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AAC using PsyTEL Ecoder
SimonSez07
post Mar 25 2002, 20:19
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I have been using the WMA format for a while now to store music from CD onto my PC at 64 kbps, but i know this is poor quality compared with AAC, so I started playing around with the PsyTEL command line encoder. I made several samples using the following command:

AACEnc.exe -vbrhi -br 64 -pns -c 15995 -profile 0 -if AUDIO.WAV

I was dissapointed to find that the bitrate was significantly larger than 64 kbps (around 105) and I heard noticable distortion during playback (with WinAmp) which made the audio sound far worse than WMA with a much lower bitrate.

I know I must be doing something wrong, because everyone assures me AAC is far superior to WMA, especially with VBR.

Any ideas what could be wrong?? This is very annoying and any suggestions would be appreciated.


Thanks,

Simon
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JohnV
post Mar 25 2002, 20:57
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Hmm, Psytel AAC is not regarded the best at low bitrates.
And I'm not the best expert in this, but I would try something like:
aacenc -internet -profile 2 -if file.wav
or
aacenc -radio -profile 2 -if file.wav
of course using the latest aacenc 2.15. However, -profile 2 uses the LTP profile which may not be compatible with future hardware players, though same goes to profile 1 (main).


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rjamorim
post Mar 25 2002, 21:16
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Don't use PNS!!!

This bitrate (105) is way too high for PNS. Try again, without using PNS.

Use PNS only when being sure your bitrate will be, at most, 64kbps.

Regards;

Roberto.


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JohnV
post Mar 25 2002, 21:41
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Yeah, I forgot to say the same as Roberto is saying..
PNS (perceptual noise substitution) should not be used here...


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SimonSez07
post Mar 25 2002, 22:47
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thanks ... i will try encoding without -pnr but ~105 kbps is still too high for what i need. i would like to quit using wma for good, but i really need the low bitrate it offers (64 kbps). is it possible to achieve this bitrate with aac and still have superior quality to wma??

- simon
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Ivan Dimkovic
post Mar 25 2002, 22:49
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Starting from 2.15, AACEnc also has -qvbr switch ("quality VBR")

aacenc -qvbr <n> ...

where n is the integer value ranging from 0 to 100

- Note, this is very alpha and experimental switch, -qvbr 100 is certainly not the best quality smile.gif
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rjamorim
post Mar 25 2002, 23:23
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QUOTE
Originally posted by SimonSez07
thanks ... i will try encoding without -pnr but ~105 kbps is still too high for what i need.  i would like to quit using wma for good, but i really need the low bitrate it offers (64 kbps).  is it possible to achieve this bitrate with aac and still have superior quality to wma??

- simon


In this case, don't use -vbrhi switch.

Try -vr, or plain CBR.

Regards;

Roberto.

Edit: BTW, if you use CBR 64, then you should use PNS.


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sven_Bent
post Mar 26 2002, 09:03
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dotn use -vbrhi

-vbrhi REALLY likes to go 160kbits :-)

thats why i only use -vr baecuse i dont like mo file size to bloatet


replace it with -vr og try some of the presets


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