gaps and repeats in long render (CD Mix)

venomkid · Post by **venomkid** » Wed Jan 10, 2007 1:38 am

Hey all, first post. You guys & gals have already posted so much helpful stuff here that I haven't had to ask a question directly until now. Thanks so much. I used the search and I haven't found an answer for this issue, so I hope this isn't a dupe.

I'm making a party CD mix for a friend of mine. It's composed of mp3s, and I've done some xfading and eq tricks and such to mix them together. It's about 78 min long.

I set it all up in the arrange view. Throughout the set I change the bpm slowly on the master. All of the clips are set to warp on Beats, 1/4 Transients, Straight. Since they are pretty dance-oriented, electronic songs, most of them have just one warp point at the beginning and simply have their BPM adjusted.

The live mix plays fine.

The render does not.

In the middle of some songs, there are repeats and/or gaps that do not appear in the original files, nor do they appear on live playback. A repeat appears at approx 21:10, a gap at approx 29:40, and a pretty sizeable stuttering glitch at approx 65:10. All of these absolutely wrench the beat out.

I tried re-rendering it, but it's the same every time. I tried blowing out the cache files and re-decoding the mp3s, no help. I've tried adjusting the transients, no help. There are no warp points where these glitches are occurring, and no major adjustments to the bpm anywhere near them. Nearly all of these occur when there is just a single clip playing, and again none of these glitches exist in the original files.

The really funny part is, when I try to render those individual sections, they do not glitch. It's only when I try to render the whole thing.

I'm using live 6.0.3 on a Thinkpad z60 1.7Ghz Pentium with 512MB of RAM, 5400rpm SATA Hitachi hard drive. I'm using ASIO4ALL drivers at 2.2in and 2.2out for live effects use, with the internal SoundMax HD sound card. It normally works like a charm.

I've never had this problem with any of my own compositions, which are much more complex than this mix, so I'm pretty baffled.

Any help is appreciated, thanks!

A.

justin · Post by **justin** » Wed Jan 10, 2007 10:53 am

what settings are u using to render the audio file - bit and sample rate?
what program are using to play the rendered file?

if ur using winamp or itunes (and maybe other players), they generally dont like files with high bit rates / sample rates... 16bit, 44.1k being the safest i think.

if u can see the glitches in an audio editor (sound forge, peak) then the problem is in the file. this should then lead back to a problem in Live 6... in the meanwhile, u can get around the issue by using another audio track to resample ur master output within live. then just record as u play thru...

venomkid · Post by **venomkid** » Wed Jan 10, 2007 5:16 pm

justin wrote:what settings are u using to render the audio file - bit and sample rate?
what program are using to play the rendered file?

if ur using winamp or itunes (and maybe other players), they generally dont like files with high bit rates / sample rates... 16bit, 44.1k being the safest i think.

if u can see the glitches in an audio editor (sound forge, peak) then the problem is in the file. this should then lead back to a problem in Live 6... in the meanwhile, u can get around the issue by using another audio track to resample ur master output within live. then just record as u play thru...

Thanks for the reply!

I am rendering to 44.1Khz, 16bit, same as the mp3s I'm playing. I'm playing back the rendered file in winamp. But when I open it up in soundforge, the sound glitches are visible in the wave map. So, as you said, I'm pretty sure this is a problem with Live 6.

Just to be a bit clearer still, I'm outputting to WAV and encoding with LAME. The audio glitches are in the WAV, so naturally they occur in the mp3 as well.

I'll try your idea of re-recording to another track. It's somewhat sad that it would come to that, though. I'd love to be able to rely on the render function.

A.

venomkid · Post by **venomkid** » Wed Jan 10, 2007 7:46 pm

Recording playback to a different track didn't help. Believe it or not, it causes the exact same glitch to occur at the same time to occur audibly.

But if I advance to just before that point in the track and record, it's fine.

I defragmented my HD as well, it didn't help.

I froze all of the tracks, same glitch.

I'm about at my wit's end here. I'm thinking about doing multiple takes to build the whole track and then outputting that, but who's to say it won't glitch in some other way?

db · Post by db » Thu Jan 11, 2007 6:23 pm

Hi,

What plug-ins are you using in that Live Set? Can you temporarily try it without any external VST plug-ins/instruments?

Do you have another computer/colleagues computer to try it on?

How large is the Live Set? Could you possible upload it to some web space (compressed as .zip, with audio files) so I can check it out?

Daniel

venomkid · Post by **venomkid** » Thu Jan 11, 2007 7:41 pm

I am using only an EQ III and Utility on each track, so there should be no external VSTs running.

I was rendering it on my laptop. I have tried re-rendering it on my desktop with the same results. It has Live 6.0.1 on it, my laptop has 6.0.3, so it doesn't seem to be a problem only with the new version, or with only my laptop.

The live set is about 200mb. I will upload the file somewhere and send the URL to the email address you contacted me with earlier.

justin · Post by **justin** » Fri Jan 12, 2007 11:02 am

sometimes i've had weird mp3 files that dont play properly - it could be one of the files is slightly corrupted.

have u tried converting the mp3 files to wav /aiff then replacing the mp3's in your set with a proper audio file?

just an idea...

venomkid · Post by **venomkid** » Sat Jan 13, 2007 4:09 pm

justin wrote:sometimes i've had weird mp3 files that dont play properly - it could be one of the files is slightly corrupted.

have u tried converting the mp3 files to wav /aiff then replacing the mp3's in your set with a proper audio file?

just an idea...

Thanks for the reply. That's an interesting idea, but I hesitate to point to the mp3s because when I render those specific mp3s outside of the mix, they don't have any problem. I also mix those same mp3s live and there are no problems. And there are some really quick timings on this mix, so running them out to WAV could introduce drift, what a pain that would be.

I'll probably give it a shot later today if I don't hear back from db, though.

djdrue · Post by **djdrue** » Wed Jun 11, 2008 8:02 am

I'm having the same problem as well, rendering just over an hrs worth of music and finding dropouts in the wave file as well.