JPEG Definition
JPEG is used for lossy compression of digital images.
Format
Format known as JPEG Interchange Format (JIF) is a pure file format which is not commonly used due to its complication of programming encoders as well as decoders that affect all aspects of the standard and also due to specific limitations of the standard.
Issues such as pixel aspect ratio definition, color space definition and component sub sampling registration.
Numerous other standards have been altered to address these issues.
Structure
JPEG file comprises of segments in sequences, each sequence starting with a marker. Several bytes exist with varying comments on the file.
SOF0 specifies a baseline DCT dependent JPEG as well as the height, number of components, weight and component sub sampling; while SOF2 specifies a progressive DCT dependent JPEG and indicates similar characteristics as SOF0.
DQT indicates one or more quantization table while DHT, one or more Huffman tables.COM comprises a text comment.
During encoding, a number of the options in the JPEG standard are not utilized as most image software makes use of JFIF format while creating a JPEG file, this indicating the encoding method.
Compression ratio
The compression ratio of image files can be altered based on need by increasing or decreasing the aggression in the divisors utilized in the quantization phase.
The suitable level of compression is dependent on the use of the resulting image.
If you familiar with the use of the web, you will notice the non uniform components known as compression artifacts that show up in jpeg files. They might take the form of blocky images or noise around contrasting edges.
Artifacts can be lowered by using a smaller level of compression or otherwise totally avoided by making use of a lossless format.
PDF files
These are files which as saved in a read only format, thereby not permitting editing in any form.
Images and tables are usually embedded in a PDF files. This provides less room for adjusting or altering content. There some apps that accommodate minimal change in PDF file content without conversion but these alterations are not effective in case of major alteration.
Uses of PDF files
They are useful for web presentation as it preserves the content intended to be shown. It is also quite useful in the court as it does not bear any electronic footprint.
In the court, documents provided are required to have no form of electronic footprint which might indicate tampering.
Pdf files are great for encrypting content. Passwords can easily be placed on then to prevent intrusion.
Pdf files are converted to jpeg files when the content of the PDF file is required in image format. Jpeg format comes in handy as it provided low storage space usage.
Conclusion
JPEG files are of different formats and these formats are indicated in the file name extensions.
Each format is distinct and yet quite similar to the others. They are all used for image format while saving up of storage space and maintaining quality.
