MPEG Source Files

MPEG is an acronym for Moving Pictures Expert Group. The Moving Picture Experts Group is a working group of ISO/IEC in charge of the development of international standards for compression, decompression, processing, and coded representation of moving pictures, audio and their combination.

• MPEG-1, the standard for storage and retrieval of moving pictures and audio on storage media (approved Nov. 1992)

• MPEG-2, the standard for digital television (approved Nov. 1994)

• MPEG-4, the standard for multimedia applications 

  • version 1 was approved Oct. 1998

  • version 2 was approved Dec. 1999.

  • version 3 is in use although it is reported to be a work in progress on the MPEG Committee's web site.

• MPEG-4 version 4 and 5 are still in development.

• MPEG-7 the content representation standard for multimedia information search, filtering, management and processing.

• MPEG-21, the multimedia framework.

For the purposes of this document, files compressed using MPEG-1 or MPEG-2 codecs are called MPEG files while files compressed using MPEG-4 codecs are called AVI files.

Troubleshooting MPEG Movies

MPEG source files are generally less troublesome than AVI because the codecs are more tightly integrated into the files however if you have a bad MPEG source file we highly recommend VirtualDub by Avery Lee to diagnose and/or repair problems. You can download the latest version of VirtualDub from the below URL or from our web site where we try to host the most recent revisions.

http://www.virtualdub.org/

http://www.jhepple.com/virtualdub.htm

VirtualDub may not work properly if you have hacked codecs installed and the developer refuses to answer questions about them or about DivX 5.1.

To repair damaged MPEG files with VirtualDub open the file with the option checked to "Popup extended open options".

From the extended options popup select "All frames (I/P/B)" to be sure that you get all data but also check the box to "accept partial MPEG streams in case your source file was split or trimmed with a file splitter that chopped off the End of File marker or some other header data.

Pick a video compression codec:

Save as a new AVI file

IPB recording.

An I-frame (Intra coded frame) contains all the data necessary to paint a complete video frame. Video encoded as I-frame only poses no restrictions on video editing insofar as cuts can be made at any frame of the file but it is very large.

As in the above examples where compression is accomplished by removing the redundancy the incomplete frames are called P-frames (Predicted frames).

If a movie was constructed of only P-frames moving objects might reveal some unwanted data from a previous pictures so B-frames (Bi-directional frames) are created from preceding- or later I- or P-frames.

An I-frame followed by a succession of B- and P-frames is called a GOP (Group Of Pictures). A typical broadcasting GOP has the structure IBBPBBPBBPBB.