Rendering Seamless Loops

[explodingPSYCH]

I'm attempting to render a seamless loop from a track I've created. I've ensured that each item is the same at the point where the cross the loop point.

On playback in the loop bracket within the Reaper session file it sounds perfect.

However, after rendering the file, then splitting it in a new reaper session with the same BPM and using the same grid spacings, I find a small click present. When I zoom in on the wave, it appears to not quite match up, even to the point of having a small gap before the end of the file where the wave isn't drawn to completion of the file.

Is this a bug or is the loop bracket playback in the original file fooling me somehow?

Here are pictures of the waveforms not meeting up on the rendered file and my render settings.

I've also tried rendering at the original SR and Bit depth I recorded (48k, 24bit) and it looks and sounds the same. Click is still present.

[bezusheist]

Are there any efx on the track being looped/rendered ?

[explodingPSYCH]

Originally Posted by bezusheist

Are there any efx on the track being looped/rendered ?

Great question! I had overlooked this initially, but I printed the FX. The only one not printed is a Vahalla verb, which is also playing seamlessly when soloed in the loop bracket within Reaper.

Of course, this is assuming that the gap in the waveform rendered is just visually in error and not an actual render error. I know for certain that the audio doesn't not become silent at the end, as pictured above.

EDIT: I'm playing with mixing down all of my FX to ensure a proper loop and that does seem to be changing the amount of click I get.

I think I'm going to cross post this in the bugs forum though, as it appears that the waveform may not being drawn correctly and/or what is being render is not what is reflected in the loop bracket playback.

[Tod]

Originally Posted by explodingPSYCH

Great question! I had overlooked this initially, but I printed the FX. The only one not printed is a Vahalla verb, which is also playing seamlessly when soloed in the loop bracket within Reaper.

Of course, this is assuming that the gap in the waveform rendered is just visually in error and not an actual render error. I know for certain that the audio doesn't not become silent at the end, as pictured above.

EDIT: I'm playing with mixing down all of my FX to ensure a proper loop and that does seem to be changing the amount of click I get.

I think I'm going to cross post this in the bugs forum though, as it appears that the waveform may not being drawn correctly and/or what is being render is not what is reflected in the loop bracket playback.

What exactly are you looping? If you're looping a wave file, you have to have the exact phase and amplitude to get no clicks. You can apply fades to reduce the clicks, but they may not work either.

It's really more than just lining up samples on the two ends.

Depending on just exactly what you're looping and what your trying to achieve, there are ways to get perfect loops.

[bezusheist]

make sure all processing is done/printed before making the loop.
Efx will "play through" the loop seamlessly because the "tail" of the efx carries over to the start. Once rendered, the efx start/end abruptly at the start/end.

[atza]

Try rendering not only loop selection.Render whole file or at least a larger portion of it containing loop section and then cut the loop from longer rendered part

[explodingPSYCH]

Originally Posted by Tod

What exactly are you looping? If you're looping a wave file, you have to have the exact phase and amplitude to get no clicks. You can apply fades to reduce the clicks, but they may not work either.

It's really more than just lining up samples on the two ends.

Depending on just exactly what you're looping and what your trying to achieve, there are ways to get perfect loops.

I am looping a mix down of a song. I had an instance of reverb that had not been printed. After printing that and adjusting a few more things, I was able to get a clean loop.

My concern is that the previous loop doesn't seem to accurately reflect what is heard in the mix and in the loop within Reaper. Specifically, if you look at the picture, you can see that there is actually a very small amount of silence where the wave form is not completely drawn. I think this may be a bug of some kind.

My initial issue of not getting a clean loop seems to have been resolved by printing all effects, even ones that sound clean when looping, but I'm still curious about this visual issue with the waveform.

[explodingPSYCH]

Originally Posted by bezusheist

make sure all processing is done/printed before making the loop.
Efx will "play through" the loop seamlessly because the "tail" of the efx carries over to the start. Once rendered, the efx start/end abruptly at the start/end.

Good point. This may have been masking an issue with the reverb. Still strange how it was visually represented in the end of the waveform. Thanks for the reminder.

[Tod]

Originally Posted by explodingPSYCH

My initial issue of not getting a clean loop seems to have been resolved by printing all effects, even ones that sound clean when looping, but I'm still curious about this visual issue with the waveform.

Yeah, that could indicate the wave file stopped before the cut. If you grab the end of the sample on left and drag it out a little ways to the right, what do you see? Do you see that slight gap where you made your cut? If so, then the gap must have been in the file before you cut it.

You did say you had split that item right there, right?

[SimonViklund]

I also want to create loops, to export and use in a video game.

I want to be able to go back to my project to change effect settings, alter loop lengths or do any other type of edit before reexporting the loops. In other words, my project needs to remain flexible. For this reason, I don't want to print the effects or set loop lengths in stone by rendering tracks.

Item fade handles (I don't know what they'r really called, check the reaper_1.jpg file attached.) only work if there are no effects on that track or any track that the audio from this track passes through, including the master track. Effects will alter the wave form and create an audible transient at the loop point.

So, the solution is to create fades similar to what the item fade handles do - but on the volume automation curve for the master track (see the reaper_2.jpg file attached.)

However, I notice that even when the fades created on the master track are way longer than what I successfully used when employing the "item fade handles" previously, there is still an audible click at the loop point. I make the fades longer and longer - and when the click eventually goes away, the fade have become so long that there is an audible "dip" in the loop audio. Grumble grumble.

So, two things:

1) Do the "item fade handles" and the volume automation curve on the master track behave differently? Should I treat them differently? Can't the automation curve on the master be used instead of the "item fade handles" in the way I tried?

2) I would like to suggest there be "fade handles" on the master track, attached to the beginning and end bracket of any region created. These "fade handles" would create fades that are applied post-FX on the master track and thereby allow the user to create seamless loops without having to wrestle with volume automation, printing effects or anything of the likes.

[Tod]

Originally Posted by SimonViklund

I also want to create loops, to export and use in a video game.

Hi Simon, do you have any audio clips of those loops?

[SimonViklund]

Originally Posted by Tod

Hi Simon, do you have any audio clips of those loops?

You mean an example loop exported as it is intended to sound?

[Tod]

Originally Posted by SimonViklund

You mean an example loop exported as it is intended to sound?

Yeah, something I can take a look at and listen to. Actually a RPP project file with a bit of audio before and after
the loop would be enough to know exactly what you're talking about.

[Travesty]

Originally Posted by explodingPSYCH

The only one not printed is a Vahalla verb, which is also playing seamlessly when soloed in the loop bracket within Reaper..

This is the culprit, the tail of the verb will not loo around when you render, you need to manually render the verb and loop it round yourself.

[Tod]

Originally Posted by Travesty

This is the culprit, the tail of the verb will not loo around when you render, you need to manually render the verb and loop it round yourself.

So what happens if you render without the verb and apply it after the fact?

[Travesty]

The way to do it is to loop your content three times, render it out and just take the middle loop. Then you get a seamless loop with reverb.

This needs to be done with all time based effects usually

If you create a region around the part you want then it is easy to extract it afterwards.

[Bri1]

I also want to create loops, to export and use in a video game.
1) Do the "item fade handles" and the volume automation curve on the master track behave differently? Should I treat them differently? Can't the automation curve on the master be used instead of the "item fade handles" in the way I tried?

^[a] yes,they do behave slightly different. [b] yes,treat them different. [c] yes they could be.

2) I would like to suggest there be "fade handles" on the master track, attached to the beginning and end bracket of any region created. These "fade handles" would create fades that are applied post-FX on the master track and thereby allow the user to create seamless loops without having to wrestle with volume automation, printing effects or anything of the likes.

^this might be a fair and `usefull` option.[but a special type for just master renders yep]

creating `proper loops` is an art initself--specially created tools were made just for that job alone.
the 1st thing to consider is zero crossings,+ secondly,offzero crossings -they can both be used,but only 1 will 'not click' on starting playbacks.
then consider mono v stereo-mono files are way easier to create and playback nice without any crossfading playback tools.

soundforge had a crossfade editor,which would easily create seemless loops,but not only that--it also created sustained and sustained+realease loop types as well-- very powerfull tools that reaper could well do with by now...sighz..
once created-certain samplers could read that event info and playback as created= perfections all round m8.

it can be done in reaper-but it's a royal pita for noobiez and laziez..
crakon while u rockon.
+devs would need to set a 'snap to samples' option for a good starter!
oh++ graphical errors at certain zoom levels in reaper occur atmo--no biggy until you want to actually use it... :/ like so> v593

[Travesty]

The guy already has a seamless loop, he's just got a problem when he renders it out, because of the reverb still being live.

The soundforge loop creator is pretty rubbish really. You can do a much better job in reaper by snipping the end off your content and Crossfading it into the start, you don't need to worry about zero crossings unless you plan to play the loop without an envelope, which would be unlikely for loop in a game. There are some great scripts available that can automate this too.

[Tod]

Originally Posted by Travesty

The guy already has a seamless loop, he's just got a problem when he renders it out, because of the reverb still being live.

The soundforge loop creator is pretty rubbish really. You can do a much better job in reaper by snipping the end off your content and Crossfading it into the start, you don't need to worry about zero crossings unless you plan to play the loop without an envelope, which would be unlikely for loop in a game. There are some great scripts available that can automate this too.

Yeah, you guys are talking about something totally different that I've never had a need to do. I thought
if I could see the audio and how it's being looped I might have some ideas. The title "Seamless Loops" got
me because I figured out how to make perfect seamless loops with samples.