md` ## File Type Box: \`ftyp\` --- ### Description > The **File Type Box** comes in the in the Audio and Video intialization segments. It is the heighest level box in these initialization segments (mp4s). The information in the \`ftyp\` have the inital information to tell teh video element how to decode the incoming segments. > There can only be one \`ftyp\` box per file and it is mandatory for the intialization segments. ### Properties > **MajorBrand**: This specifies to the video player what specifications it should expect from the files. Meaning what boxes to expect when reading the mp4 files
>**MinorBrand**: This is informative only. It does not require the files to conform to the standard's of the \`minorBrand\` but it can allow a more precise version of the \`majorBrand\`'s specifications
>**CompatibleBrands**: This tells the player that there are more brands. If the player is able to support the other brands it will play those aspects of the file (The other boxes that the compatible brand supports) ### Class View > \`\`\`javascript class FileTypeBox extends Box { majorBrand; // 32 unsigned bit minorBrand; // 32 unsigned bit compatibleBrands; // 32 unsigned bit [] } \`\`\` **NOTE**: Since it only extends box, it does not have the version and flag fields ### Example > #### Explanation >> **Size**: 28 - This means that the box is 28 bytes big
**Type**: \`ftyp\` - Specifying this box is of the type \`ftyp\`
**MajorBrand**: \`dash\` - The video player must accept \`dash\` file formats **MinorBrand**: 0 - No minor brand was specified
**CompatibleBrands** [iso6, avc1, mp41] - these are the other compatible file formats that are acceptable `