Quicktime specification pdf

MP4 files are stored with the. MP4 is an international audio-visual coding standard. Similar to most modern container formats, MP4 supports streaming over the internet.

Due to the high compression used in MP4, the resultant files are smaller in size with almost all the original quality retained. As a result, it is used as a basis for other file formats. The file format is object-oriented, consisting of a flexible collection of objects that is easily parsed and easily expanded.

Unknown objects can simply be ignored or skipped, allowing considerable forward compatibility as new object types are introduced. QuickTime itself provides a number of high-level functions that you can use to create and manipulate QuickTime files, without requiring you to understand the actual file format.

These functions serve to insulate developers from the low-level details of operation. That said, not all kinds of QuickTime files can be created without the information presented here. Note that this version of the document supersedes all previous versions of the QuickTime File Format Specification. This document begins with an overview of QuickTime atoms, then presents the structure of the QuickTime file format in detail.

Finally, a number of related topics are described in a series of appendixes. These include such topics as the handling of metadata when importing files into QuickTime, random access, and the QuickTime Image File format. QuickTime files are described in general, rather than how they are supported on a specific computing platform or in a specific programming language.

As a result, the file format information is presented in a tabular manner, rather than in coded data structures. Size - QT atom header and contents are indicated in bytes by a bit integer. In the case of a leaf atom, then this field contains the size of a single atom. Type - Type of the atom is indicated by a bit integer. Root atom always the value of atom ID as 1. Child count - A bit integer that indicates the number of child atoms of an atom. MOV files consist of consecutive chunks.

To compose MOV file, iterating chunks is needed until unknown type is detected. The first block size is 32 hex: 00 00 00 20, big-endian, high byte first , size located at offset 0. At offset 32 hex: 20 is located the second chunk, which has a size of 8 and type mdat hex: 6D 64 61 Table of Content. What is a MOV file? Atoms Atom is the basic unit of the QuickTime file. QT atom container header has the following data: Reserved: A byte element with a value of 0.