----- Original Message -----

From: Gavin Stephens

To: LPFM_Radio@...

Sent: Tuesday, November 14, 2006 10:16 AM

Subject: Re: [LPFM] audio decoding - sample rate conversion

Thanks Geoff, Ross.

 

I do use lame as that way I can easily distribute it with my scripts and I don't need to install anything in order to use it. However as Ross has mentioned, lame does downmix for encoding, but I can't use it to decode back to stereo.

 

The main thing I need to do is create a stereo file again after the decoded mp3 mono files are turned back to waves.

 

I've had a short look at the other SOX thing but I've still yet to figure it out completely. I'm not sure if it'll do exactly what I need yet, but thanks to Simon for pointing it out. I'll do more research on it later today.

 

The older fraunhofer command line decoder allowed to decode back to stereo if I remember rightly but it was picky about working on different Windows O/S's. I had it working on Windows 2000 fine, but then wouldn't work on XP or 98 etc... so I stopped considering it the moment I downloaded lame.

 

I noticed the Flea in Auckland use the FTP service from TRN. I was listening to an online stream after being told they use it. I found they must be sending studio levels to their online stream because the news files were at about -12dB with everything else around -1dB. They don't do any further processing of the file once downloaded it appears.

 

The TRN levels are actually correct for their system, just not for those normalising everything pretty close to the top of full scale digital.

 

Is The Flea apart of this lpfm mailing list?

 

I also had my first ogg vorbis listening experience yesterday to Brian's test feed. I kinda skipped right pass ogg from mp3 and mp3pro to aacplus. I'm quite impressed by the quality of ogg for streaming though.

 

Thanks again,

Gavin.

 

----- Original Message -----

From: Ross Levis

To: LPFM_Radio@...

Sent: Monday, November 13, 2006 10:45 PM

Subject: Re: [LPFM] audio decoding - sample rate conversion

I know LAME has a downmix option from stereo to mono (-a) but I don't think it can encode a mono input as stereo.  I think the -m settings assume a stereo input file.

 

Ross.

 

----- Original Message -----

From: Geoff Barkman

To: LPFM_Radio@yahoogroups.com.au

Sent: Monday, November 13, 2006 10:19 PM

Subject: SPAM-LOW: Re: [LPFM] audio decoding - sample rate conversion

H Gavin
I dunno if you use LAME but it can convert WAV to MP3
MP3 to MP3
and there are options for stereo or mono or Joint outputs too.
I think thats what you want.

LAME version 3.96.1 (http://lame.sourceforge.net/)

usage: lame [options] <infile> [outfile]

<infile> and/or <outfile> can be "-", which means stdin/stdout.

RECOMMENDED:
lame -h input.wav output.mp3

OPTIONS:
-b bitrate set the bitrate, default 128 kbps
-f fast mode (lower quality)
-h higher quality, but a little slower. Recommended.
-m mode (s)tereo, (j)oint, (m)ono
default is (j) or (s) depending on bitrate
-V n quality setting for VBR. default n=4

--preset type type must be "medium", "standard", "extreme", "insane",
or a value for an average desired bitrate and depending
on the value specified, appropriate quality settings
will
be used.
"--preset help" gives more info on these

--longhelp full list of options

Gavin Stephens wrote:
>
> Hi guys,
>
> Does anyone know of a programme that will allow me to convert a mono
> wave to stereo wave file from the command line?
>
> This may interest the od LPFM station that uses the Newstalk ZB
> affliliate units FTP service.
>
> I've been tidying up some scripts/batch files I've been slowly
> perfecting over the past 4 years after creating some for use with the
> Newstalk ZB affiliates FTP service. Orginally I created them to
> download the news, decode it, normalise it in to a system using
> everything at 98% peak audio levels, then tag the files and import
> them in to Simian automation software unattendent.
>
> Anyway, the one thing I'd like to see done is for the service to
> deliver news in an mp3 VBR format but in MONO for distribution and
> bandwidth savings. This reduces the file size from the current ACM mp2
> @256kbps stereo files of around 4.6MB for the news alone, to around
> 1.4MB. I was told the other day TRN's latest IT cheif is interested
> again in providing and MP3 option (had one of those emails about 4
> years ago saying they were looking in to it but then Ed Taylor left
> and I left the station I was with at the time), but I'm coming up with
> a means to do it easier for them again.

Cheers
Geoff Barkman
ZL4TUX