From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp014.mail.yahoo.com ([216.136.173.58]) by speech.braille.uwo.ca with smtp (Exim 3.33 #1 (Debian)) id 16f2nJ-0001YM-00 for ; Sun, 24 Feb 2002 12:50:41 -0500 Received: from igueths (AUTH poptime) at h0020780ec921.ne.mediaone.net (HELO mycomputer) (24.91.176.59) by smtp.mail.vip.sc5.yahoo.com with SMTP; 24 Feb 2002 17:50:43 -0000 Message-ID: <001501c1bd5a$b9682100$02b05b18@mycomputer> From: "Igor Gueths" To: References: <20020224142005.B28800@joana.gotss.net> <002b01c1bd46$7a5f2260$02b05b18@mycomputer> <20020224234952.A29761@joana.gotss.net> Subject: Re: oggenc weirdness Date: Sun, 24 Feb 2002 12:43:08 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-Mimeole: Produced By Microsoft MimeOLE V5.00.2615.200 Sender: speakup-admin@braille.uwo.ca Errors-To: speakup-admin@braille.uwo.ca X-BeenThere: speakup@braille.uwo.ca X-Mailman-Version: 2.0.8 Precedence: bulk Reply-To: speakup@braille.uwo.ca List-Help: List-Post: List-Subscribe: , List-Id: Speakup is a screen review system for Linux. List-Unsubscribe: , List-Archive: Hi Kerry. Now I see where you are going with this. Sorry for the lame = opinion lol!=20 ----- Original Message -----=20 From: Kerry Hoath To: Sent: Sunday, February 24, 2002 10:49 AM Subject: Re: oggenc weirdness > Sampling at 44100 is not a good idea at all, here is why. > Assume we have a 44100hz stream at 16 bits per sample so that is > 88200 bytes per second. we want to compress that to 32 kilobits per = second or > 4000 bytes per second. > A quick devision shows a 22:1 compression is involved. At such > agressive compression settings lame downsamples by default and = introduces noise > into the sample fromt he downsampling. This is agrivated by the mp3 = encoding > process. If we start sampling at 22050 rather than 44100 > then it is only a 11:1 compression ratio. > Also, mp3 is not free to use and has patent restrictions on its use. > ogg sounds better, is completely free and works well. > Below is the technical reason why you don't do 4-track tapes at 44100: >=20 > Take your average 4-track tape recorded at 15/16 inches per second. > This is half regular tape speed which is 1 and 7/8 inches per second. > On side 1 we have track 1 on the left channel and reversed track 4 on = the right channel. > On side 2 we have track 2 on the left channel and track 3 reversed on = the right channel. > the fastest way to sample these tapes is to do the following: > Sample side1 at 44100 16-bit stereo. > fiddle the wave file so that the header reads 22050 samples per = second. > This halves the speed from normal tape speeds digitally and since no = math > is involved we retain whatever quality we got into the sound card = except see note below. > Split the wave file into left channel only track one and right channel = only track 4. > Reverse the right channel. We have now got 2 tracks of aproximately 90 > minutes in length but have only sampled for 45 minutes. > This means that if we sample both sides and slice them up we sample = for 90=20 > minutes and fiddle for 10 minutes to get 6 hours of wave data on disk. > Not bad at all. > The problem is that even though the niquist frequency of 44100 samples = per second is 22050hz > most low-end soundcards don't record high frequencies say above 16khz = too well > and some tape recorders don't play them well either. > This means that some of the top end is lost by sampling at double = speed and=20 > halving sample rate. This stuff is only spoken word so > the loss is not too great. Also lame puts a lowpass > polyphase filter on the wave data at about 7500hz anyway. > I could sample at 32000hz and half the rate to 16000 but I may loose = more > high frequency component and would be incompatible with a lot of sound = hardware that won't > play back 16khz sample rates. > Sampling on a 4-track machine would also preserve more quality but = would take 4 times longer. > I just need to find a good card for the pc that is supported under = Linux and that has good > quality analog inputs. > Sound blaster live cards tend to be a bit noisy in this regard. It's = almost worth > dragging out the Gravis ultrasound max or the pas16 cards I have here. > The pas16 cards have the best line input i've heard on cheap cards but = require > a dynamic microphone and do not provide phantom power so will > not run a condenser without a Microphone pre-amp. > Anyway I've ranted long enough :-) >=20 > Regards, Kerry. > On Sun, Feb 24, 2002 at 10:18:13AM -0500, Igor Gueths wrote: > > Hi Carry. I think that mp3s are a good way to go. Wouldn't you = prefer to try to sample the audio at 44100 khz? The only problem with = that is that you might get some tape hiss or noise depending on the = playing device you are using and the age of the tape (s). Again, you = don't have to re-record the samples, but that's just my opinion on = quality. Hope this helps.=20 > > ----- Original Message -----=20 > > From: Kerry Hoath > > To: > > Sent: Sunday, February 24, 2002 1:20 AM > > Subject: oggenc weirdness > >=20 > >=20 > > > Since we're all talking about anything and everything at the = moment, here's > > > one for the list to think on: > > > I am currently sampling some 4-track material I own to keep it > > > safe in case the tapes age or snap. > > > I get the wav files as I want them; (I can summarize to the list = if > > > anyone cares with the scripts I wrote yesterday to make it all = work) > > > and these aren't Jim's scripts, I wrote these ones with comments = to aid > > > in maintainance. > > > I have a .wav file 22050 samples per second 16-bit little endian = mono. > > > I try to oggenc this file with the following command: > > > oggenc -b32 side01.wav > > > and get a message that "mode initialization failed" > > > This used to work fine in 1.0rc2 but appears to have broken in = 1.0rc3 > > > Anyone else running 1.0rc3 and seen this behaviour? > > > If I don't specify -b32 I get an encoded file which averages = 51kb/s which is far too > > > much bandwidth to waste on this stuff. At the moment I am left to = mp3 the files > > > with lame -h -b32 side01.wav side01.mp3 > > > which does work but I would preferr to use ogg. Must I downgrade = to 1.0rc2 again? > > >=20 > > > Any insites would be apreciated. > > >=20 > > > Regards, Kerry. > > >=20 > > > --=20 > > > Kerry Hoath: kerry@gotss.net kerry@gotss.eu.org or = kerry@gotss.spice.net.au > > >=20 > > > _______________________________________________ > > > Speakup mailing list > > > Speakup@braille.uwo.ca > > > http://speech.braille.uwo.ca/mailman/listinfo/speakup > >=20 > >=20 > > _________________________________________________________ > > Do You Yahoo!? > > Get your free @yahoo.com address at http://mail.yahoo.com > >=20 > >=20 > > _______________________________________________ > > Speakup mailing list > > Speakup@braille.uwo.ca > > http://speech.braille.uwo.ca/mailman/listinfo/speakup > >=20 >=20 > --=20 > Kerry Hoath: kerry@gotss.net kerry@gotss.eu.org or = kerry@gotss.spice.net.au >=20 > _______________________________________________ > Speakup mailing list > Speakup@braille.uwo.ca > http://speech.braille.uwo.ca/mailman/listinfo/speakup _________________________________________________________ Do You Yahoo!? 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