Use --force-rf64-format when decoding FLACs.

FLAC decodes to the standard WAV format by default, and makes no
consideration when a file requires more than 4GiB to do so, instead
exiting with an error.  FLAC supports two alternative formats to
workaround the limitation, rf64 and wave64.  I picked rf64 somewhat
arbitrarily, and also because ffmpeg considers it an extension of WAV.

For CD quality audio, which is 16-bit 441000 Hz stereo, this would
require a FLAC over 6 hours and 45 minutes to run into the issue.
However, it does rapidly become an issue with greator sample sizes,
rates, and channels.  If you rip a Blu-ray Disc, for example, with a
7.1 soundtrack at 24-bit 192 kHz (not atypical), the uncompressed
audio would exceed 4GiB in just under 16 minutes.

Relatively rare limitation to bump into, but here’s the fix. 😀

Author: chungy

reflac

@@ -63,13 +63,13 @@ recompress()
                      -- "$flac"
 
             if [ $VERBOSE -gt 1 ]; then
-                flac --output-prefix="$TMPDIR/" -d -- "$flac"
+                flac --force-rf64-format --output-prefix="$TMPDIR/" -d -- "$flac"
                 flac --delete-input-file -$FLAC_LEVEL -- \
-                     "$TMPDIR/$(basename -s flac -- "$flac")wav"
+                     "$TMPDIR/$(basename -s flac -- "$flac")rf64"
             else
-                flac -s --output-prefix="$TMPDIR/" -d -- "$flac"
+                flac -s --force-rf64-format --output-prefix="$TMPDIR/" -d -- "$flac"
                 flac -s --delete-input-file -$FLAC_LEVEL -- \
-                     "$TMPDIR/$(basename -s flac -- "$flac")wav"
+                     "$TMPDIR/$(basename -s flac -- "$flac")rf64"
             fi
 
             metaflac --no-utf8-convert \