'''Multimedia Container Format''', abbreviated MCF, is aan unfinished [[container format (digital)|container format]] specification and a predecessor of [[Matroska]]. The project has been abandoned since early 2004, but many of its innovative features found their way into Matroska.
==History==
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The limits of the MCF format were based on human perception and expectations of progress in bitrates of video. The [[time code]] precision of the format is limited to 1 ms. The addressing in the file is limited to 64 bits, which is extremely large. Frame size is limited by 32-bit frame size number, limiting frame size at 4 [[gibibyte|GiB]]. Time codes are stored as 40-bit integers, which caps maximum movie length at approximately 35 years. The number of distinct streams in one file is 2<sup>16</sup>, or 65536. A movie can be split into a maximum of 255 segments.
==Overhead==
Every MCF file requires around 3 KB of headers, so you really need to store at least 20 KB of data per file for it to be even remotely efficient (however, file systems would lose even much larger amounts of data because of allocation unit waste space).
The minimal possible overhead in normal situations is mostly dictated by frame overhead. This is only 7 octets in MCF! OpenDML AVI's overhead is around 40 octets (with full indices and legacy AVI compatibility) and Matroska's is around 10 octets.
When streaming and looking for lowest possible latency, the smallest possible transfer unit is one frame (with 25 octet overhead each, if using such minimal size units). The overhead is still only a half of that of OpenDML AVI file, and MCF can offer checksum protection in that! However, Matroska can do this with just about 16 octets.
