Time Stretch - What the Hell!? -Sound Forge - PC - MAGIX Community Forums Archive

Subject:Time Stretch - What the Hell!? Posted by: Recone Date:12/29/2002 11:30:58 PM After using Sound Forge 6 here at work for a couple of months, something very strange started happening. Say I grab a loop that needs to be a little longer, I fire up the time stretch, make the adjustments, preview it, sounds good right - then, I hit okay. Then, I notice that there has been some silence added to the end of the loop... It doesnt matter what the sound is or where it comes from, it happens to everything. I uninstalled and reinstalled the software and it still happens. The system is a P4 with 512 RAM running XP. Please help, its holding up my work.
Subject:RE: Time Stretch - What the Hell!? Reply by: Sonic Date:1/3/2003 11:36:11 AM a) make sure you have the latest update installed. b) check your insert/mix/ignore tail settings (right click in the effect frame and select "Configuration") J.
Subject:RE: Time Stretch - What the Hell!? Reply by: Recone Date:1/5/2003 11:45:28 PM what should I look for in there? All I see are some settings for the preview. I played around and it didnt make any difference. I have been using another computer in another studio (down the hall) for now but it would be really nice to figure this out.
Subject:RE: Time Stretch - What the Hell!? Reply by: jeh Date:5/27/2003 8:41:51 PM I am having the same problem. I got a little farther with a solution, but SF 6 is still "broken" in this area. Yes, I have the latest update (SF 6.0e, build 237). In SF 4.5, I simply select an area, pick Process \| Time Compress/Expand, select a mode (usually A03, "music 3 (less echo)") and final length, check "blend edges...", and click "OK". Done. No worries about "insert/mix/ignore tail" settings, and no extra silence appears in the output file. More to the point: It "just worked", exactly as I expected it would. In SF 6, I don't get that result at all. If I select the region between two markers and use Process \| Time Stretch to expand that time by 10%, the time between the two markers does NOT increase by 10%. Instead the selection between the two markers is slowed by 10% and the resulting excess is mixed with the material following the selection. This result does not match any reasonable expectation for the result of a function labelled "time stretch". Furthermore the "blend edges..." option is gone. In searching for a solution I found this thread. I read your reply, J., but I don't really know what an "effect frame" is; and searching for that term in the help or the doc .pdf returned zero useful results. After much searching of the doc and help for words like "insert" and "tail" I finally figured out that I could not do what I wanted by simply using Process \|Time; I would have to deal with something called the "Audio Plug-In Chainer". Well, I'm a bright boy, I can usually figure these things out. As it turns out though this doesn't solve the problem... Ok, I open the plug-in chainer and load the "time stretch" plug-in. It seems silly to have to use this "chainer" for just one plug-in, but it does give me the "insert tail" option that I need, although right-clicking in the Chainer window isn't how I get to it - I click the appropriate cryptic icon instead. (Thank you for using ToolTips. "Insert tail data".) I select my mode, my final percentage, and click the "process selection" icon. Well, it looks ok at first. But close inspection of the selected region shows that a silent gap has appeared in the file at the end of the selected region. I just tried this on a selection 0.535 seconds long, 10% expansion. There is now a silent gap of about 9 milliseconds between the last sample of the "expanded" area and the end of the selection. This is Bad, Very Bad. The same thing happens if I use the "Time Compress/Expand" plug-in (which seems to be an older one, maybe the one from SF 4.5, or perhaps SF 5, though it still refuses to show me a "blend edges" checkbox) instead. The same thing also happens if I copy and paste the selection into a new file and just use Process \| Time Stretch. As reported by Recone, a gap appears at the end of the file. Incidently, the gap is included in the final time. What I mean is: I have a file that reads 0.536 sec long, has no silence beginning or end, and I choose to expand by 10%. The dialog says my final time will be 0.589 sec. (My HP-15C says 0.5896, or 0.590 if rounded to three places, but whatever.) Click "ok". The resulting file now is indeed 0.589 sec long according to SF 6, but from 0.579 to the end is silent. It's as though the algorithm didn't quite expand it "enough" and just added silence to fill out the file to the desired final time. Is there something I'm missing in the setup???

I am having the same problem. I got a little farther with a solution, but SF 6 is still "broken" in this area. Yes, I have the latest update (SF 6.0e, build 237).

In SF 4.5, I simply select an area, pick Process | Time Compress/Expand, select a mode (usually A03, "music 3 (less echo)") and final length, check "blend edges...", and click "OK". Done. No worries about "insert/mix/ignore tail" settings, and no extra silence appears in the output file.

More to the point: It "just worked", exactly as I expected it would.

In SF 6, I don't get that result at all.

If I select the region between two markers and use Process | Time Stretch to expand that time by 10%, the time between the two markers does NOT increase by 10%.

Instead the selection between the two markers is slowed by 10% and the resulting excess is mixed with the material following the selection.

This result does not match any reasonable expectation for the result of a function labelled "time stretch".

Furthermore the "blend edges..." option is gone.

In searching for a solution I found this thread. I read your reply, J., but I don't really know what an "effect frame" is; and searching for that term in the help or the doc .pdf returned zero useful results.

After much searching of the doc and help for words like "insert" and "tail" I finally figured out that I could not do what I wanted by simply using Process |Time; I would have to deal with something called the "Audio Plug-In Chainer". Well, I'm a bright boy, I can usually figure these things out. As it turns out though this doesn't solve the problem...

Ok, I open the plug-in chainer and load the "time stretch" plug-in. It seems silly to have to use this "chainer" for just one plug-in, but it does give me the "insert tail" option that I need, although right-clicking in the Chainer window isn't how I get to it - I click the appropriate cryptic icon instead. (Thank you for using ToolTips. "Insert tail data".) I select my mode, my final percentage, and click the "process selection" icon.

Well, it looks ok at first. But close inspection of the selected region shows that a silent gap has appeared in the file at the end of the selected region.

I just tried this on a selection 0.535 seconds long, 10% expansion. There is now a silent gap of about 9 milliseconds between the last sample of the "expanded" area and the end of the selection.

This is Bad, Very Bad.

The same thing happens if I use the "Time Compress/Expand" plug-in (which seems to be an older one, maybe the one from SF 4.5, or perhaps SF 5, though it still refuses to show me a "blend edges" checkbox) instead.

The same thing also happens if I copy and paste the selection into a new file and just use Process | Time Stretch. As reported by Recone, a gap appears at the end of the file.

Incidently, the gap is included in the final time. What I mean is: I have a file that reads 0.536 sec long, has no silence beginning or end, and I choose to expand by 10%. The dialog says my final time will be 0.589 sec. (My HP-15C says 0.5896, or 0.590 if rounded to three places, but whatever.) Click "ok". The resulting file now is indeed 0.589 sec long according to SF 6, but from 0.579 to the end is silent. It's as though the algorithm didn't quite expand it "enough" and just added silence to fill out the file to the desired final time.

Is there something I'm missing in the setup???