how can i to convert a file to .m4a format with constant bitrate and constant overall bitrate?

Use Edit > Preferences > General tab > Import Settings to set your desired output format. Right-click on the file in question and click Create AAC Version.

You're probably aware but there is no point converting from a lossy format to one of a higher bitrate.

If you have a large number of files to convert and want to replace the originals in your library with the newly converted version then take a look at myConvertFormat script.

tt2

Ah, I've no idea. I don't really dwell on the internal structure of the files. As long as they playback what I expect to hear it's all good. Does AAC even do a constant bitrate version or is that the reason that AAC files are generally slightly smaller than MP3s when both have the same nominal bitrate? Anyway if iTunes won't do what you want then you'll need to look at third party software. There are plenty of audio tools out there, one must do what you want, assuming it is actually possible rather than a limitation of the format. Why is the constant bitrate important?

tt2

And using custom settings really doesn't work for you? 😟

tt2

If you select the iTunes Plus setting, which is the default, you will get Variable Bit Rate. That is not what you want.

As TT2 suggests, use the Custom Settings, and make sure VBR is not checked.

Also, after you do the conversion, both files will be in your library. Make sure you are using the newly converted file, not the original.

ed2345 wrote:

... Also, after you do the conversion, both files will be in your library. Make sure you are using the newly converted file, not the original.

Or use the ConvertFormat script. 😉

tt2

Try downloading a converter and convert it from there.

Meant to add...

Converting between lossy formats also loses some quality so you may want to maintain an archive of your original files that you could restore at a later date if needed.

tt2

Do you hav e any thoughts on playing Apple LossLess files in Windows Media Player 12 (Win7). All I get is a "format error" response when one of these tunes hits the play queue.Thanks

Sorry, I don't understand. Surely you have the same check boxes as me? Surely you can make the same selections, AAC Encode, Custom bit rate, 256k or 320k or whatever you want... Sample rate 44.1KHz, Auto Channels and VBR not selected? If you convert using these settings you should get a CBR file. Have you tested this? If so what are the results?

tt2

😟

I just tried converting the same file with & without the VRR setting. According to mp3tag neither are VBR and iTunes gives no indication one way or the other.

I take it you've tried the resulting output files with your car kit anyway, just in case?

tt2

FWIW, I tried the same experiment here, running iTunes 10.6.0.

With VBR checked, the resulting AAC file shows in iTunes as "256 kbps (VBR)."

With VBR not checked, the resulting AAC file shows as "256 kbps" and is about 0.3 MB smaller than the first one.

So, at least iTunes thinks it did it right.