# Is Gamma Still Needed?: Part 9 - Processing In Floating Point

Floating-point notation and gamma are both techniques that trade precision for dynamic range. However they differ fundamentally. Gamma is a non-linear function whereas floating point remains linear. Any mathematical manipulations carried out on floating-point encoded data will be correct whereas manipulations of gamma-encoded luma cannot be. Gamma was intended to linearize a cathode ray tube whereas floating point encoding was designed from the outset for mathematical manipulation.

Fig.1 The transfer function of a 16-bit quantizer is shown at a). If a sixteen bit number is expressed to 12-bit accuracy, the steps b) become four times larger. In floating point this can only happen in the presence of a signal, so the approximation is masked.

Fig.2 A five-bit exponent has 32 combinations. The ends of the scale denote zero and infinity, leaving fourteen negative values, zero and fifteen positive values for the exponent.

Fig.3 Addition first requires the exponents to be the same. Then the mantissae are added and the result is re-normalized.

Fig.4. When a mantissa is shifted right, three bits shifting from the end are considered. These are the guard, round and sticky bits that are used to optimize the normalization.

# ATSC 3.0: Right Place, Right Time

Many people and cultures celebrate special New Year dates. Organizations designate fiscal years. Broadcasters traditionally mark their new technology year mid-April, at annual NAB Shows. Old habits die hard.

# Is Gamma Still Needed?: Part 10 - Summary

In this final part of the series, an attempt will be made to summarize all that has gone before and to see what it means.

# HDR: Part 22 - Creative Technology - Non Standard

Read too much film and TV industry technical literature, and it’s easy to get the impression that everything about the technology is built to carefully considered specifications. As Philo Farnsworth’s wife was probably aware, though, as he tinkered wit…

# Timing: Part 1 - Sidereal Or Solar?

The subjects of timing, synchronizing and broadcasting are inseparable and in this new series John Watkinson will look at the fundamentals of timing, areas in which fundamental progress was made, how we got where we are and where we might…

# Creative Analysis: Part 20 - Cinematographer Pete Romano On Underwater Filming

There aren’t many positions in the film industry which have the prerequisite of spending an hour sunken in the waters off San Diego in a classic diving suit with a blacked-out helmet. To be fair, it wasn’t so muc…