Changing speed with changing video...

[RodneySauer]

I work on silent film scores, and one notable thing about silent films is that they did not use a standard frame rate. Since they often are too fast at 24 fps, they tend to vary project by project depending on how fast the cameras were cranked. I worked on a European video that had been transferred at 25 fps (the standard for video over there), and finished the score. Now it turns out they want to release it in the U.S. at an (equivalent) rate of 24 fps, so my score is too fast and needs to be lengthened.

I record a small orchestra using a stereo mic and a couple of spot mics (samples at www.mont-alto.com if you're curious). Digital Performer is fine at time-scaling single-voice audio, but is lousy at multitimbral music like what I record. If I time-scale the audio, it gets filled with weird low booming sounds and other artifacts that aren't acceptable for professional release.

I know that other software packages are much better at time-scaling audio, at least based on samples I've heard from MachFive 3 and Kontakt. MachFive even boasts that it uses algorithms licensed from IRCAM technology for time scaling. (Why couldn't they license this for DP while they're at it? It would be a wonderful feature for fitting music to video!)

If I were to buy MachFive for this, would there be a reasonable workflow for getting multi-track audio (or even a stereo bounce) out of DP, scaling it by a very precise amount, and bringing it back in? Ideally, I'd like to be able to re-edit some cues leaving them at the same speed, but time adjust other cues. Mostly I'd be working within 94% to 106% of the original speed.

Any help is much appreciated!

[MIDI Life Crisis]

Hey Rodney,

MachFive IRCAM will do a great job.

Nice to see you here!

[RodneySauer]

Thanks! I've got it on order, should arrive tomorrow. We'll see how it does. There's another spot where in retrospect we played a march much too slowly, so I'm hoping to fix that while I'm at it...

[RodneySauer]

Well, having acquired MachFive 3 and getting it to work (though I hardly feel I understand the program), I'm having really weird and mostly unusable results from the IRCAM Stretch, which makes me think I'm doing something wrong. Oh heavy sigh.

I exported a sample stereo audio file of my ensemble from DP as a 24 bit, 48 kHz Wav file. I exported it dry, figuring I'll add reverb after the time stretch. In MachFive, I have an empty program, and I drag my audio from the Finder window onto middle C in the Mapping window. When I press Middle-C on my piano, the sample plays. For grins, I set the Velocity Curve to 127 so it will always play at the same volume. So far, so good, but it's not time-stretched yet.

The Oscillator window pop-up menu reads "Sample," so I change it to "IRCAM Stretch." The new sound is horrible, filled with a low-end gargling! Although Speed and Tempo Factor are set to "1," it's playing it back slower than the original.

There's a popup menu on the right with different presets including Default, Complex, High Quality, LowQuality, Percussive, and Voice. This menu is not mentioned in the manual, but I messed about with it. Oddly, LowQuality sounds much better than HighQuality. Only "Percussive" gives acceptable results... maybe that's the setting I need? The fact that all of the others give me such blatantly weird artifacts makes me think I'm not doing it right, I mean this is supposed to be state-of-the-art...

Anyway, using the "Percussive" setting, I'm expecting that if I put a VI in DP attached to a MIDI line, and then I trigger my MIDI note at the correct spot, I can then record the output to a new audio track and I'll have my scaled audio.

If there's anything fishy about my workflow (from anyone who's been using this software longer than my two hours) please help set me straight... thanks!

[MIDI Life Crisis]

User IRCAM GRANULAR, not stretch. You need to set the speed control (and play with grain size, etc) to massage the file a little before re-recording it. The speed control may need to be pretty finely adjusted to get match the new frame rate. The speed control readout defaults to 1.00 (at 12:00) and goes up to 10.00 and down to 0.00. I'm not really sure what to tell you about changing by a specific percentage, so you may have to do trial and error. If you figure out your required bpm and set the speed to a metronome playback at that tempo, it may be quicker than just doing it on the fly. Either way, you can probably find the right tempo in a few minutes and spend more time with the grain size, jitter, and density settings to clean up the artifacts.

Your not changing that much of a percentage rate (at least not compared to what you can expect to get excellent results from IRCAM with). Too bad you can't just re-record the score at the new speed.

If you really get stuck, email me a snippet and I'll process it for you as an example. (This offer is time limited... )

[RodneySauer]

Well, before I got your response, I decided that rather than use the stand-alone program as I had been doing, I'd set things up as a VI in Digital Performer, which is how I want to work eventually. And suddenly, the IRCAM Stretch sounds great with all of the presets! On the one hand, things working great makes me happy; but having no explanation for why it didn't work before makes me nervous. And it looks like I can just add my Proverb settings to the VI, and not even need a post-stretch bounce-to-disk step. I do wish that there was a "One Shot" option in IRCAM Stretch so I wouldn't have to draw such a long MIDI note as a trigger, but that's minor.

When I tried the IRCOM Granular oscillator before, I was getting a weird tremolo, but that was in the standalone program. I'll experiment with that too, but it seems like IRCAM Stretch ought to work... and with a calculator by my side, I'm hoping that I won't have to do TOO much trial and error. 25 fps to 24 fps should be a stretch of 1.0417, and I can divide the audio file at silent points, have each audio file triggered by a different MIDI note, adjust the Time Stretch setting separately, and trigger them when needed.

Thanks so much!

[MIDI Life Crisis]

No problem, Rodney. That's certainly better than trying to play a live score for The Gaucho only to find the film runs a few percent (like 8-10!) slower than the DVD. How did that screening work out for you, BTW?

[profdraper]

Seems a little long winded… exporting file to the desktop, then back into MachFive, then back into the sequence. (One wonders why MOTU don't simply incorporate the IRCAM stretch tools into DP8?). Am I missing something? Am also missing PT10 elastic audio. (Have tried to drag a DP8 soundbite into MachFive, but no go). MF3 is very nice kit, nonetheless.

[bralston]

Seems a little long winded… exporting file to the desktop, then back into MachFive, then back into the sequence. (One wonders why MOTU don't simply incorporate the IRCAM stretch tools into DP8?). Am I missing something?

I asked MOTU about that at last year's NAMM and was told, "That is something to possibly look at in the future."

Being that their official answers are always cryptic...it does seem like putting it into MachFive 3 was perhaps a test of the license of the IRCAM algorithms and they may indeed find their way into DP in the near future. That is my guess anyway.

[MIDI Life Crisis]

Maybe they'll add some noise reduction tool as well... (oh please!). That with IRCAM in DP would be truly awesome!

[RodneySauer]

Just a follow up, since I found an easier workflow for using MachFive 3 to stretch the length of a recorded musical cue in Digital Performer. Still not as easy as it would be if DP just incorporated IRCAM stretching, but you skip all of the MIDI track stuff I messed with before, and it works faster than real-time.

In your Digital Performer file, create a stereo track (assuming stereo is your final mix) for the stretched sound to live on. Also, add an instrument track for MachFive. There's a popup menu in the Instrument track to "Open Instrument" if the MachFive window gets closed.

Measure how much longer or shorter you want your sound to be, in seconds.

Bypass the reverb (and anything else you might be adding to the master track), and have the tracks mixed the way you want them in the final project.

Select all tracks and bounce to disk as a stereo file. Drag that stereo file into the MachFive instrument window, into the box with a picture of a piano that reads <empty>.

Selecting the Edit tab, choose IRCAM Stretch. I change the popup preset to "High Quality," but choose whichever preset you want.

Click the info button at the far right, and read the "duration" of the sound clip in seconds. Enter than number into a calculator. Divide it by the length that you want (in seconds) and you'll get a number that represents how much you want to scale the sound (for instance, if your piece is 220 seconds long and you want it to be 228 seconds: 220/228 = 0.965).

Close the info box. Set the "Speed" knob to the number you got in the previous step. If the mouse adjustment is too coarse, double-click on the knob and you can type in a number. If you press and hold the red piano key, you'll hear the audio at the new speed.

To the right of the Preset popup menu is a little Save menu, with an icon of a floppy disk (Yikes! How dated!). At the bottom of the menu is a choice: Export with Stretch/Pitch applied. Save the file with a new name. Then drag that file from the Finder into your Digital Performer stereo track.

Check the length, adjust and repeat as necessary.

[MIDI Life Crisis]

...a floppy disk (Yikes! How dated!).

And you're scoring what with it? LOL!

Thanks for posting your version of the workflow.

(Note to the casual observer: Rodney and I both score old silent films.)

[BKK-OZ]

Just a follow up, since I found an easier workflow for using MachFive 3 to stretch the length of a recorded musical cue in Digital Performer...

Thank you for taking the time to write this all out - very generous of you, very much appreciated by me.