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Extra space in exported audio clip

Hi,

I've noticed a small timing issue when creating stems. There seems to be a bit of delay added to the actual audio data. Here's some information about my setup and the workflow I use to create these stems as well as a screenshoot showing the delayed audio (bottom) against the actual MIDI event (top).

Track Mixdown
* Type: Audio
* Input: Master
* Outout: MixDown (a bus I've created)
* Gain: -70db

For any MIDI track I want to record, I proceed as follows:
1. Enable Record on MixDown track
2. Solo MIDI track
3. Enable Transport Record
4. Rewind to beginning of song
5. Play

Once the solo'd track is recorded in full, I then export the audio clip by using Clip/Export

While this workflow is extremely tedious, it's something I can live with but the resulting audio does appear to always be just a little late. Is this related perhaps to latency or is there something I'm missing?

Thanks in advance

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rncbc's picture

yes, of course the're this round-trip latency delay when bouncing from MixDown output bus back into the Master input...

you may adjust it manually though, in the audio clip offset properties dialog, but I believe the best approach to all this is using Track > Export Tracks > Audio... and select the MixDown output bus only; also you may opt to the add the resulting stem as a new audio track cf. Add new tracks(s).

hth. cheers

I don't understand at all and wonder if the work flow I've described above is clearly understood? I'm not sending anything back into the Master input

The "mixdown" workflow I've described previously simply records the output of my solo'd MIDI track into the new audo track that uses Master as input.

Once I have recorded to the Mixdown track, what would be the benefit of exporting it over simply exporting the clip?

I'm getting the sense this track/export/audio mixdown workflow you're talking about largely assumes qtractor is being used in an isolated fashion?

rncbc's picture

re. talking about largely assumes qtractor is being used in an isolated fashion?

oh yes, I was talking about the case when you have a synth plugin inserted on a MIDI track, and thus you may render/export the stem/track in a faster than real-time fashion (ie. not bouncing), sorry

if your instruments are external to qtractor, than I'm sorry again to tell that you'll have to deal with the so called round-trip latency delay, which is obviously the cause for the issue in question.

cheers

Ah ok, this is fine as it appears to be a consistent delay which, once I am able to determine, I can work around. Thank you for the confirmation.

All the best

The time has come to create stems again and I figured I'd follow up on this thread by asking for any tips on how to exactly determine the round-trip latency? Assuming a reliable method does exist, my follow up question would be to how make use of that information. I'm guessing some value (once determined) would be added to jackd somehow (I personally use Ubuntu's studio-controls to interact with jack).

The ultimate goal here would be to end up with stems that can be dropped into a .mid file which everything in complete sync.

Thanks in advance for any tips.

rncbc's picture

Hi welcome back! many thanks to that...

well, the current situation is about trial and error and probably move your recorded clip around, by ear :)
correct latency information and reporting (through JACK and other infrastructure there is like eg. pipewire, the new kid on the block) is a dang PITA to at least comply; and to make things even worse it actually depends on your particular hardware setup... even more hairy with external outboard hardware.

please don't ever feel you're being left alone in the dark, on the bright side, it is you who decides; latency compensation is there, has been for some time, but given the huge diverse scenarios one has to deal, it's not even worth to comply with every case. and let's not talk about moving targets (when you change the ins and outs in your physical studio cables :))

so hints are, please, go with what you have and adjust and fit and purpose; if you know you have a permanent setup (well, you're not switching and juggling devices here and there, now and then, are you?) you may proceed to fix the perceived delay on JACK latency settings; however, if you're already on PW, then, you're on the bleeding edge of things that will look just different every other day ;) but it's said to underway to get better (in a few years perhaps ;))

sorry for the (somewhat kinda) rant
cheers all the way
thanks again

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