{"id":"image-avci","mimeType":"image/avci","name":"AVC Image (HEIF Container)","shortName":"AVCI","category":"Photography \u0026 Professional","extensions":[".avci",".hif"],"description":"AVCI (Advanced Video Coding Image) is a format that stores still images encoded with the Advanced Video Coding (AVC / H.264) codec inside a High Efficiency Image File Format (HEIF) container. It was developed to apply efficient modern video compression techniques to still photography.","seo":{"title":"image/avci MIME Type | Complete Developer Reference \u0026 Magic Bytes","description":"Complete reference for the image/avci MIME type: magic bytes, browser support matrix, HTTP headers, developer snippets, and technical specifications for AVC-encoded HEIF images.","faqs":[{"question":"What is the image/avci format?","answer":"The image/avci format is a still image encoded using the AVC (H.264) video codec, wrapped within the HEIF (High Efficiency Image File Format) container. It is defined in ISO/IEC 23008-12."},{"question":"Is AVCI the same as HEIC?","answer":"No. While both use the HEIF container structure, HEIC uses the HEVC (H.265) codec for compression, whereas AVCI uses the older AVC (H.264) codec."},{"question":"Do browsers support AVCI?","answer":"Native web browser support for AVCI is practically non-existent. However, certain operating systems like macOS and iOS support native viewing of .avci files at the system level."}]},"index":{"compression":["Lossy","Lossless"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Digital Photography","Camera Capture","Archival Storage"]},"technical":{"magicBytes":{"hex":"XX XX XX XX 66 74 79 70 61 76 63 69","ascii":"....ftypavci"},"container":"HEIF / ISOBMFF (ISO/IEC 14496-12)","compressionAlgorithm":["AVC (Advanced Video Coding / H.264)"],"colorDepth":["8-bit","10-bit","12-bit"],"transparency":true,"animation":false,"metadata":{"exif":true,"xmp":true,"iccProfile":true},"alphaChannel":true,"progressiveLoading":false,"hdrSupport":true},"history":{"developer":"Moving Picture Experts Group (MPEG) / ISO/IEC JTC 1","released":"2015","specification":"ISO/IEC 23008-12 (MPEG-H Part 12)"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"Apple Photos (macOS/iOS)","logo":""},{"name":"ImageMagick","logo":"image-magic.webp"},{"name":"Windows Photos (with HEIF Extension)","logo":""}],"conversion":{"convertTo":["jpeg","png","heic","avif"],"convertFrom":["jpeg","png","heic"]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/avci"}],"htmlAccept":"image/avci, .avci","fileDetection":["Check for ISOBMFF 'ftyp' box starting at byte offset 4","Verify 'avci' brand string starting at byte offset 8"]},"prosCons":{"pros":["Shares the robust, flexible HEIF container architecture that allows for rich metadata, HDR, and depth maps.","Backed by the highly ubiquitous AVC (H.264) codec, which is widely supported in hardware decoding.","Supports rectangular cropping and rotation metadata without needing to re-encode the pixel data."],"cons":["No native support within web browsers for HTML rendering.","Inferior compression efficiency when compared to newer container formats like HEIC (HEVC) or AVIF (AV1).","Easily confused with HEIC and AVIF, which use the same base ISOBMFF container."]},"specifications":{"url":"https://www.iso.org/standard/89035.html","rfc":"","mimeAliases":["image/heif"]},"developerSnippets":{"python":"import magic\nprint(magic.from_file('photo.avci', mime=True)) # May output 'image/avci' or 'image/heif' depending on libmagic configuration","nodejs":"const FileType = require('file-type');\nconst type = await FileType.fromFile('photo.avci');\nconsole.log(type.mime); // image/avci","go":"import \"net/http\"\n\nmimeType := http.DetectContentType(fileBytes)\n// Go standard library may misidentify HEIF variants; use specialized ISOBMFF parsers","php":"$mime = mime_content_type('photo.avci');\necho $mime; // May return 'application/octet-stream' or 'image/heif' without updated magic databases"},"relatedFormats":["heic","heif","avif"]}