AM Audio Snippets - Suggestions on Compression Scheme for Web posting

[W1UJR]

As many of you know, I've been collecting snippets from various AM QSOs over the years.

What prompted this posting today is that KC8DDH was kind enough to send a CD of a old 160 meter QSO with N8JRJ, K2VJH, W2UJR, and comments on Mike W2OY. I know that many would get a kick out of this one.

I'd really like to put this up on the web, have plenty of hosting space to do so, but would like to do it in a format that ia accessable to all.
I personally hate Real Player because of the nag factor of continual updates, is there another format, or better format to use?
I'd like to make these reasonally small enough to download, or just stream off the site.

Perhaps the more geekier of you have suggestions?

Tnx - Bruce W1UJR

[WA3VJB]

Bruce,

I know I can speak for many of us in the AM Community when I express appreciation for your and others efforts to archive and make available an audio database of our activities. It has baffled me that our hobby's medium of radio has very little in the way of sound file documentation. Instead most of our material has historically been limited to the printed page where the human voice and the sound that we are drawn to are lost.

Technology in recent years is slowly changing that shortfall, and it's a lot easier to rack up a set of archives than when we were using open reel tape, cassettes, VHS audio tracks, DAT machines, broadcast cartridges, and who knows what other formats of storage and retrieval.

One of the formats that provides options for the listener is the MP3 compression scheme.  It can be decoded and played by the Apple IPod,Windows Media Player, QuickTime, RealPlayer, and proprietary editing software such as CoolEdit and many others.

I have seen the MP4 format mentioned but am not familiar with it.

What is important is that your master archive be stored in an uncompressed format such as a "wav" file, so that you can burn it to DVD or CD with minimal loss of material.  This becomes important when copies are made of the material. The more you compress the sooner a "copy" starts sounding rather gnarly because of digital artifacts and other compression errors.

When it comes to settings, you will have to decide on a profile of the most likely listener. Will they be on a dialup or a high speed line?  Will people want CDs that they can play in their car or home stereo? The settings will involve a balance between the quality of the compressed format and the space/speed needed to store and access the material.

Hope that moves you ahead a little.

The following file is an aircheck recording made in Indiana by N8VR as I was making a transmission complimenting the LOUD sound of Dave, W9AD.  I have re-processed the file as a 56Kps, 12:1 compression MP3 at 44.1K sampling rate, creating a file of under 600K size..

It came to me as a 44.1K sample, 160Kbps, so I have "downconverted" and there's not much audible dirt in there related to the copy.

Best bet is to experiment, see how the end result sounds to you.

[n3lrx]

Paul,
I had considered making an auto archiver. I have a Linux box that sits there and does nothing. It's setup now as a mail server behind my firewall. there are reasons why but that's off topic..

Anyway, I was thinking the other day how I could jack a receiver into the sound card and use it as an automated aircheck machine. Don't know what good it would do but I'd thought of it. My plan was to use DTMF or some other sort of signaling code that would trigger it to record audio, then stop after a specified amount of time and upload it to my dedicated server elsewhere. The idea came to mind while I was playing with a signal generator / decoder for Linux I noticed that it could not only generate DTMF and CTCSS/PL tones but it could decode them as well.

Anyway, the idea had crossed my mind not sure if I can find the time to do anything with it but if there is an interest I'd do my best to give it a shot.

[WA3VJB]

Hey Randy,
Kinda like  TiVo for Ray-Ro, eh ?

Well why not cobble it up and dial it to listen around 3725Kc at midnight Dec. 15, the evening of Thursday into Friday.

Then we all can later take a listen to some of the activities likely to be there lighting up the "new" part of the phone band on 75m.

[Steve - WB3HUZ]

Sounds like a great idea Bruce. Suggest going with an open scheme like MP3 or MP4. Real's compression schemes are no better, maybe worse, and it's questionable how long they will be in business.

[W1UJR]

Thanks guys, I'm working with Apple's "Garageband" software for audio editing, seems to work OK, but its a BIG process to redo each and every audio clip which I have been sent over the past 5 years.

Ideally I'd like to mix it down so one can select from callsigns, rather than just a general QSO, to hear the clip.
For example, if I wanted to know what W2OY sounded like, just click on his call, and so forth.
It really takes on greater meaning when those we have on audio are now silent keys.

I'll post progess as things go forward, thanks for the suggestion, esp. Paul, excellent tips.

73 guys,
Bruce W1UJR