Apple lossless codec 'alac' not working

[mperkh]

It would be nice, to be able to encode audio books into a lossless codec, so that its possible to make final lossy encode of the audio stream at a later time.

ffmpeg supports Apple lossless codec 'alac'. Trying to produce a result with a command like this:

php ../m4b-tool.phar merge --audio-codec="alac" -d inputFolder --output-file="out.m4b"

results in that:

...
In MergeCommand.php line 328:

  could not convert /Users/test/inputFile.m4a to out-tmpfiles/inputFile.m4b

Its seems the problem is caused by the -f mp4 option, which is set on the final ffmpeg command, resulting in:

[mp4 @ 0x7ff18f00a400] Could not find tag for codec alac in stream #0, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:0 --

Omitting the -f mp4 option results in alac encoded m4a file to be correctly generated.

[sandreas]

Ok, thanks. I'll take a look in the next days :-)

[sandreas]

You were right...
Seems that ALAC is a bit tricky when using ffmpeg... since it was not officially mp4 compilant all the time (see: http://forum.doom9.org/archive/index.php/t-97014.html), ffmpeg complains when using alac in combination with -f mp4.

Should be fixed in current master, here is a build:
m4b-tool.phar.zip

Would be nice if you could test the fix.

[mperkh]

Tested and alac encoding works perfect now. Thanks a lot!