Notes on various Video and Audio Coding Standards

(a) Video Standards

Indeo Video 5.10

Useful for video distributed over the Internet for computers with MMX or Pentium II processors. This codec includes features such as a quick compression option, flexible keyframe control, chroma keying (transparency), playback effects, and on-the-fly cropping that reduces the data load. Also, this codec employs a progressive download feature that adapts to different network bandwidths. Full use of these features requires utility software available separately from Intel. This codec is designed to work together with the Indeo Audio Software codec.

Microsoft RLE

Useful for compressing frames that contain large areas of flat color, such as cartoon-style animation. This codec uses a spatial 8-bit run-length encoding (RLE) compressor and is lossless at the 100% quality setting.

Microsoft Video 1

Useful for compressing analog video. This lossy, spatial codec supports pixel depths of 8 or 16 bits.

Intel Indeo Video R3.2

Useful for compressing 24-bit video for playback from CD-ROM discs. This codec attains higher compression ratios, better image quality, and faster playback speeds than the Microsoft Video 1 codec. For best results, use the Indeo Video codec on raw source data that has not been previously compressed with a highly lossy codec. When used with a data rate for playback, this codec produces movies that are comparable in quality to those compressed with the Cinepak codec.

Cinepak Codec by Radius

Useful for compressing 24-bit video intended for CD-ROM discs or for downloadable Web video files. This codec attains higher compression ratios and faster playback speeds than the Video codec. You can set the data rate for playback; picture quality drops more noticeably at data rates below 30 KBps. Cinepak is asymmetrical—it decompresses quickly, but compression is slow enough to make it impractical for editing. For best results, use Cinepak only for exporting the final version of a video file.

(b) Audio Standards

MPEG Layer-3 Codec

Also known as mp3. This is the third coding scheme for MPEG audio compression. MPEG Layer-3 uses perceptual audio coding and psychoacoustic compression to remove parts of the audio signal that are imperceptible to the human ear. The result is a compression ratio up to 12:1 without loss of audio quality.  mp3 is a common format for distributing music files over the Internet.

ACELP.net

A net-based codec using frame-concatenation and interlacing for improved music quality. ACELP.net allows a dual-rate bit-rate of 8.5/6.5 kbps or a fixed-rate bit-rate of 5.0 kbps.

WM-AUDIO

More fully known as Microsoft Windows Media™ audio compression. This is the standard codec for Microsoft Active Streaming Format which combines fast encoding with high music quality and is optimized for Pentium II (MMX) and Pentium III (SSE/SIMD) processors. WM-AUDIO has a wide bit-rate range from 5 kbps to 128 kbps and offers high quality sound over the Internet even over 28.8 modems. WM-AUDIO is considered a future replacement for MP3.

Indeo Audio Software

Useful for music and speech distributed over the Internet. Its maximum compression ratio is 8:1. This codec is designed to work together with the Indeo Video codec.

Microsoft G.723.1

A codec intended for use in video conferencing. It offers acceptable voice quality, but is a poor choice for music or sound effects. The audio quality is lower than other codecs that use the same data rate.

L&H Codecs

Speech and music compression algorithm developed by Lernout & Hauspie.

TrueSpeech

Useful for speech over the Internet at low data rates.

Microsoft GSM 6.10

Useful for speech, used in Europe for telephony.

Microsoft CCITT G.711

This codec uses µ-Law encoding and is commonly used for digital telephony in North America and Japan.

MS-ADPCM

A Microsoft implementation of Adaptive Differential Pulse Code Modulation (ADPCM), a common digital audio format capable of storing CD-quality audio.

Microsoft IMA ADPCM

An implementation of ADPCM, useful for cross-platform audio for multimedia, developed by the Interactive Multimedia Association (IMA).