Ideal AAC Bitrate

[Akai-Shuichi]

I recently started using qaac to encode my audio...I'm wondering what do most people consider the ideal Bitrate/range to encode to? For example I have a 448kbps AC3 2.0 track and that is quite large... If it was something smaller such as a 192 AC3 2.0 I would just leave it as is.

Thanks in advance.

[kypec]

~128kbps AAC-LC for stereo is more than enough for me, I'd say transparent, well, at least on my equipment (average headphones, small desk loudspeakers or Samsung LED TV from 2011)

[tebasuna51]

If you want:
-V, --tvbr <n> AAC True VBR mode / quality [0-127]

I make some simple test and the range is not continuous (same bitrate for some values), then only there are differences with:
Qaac (Quicktime) 5.1-48KHz | 2.0-48KHz
------ -------------- --------- | ---------
-V 1 AAC-LC 119 Kb/s | 46 Kb/s
-V 9 AAC-LC 136 Kb/s | 53 Kb/s
-V 18 AAC-LC 158 Kb/s | 61 Kb/s
-V 27 AAC-LC 177 Kb/s | 69 Kb/s
-V 36 AAC-LC 198 Kb/s | 74 Kb/s
-V 45 AAC-LC 240 Kb/s | 95 Kb/s
-V 54 AAC-LC 277 Kb/s | 108 Kb/s
-V 64 AAC-LC 314 Kb/s | 120 Kb/s
-V 73 AAC-LC 351 Kb/s | 134 Kb/s
-V 82 AAC-LC 385 Kb/s | 147 Kb/s
-V 91 AAC-LC 450 Kb/s | 173 Kb/s
-V 100 AAC-LC 507 Kb/s | 195 Kb/s
-V 109 AAC-LC 581 Kb/s | 224 Kb/s
-V 118 AAC-LC 638 Kb/s | 247 Kb/s
-V 125 AAC-LC 704 Kb/s | 276 Kb/s

With:
-v, --cvbr <bitrate> AAC Constrained VBR mode / bitrate

Valid values for 2.0 (AAC-LC):
320,288,256,224,192,160,128,112,96,80,64

Like kypec say 128 Kb/s may be enough, but is your choice if you want more quality.

[pandy]

I'm wondering what do most people consider the ideal Bitrate/range to encode to?

VBR is correct way to deal with music.

[nibus]

I use qaac -cvbr (constrained variable bitrate) at 256kbps for most of my music. I can usually tell a difference between it and 128kbps, though it is small. I probably couldn't tell 256 from 192, or maybe even 160, but I go 256 just to be thorough.

CVBR files aren't as efficient as TVBR, but maybe a little safer as they sometimes allocate more bitrate. TVBR 110 would be a similar bitrate to 256.

For movies, a stereo track at TVBR 60 works quite well, and usually lands around 96-140kbps. But I use higher for music.

I found this at hydrogenaudio concerning stereo TVBR:


Q0 - Q4 = ~40 kbps
Q5 - Q13 = ~45 kbps
Q14 - Q22 = ~75 kbps
Q23 - Q31 = ~80 kbps
Q32 - Q40 = ~95 kbps
Q41 - Q49 = ~105 kbps
Q50 - Q58 = ~115 kbps
Q59 - Q68 = ~135 kbps
Q69 - Q77 = ~150 kbps
Q78 - Q86 = ~165 kbps
Q87 - Q95 = ~195 kbps
Q96 - Q104 = ~225 kbps
Q105 - Q113 = ~255 kbps
Q114 - Q122 = ~285 kbps
Q123 - Q127 = ~320 kbps