ALAC import problem

Feedback and Discussion Forum Audacity 3.x Feedback and Reviews
1

I’m trying to import an ALAC file to look for transient distortion and for some reason I’m getting about one second of white noise instead of the file. When I look at the log it is packed full of errors about things missing (they’re not) and a strange inability to read ALAC created by ffmpeg…

I have attached a log file of a CD rip made from 1 of 5 identical rips from 5 CDs on five different CD drives - “Holst - The Planets - Herbert von Karajan” (it’s an academic experiment on the longevity of CD as a medium - they are all the same, so yay to that, I guess!) but I can’t view the file in Audacity 3.1.3. I have the optional ffmpeg for Audacity installed, I tried renaming the file’s extension from m4a to alac, but that made no difference.

I know it used to work with Apple Music ripped files, but I have moved onto using EAC as Apple Music sucks at reading CDs properly leaving me with tracks of garbage. I’m doing this experiment on Windows 10 Pro v10.0.19044.1706. I’ve removed, cleared preferences and re-installed Audacity and ffmpeg for Audacity a few times and rebooted, it made absolutely no difference. In EAC I use this command to take the uncompressed digital audio from the CD and convert it to ALAC;

-i %source% -metadata “ARTIST=%artist%” -metadata “TITLE=%title%” -metadata “ALBUM=%albumtitle%” -metadata “DATE=%year%” -metadata “TRACK=%tracknr%/%numtracks%” -metadata “GENRE=%genre%” -metadata “ALBUM_ARTIST=%albumartist%” -metadata “COMPOSER=%composer%” -metadata “DISC=%cdnumber%/%totalcds%” -metadata “COMMENT=CRC:%TRACKCRC%” -acodec alac %dest%

VLC plays the file and correctly identifies it as ALAC 16 bit 44.1kHz and the comment contains the CRC (23C866FC)

Does anyone know what’s going on?
log.txt (277 KB)

2

So as VLC is able to read your file, ask VLC to export it as a .WAV file. Then you should be able to load it with Audacity. :smiley:

3

I also have the original 16 bit PCM data plus the Reed-Solomon bitstream from the comparator before the decoding logic, but I want to standardize on a lossless format, I chose ALAC mainly for historical reasons, I could use FLAC. Perhaps someone with technical knowledge of the inner workings of ffmpeg and Audacity can figure out why Audacity can’t use ffmpeg to open a file created by ffmpeg…? Audition and Logic open the files without any issue.

4

The next version of Audacity, version 3.2 will include support for FFMPEG 5.0. Perhaps this will correct your issue. You can find out for yourself by downloading and testing an alpha test version of the software from here: https://github.com/audacity/audacity/actions.

Or you can wait for the official release. We can only speculate when it will be released but two months ago, the developers were hoping for 2nd quarter.

5

Don’t hold your breath; the developers noted just this morning:

6

Developers, developers, developers, developers… cue Steve Ballmer… :laughing:

Yeah, thanks, in the end I did convert the ALAC files to WAVE using ffmpeg and then did comparisons, with that out of the way, I did many further experiments on error correction and interpolation. It’s quite surprising how damaged a CD has to be not to play and why people like to use something like Exact Audio Copy (EAC) along with AccurateRip to make sure their discs and drives are working 100% and not falling back on error correction and interpolation to fool the user into thinking everything’s just fine and dandy in the Red Book world :open_mouth: