I am working on compressing speech files. Good clarity and quality in
a small file format is the objective.

It seems many audio files are recorded in 'stereo' even though mono
should be sufficient for most speakers [except perhaps those that
speak out of both sides of their mouths?]

When a stereo wav file is encoded, are both channels mixed into 1 mono
channel?

Is it advisable to apply a notch filter to eliminate <500hz and

I think you've got a bit of reading to do, grasshopper! Google is your
friend!

NewB wrote:

"Bill in Co." <LostInTime@earthlink.net> schreef in bericht
news:UJEQb.26421$zj7.15843@newsread1.news.pas.eart hlink.net...
Hmm they always told me that unclesam was my friend ;o)

Bill in Co. said...

do it all the time) being given to someone who asks a simple and general
question about mp3 that is asked often.

However, this poster asked some specific questions about mp3 compression
as it applies to a particular function he wants to use it for. If you
can't help him, why can't you just STFU and leave it for someone who can
help him instead of repeating your tired old "google is your friend"
crap?

What exactly DO you see the function of this forum as, if not to answer
specific questions about mp3 compression that people have, Bill?

"grasshopper" is the term the wise old one uses when talking to his
young student, not something a cranky old goat who doesn't have the
answers blows someone off with.

What exactly is the search string to put in google to return something
meaningful on this question Bill? The question indicates a knowledge of
what he is doing but a desire to hear other's opinions on the matter.
--
CQ

Because in most of these cases (as I've seen in real life, with many of my
students) they want a quick answer. Hell, sometimes I spend several hours,
and often days, trying to research something like this, before I ask.
(Granted, not always, but often).

So perhaps I'm a bit sensitive to it, but I see it a LOT in RL - and here on
the net (including some support in the windows newsgroups), probably a lot more
than you do, CQ. And I have to deal with it on a daily basis, in my teaching
profession. And overall, it's gotten a lot worse in this current day and
age - a lot worse than it used to be. Everybody wants a quick answer, w/o
doing their own homework en route. That's why.

CQ wrote:

Bill in Co. said...
Well, nobody likes to wait forever but there was nothing in this guy's
question that sounded anything like an imperative that someone hurry the
hell up and help him out.

And certainly not this time when you jumped in his shit 6 minutes after
he posted the question.

Huge assumption that you have absolutely no reason to make there, Bill.
Not valid, not germane, and not important anyway. If you are tired of
dumb questions in RL then why are you here in a forum that pretty much is
designed for asking questions and without new questions would soon run
out of material?

I must go pray for the youngsters in Colorado this very minute.

Yes, and we used to be able to go to the movies for a quarter but we had
to walk ten miles through the snow to get to school.

I don't see that the post you jumped on was anything like that at all.
He was interested in some aspects of mp3 that are outside the normal use
of the format. He's not making mp3s of songs, which is what most of the
information sites deal with, and he has some specific questions. He
asked politely, wasn't demanding, indicated he had done some thinking
about the way to do it. What more would you ask?

Your reasons suck and are generally unacceptable. Take the paper back
home, re-do it tonight, and when you hand it back in tomorrow it had
better be a big improvement, mister.

--
Professor Q

CQ wrote:
Wait forever? Gimme a break....

That's YOUR opinion, CQ. It's not Gospel.

Which denomination will you be using? (just curious)
BTW - I make em throw away their calculators, and force them to use a slide
rule. That way they have to think a bit...

Yup.

If I ask you (politely) to explain the structure of the mp3 frames, in some
detail, would you do it here? Or is this something that *I* should research
on my own?

Your opinion, CQ.

Besides which, it is obvious there wasn't much of any research done - look
here:
"Is it advisable to apply a notch filter to eliminate <500hz and 6000kz that
are outside meaningful voice frequencies before encoding? Or is that an
overkill?"

A NOTCH filter won't do that. A BANDPASS filter would. And the frequency
ranges are incorrect for voice - all of which one would know with minimal
research. (As I said, not much, if any, research was done at all).

In article <4b561011j2i6knn7qjph4hs2dc92ocjcu5@4ax.com>, no1@no.not
says...
Lame, you can choose the encoding options, on of them being a mono
track...

--
Little Miss Mikey

Signature removed until further notice due to legal reasons...

"Bill in Co." <LostInTime@earthlink.net> wrote in message
news:wvZQb.26641$1e.3188@newsread2.news.pas.earthl ink.net...

Quit sucking on lemons.


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.562 / Virus Database: 354 - Release Date: 1/16/2004

Bill in Co. said...

You indicate you are a teacher yet you don't understand hyperbole and a
qualifier?

What the hell are you talking about Bill? My statement that you were
making an assumption is based on the fact that you have no way of knowing
how often I encounter anything in RL.

The statement that it wasn't germane referred to the fact that your ennui
with your real life situation is not important to the group. If you are
bored with questions then don't spend your time in a forum where
questions are the order of the day.

Of course, I went on to detail that already but it seems to have eluded
you.

I'm a non-denominational prayer. I only do it when desperation leads me
to it. As Steve Earle once said "Prayin' feels too much like beggin',
Lord".

Ah yes. Way to go Bill. Prepare them for the real world.

I'd probably stay out of it. But since the nature of the forum is mp3
discussion I would hope someone would engage the poster in a polite and
friendly exchange to further his enlightenment on the matter.

Or possibly I would provide an introduction or overview and then provide
a few relevant links to my own favorite informative sites.

I certainly wouldn't tell him to "piss off and go google it" as you seem
inclined to do often.

This all seems a bit strange coming from the man who asked me recently
"where did you read/hear they had stopped development of V3?" regarding
Winamp. Certainly an easily researched question.

<sigh>

At that point (and actually through most of my previous posts) I was
using a bit of tongue in cheek humor to try and lighten things up while
still making the point that I think your continual "go google it" answers
suck. I'm a bit saddened that you seem too dull to realize that and I
won't waste my time trying to exchange any witty repartee with you in the
future.

I'm also a bit alarmed that so many educators in this country continue to
demonstrate a complete lack of humor and creative thinking which can only
be stifling to the young people in their charge. How sad for all of us.

Your opinion, Bill.

Perhaps he isn't as good as you at research? Maybe he found what he
thought was correct information but wasn't sure so he, gasp, came to an
..mp3 newsgroup to try and learn more, just as you have often done.

In case you aren't aware, Bill, one of the web's most valuable research
tools is usenet. The OP found the group that had the most appropriate
name and asked a reasonable question in the proper manner. If you don't
want to answer that question, that is your prerogative, but why do you
constantly blow people off with this lame "go google it" shit like you
are still at the head of a classroom?

Particularly as you are no stranger to making posts asking questions that
some other users might find to be basic information.

If you knew this why didn't you share it with him instead of being a
supercilious asshat and telling him to go google it? You HAD this
information yet didn't bother to share it with him in order to teach him
some kind of object lesson about finding things for himself in life?

--
CQ

On Mon, 26 Jan 2004 01:38:10 -0000, Little Miss Mikey
<LittleMissMikey@GMX.Net> wrote in alt.music.mp3:

Perhaps my original post wasn't as clear as possible.

My main objective is to compress the speech file to as small a file
size as possible [primarily for promiscuous p2p sharing to save
bandwidth], but without sacrificing clarity too much.

I assume that saving as mono would reduce the resulting file some, but
if so, is the content of both stereo channels mixed into 1 mono
channel? or is just the content of the right or left channel
preserved?

As to the issue of filtering out sounds above and below the range
needed for human voice clarity, would applying a *bandpass* filter for
these highs and lows help reduce the final file size?

CQ wrote:
I'm not a mind reader, CQ. Some of your posts with others in here have been a
bit edgy, so to speak. YOU'RE not immune from that. Something to think
about... as to why...

We ALL make assumptions. Get off YOUR high horse.

I'm not bored with it. I might lose my patience in it sometimes. Of course
YOU never do, right?

Do you enjoy this pissing contest stuff, CQ? Of course, I am making that
"assumption", based on such 'innocent comments' as "seems to have eluded you"
I think some of the problem here lies within you too, CQ. Maybe you ought
to chill out a bit too. (Maybe both of us should, for that matter).

Well, that was a joke, but (as you apparently enjoy saying), "that seems to
have eluded you".
(/end insult)

I said do some research on the issue. And that Google was a starting point.
Which it was - and it is.

I never said 'go piss off'. (You want to throw anything else in here, while
you're at it)? Is this some hyperbole coming back around, or what?

Yup, probably guilty as charged. I never said I was perfect.

Why don't you read what YOU said. "..Your reasons suck and are generally
unacceptable..." So, are we becoming God now? Talk about arrogance..!
I'm not a mind reader, especially when you get on your high horse, and start
throwing around some insults like this. Sorry.

This wasn't witty repartee - this was you being judgemental on my post and my
feelings about issues, and then being insulting. Admit it. If not to me, at
least to yourself. Get off your own high horse. (yes, you are up there too)

It was not opinion, it was fact. Period.

I find it interesting that you get up on your own high horse here, and then
proceed to call me 'supercilious'. Why don't you look within yourself?
Maybe that's why it bothers you so much. Did you ever think of that? (It's
called projection and denial).

Are we done, or do you still want to play this thing out? Personally, I think
we can move on to other things. At least, I would like to.

And just FYI, I'm entitled to MY opinion, just as you are to yours. Don't try
to enlighten me or correct me on it - you're not at that level. Leave that
for the One Above....

Well, and maybe to put this to rest, if I overreacted, my apologies.

NewB wrote:
It was clear, just seems to have gotten sidetracked
___________________

Yes, by 1/2 assuming the stereo was sampled at 44,100 and the mono then
becomes 22,050.
______________________

The two channels are mixed. Once done, there is no way to separate them
again.
________________________

I suppose, never had occasion to do so. Seems to me that you could get
decent and small files by resampling your stereo waves to 8000 8 bit mono
and them MP3ing (is that a word? them to 32kbps. Let me check, BRB....

Back. Empirical results:
1. Original wave @ 44,100 16 bit stereo = 31,663 KB
2. Resampled wave @ 8000 8 bit mono = 1,437 KB
3. MP3 @ 32kbps from #2 = 719 KB

Doesn't sound bad at all, everything considered, even though it was music
rather than speech.

--
dadiOH
_____________________________

dadiOH's dandies v3.0...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
____________________________

dadiOH said...

Hijacked, more like it ;-). I've been hoping you'd jump in somewhere and
help the feller out while I was busy trotting around on that high horse
of mine, dads.

--
CQ

dadiOH wrote:

Got the MP3 down to 371 KB at 16 kbps, 8000 mono. Still sounds reasonable,
certainly for speech.

--
dadiOH
_____________________________

dadiOH's dandies v3.0...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico
____________________________

Bill in Co. said...

Talk about arrogance and high horses. Your God is the only one who can
possibly enlighten or correct you? What level do you hold yourself on?

--
CQ

Bill in Co. said...

Ooh. Nothing like a well qualified apology to smack of insincerity.

--
CQ

On Mon, 26 Jan 2004 14:02:36 -0500, "dadiOH" <dadiOH@xmail.com> wrote
in alt.music.mp3:

Now I am getting a bit confused [or just more so :P]

What happens of it is stereo, sampled at 11,025?

see below...



That may not be an issue. I am actually thinking of making multiple
archives such as lofi for bandwidth sharing efficiency, and a more
hifi file that would maintain at least FM radio quality, this latter
being a bit more common process.

That's about a 44:1 compression ratio if my math is correct.

I did a test run a couple days ago on one track of an audiobook. The
original EAC wav rip was 80,664,236 bytes for this 7:37 length file.

I had ogg-vorbis set for the encoding at Quality 0 [VBR I think] and
with only one extra option, --resample at 11.025. The result was a
70:1 compression while apparently preserving stereo:

Length : 7:37
Average bitrate : 19 kbps
File size : 1,140,058 bytes
Nominal bitrate : 26 kbps
Channels : 2
Sampling rate: 11025 Hz
***
Xiph.Org libVorbis I 20020717

I loaded the original .wav file and this .ogg file in winamp [with
VERY cheap speakers] and flipped them repeatedly. Neither myself [bad
ears and all] nor another person could tell any difference. I had
really expected to have some noticeable quality degradation. I'll
have to find a decent set of headphones and study it more though.

If this stereo file is mixed as mono, then I could expect about 140:1
compression right? and that without any voice-only bandpass filtering
being applied as of yet.

btw, thank you much for your helpful insights. I hope to be able to
spend some time on your wonderful webpage soon, as I expect it will
help me expedite my projects.


On Mon, 26 Jan 2004 14:02:36 -0500, "dadiOH" <dadiOH@xmail.com> wrote
in alt.music.mp3: