HydrogenAudio

Lossy Audio Compression => AAC => AAC - Tech => Topic started by: Mac on 2002-08-21 22:21:06

Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: Mac on 2002-08-21 22:21:06
Hi there!

I've been converting some old midi soundtracks into waves to slap on a cd.  They're played on an old computer with the "proper" sounding Yamaha 32 soundcard, then the audio out goes into my old amp, then back out into the line-in on my new computer.  I followed the advice from the IRC channel, to mute all inputs on both cards (except the line-in i'm recording to) and to record in 48khz because of my SB Live being best at that.

Anyway, (i just want to check if thats the best method... it doesn't produce noise that's too noticable).

One of the tracks I was sending to a mate, so I encoded it in Psytel at some fairly low settings, and found it really stunk.  I compared it to mp3, and the mp3 sadly comes out sounding better than the aac at a 10% lower bitrate.  Ivan might want to take a look at it for his AAC + SBR testing?

It's got background noise, a fatboy style pulsing instrument, some er, tones of sorts, and some real bad sounding artificial snares, yet I love it

Here is a wave of it (http://www.mwstore.co.uk/crap/E1M3%20test.wav.file)


And here is the mp3 of it (http://www.mwstore.co.uk/crap/E1M3%20test.mp3.file)

[span style='font-size:9']WinLAME rc2 : Portable Player[/span]


And here is the aac of it (http://www.mwstore.co.uk/crap/E1M3%20test.aac.file)

[span style='font-size:9']Psytel 2.15 -internet[/span]


Is there any way to make the aac come out better?  And is it any use to you Ivan?


I have other tracks that would come out equally bad I reckon.  Just say if you want them anybody
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: rjamorim on 2002-08-21 22:34:35
I have no way to download and test the files now, so...

-What bitrates are you using?
-Have you tried PNS? (For <64kbps only!)
-Tried LTP?
-Keep in mind Psytel AACenc offers no Intensity stereo, so it indeed sucks at low bitrates.

Regards;

Roberto.

Edit: Dumb Roberto! Only now noticed the -internet switch.
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: Mac on 2002-08-22 03:21:32
The AAC is 105kbs I think.  And it sounds real nasty to me!  I was thinking Ivan could try it out with the AAC + SBR once it's testable
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: layer3maniac on 2002-08-22 04:47:25
Quote
Originally posted by Mac
I was thinking Ivan could try it out with the AAC + SBR once it's testable
Or... Ivan could just send me a beta and I would GLADLY test it for him. 
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: wkw on 2002-08-22 12:15:12
I think most perceptual audio coders that uses short time transforms
usually perform very badly with midi clips.

wkw
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: Mac on 2002-08-22 18:45:47
Do you know why that is?  I would guess because all the instruments (they are from a 5yr old yamaha card) sound very electronic..  ?
Title: A nasty sample for Ivan\'s AAC + SBR ?
Post by: wkw on 2002-08-23 14:12:59
I think the problem is with the psychoacoustic model! It seemed ISO did not include midi clips in their listening samples..