MPEG-1 Layer2 and Samplitude

[Ralf Köster]

Dear collegues...

at my school we use Denon compact flash card recorders to do mobile =
recording (interviews etc).
After recording we copy the audio tracks (recorded as audio MPEG-1 =
Layer2 48 kHz mono) to the DAW and compose/edit with Samplitude (V.6).

Now I found, that there are artefacts in the tracks AFTER I load them =
into Samp. (Samp internally converts the tracks to linear PCM before you =
can edit them!) The artefacts are NOT the typical compression artefacts, =
but an approx. 1.5 kHz sinus plus all the octaves above.

If I play the MPEG tracks with regular windows media player or WinAmp =
and such, no artefacts are audible. So I'm sure it is a problem of =
Samplitude's internal decoder. But here we don't have any other editing =
software.

Because the Samp newsgroup seems closed: is there any Samp user in this =
group who has experience with MPEG audio?

And what about the others; what editing software (nondestructive =
multitrack) could be an alternative? Is there such as thing as "native" =
MPEG editing software on the market? I mean "layer 2"; I know there are =
"layer 3" editors, which can edit without the need of decompression (at =
least load and audition the files).

Thanks,
....Ralf

[Arny Krueger]

"Ralf Köster" > wrote in message

> Dear collegues...
>
> at my school we use Denon compact flash card recorders to do mobile
> recording (interviews etc).
> After recording we copy the audio tracks (recorded as audio MPEG-1
> Layer2 48 kHz mono) to the DAW and compose/edit with Samplitude
> (V.6).
>
> Now I found, that there are artifacts in the tracks AFTER I load them
> into Samp. (Samp internally converts the tracks to linear PCM before
> you can edit them!) The artifacts are NOT the typical compression
> artifacts, but an approx. 1.5 kHz sinus plus all the octaves above.
>
> If I play the MPEG tracks with regular windows media player or WinAmp
> and such, no artifacts are audible. So I'm sure it is a problem of
> Samplitude's internal decoder. But here we don't have any other
> editing software.
>
> Because the Samp newsgroup seems closed: is there any Samp user in
> this group who has experience with MPEG audio?
>
> And what about the others; what editing software (nondestructive
> multitrack) could be an alternative? Is there such as thing as
> "native" MPEG editing software on the market? I mean "layer 2"; I
> know there are "layer 3" editors, which can edit without the need of
> decompression (at least load and audition the files).

If some other decoder does a good enough job of decoding your files, why not
use it instead of the one in Samplitude?

There's an inexpensive piece of software that is called "Total Recorder" It
allows you to capture .wav files from the output of any Windows music
player.

However, if Winamp does a good enough job of conversion, you can just go
into Winamp preferences, and redirect its output to a disk file.

Then, just base your work on the .wav file you create with Winamp or Total
Recorder.

[Nil]

On 13 Nov 2003, Ralf Köster > wrote in
:

> Because the Samp newsgroup seems closed: is there any Samp user in
> this group who has experience with MPEG audio?

The news group at news.sekd.com seems to still be alive, although
most users seem to have moved over to the web forum at
<http://www.samplitude.com>.

> I know there are "layer 3" editors, which can edit without the
> need of decompression (at least load and audition the files).

I don't believe there is such thing as an editor with works directly
on mp2 or mp3 compressed files. As far as I know, they all
decompress the file for editing and then recompress it when saving.
That will result in progressive deterioration of the sound the more
you save it. You'd be better off decompressing it to wav files with
some other tool, then saving it as a compressed as the very last
step.

The LAME mp3 encoder/decoder will also work on mp2s.

[SoundCheck]

I use Samplitude v6.0, and I also work with mpeg2 files here at the
radio station. We often convert between linear, mpeg2, and other
formats. However, we use dedicated software, developed by a company
called Dalet. There is an application they provide called the
"Transcoder" that can easily convert various formats - but I don't
think this app is commercially available.

I performed a test, to see if I was able to import a short mpeg2 file
into Sam v6, and I was successful... It converted the audio without
any artifacts or sinusoids. It sounds like you might be having
problems with your power supply, as was suggested in another post...

Find a new power supply?

Good Luck!


Ralf Köster <info > wrote in message >...
> Dear collegues...
>
> at my school we use Denon compact flash card recorders to do mobile
> recording (interviews etc).
> After recording we copy the audio tracks (recorded as audio MPEG-1
> Layer2 48 kHz mono) to the DAW and compose/edit with Samplitude (V.6).
>
> Now I found, that there are artefacts in the tracks AFTER I load them
> into Samp. (Samp internally converts the tracks to linear PCM before you
> can edit them!) The artefacts are NOT the typical compression artefacts,
> but an approx. 1.5 kHz sinus plus all the octaves above.
>
> If I play the MPEG tracks with regular windows media player or WinAmp
> and such, no artefacts are audible. So I'm sure it is a problem of
> Samplitude's internal decoder. But here we don't have any other editing
> software.
>
> Because the Samp newsgroup seems closed: is there any Samp user in this
> group who has experience with MPEG audio?
>
> And what about the others; what editing software (nondestructive
> multitrack) could be an alternative? Is there such as thing as "native"
> MPEG editing software on the market? I mean "layer 2"; I know there are
> "layer 3" editors, which can edit without the need of decompression (at
> least load and audition the files).
>
> Thanks,
> ...Ralf