Help with exporting to M4A

Hello everyone,
I’ve been having a lot of problems with Audacity so the short version: when I export a file as m4a and click settings I get this small window with 2 bars from 0 to 500. I used to have from 0 to 320 (kbps like mp3) but I dont. I saw that you can choose custom FFmpeg and in there change the settings to 320bkps but for some reason the sound of the music reduces.

the long version: I have a new computer windows 7. I installed the latest Audacity 2.1.2 but it was a new version i didnt had. I dont use it in english and the entire program was from right to left. after many times trying I discovered the 2.1.1. version which was what I had. I kept the Lame_v3.99.3_for_Windows and ffmpeg-win-2.2.2 from when I first installed the latest version (idk if its the problem). Anyways I try exporting mp3,m4a,wav to m4a but the quality doesnt change and i get songs in 190± kbps instead of 256/320 (depends what I used to choose).

*I added a pic 1st from m4a settings 2nd mp3 settings

If anyone knows how to change the settings in order to get the best quality with m4a I would be so grateful. Thanks.

Hello, the M4A quality slider doesn’t work with the version of FFmpeg (2.2.2) that we recommend, as noted in the 2.1.2 Release Notes: ( You can use the workaround mentioned in that link to export using “Custom FFmpeg Export” and type in the required quality, or you can export as WAV and convert to AAC in iTunes.

Or you can use Audacity’s command-line export and point Audacity to an alternative AAC encoder like Nero AAC.


Thanks for letting me know the version of Audacity I used doesn’t support FFmpeg 2.2.2. I tried the custom FFFmpeg export but then I set myself a specific rate of kbps and I like when it does that automatic depending on each song. I also exported to WAV but I read in some forums that m4a to wav to m4a again reduces the quality because something “loosely” in the file WAV I dont quite know well about all that.

Anyways I updated to 2.1.2 but the problem still happens

the song
the export settings for m4a with still 500 bar
the exported file with 195 kbps

Audacity 2.0.6 and later (including 2.1.2) do support FFmpeg 2.2.2, but that version of FFmpeg 2.2.2 is built with a specific AAC encoder called “libvo_aac” that is fixed bit rate. The AAC quality slider in M4A export is variable bit rate and so has no effect with the libvo_aac encoder.

Every encoding as AAC is lossy, so you want to encode to AAC only once.

If you already have an M4A and must re-encode it as another M4A, the first conversion from M4A to WAV won’t make it worse (because WAV is lossless) but neither does it make it better. If you want to encode to AAC in iTunes instead, then exporting to WAV from Audacity is the correct thing to do.

What edits are you making to these files? If it is just a volume adjustment, or trimming silence, you can do that with other software that edits the AAC stream “directly” without re-encoding, which avoids any quality loss at all.

See the explanation above. The Release Notes for 2.1.2 say it is a problem and so your copy of Audacity 2.1.2 has the problem.

If you want to compile FFmpeg 2.2.2 yourself without libvo_aac, then that would use FFmpeg’s built-in AAC encoder instead and the slider would work, but then if you wanted to export below 22050 Hz project rate the file would be corrupt. That’s why we “recommend” FFmpeg 2.2.2 built with libvo_aac.


Thank you Gale for answering even tho I don’t quite understand everything.
I use Audacity to increase volume, cut length, edit and cut parts to make the song shorter, check volumes to compare stuff and tbh sometimes I speed up songs just for fun without saving.
Most of my songs if I edit them I export as m4a or mp3. since I’m having all these problems I started to export to WAV and through itunes to m4a. but I saw theres 2 versions 32bit WAV and 16bit WAV and I got confused with what format I need.
From what I remember I would export m4a and get 250-280kbps without changing the settings and with mp3 always 302bkps. now this 0-500 slider that doesnt affect anything like you said that is already build in, does that mean I can’t get to the automatic settings I used to have?
Also does Audacity reduces quality? :frowning: ugh I’ve been using it for years.

"If you want to compile FFmpeg 2.2.2 yourself without libvo_aac, then that would use FFmpeg’s built-in AAC encoder instead and the slider would work, but then if you wanted to export below 22050 Hz project rate the file would be corrupt. That’s why we “recommend” FFmpeg 2.2.2 built with libvo_aac. " I’m sorry but I dont understand this.

Is there a solution to bring back an older version of ffmpeg before 2.2.2 or like how can I get back to what I used to have without using any other programs besides itunes?.
Sorry for the messy reply but that’s basically where I’m at with this.

What is the problem with choosing “Custom FFmpeg Export” and typing in the constant bit rate you require?

You can do all of that losslessly, except the speed up, with MP3DirectCut. See:

16-bit WAV is fully sufficient for converting to AAC in iTunes.

There are no automatic settings apart from the default values. But because libvo_aac is fixed bit rate, the bit rate and so the size of the exported file does not change according to how easy or hard it is to encode the file. With variable bit rate, the bit rate and file size does change according to ease of encoding. If the file is easy to encode, the file size is smaller.

If variable bit rate AAC is what you want, then in Audacity 2.1.2 you must use another AAC encoder, such as Nero, and use “(external program)” to export. Or, export as WAV and convert to AAC in iTunes.

If you don’t like Constant Bit Rate MP3 export at 320 kbps, then you can change it. But 320 kbps Constant Bit Rate is the “best quality” for MP3, which is what you asked for.

Are you saying that the quality controls in MP3 export do not work when you run Audacity in the right-to-left language that you showed? Do you need to use a right-to-left language?

If the edits you want to do require re-encoding the file rather than editing the file directly, then given MP3 and AAC are lossy formats, re-encoding in those formats does lose quality. Think of re-encoding the file in a lossy format like making a photocopy of a photocopy. The second photocopy has worse quality.

With direct editing of a lossy format, which Audacity does not do, it is like cutting the top and bottom off the first photocopy. The quality of what remains is the same.

You can go back to Audacity 2.0.5 from and install the older FFmpeg 0.6.2 instead over the top of your FFmpeg 2.2.2 installation.

Doing that will not prevent you losing quality when re-encoding as AAC. If you export using a high bit rate you may not even notice the quality loss, but the loss is there and is visible in a spectrum analyzer. If you do not accept the quality loss inherent in re-encoding AAC and MP3, you must use a lossless format like WAV or FLAC instead, and accept the file size will be larger.

These are the laws of audio formats, and all audio editors must obey those laws.


Because unlike mp3 which I always have at 320bkps, with m4a I like it in itunes quality (around 256 ±) and writing the exact bitrate from the original file to the converted one to match is too much and probably won’t worth much.

I converted some songs to WAV 32bit and then m4a via itunes should I re-do it as WAV 16bit or it doesnt matter?

If I use Nero will the quality reduce or because I edit in Audacity I should find a different program? HQ is important to me but I never noticed any quality change once I export on high settings. Should I stick to m4a->WAV->m4a or is it a mistake to do so?

From the examples I gave you what I use Audacity for would you recommend me to continue with it or its not the best for my purposes?

Regardless, you are not matching the original M4A file except in bitrate - you are degrading it, even at the same bitrate, just the same as you degrade it if you use the VBR slider in Audacity 2.0.5.

Doesn’t matter. 32-bit WAV is marginally superior to 16-bit WAV.

Please, AAC is LOSSY. You will degrade your files when you encode in AAC whatever application you use. If you don’t like that, then either don’t use that format or use MP3DirectCut to do limited “direct” editing of MP3 or AAC (delete/cut/paste and volume changes only, no filtering or speed changes).

Equally if you can’t hear the losses, and did not know about them until you asked here, why worry about it?


Thank you Gale for explaining to me. I think I’m going to stick to 2.1.1 since 2.1.2 keeps flipping and showing things reverse from end (right) to start (left) when i change it to Hebrew since I’m not a native speaker. I know its a bug but I rather use the older version. I’ll just export to wav 16bit and to m4a again with itunes. Ive been using Audacity for years and I’m converting in HQ anyways so i dont notice a difference. Sorry if I repeated my questions a lot I truly have no knowledge about file formats and all the laws. have a good day :slight_smile:

It isn’t a bug that some dialogues and other interface elements reverse in 2.1.2 running in Hebrew - they should reverse. The wxWidgets upgrade in 2.1.2 allows that reversal, but it is I agree much less functional than in 2.1.1 where the interface is not reversed. That is the real problem - Audacity has never been properly coded to allow for right-to-left languages.