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Re: Action item. definition and use of Clean audio in European television

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Tue, 24 May 2011 10:57:48 +1000
Message-ID: <BANLkTi=BHsjnvtTdJVTwP0OjOgw3kqx4=A@mail.gmail.com>
To: David Singer <singer@apple.com>
Cc: Sean Hayes <Sean.Hayes@microsoft.com>, "HTML Accessibility Task Force (public-html-a11y@w3.org)" <public-html-a11y@w3.org>
On Tue, May 24, 2011 at 12:43 AM, David Singer <singer@apple.com> wrote:
> On May 21, 2011, at 2:39 , Silvia Pfeiffer wrote:
>>> I don't think we should (a) stray from normal industry parlance or (b) assume that it's always the speech that is the main program content.
>> I agree. Since we are talking about a technology that diverges from
>> what the industry labels as "clean audio", we should therefore not use
>> the same term.
> Can you say how you think we are differing from the concept of 'clean audio'?  I agree that the way clean audio is achieved in various systems varies (quite widely) -- e.g. by isolating to a channel or two in some multi-channel environments, but I think we can achieve clean audio in HTML (and we should, and should at least conceive of the labeling for all sorts of conditions, such as high-contrast video).

Calling a video track that has high-contrast video "clean" is not
really appropriate either. I'd much prefer such a track to actually be
called "high-contrast" so its content makes sense. A "clean" video
channel could be all sorts of other things, too, such as "cleaned from
blocking artifacts" or "cleaned up brightness", or "cleaned up white
balance" etc. It doesn't really mean anything to call a video track
"clean" - it it particular doesn't tell us what to use it for.

But back to audio.

I am mostly objecting to the term "clean audio" from the point of view
that most people understand something else as "clean audio" - just
search for the term and you will find that it refers to the quality of
an audio recording more than to the ETSI/BBC way of using it: it means
avoidance of clipping, interference, noise reduction, audio
restoration etc. To an audio person, a "clean audio" channel indicates
that this is a replacement recording to the main audio channel with a
higher-quality recording.

However, where ETSI/BBC and us use "clean audio", we refer to the
possibility of separately increasing the volume of the foreground
sound. And it ETSI's spec in particular it is reduced to adding a
speech-only channel. This is why I am suggesting the term "speech" to
be more appropriate.

ETSI actually call a channel that contains speech-only for "clean
audio" purposes a "hearing impaired" channel. At least this describes
what the channel is being used for. "speech" would describe what it
contains. "clean audio" give a false indication of better sound
quality. I would be ok with "foreground sound", too, but I would be
very unhappy about the term "clean audio".

Received on Tuesday, 24 May 2011 00:58:35 UTC

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