Hi,
I have a bunch of quadraphonic FLAC files (PCM 4.0).
When I play those files from Audirvana (connected to a 7.1 channel DAC via HDMI), I get sound in the Left, Right, Center and LFE channels (instead of front Left Right and surround Left Right) !
I double checked the flac files WAVEFORMATEXTENSIBLE_CHANNEL_MASK which seems to be set to a correct value (0x603 = FL / FR / SIDE_LEFT / SIDE_RIGHT).
I’m not sure if Audirvana uses this tag to open the audio device with the right channel layout…
Currently, I worked around this problem by creating a script that uses “sox” and “metaflac” to convert 4.0 flac files to 5.1.
It works fine, but the files are not true quadraphonic files anymore.
#!/bin/sh
for file in *.flac
do
echo ---------------------------
echo “$file”
filename=$(echo “$file” | cut -f 1 -d ‘.’)
echo Extracting LEFT and RIGHT to "$filename"_FRONT_LEFT_RIGHT.wav
sox "$file" "$filename"_FRONT_LEFT_RIGHT.wav remix 1 2
echo Extracting SURROUND LEFT and RIGHT to "$filename"_SURROUND_LEFT_RIGHT.wav
sox "$file" "$filename"_SURROUND_LEFT_RIGHT.wav remix 3 4
echo Creating FRONT CENTER Channel "$filename"_FRONT_CENTER.wav
sox "$filename"_FRONT_LEFT_RIGHT.wav "$filename"_FRONT_CENTER.wav remix 1,2 highpass 300 lowpass 3500
echo Creating LFE Channel "$filename"_LFE.wav
sox "$file" "$filename"_LFE.wav remix 1,2,3,4 lowpass 120
echo Merging Channels to "$filename"_51.flac
sox -M "$filename"_FRONT_LEFT_RIGHT.wav "$filename"_FRONT_CENTER.wav "$filename"_LFE.wav "$filename"_SURROUND_LEFT_RIGHT.wav "$filename"_51.flac
echo Copying tags from "$file" to "$filename"_51.flac
metaflac --export-tags-to=- --no-utf8-convert "$file" | metaflac --import-tags-from=- "$filename"_51.flac
echo Changing WAVEFORMATEXTENSIBLE_CHANNEL_MASK to 0x003F in "$filename"_51.flac
metaflac --remove-tag=WAVEFORMATEXTENSIBLE_CHANNEL_MASK "$filename"_51.flac
metaflac --set-tag=WAVEFORMATEXTENSIBLE_CHANNEL_MASK=0x003F "$filename"_51.flac
echo Cleaning up
rm "$filename"_FRONT_LEFT_RIGHT.wav
rm "$filename"_FRONT_CENTER.wav
rm "$filename"_LFE.wav
rm "$filename"_SURROUND_LEFT_RIGHT.wav
mv "$filename"_51.flac "$filename".flac
done