64kbps aacPlus sample rate?

[LouisC]

If I wish to stream at 64kbps aacPlus using sc_trans, what sample rate is recommended for a stereo broadcast? 44? 22?

[jaromanda]

I do 48000

Looking at the source code for 3gpp encoder ... the minimum sample rate for HE-AAC is 32000 ... lower rates are upsampled to 32000 ... but that's the 3gpp reference code

[www.maxa.es]

sample rate don't make any difference, because in lossy formats, the bitrate will automatically decide which spectrum to restitute.

if you want "won" some quality, you can broadcast in mono (but it makes really an huge difference for music programs).

[jaromanda]

Originally Posted by www.maxa.es

you can broadcast in mono

not if you want to answer the question, you can't

Originally Posted by LouisC

what sample rate is recommended for a stereo broadcast? 44? 22?

Originally Posted by www.maxa.es

sample rate don't make any difference, because in lossy formats, the bitrate will automatically decide which spectrum to restitute.

really? so 22050 will be EXACTLY THE SAME as 44100?

[www.maxa.es]

in aac, you can't change the sample rate because it's the bitrate who decide witch spectrum restitute.

in mp3, you can use 22 or 44 KHz, sample rate and you can see it don't make any difference because 22 KHz restitute also the spectrum until 20 KHz.

In fact, you can use 22 sample rate on mp3 until 80 kbps. So you never had a great quality with 22 KHz sample rate. It just mean that, until 80 kbps, mp3 encoder has approximativly the performance of a 22 KHz sample rate. But in reality, trebble are restitue too, because the bitrate decide of the sample rate on mp3 shoutcast encoders.




now the original poster broadcast in aac, and in aac shoutcast, you can't change sample rate. the only other way to change sample rate, is to configure soundcard to 22 or 44 khz, if you don't select "winamp" in this menu.

in this case, it's highly recommended to set your soundcard or 44 KHz, because you will enjoy all the capacities of your sound hardware.

[jaromanda]

Originally Posted by www.maxa.es

in aac, you can't change the sample rate

In HE-AAC you can quite clearly use 36000, 44100 or 48000 samplerate at least - depending on the front end, you can use ANY samplerate, as long as the encoder itself gets one of the above three samplerates - at least, the source code I have in front of me works that way