw, they get around the legal restriction. My guess is that the code in question is only a small part of dcraw, and a tiny fraction of ACR, and you'd find that the vast, vast majority of ACR is all home-grown Adobe code.
                                • 13. Re: dcraw?
                                  DavidRitch-BPYbxw Level 1
                                  I have no proprietary information from Adobe, so I can freely speculate, unbound by the sort of restrictions that Jeff has. So - here's my take on this.

                                  Consider what a raw converter does. It has to read sensor data in a multitude of formats, and convert those into a common data structure with camera-specific parameters. Then, it uses common proprietary algorithms, shaped by those camera-specific parameters and user settings, to convert into an image object. Then, it saves the object.

                                  Clearly, the proprietary magic comes in in the conversion from a common data structure containing the raw sensor data to the image. Why would Adobe choose invest in developing proprietary software to read all the different raw file formats? Especially since many camera manufacturers encrypt and obfuscate their formats? Especially since dcraw already does this well? Using dcraw's libraries in this way does not impact Adobe's ability to perform its magic of image manipulation.

                                  Adobe may use other parts of dcraw, too, but they'd be silly not to use its abilities to read a multitude of raw file formats. I believe that this was that Jeff was alluding to.

                                  • 14. Re: dcraw?
                                    Level 1
                                    Jason wins a gold star...

                                    • 15. Re: dcraw?
                                      Another Photographer Level 1



                                      I understand Idimager also uses DCRaw, but Idimager is primarily a digital asset mamager not a RAW editor.