[paranoia] Mono

[Sibbald, Alister]

A very good point Dave. I agree.

I suppose the problem this leaves Boris with is to work out which of these
three options it is. Maybe, to paraphrase what someone said, the best
approach is "if it sounds OK, it is OK". If it is truly caused in the manner
you suggest, the way to fix it would be to do what a mono switch on an
amplifier does, and simply to average the two channels together and write
out the averaged signal ot both channels. However, if it already sounds OK,
this seems a little unnecessary.

        Regards
                Alister

<p>-----Original Message-----
From: Dave Lewis [mailto:lewis at synergymicro.com]
Sent: 23 September 2003 14:44
To: paranoia at xiph.org
Subject: RE: [paranoia] Mono

<p>>I'm not sure that's right Jack.
>If the programme material is Mono, then by definition both channels 
>must be identical. It is either a historical recording, which came 
>from a single track mono tape, or a more modern mix-down to mono, 
>which results in the same thing ( although I'm not sure why anyone 
>would want to do the latter ).
>
>Either way, if the source was a single mono channel, the CD creation 
>process should simply have duplicated that Mono channel on both Left 
>and Right.
>
>Therefore, if Boris is getting different data, I can only see two 
>possibilities:
>
>1 The CD is simply mis-labelled and is not in fact Mono. In other 
>words, Paranoia is doing it's job correctly, but the source data 
>really is different. I can't see there is much potential for this. 
>CD Publishers are unlikely to label something Mono unless they 
>really have to, for obvious marketing reasons.
>
>2 The CD is Mono, but Paranoia is not correcting all errors. It may 
>for example be interpolating over errors in one channel but not 
>having to interpolate over errors at the same point in the other 
>channel.

   A third possibility is that an analog mono source was fed into both
channels of the mastering digitizer. HIGHLY unlikely that both channels
would produce identical digital data no matter how carefully the inputs
were matched. Since this seems to be the simplest way to master a mono
CD, I think it's the most probable explanation.
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