AAC+ to AAC

[Lobaba]

Hi,

I know the title might seem funny but it's all for a reason. I have a 6.1 channel HE-AAC which I demuxed from a mkv file which I wanted it to be played on my Cowon A3. I thought converting it to LC-AAC stereo would solve my problems and it did with one problem:

A drastic drop in the 'surround' feeling as well as volume. I used Nero Encoder through mediacoder. Can someone enlighten me on what exactly did I lose when I converted to LC-AAC from HE-AACv1 through nero encoder via mediacoder?

Thanks very much in advance.

[skromnibog]

That is caused most probably by downmixing (6.1->2 channels) algorithm that is used and has nothing to do with AAC Encoder. AAC Encoder will just reduce quality of your sample/music as would any transcoding from a lossy source to lossy destination.

[Lobaba]

Ok, cool. So is there any way to minimise the effects of downmixing or is there a good free encoder to do the job?

I was thinking of re-encoding and set it to have a gain of 10db. Wonder if that's a good idea...

[tebasuna51]

Ok, cool. So is there any way to minimise the effects of downmixing or is there a good free encoder to do the job?

I was thinking of re-encoding and set it to have a gain of 10db. Wonder if that's a good idea...

The NeroAacEnc is free and, maybe, the best encoder to use.

With a stereo file the 'surround' feeling can be missing, you can make a Dolby ProLogic II downmix and some surround effects can be recover with a player decoder than support dpl II.

To avoid the low volume you need a Normalize pass, after the Downmix, and before send the audio to the encoder.

You can use BeHappy/AviSynth to do the job.

[Lobaba]

The NeroAacEnc is free and, maybe, the best encoder to use.

With a stereo file the 'surround' feeling can be missing, you can make a Dolby ProLogic II downmix and some surround effects can be recover with a player decoder than support dpl II.

To avoid the low volume you need a Normalize pass, after the Downmix, and before send the audio to the encoder.

You can use BeHappy/AviSynth to do the job.
I think I will pass on the first option since I doubt my portable Cowon A3 supports dpl II =/

Normalizing is the same as letting the audio stream have a gain in db right...?

[tebasuna51]

You can select the Downmix method with BeHappy.

Normalize is apply the max gain without distort.
The soft make a first pass to see the max peak, then calculate the max gain possible to apply at second pass.

[skromnibog]

So is there any way to minimise the effects of downmixing or is there a good free encoder to do the job?
Encoder has no effect on downmixing. And as tebasuna51 already pointed out, Nero AAC Encoder is free.

[Lobaba]

You can select the Downmix method with BeHappy.

Normalize is apply the max gain without distort.
The soft make a first pass to see the max peak, then calculate the max gain possible to apply at second pass.

Damn, I followed the instructions here (http://forum.doom9.org/showthread.php?t=104686) but I keep getting the character error.

P.S. Tried the BeHappy package as well and is it me or does it not work in vista =/ It just hangs when I try to downmix..