Video Codec Used on the Windows 95 CD

When Microsoft launched Windows 95, the retail CD-ROM included a multimedia showcase featuring full-motion music videos and trailers in the Audio Video Interleave (AVI) format. This article identifies the primary video codec used to encode these iconic files, explains why it was chosen, and details how it delivered digital video on 1990s personal computer hardware.

The Primary Codec: Cinepak

The video codec commonly used to encode the famous AVI files on the Windows 95 installation CD was Cinepak (identifiable by the FourCC code cvid). Originally developed by Peter Barrett at SuperMac Technologies and later acquired by Radius, Cinepak was the industry standard for software-based digital video throughout the mid-1990s.

The most notable media files included in the \FUNSTUFF\VIDEOS directory on the Windows 95 CD-ROM were:

  • Weezer – "Buddy Holly" (WEEZER.AVI)
  • Edie Brickell – "Good Times" (GOODTIME.AVI)
  • Theatrical trailer for the film Rob Roy (ROBROY.AVI)

All three of these high-profile showcase files were encoded using the Cinepak codec at a resolution of 320x240 pixels (Quarter VGA) at roughly 15 frames per second, paired with uncompressed PCM audio.

Why Microsoft Chose Cinepak

During the development of Windows 95, dedicated hardware decoders (such as MPEG-1 add-in cards) were rare and expensive. Most consumers ran personal computers powered by Intel 80486 or early Pentium processors, alongside single-speed (150 KB/s) or double-speed (300 KB/s) CD-ROM drives.

Microsoft required a video format that could satisfy several technical limitations:

  1. Asymmetric Compression: Cinepak was an asymmetric vector quantization codec. While it took a tremendous amount of computational time and horsepower to compress the video during production, decoding required very little processing power.
  2. Software-Only Playback: Cinepak files could be decompressed entirely via software on a standard 33 MHz or 66 MHz 486 CPU without dropping significant frames.
  3. CD-ROM Bandwidth Optimization: Cinepak was designed specifically to stream within the restrictive 150 to 300 KB/s throughput ceilings of contemporary optical drives.
  4. Color Palette Management: The codec handled 24-bit true color gracefully, but crucially, it could efficiently dither down to 8-bit (256-color) displays, which were standard on most consumer monitors at the time.

Secondary Codecs on Windows 95

While Cinepak was the primary format used for the promotional full-motion video files, Windows 95 included native playback support for other video compression formats. Intel Indeo Video (specifically Indeo 3.2, FourCC: iv32) was another popular software codec bundled with the operating system for multimedia applications and CD-ROM games. Microsoft also supported its own legacy format, Microsoft Video 1 (FourCC: MSVC or CRAM), though it offered significantly lower quality than Cinepak and was largely phased out for high-profile video showcases.