Audio Encoding in Gknot

[iryx]

A quick question.

I'm trying to encode only audio in Gknot. I followed Doom's Gknot guide to the letter but that's where soemthing goes wrong.

To be more precise, I'm trying to encode a ac3 file using the "Audio 1" encoding tab under "Encoder/Add Job." I select the ac3 file and
choose the "MP3, custom Parameters(Experts)" and enter these Lame
parameters: "--alt-preset 128" like described in Doom's Gknot guide, instead of the default MP3 parameters for lame which are "-h --abr 128." I'm no expert but shouldn't that first method work? When I try
using "--alt-preset 128" for Lame I get the following error:
"ERROR: MP3-File-Size is zero. Transcoding failed."

Not sure what I'm doing wrong. Maybe somebody can clarify what each one of these param for Lame does and if it makes a difference which one I use.

Something else that I don't get is why every time I want to do the audio at 96kbit/sec using Lame, the output is terrible. The audio is going either way to fast (like i was fast forwarding it) or the sampling rate is no longer 48khz. I can do that fine when using Vob2Audio, what am I doing wrong with Lame?

Thanks in advance for any help guys.

[hyperion]

Hey

1) Does it work with "-h --abr 128"?

2) Taking from "GordianKnot_HowTo.txt"

'audio-bitrates below 128 (in lame) can cause sync-problems (and sound terrible), because lame is automatically downsampling to 32 or even 22kHz. i highly recommend to use 128 or 160 and nothing else. to avoid downsampling you have to add "--resample 48" to your lame commandline options if you encode at low bitrates.'

Cheers
Hyperion

[iryx]

It does work with "-h --abr 128." I just wanted to follow Doom's
guide since I have no clue what Lame's options mean.

Thanks for the tip about resampling. I should have read that guide :-)

[hyperion]

"--alt-preset 128"

Have looked in the readme to lame and couldnt find anything.

Well im no expert either..

Have always used the standard Gknot. (Which BTW gives a great result. Better than CBR by fare and normally smaller filesize/more bitrate to video ;)

Others would have to explain this, while
i cant see any reason to not use the default vault..

Cheers
Hyperion

[jggimi]

"--alt-preset" is a Lame 3.9 parameter. 3.9 is newer than the lame included in GKnot. Doom9's guide has you install the newer lame ... it's possible you missed that step.

[iryx]

That must have been it. Silly me forgot how to read :-)

Thanks for your help. Any difference between that and "-h --abr 128"?

I won't be able to try it now. I'm fed up with WinXP, I got to reinstall Win2K.

[tangent]

Yes. --alt-preset 128 is tuned for the best quality you can get with ABR at 128kbps, so will have better quality than -h --abr 128