Last year, the Open Mobile Video Coalition (OMVC) released a specification, the ATSC Mobile DTV Receiver Profile Guidelines. The spec, issued by the OMVC Technical Advisory Group (OTAG), recommends two profiles for mobile receivers: a required Base Profile and an optional Enhanced Profile. (Let’s call it an “E-Profile”). So consumers can sort it all out, it’s conceivable that support for the Enhanced Profile could lead to a class of devices with a user-recognizable label. Although the OTAG spec concerns implementation of the ATSC A/153 standard, many of the embodied concepts apply to other systems throughout the world, such as DVB-MHP (Multimedia Home Platform).
Video and audio, while customizable, will likely converge to common formats. H.264 (Base Profile Level 1.3 and Main Profile up to Level 3.1) is recommended by OTAG for both mobile profiles, at supported resolutions. Although Scalable Video Coding (SVC) is a broadcast option, OTAG has not entered it into a mobile profile, citing a lack of marketplace maturity for SVC-compatible consumer products. However, DVR-pause is required, and impulse recording and scheduled DVR are “desirable” in the E-Profile. These step-ups will require additional storage memory. As an example, a combined data rate of 600kb/s for audio and video (reasonable for 416 x 240 resolution) would require 4.5MB for each minute of stored content — not too demanding given today’s flash memory prices.
The Scalable Full-channel Mobile Mode (SFCMM) is an optional transmission mode that scales mobile payload capacity up to the total available from the channel; such a device, of course, would not support legacy mobile broadcasts. SFCMM is deemed “desirable” in the E-Profile, as is a second tuner. HE-AACv2 (w/SBR) (High-efficiency Advanced Audio Coding with Spectral Band Replication) is required for all devices, as constrained in A/153 Part 8, with the average loudness of the audio at -14dB LKFS.