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When bouncing: Offline or realtime?


Fulmason23777
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There is no definitive answer to that.

You can use both but there are times when you have to use realtime like for example when bouncing external synths.

And there are times when the computer's CPU can't cope with the load and when the only option (unless you want to render tracks) is to use offline bounce.

 

So is there any degradation of sound when bouncing offline? My friend told me that you should always bounce in realtime because "it will sound better compared to bouncing offline".. something to do with the computer's processing and blah blah blah. Was my friend BS-ing me?

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If you are bouncing your final mix to send to a mastering engineer and you choose to bounce offline, make sure you listen to your mix before you send it out for mastering. fisherking's post is one good example why.

 

My preference in that case is realtime bouncing since you need to listen to your bounce anyways before you send it out.

 

However, I use offline bounce while I'm working on my project in the case of bouncing specific tracks or regions.

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So is there any degradation of sound when bouncing offline? My friend told me that you should always bounce in realtime because "it will sound better compared to bouncing offline".. something to do with the computer's processing and blah blah blah. Was my friend BS-ing me?

 

If "a friend tells you something" and cannot back it up with understandable, plausible and factual evidence, then most likely they probably don't know what they are talking about it, and just heard someone else say it and believed them and are just rehashing the same information.

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I'd think audio degradation would be a greater concern in realtime bouncing - e.g., something happens to fire up for long enough to steal a few CPU cycles or disk rotations, briefly depriving Logic of what it needs to keep up with the realtime rendering and hence adding some garbage to the result. Offline is effectively immune from such issues, as far as I know. I agree with those that have said realtime is essentially to accommodate external instruments or processing ... and for my part, I always opt to bring external instruments "into the box" as separate audio tracks before I even begin mixing, so that everything can be done offline thereafter (because all of my processing is "in the box" already).
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So is there any degradation of sound when bouncing offline? My friend told me that you should always bounce in realtime because "it will sound better compared to bouncing offline".. something to do with the computer's processing and blah blah blah. Was my friend BS-ing me?

 

If "a friend tells you something" and cannot back it up with understandable, plausible and factual evidence, then most likely they probably don't know what they are talking about it, and just heard someone else say it and believed them and are just rehashing the same information.

 

Yeah. I didn't buy it. I was just relaying what he said. It didn't make sense to me either. But I hate when people do that.. simply say things without being able to back it up.

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Yeah. I didn't buy it. I was just relaying what he said. It didn't make sense to me either. But I hate when people do that.. simply say things without being able to back it up.

 

In case any part of your last sentence was related to my last response, let me state that the equivocation in my response was solely because I'm not one of Logic's programmers, and hence cannot know every detail of what Logic may do internally. But I will unequivocally state that, in audio software in general, any time offline processing is an option it is not subject to many of the toughest problems that real time processing is. How much of a risk for audio glitches one runs with a realtime render is subject to numerous factors such as the hardware capabilities, buffer sizes, other processes, etc., but my point is that offline processing doesn't need to worry about filling buffers in real time, or running DSP algorithms in real time. In offline processing it is just dealing with streams of either integral or floating point values. Hence even a computer that is far too slow to render audio in real time can produce exactly correct results in an offline render (as long as the software's offline render isn't bugged, and if you give it enough time to finish).

 

Yes, I have coded audio software that did these exact tasks in the course of my career, so I'm not blowing smoke. Offline rendering was much easier to write, for the reasons I have given.

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  • 2 years later...

Hi all,

 

I've been trying to figure something out about offline vs realtime bounces and came across this thread. I'm bouncing a track and have some soft-limiting applied on the Stereo Output bus. Whenever I bounce offline, the limiter does NOT seem to work. When I do a realtime bounce, it works better, although the output volume still peaks above the -4db level that I had set on my limiter. What am I doing to get this result? I thought that offline bounces included on FX applied on the master output channel...right? And why isn't the highest peak -4db, which is what I set on the limiter?

 

Thanks in advance.

 

Gary

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What actually are the factors which should drive that choice? It intuitively seems to me that "non-realtime" processing would be advantageous whenever possible, simply because the computer "knows" that it doesn't have to get everything done "in time," doesn't have to "decide not to do something for load-shedding reasons," and so on, and it also seems to me that the outcome should be exactly the same (if the workload can be done [also...] in real time on a particular machine) . . . But, what is the bright-line rule here?

 

In particular, what cannot be done in not-real-time?

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In particular, what cannot be done in not-real-time?

 

Anything that includes the real-world - eg, live instruments coming in on inputs, and routing to external hardware FX processors and back again, as Logic can't speed up the whole universe (feature request for LP11... ;)

 

Otherwise, the numbers should be the same.

 

What limiter are you using, and what null-testing did you do between the realtime, and offline bounced versions (you'll need to remove any random modulation FX and so on to do null-testing.) In other words, how are you verifying the files are different?

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So is there any degradation of sound when bouncing offline? My friend told me that you should always bounce in realtime because "it will sound better compared to bouncing offline".. something to do with the computer's processing and blah blah blah. Was my friend BS-ing me?

If anything, offline can sound better. There used to be a problem (back in 8.x I believe) where the low order bits could cause measured (but not audible) distortion during realtime playback, but this abnormality was absent from the offline bounce. This could be monitored by recording or measuring the live output. I've done this recently via AUNetSend to Spectre at 32 bit float and no such issue exists in LPX.

 

Some instruments, such as some Native Instruments plug-ins, allow for higher quality processing with offline bounces. This is a preference you can set inside the instruments. It uses a lower quality processing for realtime processing to avoid CPU overloads, but renders at a higher quality once it's offline.

 

Projects with a lot of small files and automation data could (or can, since I haven't tested it recently) have small timing differences. Since we tend to set our automation data based on what we hear during realtime playback, that's not necessarily an argument for using offline bounce. To the contrary.

 

Doing null tests with simple, non-random and LFO synced mixes I've never come across any differences between an offline and realtime bounce.

 

So whatever way you're doing it, be paranoid and always double check what you bounced ;-) This goes for all DAWs, not just Logic Pro.

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  • 2 years later...

OK, I had a bizarre experience this evening. I was bouncing a mix to mp3. Default settings. Done it hundreds of times. For some reason the bass guitar track just completely dropped out at two points upon playback. Playing back the track in Logic - sounds great. So I tried disabling the two plugins on the bass guitar track - no difference. Looking at the mp3 dialog to see what I could try. So I do a realtime bounce - problem solved.

 

So, I'm wondering why. And why now. Why THIS particular song? What the hell!

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  • 1 year later...

Hi,

 

I've had this issue when bouncing that I resolved making it online, but I don't have external gear.

 

I'm bouncing a 20 sec part of an episode of the movie I'm working on (About 20 minutes total).

The project is made of about 100 midi tracks but the part I'm working on only uses 4 tracks and when bouncing offline the volumes are completely different than when doing this online.

 

What could it be?

 

I've bounced offline thousends of tracks and nothing of this kind has ever happened.

 

Thank you

Marco

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  • 2 years later...
Late to the topic, but I’ve had quite a few instances where mysterious artifacts, the latest sounding like a second of fireworks going off, appear in the mix after bouncing offline. No external instruments, most tracks frozen. Problem gone after real-time bounce.
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  • 4 weeks later...
  • 7 months later...
On 8/5/2013 at 5:48 PM, anp27 said:

So is there any degradation of sound when bouncing offline? My friend said that you should always bounce in realtime because "it will sound better compared to bouncing offline".. something to do with the computer's processing and blah blah blah. Was my friend BS-ing me?

It’s possible he may have had a point ;)

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