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AES-21id, Screen-less navigation for high-resolution audio on Blu-ray Disc
AES-21id-2011 AES Information Document for audio-file transfer and exchange - Screen-less navigation for high-resolution audio on Blu-ray Disc has been published.
High-resolution audio, presented as uncompressed LPCM, has been waiting for a suitable transport format for some time. The Blu-ray Disc (BD) format offers such a transport and supports the necessary linear and lossless codecs as part of its basic specification. While many BD players can be found in home theatre and games environments, there are some issues that need to be addressed before they can be introduced into a hi-fi environment that does not have a screen to present visual menus for audio stream setup and track selection. This recommended method specifies a structure for authoring a BD ROM to enable playback in screen-less consumer systems, and to provide simple track selection from the remote control.
From the time of its general introduction in 1983, Compact Discs and CD players have become a familiar part of consumer hi-fi systems. The method of operation has been consistent during that period: put a disc in the tray; accept track 1 by default or select another; press Play. No other setup was expected or available.
The DVD was introduced in the late 1990s primarily to carry movies as a replacement for consumer videotape formats. All user interaction was intended to be directed by a remote control, with visual feedback from the screen that was automatically available in a home-video system. High-resolution audio was not a primary factor in the initial design of DVD, in part because the data capacity of a DVD, although considered large at the time, was insufficient to carry multi-channel uncompressed LPCM (for example).
The introduction of the Blu-ray disc (BD) format in 2006 offered sufficient data capacity for high-resolution audio to be considered practically and without compromise. More importantly, the basic specification of the BD included a wider range of lossless audio coding options, including up to 8 channels of high-resolution LPCM.
Like their DVD precursors, BD players are designed to be used in conjunction with a video screen, and so screen-based visual feedback was again assumed for operational control. While this will be satisfactory for some users, many audio users will still prefer the simplicity of CD operations. Additionally, in many consumer hi-fi systems, there will be no existing screen and the extra cost of providing a screen just to see the menu could make the high-resolution audio proposition impractical.
It is possible, without making any changes to the BD player, to provide the necessary functionality for screen less playback of high-resolution audio. The necessary functionality can be provided using programming that is included at the authoring stage of the disc.
The screen-less modes described here are a function of programming during the disc mastering stage. They use the standard BD capabilities and do not seek to limit them in any way.
This document was proposed as a Call for Comment under the document number AES-17id. During the comment process it was pointed out that this document could be confused with existing documents such as AES17 on digital audio measurement. Accordingly, without changing the content, the document has been re-designated AES-21id to avoid any such confusion.
Posted: Tuesday, April 26, 2011