Aspect ratios

Revision as of 16:01, 9 May 2013

Introduction

Diagram above is an example of the calculations one can do with a DVD source (left side). This is an oversimplified DVD example (numbers are not 100% accurate, the math is), but it should help in understanding what is going on.

Acronyms and their possible meanings

AR: Aspect Ratio

DAR: Display Aspect Ratio

FAR: Frame Aspect Ratio

IAR: Image Aspect Ratio; Intended Aspect Ratio

MAR: Movie Aspect Ratio; Modified Aspect Ratio

OAR: Original Aspect Ratio

PAR: Pixel Aspect Ratio; Picture Aspect Ratio

RAR: Raster Aspect Ratio

SAR: Sample Aspect Ratio; Signal Aspect Ratio; Source Aspect Ratio; Storage Aspect Ratio

Online Calculators

http://smok3.bplaced.net/resize/

http://www.digitalrebellion.com/pixel_calc.htm

http://www.digitalrebellion.com/aspect_calc.htm

Software DVD players and DAR

http://www.doom9.org/aspectratios.htm

Specifications

mpeg-1 specs: http://forum.doom9.org/showthread.php?p=685662#post685662 (ISO/IEC 11172 Part 2, Chapter 2.4.3.2 "Sequence header"; pel_aspect_ratio)

mpeg-2 specs: http://forum.doom9.org/showthread.php?p=685658#post685658 (DAR, SAR)

mpeg-2 specs: http://forum.doom9.org/showthread.php?p=685854#post685854 (ISO/IEC 14496 Part 2)

mpeg-4 specs: http://forum.doom9.org/showthread.php?p=686948#post686948 (no SAR)

h264/AVC specs: http://forum.doom9.org/showthread.php?p=686958#post686958 (only SAR)

ITU standard

http://www.doom9.org/capture/par.html