Page 19 - ITU Journal, ICT Discoveries, Volume 3, No. 1, June 2020 Special issue: The future of video and immersive media

ITU Journal: ICT Discoveries, Vol. 3(1), June 2020

JPEG Pleno: Standardizing a coding framework and tools for plenoptic imaging

modalities
Pages 85-99

Pekka Astola, Luis A. da Silva Cruz, Eduardo A. B. da Silva, Touradj Ebrahimi, Pedro Garcia Freitas,
Antonin Gilles, Kwan-Jung Oh, Carla Pagliari, Fernando Pereira, Cristian Perra, Stuart Perry, Antonio M.
G. Pinheiro, Peter Schelkens, Ismael Seidel, Ioan Tabus

JPEG Pleno is an upcoming standard from the ISO/IEC JTC 1/SC 29/WG 1 (JPEG) Committee. It aims to
provide a standard framework for coding new imaging modalities derived from representations inspired by the
plenoptic function. The image modalities addressed by the current standardization activities are light field,
holography, and point clouds, where these image modalities describe different sampled representations of the
plenoptic function. The applications that may benefit from these emerging image modalities range from
supporting varying capture platforms, interactive content viewing, cultural environments exploration and
medical imaging to more immersive browsing with novel special effects and more realistic images. These use
cases come with a set of requirements addressed by the JPEG Pleno standard. Main requirements envision
high compression efficiency, random access, scalability, error-resilience, low complexity, and metadata
support. This paper presents a synopsis of the status of the standardization process and provides technical
insights as well as the latest performance evaluation results.
View Article

A new set of directional weights for ITU-R BS.1770 loudness measurement of
multichannel audio

Pages 101-108

Leandro Pires, Maurílio Vieira, Hani Yehia, Tim Brookes, Russell Mason
The ITU-R BS.1770 multichannel loudness algorithm performs a sum of channel energies with weighting
coefficients based on azimuth and elevation angles of arrival of the audio signal. In its current version, these
coefficients were estimated based on binaural summation gains and not on subjective directional loudness.
Also, the algorithm lacks directional weights for wider elevation angles (||≥30). A listening test with
broadband stimuli was conducted to collect subjective data on directional effects. The results were used to
calculate a new set of directional weights. A modified version of the loudness algorithm with these estimated
weights was tested against its benchmark using the collected data and using program material rendered to
reproduction systems with different loudspeaker configurations. The modified algorithm performed better than
the benchmark, particularly with reproduction systems with more loudspeakers positioned out of the horizontal
plane.

View Article

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