Thursday, April 30, 2009

Video file formats, what and when to use

Weightless. Photo CC By: Sam Pullara

Video file formats are a real nightmare! And after 10 years of amateur video production, I still don't have a clear understanding on how they work. So what I am about to tell you is what works for me, considering I try to produce video that works for many.

Sites like Youtube - or specifically Flash Video have helped solve this compatibility problem for viewing on the Internet, but its still a problem for those who like to download and perhaps even edit videos.

So what format should I use?
Here are my 3 rules of thumb - that work for me:
  1. The master copy of your digital video should be in AVI set to play at 25 frames per second, displaying a size of 720x576 pixels.
  2. Use this master AVI to export Internet ready versions in MP4, WMV and Ogg Theora, all set to play at no less than 12.5 frames per second, displaying at 320x240 pixels.
  3. Upload the MP4 to your preferred video publishing service (eg Youtube or and that service will convert your video to the Flash Video format for reliable playback on all computers.

Why AVI as the master format?

Because it is an old, long used format that is generally reliable on the widest range of computer software and players. As the Wikipedia entry for AVI says: ...the age of the AVI format, being widely supported on a vast range of operating systems and devices, and the availability of video editing and playback software ... help keep the AVI file format popular amongst amateur videographers.

Why the 3 export formats?
Video for the Internet needs to be a small file size, but not so small that it makes it unwatchable. An MP4 at 320x240 pixels gets good file compression and can play on Windows, Macintosh and Linux, not to mention iPods. A WMV gets very good compression, and is reliably played on Windows based computers including PDAs. And Ogg Theora also gets good compression, but is the only non-commercial, open standard video format that plays on Linux, and that is accepted by Wikipedia and other free and open source initiatives - who tend to have longer term, commercial free, sustainability in mind. If you offer people the choice of these 3 formats, you have all bases covered nicely.

But how do you get video into all those formats?
There are a few free to use video converters you can use. These applications can take just about any video format and convert it into any other format. I use SuperC, largely because it was one of the first to become available, and it can do so much in the one application. Its not always easy to use, so sometimes I prefer simpler tools such as Videora iPod converter, or Pazera Video Converters. Alternatively, you can upload your video to and they will convert your video on their website for you.

More information on encoding can be found on the Wikipedia entries for each format.
  1. AVI
  2. MP4
  3. WMV
  4. Ogg Theora

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Chris Harvey said...

For the part about Ogg I think you should replace the word non-commercial with royalty free. There's some devices you buy like dvd/video and audio players/recorders that support Ogg.

You can play Ogg on other systems as well as gnu/linux if you install the codecs, the thing is that being royalty free means you could bundle it with any system which makes me wonder why Ogg isnt supported by all operating systems by default.

Probably one of the things to get your head around is that you have a multimedia container format which usually contains encoded audio and video.

You've probably noticed this in your conversion programs.

brent said...

native ogg-theora support is coming soon to a browser near you -- Firefox 3.5. Possibly before the end of the year.

sparkered said...

Are good file online conversion sites, upoload you file download a a conversion.

Leigh Blackall said...

Thanks guys. Chris, I'm not sure how to simplify the container and codec information for the avergae amature.. ie. I'm not sure I even know enough about it! For example, when I make an MP4 I select the H264 codec.. does that sound right? But I dunno what is the most common codec used in the AVI for mastering and archiving, or for the WMV or OggTheora. It seems to me that most converters and editors come with the codec preset and that works most of the time.. Not a good way to fly I know... can you have a go at explaining and advising codecs in these containers Chris?

flowney said...

I think that there is some confusion here between Containers and CODECs. AVI is a container. As such, it can contain media compressed with various CODECs. Some of those CODECs, the more obsolete ones, can make an .avi file virtually unreadable in many situations.

MPEG-4 would be a better choice. Even Microsoft, the kimg of proprietary schemes, is beginning to support MPEG-4 in Silverlight.

Chuck McCann said...

For video and audio converting -- also check out ''WinFF'' when you get a chance. It's been pretty cool to me.

Thanks for the article, Leigh.

Col said...

Some useful points there Leigh.

I'm not sure how 720 x 576 came to be so commonplace though - if you convert 768 x 576 to 320 x 240 you will maintain the 4:3 (standard tv) aspect ratio and not distort (or letterbox) your original video.

(If it's a widescreen video though, this can be disregarded)

Leigh Blackall said...

Good point Col! My guess is that letter box became popular, and so 720 did. Perhaps I should change the recomendation to 768 do you think?

alexanderhayes said...

Nice post Leigh.

We ( EDUPOV ) are heavily embroiled in a formatting discussion as to what constitutes value when it comes to formatting transaltions not only for web production but for where things mash with broadcast and mobile compliance.

What we are proposing a build regime for is an ad-free video convertor "bridge" that permits it's core container as an embed elsewhere, allowing formats in and formats out to be as multi-directional as possible.

Super-C is a nightmare and Pazera proves problematic behind certain firewalls and other web based convertors are so heavily enriched with ad-ware , popups and other shite.

Perhaps you could steer us to some "bridge" based products that are free as in freedom and as plain as a sparrow in the rain.

Word verification for the day is 'chdumb' :)

Frank Lowney said...

If you have a Mac and QuickTime Player Pro ($29.95) you can add "components" to play just about anything out there. The two most popular of these components are WMV (free) and Perian (also free). Unfortunately, these two are not available for the Windows version of QuickTime Player Pro.

Having a Mac and QuickTime Player Pro is great if you're consuming video. However, if you are disseminating video, it can't be assumed that the audience has the wherewithal to play what you make, regardless of window size, aspect ratio and the rest.

The WC3 is finishing up the HTML 5 specification which may offer some relief with the "video" tag. The current issue is that the committee can't get consensus on whether Ogg or H.264 will be THE codec.

The "video" tag would eliminate the need for Plug-ins, including Flash, which would be a boon to web developers using video. Both Ogg and H.264 are open standards but the argument is over the idea of "patent free." Clearly, H.264 is not patent free but some fear that Ogg isn't either and that eventually a "submarine patent" will surface and wreck everything.

My own opinion is that the MPEG-4 container with H.264/AAC CODECs is the best way to go. Of course Microsoft could be a spoiler here as it hasn't yet said that it will support HTML 5 as Apple, Google and Mozilla foundation have.

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