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Rockbox mail archiveSubject: RE: Frequency as it relates to recording qualityRE: Frequency as it relates to recording quality
From: Ofir Carny <Ofir_at_vidius.co.il>
Date: Thu, 10 Apr 2003 14:49:42 +0200 Hi, Coming from the area of telephony I always assumed that CD PCM (as in music CDs) was non linear too, is it completely linear? I can't see any reason to do anything that way. Am I missing something here? -----Original Message----- From: Eric Woudenberg, Minidisc.org Editor [mailto:minidisc_at_zoot.minidisc.org] Sent: Thursday, April 10, 2003 3:14 PM To: rockbox_at_cool.haxx.se Subject: Re: Frequency as it relates to recording quality Hi Ofir, >AFAIR and according to >http://www.wikipedia.org/wiki/Sampling_frequency the ph one uses >8Khz, if the phone is good enough for you (and don't consider noise, >etc., that's unrelated), it should be good enough for voice. My >experience is similar, as long as I am rec ording voice, I can >downsample as far as I can (at least with the original arc hos FW) >and hear no difference, I can also compress a lot (I think I used the >lowest level once). AFAIR phones uses 64kbps PCM - and that means 8 >bit depth (I ran across 32kbps ADPCM too), US telephones use 8bit u-law (Europe uses 8bit a-law), which are non-linear encoding schemes roughly equivalent in dynamic range to 12bit PCM (but with more noise). >and that usualy seems OK to me, voice confere ncing and VoIP usually >go so low that it's scary and so did early cell phones. Telephones are not perfect for voice -- try differentiating an "S" and "F" spoken alone. Rick ********************************************************************** This email and attachments have been scanned for potential proprietary or sensitive information leakage. Vidius, Inc. Protecting Your Information from the Inside Out. www.vidius.com ********************************************************************** Received on 2003-04-10 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |