HydrogenAudio

Lossy Audio Compression => AAC => AAC - General => Topic started by: Decepticon on 2002-03-13 03:08:23

Title: Does PsytelDrop use MPEG-4 ACC & Low Complexity profile
Post by: Decepticon on 2002-03-13 03:08:23
Hi,

I have been using the FAAC encoder for a while now, but people tell me Psytel is better, so I have decided to give it a try. What I want to know is whether the PsytelDrop GUI encodes using the Low Complexity AAC profile in its various VBR and CBR modes? I didn't see a choice, so I would like to make sure.

Also does it output a MPEG-2 or MPEG-4 AAC file by default? I would like to output a MPEG-4 Low Complexity AAC file.

Thanks
Title: Does PsytelDrop use MPEG-4 ACC & Low Complexity profile
Post by: rjamorim on 2002-03-13 03:31:09
Quote
Originally posted by Decepticon

I have been using the FAAC encoder for a while now, but people tell me Psytel is better, so I have decided to give it a try. What I want to know is whether the PsytelDrop GUI encodes using the Low Complexity AAC profile in its various VBR and CBR modes? I didn't see a choice, so I would like to make sure.


Low Complexity is always the default with Psytel, because it's less buggy than Main, and already has hardware support. (Expanium). And there's not much quality difference to LTP.

Quote
Also does it output a MPEG-2 or MPEG-4 AAC file by default? I would like to output a MPEG-4 Low Complexity AAC file.


A Raw MPEG4 AAC LC file is identical to a RAW MPEG2 AAC LC file. The only difference between them would be 2 bits in the ADTS header. Nothing changes quality wise.

The MPEG version only changes when you select a MPEG4-only tool: PNS, LTP...

Regards;

Roberto.
Title: Does PsytelDrop use MPEG-4 ACC & Low Complexity profile
Post by: Decepticon on 2002-03-13 03:55:05
Quote
Originally posted by rjamorim
A Raw MPEG4 AAC LC file is identical to a RAW MPEG2 AAC LC file. The only difference between them would be 2 bits in the ADTS header. Nothing changes quality wise.

The MPEG version only changes when you select a MPEG4-only tool: PNS, LTP...


I want to output to MPEG-4 for compatibility with an MPEG-4 video file as opposed to any possible quality differences. Is there a safe way to force MPEG-4 output without using those MPEG-4 specific tools? From what I understand those tools (LTP and PNS) are not widely supported, so I am not sure if using those tools would produce an MPEG-4 AAC file that is incompatible with upcoming MPEG-4 video decoders. But maybe I understand the tools wrong...

Thanks
Title: Does PsytelDrop use MPEG-4 ACC & Low Complexity profile
Post by: rjamorim on 2002-03-13 04:45:43
Just create a RAW AAC LC file.

It should be compatible with any MP4 video player. (Ivan can give you more info on this tough, he tested (nearly) all mp4 players out there)

And, since it's RAW, there's absolutely no difference it it's regarded as MPEG2 or MPEG4.

Anyway, I guess that, if you really want to force a MPEG4 AAC, you should ask Ivan. He has lots of hidden switches in AACenc (I.E: Switches not shown in the help screen). Who knows? Maybe there's something to force MPEG version...

Regards;

Roberto.
Title: Does PsytelDrop use MPEG-4 ACC & Low Complexity profile
Post by: Decepticon on 2002-03-13 06:03:28
Thanks for your help. I am interested in compatibility with the Xcard MPEG-4 PCI decoder card that will be coming out later this month:

Sigma Designs Xcard Specs (http://www.sigmadesigns.com/products/xcard_features_specifications.htm)

I am not sure if it will decode RAW AAC audio embedded in an MP4 file properly, so I would prefer encoding it flagged as MPEG-4 output since that is what they specify.

So, Ivan, any hidden switch I could use?

Thanks