Microsoft KB Archive/118591

= Calculating the Disk Space Required for an AVI File =

Article ID: 118591

Article Last Modified on 10/7/2003

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APPLIES TO


 * Microsoft Video for Windows 1.0
 * Microsoft Video for Windows 1.1 Standard Edition

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This article was previously published under Q118591



SUMMARY
This article provides information about how to calculate the hard disk space required for digitized video and audio.



MORE INFORMATION
To calculate the disk space required for an AVI file, use the formulas below to determine the disk space required for captured uncompressed video and audio.

Video
The following two equations are used to determine the total disk space required for capturing raw, uncompressed video with no audio:


 * 1) Transfer rate (bytes/minute) = (frame height [pixels] * frame width [pixels] * frame rate [frames/second] * 60 [sec/min] * color depth [bits/pixel]) / 8 (byte/bits)

NOTE: The frame height in pixels multiplied by the frame width in pixels yields pixels per frame. The color depth could be 8 bits per pixel, 16 bits per pixel or 24 bits per pixel.
 * 1) Disk space (bytes) = transfer rate (bytes/minutes) * length of captured video (minutes)

Audio
To calculate the hard disk space required for captured audio, use the following two equations:


 * 1) Transfer rate (bytes/minute) = (sampling rate [kilohertz] * 1000 * sample size [bits] * 60 [sec/min] * 1, or 2 if in stereo) / 8 (byte/bits)

NOTE: The sampling rate is multiplied by 1000 to convert the value to hertz. If the audio track is in stereo, multiply the equation by two.
 * 1) Disk space (bytes) = transfer rate (bytes/minute) * length of captured audio (minutes)

Video and Audio
Combining the above equations provides a quick way to calculate disk space required for both audio and video; this is specified in the following equation:

Total disk space required for an uncompressed AVI sequence = ([frame height * frame width * frame rate] + [sampling rate * 1000 * sample size * 1, or 2 if in stereo] * 60 [sec/min] * color depth * length of captured video) / 8 (byte/bits)

NOTE: If the audio is in stereo, multiply the audio transfer rate by two. This information can be used to find the space required on a hard disk as well as a CD-ROM.

Additional query words: 1.00 1.10 vfw transfer rate disk space avi

Keywords: KB118591

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