AW: [AUDITORY] MPEG-1 Layer 3 Question: Pause at beginning of files after decoding (not framing)

[Hermann Stemberger <hermann@xxxxxxxxxxxxx>]

Thank you, all, responding to this topic.
The link http://lame.sourceforge.net/tech-FAQ.txt
gave me the appropriate information easy enough for me to understand.

All the best,
Hermann

-----Ursprüngliche Nachricht-----
Von: BRIAND Manuel RD-TECH-LAN [mailto:manuel.briand@xxxxxxxxxxxxxxxxxx] 
Gesendet: Montag, 23. Oktober 2006 10:25
An: Hermann Stemberger
Betreff: RE: [AUDITORY] MPEG-1 Layer 3 Question: Pause at beginning of files
after decoding (not framing)

Dear Hermann,

This time shift corresponds to the delay introduced by the decoder: the time
(delay) needed to process one frame from the input to the output...

> e.g. because the decoder needs time to start)?
I would say the decoder need samples to process!

Hope this help,
Manuel

-----Message d'origine-----
De : AUDITORY Research in Auditory Perception
[mailto:AUDITORY@xxxxxxxxxxxxxxx] De la part de Hermann Stemberger Envoyé :
samedi 21 octobre 2006 15:00 À : AUDITORY@xxxxxxxxxxxxxxx Objet : [AUDITORY]
MPEG-1 Layer 3 Question: Pause at beginning of files after decoding (not
framing)

Dear list,

When I encode a WAV-file into MPEG-1 Layer 3 (MP3), no matter if I use the
"original" patent pending Fraunhofer algorithm or the LAME algorithm I
always get a few thousand sample values digital Nulls:
When I decode those MP3-files again to WAV again, the signal starts
3000-4000 samples later than in the original WAV.
I know about framing in MP3 - but AFAIK this should just happen to the end
of the file, not to the beginning of it.

There is no signal cut, the signal is just being moved forward.

Does anyone know why this happens and if this is an artifact or purpose
(e.g. because the decoder needs time to start)?

I'm doing the whole thing for looking at simultaneous masking on one of the
patent pending Fraunhofer MP3-features(not the mp3-pro).
I always have to move manually the mp3-decoded file sample-accurate to the
original Linear PCM-file to get the difference-signal via phase inversion of
one of them.

Thank you in advance,
Hermann Stemberger