.48 clicks on songstart, also during wavexport

LPChip · May 28, 2007, 00:12:03

Full Version:
OpenMPT v1.17.048

Description of the bug:
I've exported a song to wav, and it starts with a crack, like the soundbuffers still contain some info. Maybe its related to the volume bug, but since I don't think it is, I haven't added it there. (still need to verify that bug)

How often does it happen?:
I'm not really sure. It happens alot, but not sure if it happens always. Cus if I hit play several times, one time it can click while it doesn't on another.

EDIT: it always seem to happen if you let the song naturally loop without having it set to loop.
EDIT2: Okay, I can now confirm that it doesn't happen always on a wav export, but it does always happen if something loud was being played before. Solution could be to clear the audio buffers when you press stop, or atleast make sure that those are cleared when you export to wav.

How to reproduce (step by step description):
One way to guarantee this click, is by playing a song that has little movement (volume?) in the beginning, and then at another part, much more happening with more volume. Play the song, skip to the more busy part, and stop the song. Now either play from start or export to wav, and a big click is guaranteed.

rewbs · May 28, 2007, 00:25:10

Two questions:
. Does the song involve global volume changes?
. Is this behaviour new in v1.17.02.48?

LPChip · May 28, 2007, 10:30:47

Quote from: "rewbs"
. Does the song involve global volume changes?

Not at all. Not even a fade out or anything. It starts with the volume set in the general tab, which is 128, and it stays that way entirelly

Quote from: "rewbs"
. Is this behaviour new in v1.17.02.48?

I honestly don't know, but previous wav exports of this song didn't had this problem, and last night when trying the .48 build, it suddenly had them. Could be a coincidence, but I doubt it, cus I can easilly recreate it.

EDIT: confirmed that it also exists in .47 and .45

EDIT2: It might have something to do with doing a wav export while the song is playing.
EDIT3: I exported to wav from .45 after playing the song in the middle, then stop the song, then do a wav export. There's a click, but its not big.

rewbs · May 28, 2007, 19:18:22

Does the song use plugins? If so, can you check whether one or several plugins might be related to the pop by bypassing them 1 by 1?
Can you provide a simple test case?

LPChip · May 28, 2007, 21:31:16

Ugh...

And I was so sure that since I am not using a reverb plugin, that plugins were ruled out.

I now listened to the wave export with headphones, and I hear the echo I added during the song start.

Strange though that it still echos after I press the stop button, and leave it stopped for say... 10 minutes. Thats a long echo

Rewbs, would it be possible to keep the soundbuffer open after you hit stop for say... 1 second? So it just plays silence during that second?

It will solve alot of problems.

bvanoudtshoorn · May 29, 2007, 03:13:12

I've noticed that with a lot of plugs, they seem to just be "suspended" when you hit stop. That's why I've taken to putting an empty (half-length) pattern at the beginning of each of my tracks. That way, any reverbs / instrument tails / what-have-yous will have time to die off... It would be nice if MPT did what other music systems did, and actually just sent a "note off" to all the plugs. But yes, include a "Panic" button which kills all the sound straight away.

rewbs · May 29, 2007, 07:57:14

LP, just to confirm - the clicks you were getting were do to a lingering echo tail from a plugin?

bvanoudtshoorn - we do send note-offs to plugs when you hit stop, I don't think the issue is that simple unfortunately. Many plugins (NB: not all, so this is a typical VST type issue) don't clear their internal buffers on stop despite the multitude signals we send. I'm pretty sure we send all the signals we're supposed to on song stop, but I'll double check (plugin developers welcome to correct me). I believe other hosts let plugins continue to process silence after the stop button is hit so the tails die off. In fact, according to the VST spec, plugins should permanently be processing silence when the track is stopped, until they explicitly claim they don't need to (which many older plugins don't bother doing, so they just keep chugging along). Anyway, for various reasons we don't implement this aspect of the spec at the moment, which is a known issue.

LPChip · May 29, 2007, 09:41:34

Quote from: "rewbs"LP, just to confirm - the clicks you were getting were do to a lingering echo tail from a plugin?

I can't confirm that with 100% certainty, but its most likelly to be a yes, cus the click was on a different volume, depending on when I stopped or not. Appearantly that was when the note was just triggered, and I hitted stop, so I had a big volume on my echo.

But I really think this should be fixed, even if you'd just make a button to play silence so you can manually clean the buffer.

Saga Musix · May 29, 2007, 17:37:20

Quote from: "bvanoudtshoorn"I've noticed that with a lot of plugs, they seem to just be "suspended" when you hit stop. That's why I've taken to putting an empty (half-length) pattern at the beginning of each of my tracks. That way, any reverbs / instrument tails / what-have-yous will have time to die off... It would be nice if MPT did what other music systems did, and actually just sent a "note off" to all the plugs. But yes, include a "Panic" button which kills all the sound straight away.

that's btw the same thing i do. i even did this in the original modplug, but for other reasons: my old mp3 player always had cut the first and last second of a track :lol:

LPChip · July 21, 2009, 10:33:33

What are we going to do with this bug?

Saga Musix · July 21, 2009, 10:46:07

I know that it only happens with a couple of VSTs, but I don't know if the playback buffer is cleared at song start, so this could maybe be fixed...

LPChip · November 06, 2010, 12:03:23

Bug submitted to the issue tracker.