1) It seems that some programs (eac3to) write the value of
WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag with uppercase 'x' (e.g. 0X3)
(see <http://forum.doom9.org/showthread.php?p=1728852#post1728852>)
Also, from MediaInfo changelog
<https://mediaarea.net/MediaInfo/ChangeLog>:
Version 0.7.74, 2015-05-25
x VorbisComment: WAVEFORMATEXTENSIBLE_CHANNEL_MASK "0X" ("x"
in uppercase) is accepted now
In flac we have:
if(strncmp(p, "=0x", 3))
return false;
so it's case-sensitive. Should it be changed to case-insensitive
FLAC__STRNCASECMP?
2) Previously flac accepted mono files with 0x0001 channel mask; mono files
with correct value (0x0004 = front center) were rejected without
--channel-map=none option.
(see <http://sourceforge.net/p/flac/feature-requests/96/>)
It was fixed, but now flac accepts mono files with three different channel
masks:
0x0001 (FL), 0x0002 (FR), 0x0004 (FC).
Should flac reject the first two masks when there's no --channel-map=none
option?