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Topic: Using musicbee, qaac64 won't change sample rate while converting to alac (Read 842 times) previous topic - next topic
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Using musicbee, qaac64 won't change sample rate while converting to alac

Hi everyone, this is my first post here. I'm new to audio conversion and I'm encountering a problem. Using the Musicbee GUI and qaac64.exe, I'm trying to convert my music collection to alac with a sample rate below or equal to 48kHz so that I can transfer it to my ipod classic. I'm currently using this set of command line options : "--ignorelength --native-resampler=bats,127 --no-optimize --alac -o [outputfile] -", added the "native-resampler" option to try and fix the problem described subsequently, I don't know what it does. This works pretty well, but when I try changing the output's sample frequency by adding the --rate option, I get errors when running the conversion from the GUI. Sadly I couldn't test this command line outside of Musicbee as I get the error "Not available input file format" when trying with a flac file (execution goes like this, from the folder containing qaac64.exe :
Code: [Select]
qaac64.exe --ignorelength --native-resampler=bats,127 --no-optimize --alac -o test.m4a -
qaac 2.80, CoreAudioToolbox 7.10.9.0
Mother.flac
.
What am I doing wrong ?
I had no time to test more files as of right now, but this seems to occur with files with a 192kHz sampling rate, in case that gives you a lead to an already encountered problem. Thanks for reading.

Re: Using musicbee, qaac64 won't change sample rate while converting to alac

Reply #1 –
When you resample, qaac converts samples to float32. However, ALAC doesn't support float32.
So samples must be quantized to int16 or something when encoding to ALAC, but qaac doesn't automatically do it for you since quantizing is not a lossless process and qaac cannot pick which format you want (16bit/20bit/24bit?).
Hence, you need to explicitly specify "-b 16" or something.

Finally, --native-resampler=bats,127 is the highest quality setting for CoreAudio resampler but is slow as hell.
There's no reason to pick it over the default soxr resampler.

Re: Using musicbee, qaac64 won't change sample rate while converting to alac

Reply #2 –
Alright that did the trick, thank you nu774, and merry christmas.