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NISO/DAISY on Audio Playback Controls

From: Harvey Bingham <hbingham@acm.org>
Date: Thu, 30 Nov 2000 01:51:31 -0500
Message-Id: <5.0.0.25.2.20001129131031.02643610@pop.rcn.com>
To: <w3c-wai-ua@w3.org>
Summary:

[HB comments by Harvey Bingham.
UAAG1.0 does address some of the audio playback issues.
Many other issues, specific to digital talking books, go beyond what
UAAG addresses. The intent for playback devices is that these
capabilities are appropriate for some classes of players, noted by the
digit-letter codes. Players: 1=basic, 2=advanced, 3=computer-based;
feature: A=essential, B=highly desirable, C=useful.]

Reference:

Playback Device Guidelines for Digital Talking Books
Prioritized List of Features for Digital Talking Book Playback Devices
      http://www.loc.gov/nls/niso/features.htm
Version Date: December 30,1999

[HB The National Information Standards Organization (NISO) is allowed to make
standards, at least in USA. The international Digital Audio Information
SYstems (DAISY) Consortium of libraries for the blind and visually
impaired is developing this as a NISO "standard."]

3. Audio Characteristics

3.1 Sound quality (1A, 2A, 3A) (To be quantified)
Audio material shall be distributed in a form that provides a minimum of FM 
quality sound to the user. (This section will be expanded, based upon Audio 
Engineering Society project AES-X74, Recommended Practices for Internet 
Quality Descriptions.)
[HB UAAG has nothing comparable.]

3.2 Volume control (1A, 2A, 3A)
The user can adjust the volume to meet hearing and listening conditions.
[HB Checkpoint 4.10, ?4.11]

3.3 Tone control (1A, 2A, 3B)
The user can adjust the equalization (the amount of low, mid-range or high 
frequencies) to suit individual tastes and listening conditions. The device 
shall include a high-frequency adjustment to compensate for age-related 
hearing loss.
[HB No mention.]

3.4 Variable speed, with pitch restoration (1A, 2A, 3A)
Playback speed is adjustable over a range from 1/3 to at least 3 times the 
normal playback speed, and the pitch of the narration is not altered by the 
speed change. The Time-Scale Modification system shall not produce audible 
chopping, burble, or reverberation and shall not skip over significant 
units of sound at high playback speeds.
[HB 4.12: 120 to 400 words per minute. No mention of pitch restoration.]

3.5 Pitch restoration control; independent of speed (1B, 2B, 3B)
Although pitch restoration may be the default, the user can adjust the 
pitch of the narrator's voice independent of the speed to make it more 
intelligible at extreme speeds, or to compensate for hearing loss.
[HB No mention.]

3.6 Amplitude compression (1C, 2C, 3C)
Gives the user a method of narrowing the volume range between the quietest 
and the loudest portions of a talking book. This would be useful when 
listening to the book at a distance, in a noisy environment, or for a 
person whose hearing has limited dynamic range. The AC-3 audio compression 
standard includes this function.
[HB No mention.]

3.7 Stereo (3B)
Could be useful in auditorially displaying spatial arrangements of 
information, such as matrices in T.V. Raman's ASTER system.
[HB No mention.]

3.8 Balance control (stereo) (3A)
[HB No mention.]

Regards/Harvey Bingham
Received on Thursday, 30 November 2000 01:52:47 GMT

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