Audio in mp4's.

[Ararat]

Hi all,
I've recently started using H.264 to archive my HDTV caps (using TMPGEnc XPress), and it uses AAC for the audio rather than MP3 that was used when I archived to avi (XviD using AutoGK). What I wanted to know is, what bitrate do I need to use for AAC to achieve a similar quality level to 128kbps VBR MP3? I had tried lower bitrates with MP3, but the quality was noticibly lower.

At the moment I've been using 128kbps, as that's the bitrate I used in MP3, but I was wondering if I could get the same quality with 96kbps or even get away with 64? Perhaps something in between?

(btw, you probably already assumed, but I'm talking about stereo, and the bitrate would be the total for both channels).

Thanks in advance for any help.

[Avenger007]

Imo, try using Nero AAC VBR mode with q=0.4 +/- 0.5 if you want HQ stereo audio. You could go lower if you want to encode multichannel.

BTW, this thread belongs in the Audio Encoding forum.

[Ararat]

Oh yeah, sorry, I was looking for audio, but couldn't find anything... now that I look at the top, I see that I had already entered the video section, which would be why. Is there any way to move it?

[Ararat]

So.... can anyone answer what sort of bitrate I would need for AAC to match 128kbps MP3?

[tebasuna51]

You can try between -q 0.35 and -q 0.4 to match similar quality than 128 Kb/s mp3 VBR

[Ararat]

Yeah thanks guys, except that I use TMPGEnc XPress, and I can't enter q values like you are suggesting. It only takes bitrates (though it does do it in VBR).