Codecs for Images

  • It is a device or computer program for encoding or decoding a digital data stream or signal.
  • Codecs encodes data stream or signal for transmission and storage, possibly in encrypted from, and the decoder function reverses the encoding for playback or editing.
  • The codecs stands for coders/decoders.


Uses:
  • It is used in videoconferencing, streaming media, and video editing applications.

Codecs for Images:

  • The image codecs is a method of compression/decompression of image file or image data.
  • There are various kinds of image codecs available.
                       1. BMP
                       2. GIF
                       3. JPEG
                       4. JPEG 2000
                       5. MJPEG
                       6. TIFF
                       7. PNG
                       8. WBMP


BMP (Bitmap) :

Benefits:

  • Good photo quality.
  • Bitmap codes may translate well to dot format output device. Such as CRTs and Printers.
Downfalls:
  • BMP codecs are limited to RGB images.
  • It makes file size large.
  • Not support all the platforms.


GIF (Graphic Interchange Format) :

Benefits:

  • It creates transparent, interlaced, and animated graphics for the Web.
  • It supports are all graphic browser.
  • No image information is lost.
Downfalls: 
  • It is not good for photographic images due to its limited number of colors i.e 256 colors.


JPEG (Joint Photographic Expert Group) :

Benefits:

  • Low complexity.
  • Picture quality good.
  • Allows to reduce the file size.
Downfalls:
  • Single resolution and single quality.
  • No target bit rate.
  • No lossless capability.


JPEG 2000:

Benefits:

  • Improve coding efficiency.
  • Full quality scalability.
  • From lossless to lossy at different bit rate.
  • Spatial scalability.
Downfalls:
  • Required more in memory compared to JPEG.
  • Requires more compilation time.


Encoding and Decoding of JPEG 2000:


 MJPEG (Motion Joint Photographic Expert Group) :

Benefits:

  • It is a lossy codec but at 100% quality.
  • At WWW data rate (5-20k), JPEG may produce better result than cinepak.
Downfalls:
  • Large image and high frame rate movies usually don't play smoothly.


TIFF (Tagged Image File Format) : 

Benefits:
  • It is uncompressed retains best quality of image.
  • Encoding scheme is lossless.
Downfalls:
  • This codecs produce large file size.


PNG (Portable Network Graphics) :

Benefits:
  • It is better compression than GIF codec.
  • It is a best one for creating complex live transparency, high color graphics and better compressed low color graphics.
  • Supports all platforms.
Downfalls:
  • It doesn't support animation.
  • It doesn't use predictive frames.


 My notes images: