Encoding video files for DVD by Matt Ottewill

Video codecs

DVD and CD do not have enough storage capacity to hold long uncompressed PAL or NTCS TV and DV video files. Files must therefore be compressed using a codec (compression/decompression algorithm). Codecs compress files before storage and uncompress them before they playback.

DV codec

DV video is compressed using the DV codec which squashes the huge amount of data produced by a camcorders CCD in order to record it onto DV tape. Even after compression DV files need 216Mb of storage for every minute of video. That means that a DVD disc could only contain about 20 minutes of video.

MPEG codecs

To fit video onto optical discs (DVD and CD) it must first be compressed using a codec. A popular codec for CD video is Sorensen and the preferred choice for CDROM.

The Motion Pictures Expert Group (MPEG) has also developed video codecs.

There are 2 primary MPEG video codecs ...

MPEG-1

The MPEG-1 codec was developed for CDROM video discs. It has a low bit rate of up to 1.8 Mbps (Mega bits per second). 1.4Mbps is a more typical bit rate.

Because of this low bit rate, frame sizes is restricted to 352 x 288 for PAL and 352 x 240 for NTSC.

MPEG-1 is commonly used for CD-ROM and the Internet and although supported by the DVD standard is not normally used for DVD video discs.

MPEG-2

The MPEG-2 codec is the first choice of DVD video authors. It allows bit rates of up to 9.8 Mbps.

This bit rate permits the full frame sizes of PAL (720 x 576) and NTSC (720 x 480).

Therefore, MPEG-2 creates video files of full broadcast quality.

What do I need to encode video to MPEG-2?

Video files (such as DV) can be encoded with several programs ...

QuickTime Pro

Apple's collection of system codecs, QuickTime, which includes a playback utility called the QuickTime player. By purchasing an unlock code from Apple (about $35) the QuickTime player becomes a powerful authoring program. Among its features is file/codec conversion. QuickTime pro can convert DV video files into MPEG-2.

Find out how QuickTime can replay MPEG-2

You can export video edits straight from Apple's Final Cut Pro (or Express) into (QuickTime) MPEG-2 format.

Discreet Cleaner

Discreet's Cleaner is a professional file conversion and compression utility. It is extremely well featured and creates better MPEG-2 files than QuickTime Pro.

Choosing MPEG-2 bit rates

The bit rate you choose will determine ...

Picture quality
Frame size
File size
How much strain will be put on a computer's CPU when it is using a "soft MPEG codec" to play and display DVD on a monitor

What bit rate settings should I use?

When choosing a bit rate you need to consider ...

Total running time of your video files. Will too high a bit rate make them too big to fit on a disc?
Will too high a bit rate put too great a strain on computer CPU's or DVD video players? Older computers may strain to handle 6 or 7Mbps.

Maximum bit rate limit

The MPEG-2 codec allows for encoding between 1 and 9.8Mbps. In practice 8Mbps is the maximum bit rate you should use, for 2 reasons ...

You need to allow some bandwidth for audio and subtitles
Some DVD-video players will struggle to decode bit rates above 8Mbps

Constant and variable bit rates

MPEG-2 encoders normally give 2 additional options ...

Constant-bit-rate encoding (CBR) This setting means that your bit rate will remain constant whatever is happening in the video. This means that scenes of high on screen activity and movement may look noticeably worse than more static scenes.

Variable bit rate encoding (VBR) This setting takes account of the amount of on screen activity and adjusts the bit rate to ensure good quality throughout. When there is low activity the bit rate lowers and when there is high activity it increases.

Try our video data rate calculator

A utility to help you determine the highest possible video data rate for your DVD.
OSX Mac (1.8 Mb Zip Mb)
PC (1.7 Mb Zip Mb)
Shockwave (92Kb

Suggested settings

Encoding for DVD-video players

If you are authoring a DVD video disc you should do the following ...

Use the MPEG-2 compression codec
Encode files using Cleaner rather than QuickTime if possible
Use VBR encoding
Use a maximum bit rate of 8Mbps but consider using between 5.5 and 6.5Mbps if your video does not contain lots of activity or you have limited disc space.

Encoding for computer DVD drive playback

Use the MPEG-2 compression codec
Encode files using Cleaner rather than QuickTime if possible
Use VBR encoding
Encode some small video edits containing screen high activity and test them on the lowest spec target computer you want them to playback on.