Transcoding WMA to AAC - Bitrate advice

[nibus]

I need to transcode some WMA 192kbps files to AAC for iPod compatibility. I know transcoding is bad in general but I don't have any other option. I am using dbPowerAmp with NeroAacEnc.exe for the conversion.

I was thinking I would do AAC VBR @ 176kbps, as AAC is slightly more efficient than WMA and also to accommodate slight quality loss from transcoding.

But would it be wise to go lower - like 160/144/128 ? I'm not positive how much quality is lost during most transcodes, but from my A/B tests it seems pretty minimal in this case.

[Dark Eiri]

Do AAC VBR 0.5 or maybe 0.55. that will choose a bitrate that's enough for you.

[roozhou]

Always use a quality mode unless you have to use accurate bitrate. And you don't need to care whether the source is lossy or lossless, or whether the source is MP3 or WMA. Just stick to one quality level. e.g. 0.5 for neroAacEnc.

[nibus]

What I'm worried about with the -quality setting is the odd file where the size might be larger than the original WMA. Does the quality mode yield more efficient results than just specifying a VBR?