What Is Pure Motion Capture?

Pure Motion Capture is a program which allows you to capture video and audio using your analogue capture card or DV (Digital Video) Firewire card.

What Is Video Capture?

Video capture is the process of converting moving video from a source to a movie file on your PC. Capturing turns the data from an analogue or digital source such as a video camera or VCR into a digital form which is stored in a file on your PCs hard disk. A capture card is required to provide the interface between the PC and video source. 

Once you have captured some video to a file (usually in the form of a AVI file) you can:

• Play the file using a player such as Windows media player
• Edit the file to trim it, apply an effect or combine other movie files using a video editing program
• Write the file out to CD or Zip disk
• Publish the file on the internet

The process of video capture is outlined in the figure below:

Analogue Or Digital?

All files stored on computers are stored as digital data. A movie file on your PC's hard disk is therefore always stored as digital data. Until recently, all consumer video source devices such as video cameras and VCRs were analogue. Recently however, affordable digital video cameras have become commonplace. Digital camcorders generally offer a better quality picture over their analogue counterparts but the reader should be aware that the process of capturing from a digital source is different from capturing from an analogue source.

Analogue Capture Process

When capturing from an analogue source, an analogue capture card is used which connects to the source via one of the following cables:

• Composite video cable
• S-video cable
• UHF (coaxial aerial) cable

Using the capture software, the user has a choice of picture resolution, frame rate, colour depth and compression (see here for more details of these terms). These options allow the user to suit the quality of the captured video to their particular application and minimise the disk space required for the movie files.

Note: If you have a digital video camera that has a composite video out connector or a S-video out connector you can still use an analogue capture card in exactly the same way you would use one with an analogue camera.

DV Capture Process

DV capture is achieved by connecting the Firewire or i-Link port on your camcorder to a digital capture card. The connection is made via a Firewire cable, usually supplied with the Firewire card. Because the format of the data transmitted from the source to the capture card is fixed, namely DV format video, the user may have little or no control over the quality of the captured video. DV video is very high quality but has the disadvantage of requiring lots of hard disk space.

Analogue And DV Summary

A Word About Audio

So far, we have only considered capturing video but what about capturing sound too? Exactly how this is achieved depends on your capture hardware.

If you have a Firewire DV capture card:

The audio information is encoded in the DV format data hence when you capture using a Firewire card, you capture both video and audio simultaneously.

If you have an analogue capture card with build in audio-in sockets:

Here, you will need to connect an audio cable from your source to your capture card. 

If you have an analogue capture card without audio-in sockets:

You will need to capture the audio using your sound cards line-in or mic socket. Connect an audio cable from your source to the line-in or mic socket and select the audio source for recording using Windows volume control. Show me how to do this

What Do I Need For Video Capture?

You need to following items to perform capture:

• A video source such as a camcorder or VCR
• A PC with suitable large hard disk
• A capture card
• Some capture software

For more details on the specification of PC you need see hardware requirements.