OGG: Support for "loop_start" and "loop_end" (for streaming music in Doom ports)

[Lollie]

Hi all! I have a very niche feature request, everyone's favorite kind.

I've occasionally had to fiddle with looping OGGs — one of the more common reasons has been for Doom ports. I've only just learned of XMPlay, and pairing it with the "OGG Tag Support" plugin has given me a much easier way to edit Vorbis metadata, which I'm very happy to have.

XMPlay natively supports "loopstart" and "looplength" just fine, but Doom ports rely on "loop_start" and "loop_end" instead. It's apparently been this way for ZDoom since 2010, and ports like Chocolate Doom, PrBoom+, and Nightdive's recent "Doom I + II" re-release all support them too. Even the Duke Nukem 3D port "EDuke32" has gotten in on the action.

(Additionally: Doom ports also support looping FLACs using the same tags. I've yet to check if XMPlay supports looping FLACs.)

I will note, this is a bigger ask than it sounds on the surface. To lay out the differences, citing ZDoom Wiki:

• In XMPlay, "loopstart" and "looplength" only accept sample positions. In Doom ports, "loop_start" and "loop_end" can be a sample position OR a timecode in the mutable format of 00:00:00.000 (HH:MM:SS.sss), accurate to one millisecond.
• In XMPlay, "looplength" is a duration, and is offset by "loopstart" if present. In Doom ports, "loop_end" is just a straight sample/timecode.
• In order to determine whether a value is a sample or a timecode, ZDoom checks whether a colon ( : ) is present. "44100" would be parsed as a sample position, while "0:01", ":01.0", "0:01.000", and any other variations would all be parsed as timecodes.
• If a tag's value contains anything other than 0-9, more than two colons, or more than one decimal ( . ), it is ignored.

With all that said: What are the chances of having these tags recognized in XMPlay?

[Ian @ un4seen]

Here's an update for you to try:

    www.un4seen.com/stuff/xmplay.exe

The "timecode" stuff is untested as I don't have any test files for that, so please let me know if there's any problem with it, and if so, upload an affected file to have a look at here:

    ftp://ftp.un4seen.com/incoming/

If all is well, I'll look into adding support in the FLAC plugin too (it doesn't currently support looping).

[Lollie]

Oh wicked, thank you! These tags work perfectly fine with samples.

Timecodes don't seem to do anything right now, so I've just uploaded a zip called "Timecode Loop Tests.zip" to the FTP. It's just a basic test tune, set up with timecodes in a few different forms. It should loop between 0:05 and 0:17.

[Ian @ un4seen]

Thanks for the test files. Here's another update to get the timecodes working too:

   www.un4seen.com/stuff/xmplay.exe

Let me know if there's still any problem with it.

[Lollie]

As far as I can tell, it works perfectly! I've tried every different form of timecode that I can think of, and they all work as expected. Thank you so much!

[Ian @ un4seen]

Good to hear it's working well. Here now is a FLAC plugin update that should have the same looping support:

    www.un4seen.com/stuff/xmp-flac.dll

Let me know if you see any problem with it.