HydrogenAudio

Hosted Forums => foobar2000 => Support - (fb2k) => Topic started by: Rollin on 2021-05-06 16:37:21

Title: Removing tags from FLAC files also removes WAVEFORMATEXTENSIBLE_CHANNEL_MASK
Post by: Rollin on 2021-05-06 16:37:21
When using "Remove tags from file(s)" on FLAC files, WAVEFORMATEXTENSIBLE_CHANNEL_MASK is also removed. So, files with non-standard channels layout (and even some standard layouts - 6.1, for example) cannot be decoded correctly after this. This seems like undesirable behavior.

Also fb2k decodes 7-channel FLAC without WAVEFORMATEXTENSIBLE_CHANNEL_MASK as FL-FR-FC-LFE-RL-RR-FCL, but according to Vorbis standard channel mapping it should be decoded as FR-FL-FC-LFE-RC-SL-SR - https://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-810004.3.9
Quote
seven channels
    the stream is 6.1 surround. channel order: front left, center, front right, side left, side right, rear center, LFE

Actually, default decoding 7-channels as FL-FR-FC-LFE-RL-RR-FCL has no meaning at all, because there is no standard layout like this in any format.

Don't know if it always worked this way. I tested only 1.6.2 and 1.6.6 beta 6.
Title: Re: Removing tags from FLAC files also removes WAVEFORMATEXTENSIBLE_CHANNEL_MASK
Post by: Case on 2021-05-06 18:39:06
Why do you link to Vorbis specs if you talk about FLAC? Vorbis uses odd channel orders that aren't used anywhere else. FLAC has its own specs, check https://xiph.org/flac/format.html#frame_header (https://xiph.org/flac/format.html#frame_header).
Title: Re: Removing tags from FLAC files also removes WAVEFORMATEXTENSIBLE_CHANNEL_MASK
Post by: Rollin on 2021-05-06 18:56:43
Thanks for correction. But in FLAC specification we can see that 7-channel is "front left, front right, front center, LFE, back center, side left, side right", so not FL-FR-FC-LFE-RL-RR-FCL anyway
Title: Re: Removing tags from FLAC files also removes WAVEFORMATEXTENSIBLE_CHANNEL_MASK
Post by: Peter on 2021-05-07 20:27:24
Good find, thanks for reporting.
Removal of tags should not alter decoding output, this will be addressed in a future update.
Title: Re: Removing tags from FLAC files also removes WAVEFORMATEXTENSIBLE_CHANNEL_MASK
Post by: Peter on 2021-05-10 11:51:01
Fixed in beta 7.
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