Does all the technical jargon about digital video file formats drive you bonkers? Join the club! Confusion over video file formats is probably the single biggest hang-up for people wanting to upload video to the web. The good news is that with just a little bit of basic knowledge, you shouldn't have any trouble.
First, keep in mind there are 2 broad categories of video formats. Some formats are meant for your finalized video and are called sharing formats. Other formats are used more in the beginning stages of a video project. They are good as raw video master clips. These formats will have higher resolution and larger file sizes than the sharing formats.
Considerations for Internet Video File Formats
If you are making and uploading video to the web, you need to be aware of video formats in any one of these three stages of the process:
- What kind of video comes out of your camera? This is often referred to as the source video or raw video format.
- What kind of video does your video editing program accept? You want to make sure that whatever comes out of your camera is supported by the video editing program you want to use.
- What kind of sharing format is best for the online video platform you've selected ?
When you are evaluating whether a format is the "right" one or not, the three main evaluating criteria are:
- Size of the file
- Resolution and overall appearance of the file
- Compatibility of the file
Depending on how the video clip will function, any one of a dozen or so popular formats will be among the "best" one to choose.
For the Internet, you want smaller file sizes. Even though the web's capacity for video delivery keeps growing, and most people have broadband, it is still best to keep file sizes as small as possible. A large video file is more likely to encounter buffering issues and drive the viewer crazy. The smaller the file size while still maintaining high quality, the easier it will stream, which may very well make the difference between whether someone bothers to watch or not.
There can be huge differences in size from format to format depending on the compression used. I've experimented around with this and I can take the same video, convert it to QuickTime and get an 80 megabyte file or convert it to an mpeg 4 with h.264 compression and get a 10 megabyte file (you can also compress QuickTime using .h264 video codec but...that is another topic)
Rapid Movement and flashy stuff within the video can add to the file size and are more difficult to compress with resulting high-quality. So, it is important to keep that in mind when creating your video.
Common Video File Formats
Now let's go over the most common video file formats. As you probably know, the last 3 or 4 letters on the end of a video file's name indicates format or file container. Just like .doc indicates a word file, .mov indicates a QuickTime move file; .wmv stands for windows media video and so forth.
Here are the common ones, in alphabetical order.
AVCHD (Advanced Video Codec High Definition):
AVCHD (.mts) is a high end, high-definition (HD) format originally developed by Sony and Panasonic for HD home theater systems. It's not a sharing format for the web because it is so huge, but it has become very common as a lot of newer HD camcorders record in this format. Video in this format would be for the beginning of your video project and serves as a master clip you would use to edit with.
AVCHD is in its infancy as a format and since it's still fairly new and compatibility with certain video editing programs may be an issue. Some video editing software applications have begun to support this format but many of can not handle it well yet. Additionally, playback of AVCHD files requires speedy CPUs and a sufficient amount of RAM. That makes this format a little difficult to work with but it maintains high quality. As time goes by, it will no doubt become easier to use.
.AVI (Audio Video Interlaced):
This is a long-time standard developed by Microsoft and has been around as long as digital video has. .AVI files (particularly when uncompressed) tend to be HUGE, way too big for the internet. AVI is more for the beginning of a video project, not the end. In that sense, it is not really a sharing format. They'll slide into just about any video editing program and the quality is still high enough to be a master clip.
AVI is windows-based and is virtually universal. Problem is, not all AVIs are created equally and you can still run into compatibility issues. AVI is what's known as a container format, which means it contains multiple streams of different type data, including a control track and separate video and audio streams. Now, what streams inside the container is not necessarily the same from one avi video to the next as the codecs used for compression can vary.
.FLV (Flash Video Format):
Next, we'll talk about the .flv format. Flash video is the single most common sharing format on the web today. You'll see the .FLV file extension on videos encoded by Adobe Flash software to play within the Adobe Flash Player. Virtually everyone (99%) has the adobe player installed in their browser and so this has fast become the most common online video viewing platform.
Almost all the video sharing sites stream video in flash. You can upload formats other than flash, and those sites will convert it into flash for streaming to the end user. Notable users of the Flash Video format include YouTube, Yahoo! Video, MySpace, and many others. Many television news operations are also using Flash Video on their websites. Most of those sites accept uploads in a handful of formats like QuickTime, mpeg4, or wmv, and then they convert it to flash or MP4 before actually putting it out on the net.
In addition to the nearly universal flash video player, FLV is popular because it gives one of the smallest file sizes after compression yet it retains fairly good quality.
If you self-host your own videos, you should convert them to flash for greatest compatibility with the highest number of Internet viewers.
Although FLV's are the most common format found on the web today, the standard is moving towards the use of using MP4 H.264 files within flash players as it is compatible with both online and mobile, not to mention some HTML5 browser support (Safari, Chrome).
.MPEG (Motion Picture Experts Group):
MPEG was developed by the Motion Picture Experts Group. This international group was established in 1988 to develop standards for digital audio and video formats but they're not the only group doing so as anyone who studies digital video files formats knows.
MPEG-4 Part 14 (.MP4):
MPEG-4 Part 14 is a great sharing format for the internet. It's small but looks fairly clean. It's the video format employed by a growing number of camcorders and cameras and it is highly recommended.
In fact, YouTube recommends using MP4 format. YouTube accepts multiple formats, and then converts them all to .flv or .mp4 for distribution.
As mentioned earlier, more and more online video publishers are moving to MP4 (with H.264 as the video compression codec) as the standard internet sharing format with use within both Flash players as well as HTML5. This is the format that we recommend for online delivery.
.WMV (Windows Media Video)
A .WMV file indicates a windows media video file. Windows Media Video is used for both streaming and downloading content via the Internet. Microsoft's Windows Media Player, an application bundled with Windows operating systems, is built for WMV files. WMV files are tiny. WMV will give you one of the smallest final file sizes. As you might expect, this means they are compressed so much they really do not look very good. In fact, I'd say the resolution is pretty crummy. But a tiny file size can be a real advantage for some things. If you get an email with an actual video attached instead of just a link to a video, it is probably a wmv file. They are the only ones small enough to attach to an email.
.MOV is the file extension used to identify an Apple Quick Time Movie. .MOV is an extremely common sharing format. It is considered one of the best looking and it does look great but the files sizes are big. QuickTime hasn't been a Mac-only program for quite some time. QuickTime versions and players exist on almost all PCs. Some people argue that QuickTime is far superior to similar Windows based applications and I personally would fall into that camp. The vast majority of the videos I personally upload to the web are QuickTime format, followed by MPEG4.
If you see a video file on your computer labeled MSWMM, be aware that this is a windows movie maker project file and not a video or movie file designed for sharing. MSWMM will only play within Movie Maker. When you want to save your movie to share it, use Movie Maker to convert it into a sharing format, such as .mpeg4 or .wmv. The difference between sharing formats and project file formats confuses many people. No matter what video editing software you use, a project file is designed for working on within the editing program. You must convert the project file to watch it on any other player.
I hope this information helps you navigate your way through the alphabet soup known as digital video file formats.
About our Guest Author:
Lorraine Grula is a longtime video photographer and producer who now shares her expertise online. Lorraine is available for personal consultation and offers one-on-one video production services. She also runs a blog about video production - www.VideoProductionTips.com