Disclaimer: This tutorial does not address creating video for TV broadcast or distribution in theaters.
A previous tutorial discussed codecs for editing video. This tutorial focuses on video codecs and formats for distribution to viewers.
Codecs used for editing video, such as DV-AVI, don’t work well for distributing video because the large file sizes involved with editing video are difficult to distribute to viewers.
With output formats and codecs the correct choice may be completely different from project to project because the audiences are different. People creating video for themselves need to make sure only that the video plays on their TV or computer. If you’re creating free video, such as tutorials, containing costs may be more important than making sure everyone can view your videos. If you’re creating advertising for a business then supporting most or all potential customers may be more important than minimizing costs. Specific audiences may also have specific requirements; some audiences are more tech savvy and comfortable viewing Web video than others.
Once upon a time, not long ago, if you wanted to provide someone video, you sent them a tape that was the only choice.
Pluses: Nearly universal availability of VHS tape players
Minuses: Incompatibility between NTSC and PAL standards, high cost of duplication and distribution, poorer video and audio quality than DVD, inconsistency of safe area.
Pluses: Higher quality than VHS
Minuses: The same as VHS but less availability of SVHS tape players.
Pluses: The high quality leader, lower distribution costs than VHS tape but much higher than some alternatives.
Minuses: Duplication costs similar to VHS tape, inconsistency of safe area, currently less availability of DVD players than VHS tape players, incompatibility of NTSC and PAL standards, inconsistency of support by players for DVD-R, DVD-RW, DVD+R, and DVD+RW formats. DVD-R and DVD+R have more support by set-top DVD players than DVD-RW or DVD+RW. See www.DVDRHELP.com for compatibility of specific DVD players/
Pluses: Lower duplication costs than DVDs.
Minuses: Very poor image quality, lack of support in many set-top DVD players, inconsistency of safe area.
SuperVideoCD (uses MPEG-2)
Very similar to VideoCD except somewhat better image quality but even less support by set-top DVD players.
Windows Media, Real Media, and QuickTime are file formats, or wrappers, that may contain many different codecs. MPEG-1 (.mpg), MPEG-2 (.m2v), MPEG-4 level 3 (.mp3), and MPEG-4 (.mp4) are codecs that use only specific file extensions. DivX and Xvid are codecs that can be used for video but are most appropriate for limited distribution videos and are not discussed further in this tutorial.
All computer formats can be delivered at low cost over the Internet or at higher quality but also higher cost using CDs or DVDs.
Video distribution over the Internet, using a Web server or e-mail, needs to minimize file size to enable timely distribution of video. This requirement for minimized file sizes results in small video sizes (measured in pixels) and compromises on quality. Because of the small file sizes and limits of compression technology, videos should minimize the use of: unnecessary movement such as zooming in or out, pans, rolling or crawling titles, use of sophisticated graphics, and use of split screen or picture-in-picture. Close-ups are encouraged instead of long shots.
There are three different methods for distributing video over the Internet. Download is the complete download of the video file before the video starts. Progressive download allows the video to start as the file is downloading in the background. Streaming requires specific Web server software to adjust the rate of download to match the speed at which the person’s PC or Mac is receiving the video. Windows Media, Real Media, and QuickTime all support all variations while the MPEG variations don’t support streaming. While streaming video would seem to provide the best experience, in practice network firewalls may interrupt the feedback information to the streaming server resulting in severely degraded video. Although streaming technology allows for the combining of video streams for 56k to 1000k or more into one file, this can also result in poor video where widely different stream speeds are combined into one file because different Internet connection speeds require different trade-offs of video size, audio, quality, etc.
Trade-offs...
Creating Internet video involves a series of decisions that affect the overall viewing experience.
1) Long download times allow for larger file sizes and also better video but may also result in less people waiting to see the video.
2) Clearer video may require smaller viewing size, in pixels, and therefore reduce the emotional impact of the video.
3) Sharper video may result in fewer frames per second, making the video appear more like a slideshow.
4) Smoother running video may result in fuzzier video.
5) Better audio can cause poor video quality.
The following are some example bandwidths and file sizes. Adjust these for your video and codec.
Dial-up modem: 56K modem, 160 x 106. Note: 56k modems actually run at 44kbps with 8kbps for overhead and a minimum of 8 kbps for audio, leaving very little for the actual video.
DSL/Cable Modem: 300kb, 320 x 240.
CD: 1000kb, 520 x 346.
Choosing between all the options for Internet video is a bit daunting. The best choice may be dependent on your audience. For a free service, like tutorials, picking one popular format is the best plan. For a commercial service, supporting multiple formats is likely the best plan. Each codec has their strengths and weaknesses and it is best to test them with your own video and decide based on testing which codec or codecs you need to use.
See documentation at http://www.microsoft.com/windows/windowsmedia/9series/sdk.aspx . The free encoder is at http://www.microsoft.com/windows/windowsmedia/9series/encoder/default.aspx
Windows Media 9 plug-in for Premiere is located at http://www.microsoft.com/windows/windowsmedia/premiere/
Pluses: Mostly widely installed media player, very good compression, good free encoder
Minuses: Version 9 doesn’t work with Win98fe, Macs, and Netscape. Premiere plug-in tends to not encode as well as the stand-alone encoder.
See documentation at http://www.realnetworks.com/resources/documentation/index.html
Version 9 plug-in for Premiere is available at http://forms.real.com/rnforms/resources/extensions/premiere/index.html
Pluses: Best compression. Works on all platforms. Widely used for free, paid, and premium services. Players are fairly popular.
Minuses: Customization needed to reduce clutter/Ads.
Note: 2 pass encoding and variable bit rate streams options may improve quality. From Real Media Export screen: Preferences button>Video codec>click check boxes.
See documentation at http://www.apple.com/quicktime/authoring/embed.html
Pluses: Works on all major platforms.
Minuses: Sorenson and Sorenson3 codecs have significantly worse compression than Real Media or Windows Media. Sorenson Squeeze codec produces good quality video with reasonable file sizes but is relatively expensive compared to the alternatives. The Premiere 6.5 QuickTime export option does not support steaming QuickTime (“hinted”).
Pluses: Will play on almost any media player.
Minuses: Poor compression. Lack of flexibility and tuning options. Download only.
MPEG-3 (audio)
Pluses: Good quality sound. Will play on almost any media player. Widely accepted format.
Minuses: Poorer compression with larger file sizes compared to Windows Media and Real Player. Download only.
Pluses: Can produce very clear video. Can be viewed with Real Player and QuickTime Players.
Minuses: Comparatively large file sizes. Not widely used or accepted at present.
All of the Internet video formats and codecs can also be run from a computer CD. To some degree, compression and file sizes may not be as important when running video from a CD because the constraints involved with Internet connect speeds have been removed. For slower computers, transferring large files from a CD may negatively impact the viewing experience.
DVD (mpeg-2) video can also be distributed from a CD with about 15 minutes of video possible. MPEG-2 video is high quality. Playable on a Windows PC with a CD or DVD drive or a Mac with a DVD drive.