AAC & MP3 on Mac using 1.3.8

[takken]

This is an end PS put here at the beginning to note strange resolution of some of the problems:
I eventually noticed that the audacitity.cfg file contained a lot of old stuff. Install of Audacity 1.3.8 did not remove the old audacity.cfg file written by previous versions. So I quit the program, removed the legacy audacitity.cfg and then started and quit Audacity 1.3.8 again forcing it to write its own new audacity.cfg file.
That solved the AAC export problem. The exported .m4a files are now fine (and so are the other FFmpeg formats ac3, amr and wma).

Another problem disappeared, too, at the same time, a preferences setting issue I hadn't mentioned before. It used to be that no matter what I set Playback Device to, the setting would not take. And when I'd open Preferences again Playback Device was always set to "Built-In Line Output". It looks like legacy audacity.cfg files can cause all sorts of problems.

The strange thing is that when I tried to reproduce the .m4a export problem, I couldn't, so I am not sure my claims are correct. I quit Audacity 1.3.8, put back the old audacity.cfg file and then restarted Audacity 1.3.8. This should have forced the program to read and use the old stuff and so presumably again export .m4a files that contain all zeros. But, no, Audacity 1.3.8 now exports correct .m4a files no matter which audacity.cfg file was read during program load. And I still don't know why at one time all compressed format exports gave 10 sec of music followed by all zeros.

Any way, I am mostly happy now that I can export AAC, but just a little uncertain.

There is still the inherent conflict between Apple's invisibility protection of Mac core UNIX file locations and the way Audacity's "Preferences Libraries Locate" wants to Browse. There is no way for the average user to see or specify the library location /usr/local/lib/audacity/
=====================================



(Using Audacity 1.3.8 on MacPro quad '09 with OS 10.5.7)
Saw your post, Koz, about instability on modern Macs,
and that I should stick to running Audacity 1.3
Though not 1.3, I've run four versions of Audacity in previous years and don't recall that any of them would export AAC. Can't live without the nice time-line markers.

Any way, I was excited to see that 1.3.8 is supposed to export AAC.
Logically who else would want to do that besides someone with a modern Mac?
So I tried it and did ran into problems, but not ones I would expect.
On my machine Audacity 1.3.8 does find the libraries for AAC, butis no longer able to find the library for MP3. Still, it exports MP3 anyhow - sort of.

Some of the below relates to wording suggestions for instruction web page:
http://manual.audacityteam.org/index.ph ... encoder.3F

Problem 1) Please give actual file names on the instruction page:
The user is told how how to download and install libraries for
"the LAME MP3 encoder"
and for
"the FFmpeg Import/Export Library"
For the first we are given the actual file name, "libmp3lame.dylib"
For the second there is reference to "the FFmpeg library"
But there is apparently no such file with that name.
After the two installs, the files I find that I have at /usr/local/lib/audacity/ are:
audacity
libmp3lame.dylib
libavformat.52.dylib
libavutil.dylib
libavcodec.52.dylib
libavformat.dylib
libavcodec.dylib
libavutil.50.dylib
Are the latter six files "the FFmpeg library"?
Why is there a file called "audacity" in the directory /usr/local/lib/audacity/?

Problem 2) I am not logged in as root, so when I "Browse" (in Edit > Preferences: Libraries > Locate) I can not see or navigate to /usr/local/lib/audacity/
Turns out that this is OK for the FFmpeg libraries newly installed for the first time on my computer, but not for the MP3 library. In "Edit > Preferences: Libraries > Locate" Audacity tells me that it "has automatically detected valid FFmpeg libraries." But when I click to locate the MP3 library it does not say that. Instead the window that pops up has in it the location where libmp3lame.dylib used to be when I ran the previous version of Audacity. So it seems to me that I have four options for trying to direct Audacity to /usr/local/lib/audacity/libmp3lame.dylib. But none of them work:
a) Edit the preferences file directly. [I can't find it in the usual places.]
b) Put /usr/local/lib/audacity/ in the "locate Lame" pop-up window, replacing the old previous location that Audacity is remembering. [This does not take.]
c) Put a copy of libmp3lame.dylib in the old location that Audacity is insisting on remembering. [Not something I want to do.]
d) Log in as root. [Shouldn't have to do this, and might not work anyhow because that might not create the preferences file needed for my standard user login.]
So I am stuck.
Any suggestions?

Problem 3) Weird exports
Uncompressed exports are fine, but not MP3 or AAC exports.
The generated .mp3 .m4a and .ac3 files give the first 10 sec of audio correctly but then suddenly switch to all zeros. The time at which output of zeros starts is the same for all three, which seems to indicate that this is not a library problem but something wrong with Audacity 1.3.8 implementation or something uniquely wrong on my computer. Maybe it is a version of "instability" on modern Macs.
Any suggestions?

Problem 4) Options in AAC Export:
What does "Quality" mean?
The numbers that can be chosen are from 10 to 500.
But the usual way of specifying quality for AAC and MP3 compression is bit rate.
The choice is usually between 128 and 256 kbps as at the iTunes store.
(See http://blogs.pcworld.com/staffblog/archives/003993.html)
How do the "Quality" numbers relate to kbps?

[kozikowski]

I've posted to the administrators. You're way more stuck than anything I can do to help.

You're right, you should not need to be root to straighten this out. Did you try to dig down to those folders in Terminal? "Administrator" should be able to do that .. at least I can.

I would recommend rolling back to 1.3.7, but as you noticed, that one doesn't deal with AAC. You could pull your sound files into iTunes and then pull out the AAC version -- assuming you set iTunes up that way..

Koz

[waxcylinder]

Any way, I was excited to see that 1.3.8 is supposed to export AAC.
Logically who else would want to do that besides someone with a modern Mac?

Who? Someone like me who runs a couple of Windows PCs and has iTunes on them and uses those libraries to feed his iPods! And I am not alone in doing this - one of the great marketing coups pulled off by Apple was to get iTunes/iPod running so seamlessly on the PC/Windows environment.

Like Koz, your posting is way beyong my technical expertise. I do however have a workaround for you - and this is what I have been doing for the last couple of years to go from Audacity projects to AAC on my iPods.

1. Record and edit the project in Audacity
2. Export as a set of WAV files (to facilitate correct ordering later I Label the tracks 01 <track_name_1>, 02 <track_name_2>, etc.)
3. Import the WAV files into iTunes
4. Use iTunes to make AAC copies (at your chosen bitrate) in the library of the WAV files
5. Delete the WAV files from the library.
6. Edit the metadata tags of the tracks/album
7. And last but not least - backup my updated iTunes library (I actually don't do this after every update - but I do try to do it at least evry couple of weeks so I have a roll-back point).

WC

[kozikowski]

And here's the other two pieces of information.

http://forum.audacityteam.org/viewtopic ... 002#p47098

Koz

[Gale Andrews]

(Using Audacity 1.3.8 on MacPro quad '09 with OS 10.5.7)
I was excited to see that 1.3.8 is supposed to export AAC...
Some of the below relates to wording suggestions for instruction web page:
http://manual.audacityteam.org/index.ph ... encoder.3F

Problem 1) Please give actual file names on the instruction page:
The user is told how how to download and install libraries for
"the LAME MP3 encoder"
and for
"the FFmpeg Import/Export Library"
For the first we are given the actual file name, "libmp3lame.dylib"
For the second there is reference to "the FFmpeg library"
But there is apparently no such file with that name.
After the two installs, the files I find that I have at /usr/local/lib/audacity/ are:
audacity
libmp3lame.dylib
libavformat.52.dylib
libavutil.dylib
libavcodec.52.dylib
libavformat.dylib
libavcodec.dylib
libavutil.50.dylib
Are the latter six files "the FFmpeg library"?
Why is there a file called "audacity" in the directory /usr/local/lib/audacity/?.

Problem 2) I am not logged in as root, so when I "Browse" (in Edit > Preferences: Libraries > Locate) I can not see or navigate to /usr/local/lib/audacity/
Turns out that this is OK for the FFmpeg libraries newly installed for the first time on my computer, but not for the MP3 library. In "Edit > Preferences: Libraries > Locate" Audacity tells me that it "has automatically detected valid FFmpeg libraries." But when I click to locate the MP3 library it does not say that. Instead the window that pops up has in it the location where libmp3lame.dylib used to be when I ran the previous version of Audacity. So it seems to me that I have four options for trying to direct Audacity to /usr/local/lib/audacity/libmp3lame.dylib. But none of them work:
a) Edit the preferences file directly. [I can't find it in the usual places.]
b) Put /usr/local/lib/audacity/ in the "locate Lame" pop-up window, replacing the old previous location that Audacity is remembering. [This does not take.]
c) Put a copy of libmp3lame.dylib in the old location that Audacity is insisting on remembering. [Not something I want to do.]
d) Log in as root. [Shouldn't have to do this, and might not work anyhow because that might not create the preferences file needed for my standard user login.]

I am not on a Mac. Koz could experiment with any issues not being logged in as root, but if there are any problems that can't be resolved we can see if we can get our Mac developer (Leland) to drop by. The problem with the instructions is that part is different for the three platforms, and part (the "Installation" bit farther down) is common to them. No doubt the instructions could be slightly improved but we don't have space for per-platform instructions each of which include a carbon copy of the "installation" section.

You should always be able to use browse in the Locate Lame dialogue and select the new dylib.
Location of Preferences and how to reset them are described here.

You should also always be able to just delete the old dylib and drop the new one into the Audacity installation folder where it will be detected. This definitely works on Windows. You can have the .cfg settings file pointing to some location of the LAME dll, but if you have the dll in the Audacity installation folder, Audacity will find it and use that.

I suspect from your description that automatic detection of the dylib (in your case from /usr/local/lib/audacity) is already happening. In Audacity Beta you don't need step 3 of the instructions "The first time you use the "Export as MP3" command, Audacity will ask you where libmp3lame.dylib is saved". However the problem is that because this is the internet and everything is searchable, users of the 1.2 Stable version can and do find that page. Those users do need to point Audacity to the LAME library manually.

Problem 3) Weird exports
Uncompressed exports are fine, but not MP3 or AAC exports.
The generated .mp3 .m4a and .ac3 files give the first 10 sec of audio correctly but then suddenly switch to all zeros. The time at which output of zeros starts is the same for all three, which seems to indicate that this is not a library problem but something wrong with Audacity 1.3.8...

You need to re-download the FFmpeg installer. Please read Known Issues since release. And use the "MP3 files" filter in the export window when exporting MP3s, don't use custom FFmpeg export for MP3 export.

Problem 4) Options in AAC Export:
What does "Quality" mean?
The numbers that can be chosen are from 10 to 500.
But the usual way of specifying quality for AAC and MP3 compression is bit rate.
The choice is usually between 128 and 256 kbps as at the iTunes store.
(See http://blogs.pcworld.com/staffblog/archives/003993.html)
How do the "Quality" numbers relate to kbps?

I don't like this either and argued against it at the time, but part of the reason as I recall is that this is how the libfaac AAC encoder in the FFmpeg library handles quality. A higher quality setting does increase the bit rate but the sample rate (project rate you export at) is a factor in quality too. You can easily export a number of AAC files at different quality settings to see the bit rates produced (check them by control-click > Get Info in iTunes).

I'll look again at the discussion we had at the time and see if I can get some more information on quality settings and their approximate relationship to bit rate. If so they will appear in the Manual.


Gale

[takken]

Hi Gale,

Point 1)
By not being able to "Browse" I was referring to a Mac issue, not an Audacity issue. Users on a Mac, even administrator users, are not allowed access to the core system UNIX files. One has to be logged in as root (or "super user") to access them or even just to see them, and Apple has even made it impossible for the novice to figure out how to do that. The only common access Apple allows to core UNIX locations is to let a software installer write files there - if but only if the person running the installer can give a proper administrator password. And that is what the MP3 and AAC library installers now do on a Mac. They write to the protected, invisible UNIX location /usr/local/lib

In my case the Audacity preferences file (audacity.cfg) had a different, now incorrect, location for the MP3 library - the location used by a previous version of Audacity. It is impossible for a Mac user to then Browse, within Audacity selection windows, and get to the correct invisible UNIX location /usr/local/lib. This is a generic problem - a conflict in the way the Mac protects system location access and the way Audacity is set up for user browsing.

Point 2:
Your link helped a lot. When looking for the Audacity preferences file on my Mac I had overlooked the location ~/Library/Application Support/audacity, and also did not know the file name is audacity.cfg. So I edited file audacity.cfg directly with a text editor and put in the correct /usr/local/lib/audacity path to libmp3lame.dylib. The file audacity.cfg already contained this correct path to the FFmpeg AAC libraries.

The result is a mysterious half fix. Export of MP3 files is now correct. The new surprise is that export of AAC files gives all zeros. Strange. Before I edited the preferences file the exports of all compression formats gave 10 sec of music followed by all zeros.

The FFmpeg AAC library files are in the right place, /usr/local/lib/audacity/, and audacity.cfg does list this path correctly.
Have not spent time playing with this one yet to try to figure it out.


Update:
[Possible conclusion is that there might be something wrong and not related to Mac in the way Audacity 1.3.8 exports AAC but not AC3.]

I've tried quitting and restarting Audacity 1.3.8 and even rebooting my computer, but I consistently get the following result for compressed format exports:
MP3 exports give .mp3 files that are fine.
AAC exports give .m4a files that have all zeros.
AC3 export gives .ac3 files that are fine if I force them to play in QuickTime.
(They open by default in VLC which I can't get to play just audio.)

This is with the following in the audacity.cfg file:
[MP3]
MP3LibPath=/usr/local/lib/audacity/libmp3lame.dylib
[FFmpeg]
Enabled=1
FFmpegLibPath=/usr/local/lib/audacity/libavformat.52.dylib
And when I check those locations the files are indeed there and non-zero in size.
I downloaded and reinstalled the FFmpeg libraries again, but there was no change in 1.3.8's export behavior.

Your link to the "Known Issues since release" page says a Windows & Mac bug has been fixed as of Aug 1 for the FFmpeg installers. Maybe not.

Concerning AAC bit rate:
[Possible conclusion is that the AAC export bit rate might not be changed by the "Quality" slide bar.]

I found that file audacity.cfg is overwritten by Audacity when Audacity quits.
And there are records in file audacity.cfg for the settings for AACQuality and AC3BitRate that Audacity has been using before the quit.
Using the "Quality" slide bar in AAC export options, I tried three different settings for AACQuality -- 65, 131 and 160,
and then quit Audacity 1.3.8 to force it to overwrite file audacity.cfg
Then when I opened and read file audacity.cfg and looked in the [FileFormats] section,
I always found AC3BitRate=160000,
independent of the value for AACQuality.

[takken]

I've posted to the administrators. You're way more stuck than anything I can do to help.

You're right, you should not need to be root to straighten this out. Did you try to dig down to those folders in Terminal? "Administrator" should be able to do that .. at least I can.

I would recommend rolling back to 1.3.7, but as you noticed, that one doesn't deal with AAC. You could pull your sound files into iTunes and then pull out the AAC version -- assuming you set iTunes up that way..

Koz

Hi Koz,
Thanks for the note. Yes, I use Terminal to see that the FFmpeg files are at /usr/local/lib/audacity/ and to see that they actually contain something. But that doesn't help the Audacity location selection windows in preferences see hidden files. I am getting very strange behavior. See note two to Gale.
Right, iTunes will convert file formats, but the procedure is a pain to go through.

[takken]

And here's the other two pieces of information.

http://forum.audacityteam.org/viewtopic ... 002#p47098

Koz

That's about level meters. Did you mean to send me a different link?

[takken]

4. Use iTunes to make AAC copies (at your chosen bitrate) in the library of the WAV files
5. Delete the WAV files from the library.
WC

Hi wax, Thanks for the suggestion.
I tried something like that using AIFF instead of WAV, and it seemed like too much work.
Maybe the trouble is that haven't figured out the best ways to execute reformatting with iTunes.

How do you carry out your step 4?
Do you set iTunes preferences and then drag each song name out of iTune playlist, and put it on the desktop or some folder of choice, this making a reformatted file?

And how do you carry out your step 5?
I can't tell what the file format is by looking in an iTunes playlist,
so I can't delete the uncompressed as opposed to the compressed file of the same song name.
Do you go to the actual iTunes library subfolders to see and change their file contents?

[Gale Andrews]

Hi takken,

I had not heard of issues with Mac users browsing in Audacity for the FFmpeg or LAME libraries not being able to see them without being logged in as root. It sounds as if we ought to address this especially given FFmpeg libraries are not autodetected. Koz, you mentioned a few weeks ago the LAME installer wanted a password. Is this the same issue? Are these issues recent/something occurring with recent mac updates?

Concerning zeroed AAC files, are you sure the FFmpeg installer you downloaded was the one with 20090729 in the title? That's the one you need (4987629 bytes).

Concerning AAC quality, you say that in audacity.cfg "I always found AC3BitRate=160000, independent of the value for AACQuality", but AC3 is nothing to do with the QuickTime AAC format. The cfg file stores only the last used AAC quality settings. I exported from Audacity three copies of the same half minute track at AAC quality 10, 238 and 500 and the respective bit rates according to QuickTime and iTunes were 16, 72 and 104 kbps. So, "quality" does have an effect on bit rate and of course on file size.

Here is how to convert to other formats in iTunes. I would just export AIFF from Audacity to the Desktop, then drag from Desktop into the iTunes window. As I said, control-click > Get Info for file information in iTunes.


Thanks

Gale