Reviewed Codecs, Video File Formats Explained

3GP, WMV, AWF, what do these things mean and why does there have to be an alphabet soup at the end of all of your video files?

Back in the days when the computer was just used for basic functions like word processing and doing spreadsheets all you had to worry about was putting the VHS tape (and later the DVD) into the player and just hitting play.

Nowadays, with the advent of digital media, torrenting and media capable phones a video file isn’t a video file without having a bunch of incomprehensible numbers and letters tacked on the end.

So what do all these letters mean and how can you get them to work on your TV, MP4 player, computer or cell phone?

Before we take a look at the alphabet soup of terms we had better decypher three phrases that, if you spend any amount of time online looking for answers your are going to come across quite frequently.

Those are the terms container, codec and compression.

Codec stands for compression/decompression and refers to how video and audio files are squeezed down into a size which can be transported/carried in some way, a Codec can also be referred to as a compression standard.

For the purposes of people watching digital media a codec is what decyphers how a video is compressed and turns it into pictures and sounds on the screen.

The compression refers to the current size and the amount it has been reduced by.

The container is the file it is held in. Certain compression methods only work with certain files so both the codec and the file type go hand in hand.

So with that out of the way lets take a look into the bowl of alphabet soup which is codec and video file standards.

AVI: The .avi video file format was originally set up by Microsoft but has been altered by different compression standards so that there are different forms.

AVI is an incredibly common ‘container’ for video information and can be found on everything from cell phones, to cameras to some higher spec’d spy cameras.

Divx: Divx is a compression standard most commonly used for encoding files from DVD onto a digital media source. It is usually enclosed in an avi folder.

However, there is a DIVX container and the odd .divx file will apear from time to time.

Xvid: Xvid is an open source variant of Divx. It is appearing more frequently on torrenting sites and other places across the interwebs and is also held in an avi container.

3ivx: This is a compression standard that is held within the MPEG-4 file format. It isn’t used nearly as frequently as Divx or Xvid

3GP: A small, low resolution container format designed by Third Generation Partnership Project (3GPP) for use on third generation GSM phones. It is also popular with spy watch and spy pen manufacturers as it’s low resolution format allows a lot of footage to be stored on a small file.

3G2: A small, low resolution container format designed by Third Generation Partnership Project (3GPP) for use on third generation CDMA phones.

WMV: Windows Media Video (WMV) is a compressed video file format used for different codecs developed for use with Microsoft products.

If you’re using windows and you have used Windows Media Player at some time or another there is a good chance you have used this format it can come in either .wmv or .asf containers.

RMVB: RealMedia Variable Bitrate is the container used for videos recorded using the Real Media media player. This is a popular format in Asia.

OGM: OGM is the video version of the OGG open source container designed to support the free sharing of information. OGM files are usually compressed using the Theora compression standard.

MOV: This is one of Apple’s two QuickTime container formats (think of WMV or RMVB but for Macintosh) The only other place that you are likely to see it on websites that haven’t been taken by the flash revolution (more about this later).

QT: This is one of Apple’s two QuickTime container formats (think of WMV or RMVB but for Macintosh) The only other place that you are likely to see it on websites that haven’t been taken by the flash revolution (more about this later).

MPEG-1 Part 2: This is a compression standard developed by the Movie Picture Experts Group way back in 1991. It was designed to squeeze VHS quality video into a size best used for CD transfers. It subsequently became the compression standard of choice for VCDs but isn’t something you’d see very often today.

This compression is used by the .mpeg, .mpeg-2, .mkv and .avi containers.

MPEG-2 Part 2: Also known as H.262 MPEG-2 is a step up from MPEG-1 and allows higher resolution and faster processing speeds.

DVDs and DTV broadcasters are most wont to use this codec, although it is gradually being replaced by MPEG-4.

This compression is used by the .mpeg, .mpeg-2, .mkv and .avi containers.

MPEG-4 Part 2: MPEG-4 Part 2 is a compression standard which is an improvement on MPEG-2.

While you might not think you have seen MPEG-4 part two before there is a good chance you have as DivX, XviD or 3ivx are all variants of the standard.

You can find MPEG-4 Part 2 in the following containers .divx, .avi, .wmv, .3g2, .3gp, .flv, .mkv, .mp4 and .ps.

MPEG-4 Part 10: Also known as H.264 MPEG-4 part 10 is the next step up in the MPEG family delivering the same quality of video in a smaller package.

It’s used by both HD DVD (in an .EVO container) and Blu-ray (in a .m2ts container) and has been adopted as the DTV standard by such forward thinking countries as France, Hungary and Lithuania.

You can find it in .mp4, .mkv, .flv, .3g2, and .3gp files.

VOB: DVD Video Object, .vob is DVD’s standard container, and what you get when you rip a DVD.

EVO: standing for enhanced VOB .evo is the container that is most commonly used in HD DVDs (AKA the next Batamax)

M2TS: a file format used for Blu Ray discs. the .m2ts format is sued by the MPEG-4 part 10 compression standard.

MPEG-4 Part 14:This is a compression standard developed in conjunction with quicktime which plays very nicely with Apple products (read iPhone and iPod) but also gets along with Nintendo’s DSi and Playstation’s PSP without any need for conversion.

The MPEG-4 part 14 codec can mostly be found in the .mp4 video format.

H.261: The grand daddy of video compression standards and long since defunct. It was designed to transfer video over telephone lines for teleconferences.

H.263: H.263 is designed to send video through less than ideal conditions. As a result it is used to encode most Flash video and to send video over mobile networks.

It is supported by the file formats .3gp and .3g2

AVC: This is a compression standard used for blu ray discs, which is more flexible than the H.264 standard as it can be held in .mp4, .mkv, .flv, .f4v, .evo, .3g2 and .3gp container files.

VC-1: a Microsoft developed alternative video codec to H.264. It is most commonly found on Blu-ray and HD DVD discs and is the official video codec of Xbox 360.

It is usually found in the .ts, .evo, .mp4, .m2ts and .mkv container files.

FLV: Flash video. If you have ever downloaded a video from the internet then you have seen this video container before. Until recently it was a format that was strictly just for the computer however, some MP4 players have been able to play this format.

SWF: This is another form of flash file. Not so commonly used by YouTube it is more commonly used in flash animations and videos, like ‘peanut butter jelly time’.

MKV: The video version of Metroska, the most popular container on the block at the moment with torrent fans.

.mkv files can handle pretty much any compression standard, can be stuffed with subtitles and all sorts of other goodies and have the tendency of giving a better resolution at a smaller file size.

MJpeg: Standing for Motion Jpeg this is a format that works a little like an animated GIF. It is used a lot in digital video cameras and still cameras.

MXF: .mxf is a container format that is used for professional videography purposes essentially because it supports full time code and metadata.

Dirac: an open and royalty-free video codec developed by BBC Research. Designed to provide high-quality video compression from web video up to ultra HD[1] and beyond it can be wrapped in .mp4, .mkv, and .ts folders.

DVR-MS: A container format most famous for holding digital rights management information that prevented people recording files onto their own computers. It is encoded with the MPEG-2 standard and audio using MPEG-1 Layer II or Dolby Digital AC-3 (ATSC A/52).

HDV: a format for recording and playback of high-definition video on a DV cassette tape.

DVCPRO HD: a codec first developed for video tapes in 1995.

AVCHD: AVCHD is a format for the recording and playback of high definition video.

But it is not enough to know all these codecs, you’ve got to transform them into something useful. Thankfully there are several freely available online including:

• Mediainfo mediainfo.sourceforge.net/en
• Format Factory formatoz.com/

And if you run across a media file and are not sure what type of codec it is using or which type of file it is housed in try out AVS codec reader free-codecs.com/download/avicodec.htm a diagnostics tool for media files.

If you often run across new codecs bookmark this page. And if there is anything we’ve missed let us know in the comments and we will be sure to add it into this blog post.