Jpeg, remove chroma, keep only luma without recompressing?











up vote
0
down vote

favorite












Is it possible to strip down chroma information from a jpeg file without loss on the luma?



Ideally I'd like a smaller file-size, greyscale version of an existing and optimized image.






image-processing imagemagick jpeg mogrify







share|improve this question






















  • I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
    – fmw42
    Nov 21 at 18:18















up vote
0
down vote

favorite












Is it possible to strip down chroma information from a jpeg file without loss on the luma?



Ideally I'd like a smaller file-size, greyscale version of an existing and optimized image.






image-processing imagemagick jpeg mogrify







share|improve this question






















  • I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
    – fmw42
    Nov 21 at 18:18













up vote
0
down vote

favorite









up vote
0
down vote

favorite











Is it possible to strip down chroma information from a jpeg file without loss on the luma?



Ideally I'd like a smaller file-size, greyscale version of an existing and optimized image.






image-processing imagemagick jpeg mogrify







share|improve this question













Is it possible to strip down chroma information from a jpeg file without loss on the luma?



Ideally I'd like a smaller file-size, greyscale version of an existing and optimized image.






image-processing imagemagick jpeg mogrify




image-processing imagemagick jpeg mogrify






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 21 at 14:31









Vincent Tschanz

163




163












  • I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
    – fmw42
    Nov 21 at 18:18


















  • I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
    – fmw42
    Nov 21 at 18:18
















I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
– fmw42
Nov 21 at 18:18




I am not really sure what you want, so this may not be relevant. But you can change the sampling factor with ImageMagick. See imagemagick.org/script/command-line-options.php#sampling-factor
– fmw42
Nov 21 at 18:18












1 Answer
1






active

oldest

votes

















up vote
0
down vote













Assuming the scans are not interleaved, you could update the SOF marker to have one scan and then delete the 2d and 3d scans from the input stream.






share|improve this answer





















    Your Answer






    StackExchange.ifUsing("editor", function () {
    StackExchange.using("externalEditor", function () {
    StackExchange.using("snippets", function () {
    StackExchange.snippets.init();
    });
    });
    }, "code-snippets");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "1"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














     

    draft saved


    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53414337%2fjpeg-remove-chroma-keep-only-luma-without-recompressing%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    0
    down vote













    Assuming the scans are not interleaved, you could update the SOF marker to have one scan and then delete the 2d and 3d scans from the input stream.






    share|improve this answer

























      up vote
      0
      down vote













      Assuming the scans are not interleaved, you could update the SOF marker to have one scan and then delete the 2d and 3d scans from the input stream.






      share|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        Assuming the scans are not interleaved, you could update the SOF marker to have one scan and then delete the 2d and 3d scans from the input stream.






        share|improve this answer












        Assuming the scans are not interleaved, you could update the SOF marker to have one scan and then delete the 2d and 3d scans from the input stream.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 21 at 21:16









        user3344003

        14k31336




        14k31336






























             

            draft saved


            draft discarded



















































             


            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53414337%2fjpeg-remove-chroma-keep-only-luma-without-recompressing%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            -

            Popular posts from this blog

            Contact image not getting when fetch all contact list from iPhone by CNContact

            Image
            up vote 0 down vote favorite I know this question already asked but not getting solution. From this code I will get all the information from the contact but image not found when open vcf files on mac os, also not getting when share this file. I use this stackoverflow link here but It's not help full. var contacts = [CNContact]() let keys = [CNContactVCardSerialization.descriptorForRequiredKeys() ] as [Any] let request = CNContactFetchRequest(keysToFetch: keys as! [CNKeyDescriptor]) do { try self.contactStore.enumerateContacts(with: request) { (contact, stop) in // Array containing all unified contacts from everywhere contacts.append(contact) } } catch { print("unable to fetch contacts") } do { let data = try
            Read more

            count number of partitions of a set with n elements into k subsets

            Image
            up vote 6 down vote favorite 1 This program is for count number of partitions of a set with n elements into k subsets I am confusing here return k*countP(n-1, k) + countP(n-1, k-1); can some one explain what is happening here? why we are multiplying with k? NOTE->I know this is not the best way to calculate number of partitions that would be DP // A C++ program to count number of partitions // of a set with n elements into k subsets #include<iostream> using namespace std; // Returns count of different partitions of n // elements in k subsets int countP(int n, int k) { // Base cases if (n == 0 || k == 0 || k > n) return 0; if (k == 1 || k == n) return 1; // S(n+1, k) = k*S(n, k) + S(n, k-1) return k*countP(n-1, k) + countP(n-1, k-1); } // Driver program int ma
            Read more

            A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

            Image
            0 I found a lot of questions abount appendices and ToC. Many users want appendices to be grouped in an Appendix part, however some problems arise with ToC, hyperref, PDF viewer bookmarks, and so on. There are different solutions which require extra packages, command patching and other extra code, however none of them satisfies me. I almost found an easy way to accomplish a good result, where appendices are added to bookmarks in the right way and hyperref links point to the right page. However, the number of the "Appendix" part page is wrong (it's the number of appendix A). Is there any EASY way to fix that? This is a MWE: documentclass{book} usepackage[nottoc,notlot,notlof]{tocbibind} usepackage{hyperref} begin{document} frontmatter tableofcontents mainmatter part{First} chapter{
            Read more