Understanding various Video Codecs

July 1, 2008

The Video codecs is a method of compression/decompression of video file, video data or streaming video format. The codecs stands for Coders / Decoders.

There are various kinds of video codecs available. Since these codecs have been implemented by different algorithms by number of companies; they have different specification and application in various fields. These video codecs generally complies Industry standards.

The various software video codecs are:

  • H.264 / MPEG-4 AVC
  • Mpeg-4
  • DivX
  • x264
  • Real Video
  • Sorenson
  • Mpeg-1
  • Mpeg-2
  • H.261
  • H.263

These various Video codecs are technically differentiated from each other based on various factors which includes compression technology / algorithm, platform supported, sampling, OS supported etc

One can easily compare the various Video codecs on wikipedia. But still there is confusion which codec is the appropriate? However it also depends on application. But understanding pros & cons of some of these codecs gives us the better information and insight depth.


H.264 / MPEG-4 AVC

Overview

H.264 is also known as MEPG-4 AVC. H.264 uses the latest innovations in video compression technology to provide consistently crisp and clear video for the best possible viewing.

Pros

  • H.264 delivers incredible video quality at data rates one-fourth to one-half the size of previous video formats
  • H.264 offers dramatically lower bit rates and better picture quality than MPEG-2, MPEG-4 or H.263+
  • It is 2X times more efficient than MPEG-4. and file size is 3X times smaller than comparable MPEG-2 Codecs
  • It is easy to integrate and covers wide range of picture format. Hence used in large application segment.

Cons

  • H.264 requires longer encoding time
  • It is certainly not constricted and low-bandwidth friendly
  • More Hardware overhead is also one of the limiting factor
  • Licensing agreements are complicated.


MPEG-4

Overview

MPEG-4 is a standard currently under development for the delivery of interactive multimedia across networks. As such, it is more than a single codec, and will include specifications for audio, video, and interactivity.

The video component of MPEG-4 is very similar to H.263. It is optimized for delivery of video at Internet data rates. One implementation of MPEG-4 video is included in Microsoft’s NetShow.

Pros

  • Good image quality at low data rates

Cons

  • Standard is still being designed


DiVx

Overview

DivX is a brand name of products created by Divx Inc. The DivX codec uses lossy MPEG-4 Part 2 compression and it isfully MPEG-4-Advanced Simple Profile compliant; MPEG-4 ASP.

Pros

  • The Divx codec is quite simple to set up and use
  • It is popular due to its ability to compress lengthy video segments into small sizes while maintaining relatively high visual quality.

Cons

  • It’s a commercial codec, so in order to get all the options you have to pay money for it.


x264

Overview

x264 is a freely available open source implementation of the h.264 standard. H.264, or AVC as it is sometimes known is a very advanced compression method that is part of the MPEG-4 standard.

Pros

  • It offers the best quality at the smallest filesize

Cons

  • x264 (or any h.264 codec for that matter) is that it can take bit of CPU power to play


Real Video

Overview

Real Media currently has only two video codecs: Real Video (Standard) and Real Video (Fractal). Please bear in mind that this page only compares the one to the other.

Pros

  • RealVideo (Standard) is usually best for data rates below 3 KBps.
  • It works better with relatively static material than it does with higher action content.
  • It usually encodes faster.

Cons

  • RealVideo (Standard) is significantly more CPU intensive than the RealVideo (Fractal) codec.
  • It usually requires a very fast PowerMac or Pentium for optimal playback.


Sorenson

Overview

The Sorenson Video Codec produces excellent Web video suitable for playback on any Pentium or PowerMac. It also delivers outstanding quality CD-ROM video at a fraction of traditional data rates.

Pros

  • Provides much higher image quality than Cinepak, with smaller files. It is often possible to get twice the image quality at less than half the data rate.
  • Tuned to work well from 2 – 100 KBps.
  • Supports Media Cleaner Pro’s variable bitrate encoding, which provides the best possible results at any data rate.

Cons

  • Playback of CD-ROM video requires faster computers than Cinepak
  • Movies larger than 320×240, or at data rates above 100 KBps, do not play smoothly except on high-end machines (such as a Macintosh G3). While picture quality is usually outstanding at higher rates, you should test these movies on your target machines to determine if playback performance is acceptable.



MPEG-1

Overview

MPEG-1 provides excellent image quality at CD-ROM data rates. One of the most popular uses of MPEG-1 is the VCD, or “white book” video CD. MPEG includes both audio and video compression.

The biggest problem with MPEG is that it has high requirements for playback. Either a dedicated MPEG decoder card must be installed, or a high-end CPU is required for software-only playback. Because of this limitation, MPEG-1 has not gained wide acceptance in consumer titles.

Pros

  • Excellent image quality

Cons

  • Very high playback requirements
  • Majority of installed base not capable of viewing MPEG
  • Licensing fees (typically US $0.04 – $0.40 per unit) are required to distribute MPEG-2 video. There may also be fees for MPEG-1; there is some uncertainty regarding this.
  • Not well-suited to WWW video (the upcoming MPEG-4 standard will address this)


MPEG-2

Overview

MPEG-2 is a standard for broadcast-quality digitally encoded video. It offers outstanding image quality and resolution. MPEG-2 is the primary video standard for DVD-Video

Pros

  • Excellent image quality

Cons

  • Very few people are currently capable of viewing MPEG-2
  • Licensing fees (typically US $0.04 – $0.40 per unit) are required to distribute MPEG-2 video.


H.261

Overview

H.261 is a standard video-conferencing codec. As such, it is optimized for low data rates and relatively low motion.

Pros

  • H.261 is optimized for low data rates.
  • H.261 has a strong temporal compression component, and works best on movies in which there is little change between frames.

Cons

  • Not generally as good quality as H.263.
  • It may not play well on lower-end machines.



H.263

Overview

H.263 is a standard video-conferencing codec. As such, it is optimized for low data rates and relatively low motion.H.263 is an advancement of the H.261 standard; mainly it was used as a starting point for the development of MPEG (which is optimized for higher data rates.)

Pros

  • H.263 is optimized for low data rates.
  • Generally better quality than H.261
  • H.263 has a strong temporal compression component, and works best on movies in which there is little change between frames.

Cons

  • H.263 is CPU intensive
  • It may not play well on lower-end machines.


To commercialize these video codecs couples of portals are available where you can compare and procure them. Such portals are design-reuse, chipestimates, IPsupermarket.com which allows you to buy/sell or license these video codecs.


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