{"id":"image-jxsi","mimeType":"image/jxsi","name":"JPEG XS Image (HEIF Container)","shortName":"JPEG-XS-(HEIF)","category":"Professional \u0026 Video Production","extensions":[".jxsi",".jxs",".hif"],"description":"The image/jxsi MIME type represents a single JPEG XS (Extra Speed) image, or a static collection of images, encapsulated within a High Efficiency Image File Format (HEIF) container. It merges the ultra-low latency, low-complexity wavelet compression of JPEG XS with the robust metadata, color profiling, and object-based architecture of the ISOBMFF standard.","seo":{"title":"image/jxsi MIME Type | Complete Developer Reference \u0026 Magic Bytes","description":"Complete reference for the image/jxsi MIME type: magic bytes, software support, HTTP headers, developer snippets, and technical specifications for HEIF-encapsulated JPEG XS images.","faqs":[{"question":"What is the difference between image/jxs and image/jxsi?","answer":"While image/jxs is the broader MIME type for JPEG XS files (often encapsulating standard codestreams), image/jxsi specifically denotes that the JPEG XS image data is housed inside a High Efficiency Image File Format (HEIF) container, granting it advanced metadata and collection features."},{"question":"What is the magic byte for an image/jxsi file?","answer":"Because it uses the HEIF/ISOBMFF container structure, an image/jxsi file begins with a 4-byte box size, followed by the 'ftyp' identifier, and the major brand 'jxsi'. The hex sequence is XX XX XX XX 66 74 79 70 6A 78 73 69."},{"question":"Is image/jxsi supported in web browsers?","answer":"No. JPEG XS is engineered for ultra-low latency hardware decoding in live broadcast (like SMPTE ST 2110) and medical imaging. It is completely unsupported in consumer web browsers."}]},"index":{"compression":["Lossy (Visually Lossless)","Mathematically Lossless"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Live Broadcast Infrastructure","Medical Imaging \u0026 Archival","Video over IP Networks","Automotive \u0026 Drone Systems"]},"technical":{"magicBytes":{"hex":"XX XX XX XX 66 74 79 70 6A 78 73 69","ascii":"....ftypjxsi"},"container":"HEIF / ISOBMFF (ISO/IEC 23008-12)","compressionAlgorithm":["JPEG XS (ISO/IEC 21122-1)"],"colorDepth":["8-bit","10-bit","12-bit","14-bit","16-bit"],"transparency":true,"animation":false,"metadata":{"exif":true,"xmp":true,"iccProfile":true},"alphaChannel":true,"progressiveLoading":false,"hdrSupport":true},"history":{"developer":"Joint Photographic Experts Group (JPEG)","released":"2019","specification":"ISO/IEC 21122-3 (JPEG XS Part 3) / HEIF"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"intoPIX FastTICO-XS","logo":""},{"name":"ImageMagick","logo":"image-magic.webp"}],"conversion":{"convertTo":["jxs","heic","jpeg","tiff"],"convertFrom":["jxs","tiff"]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/jxsi"}],"htmlAccept":"image/jxsi, .jxsi, .hif","fileDetection":["Check bytes 4-7 for the standard ISOBMFF 'ftyp' box identifier","Verify the major brand string at bytes 8-11 is exactly 'jxsi' (6A 78 73 69)"]},"prosCons":{"pros":["Provides sub-millisecond encoding and decoding latency while retaining visually lossless quality","Brings the extensive metadata, EXIF, XMP, and color-profiling capabilities of the HEIF container to JPEG XS","Allows grouping of multiple high-quality JPEG XS frames into a single collection file"],"cons":["Zero web browser compatibility, limiting it entirely to professional and industrial hardware workflows","Extremely niche adoption compared to standard HEVC-based HEIC or raw JPEG XS codestreams","Requires custom parsing logic to extract the JPEG XS codestream from the HEIF boxes"]},"specifications":{"url":"https://jpeg.org/jpegxs/","rfc":"","mimeAliases":["image/heif"]},"developerSnippets":{"python":"import magic\nprint(magic.from_file('photo.jxsi', mime=True)) # May default to generic 'image/heif' or 'application/octet-stream'","nodejs":"const FileType = require('file-type');\nconst type = await FileType.fromFile('photo.jxsi');\nconsole.log(type?.mime); // Parsers may fail to recognize the specific 'jxsi' HEIF brand","go":"import \"net/http\"\n// Custom ISOBMFF box parsing is required to read the 'jxsi' brand inside the ftyp box.","php":"$mime = mime_content_type('photo.jxsi');\necho $mime; // Standard environments typically map this to application/octet-stream"},"relatedFormats":["heif"]}