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  #1  
Old 04-13-2008, 06:29 AM
rkuo rkuo is offline
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Default The webcam method of properly calibrating Rock Band

http://www.rkuo.com/blogs/rkuo_blog/...Rock-Band.aspx

One of the most important things you need to do when playing Rock Band is calibrate the game to your home theater system. Most flat screen TV's and some audio systems introduce latency between when a signal is received vs when it is displayed. If you don't account for this behavior by calibrating the game, your timing will be thrown off in subtle ways. If you are playing with an electronic drum kit, I have to assume you're taking everything seriously and want to play the game right.

The key to this calibration vs other methods (and hence why I call it "reliable") is that it involves the use of a webcam to properly set the first calibration step, which completely eliminates human error from the equation. No more guessing involved.

Adjust Audio/Video Sync

1. From the Rock Band main menu, pick Options/Calibrate System.

2. Select the "Manually Set" option.

3. You should be on the "Adjust Audio/Video Sync" screen. Take your best shot at lining up the target with the click per the instructions on the screen, but don't leave the screen once you finish.

4. Now, point your webcam at the screen and record the screen + the audio for a few seconds. I used the QuickCam application bundled with my Logitech QuickCam.

5. Open Windows Movie Maker (I'm using the Vista version).

6. Drag the recording into Windows Movie Maker.

7. Now drag the clip to the video timeline at the bottom

8. Expand the video track by clicking the plus box on the left of the track so you can "see" the associated audio track.

9. Zoom in as far as you can using the Page Down key so that you can see the blips of sound generated by the calibration process.

10. Use the frame step buttons ("J" and "L") to move the position indicator just after one of the calibration sound blips.

11. Next, use the frame step buttons ("J" and "L") to move the position indicator to the first frame where the target turns white that is closest to the calibration sound blip you are working with.

12. The goal is for you to adjust the A/V offset such that the first frame where the indicator fills with white is also the first frame displayed after the "blip" plays. Based on the differences you see between steps 10 and 11, adjust the A/V offset by moving the target and repeat steps 4-11 until you achieve synchronization, then press OK to go to the Lag Compensation screen.

Voila! You have correctly calibrated this step without any guessing involved.

Lag Compensation

Oddly, the description on this screen which says "Some TV's introduce a delay that makes playing difficult" appears to have nothing to do with this step whatsoever. What you're trying to do here, as far as I can tell, involves compensating for the lag between your controller and the console.

The step does involve some human error, but it's fairly easy to check the results of this step now since the previous calibration step we executed using the webcam is guaranteed to be accurate.

1. At the Lag Compensation screen, select the Calibrate option.

2. Follow the calibration screen instructions and strum or hit your drum pad to the clicks of the notes. Two things here are important. First of all, close your eyes and do not look at the screen while you perform this step. Harmonix should never have put the moving note and target into the calibration screen here as it misleads people into looking at the screen and not playing to the calibration blips. Second, be sure to use the same method of playing that you are using to calibrate. For example, don't calibrate this step by using the buttons on the drum controller if you're going to be playing by hitting the drum pads.

3. You will receive a result which should be positive...something like 30 ms, in my case, with my drum kit. If you have a negative number, you really screwed up as that would mean your inputs are arriving at the console before you enter them.

4. Feel free to repeat step 2 a few times to double check your results or to get a better average setting. You may want to manually set your offset after checking your calibration a few times.

5. Go ahead and select continue to save your calibration settings.

6. Now, we're going to test your settings. Go to practice mode and select a song like "I Think I'm Paranoid" or "Dead on Arrival". Choose to repeat the first couple of intro sections and play them at full speed.

7. The goal is to ensure the timing window for each hit is centered around the targets at the bottom of the screen. Let's use the drums as an example. Calibrating with the red drum, first try hitting the red notes exactly with the sound of the drum in the game and verify that the hit happens when the note is completely centered on the target. Next, try hitting the note earlier and earlier relative to when the note arrives at the target. The hits should start to "fail" when you strike barely before the note gem touches the target. Now, try to hit the note later and later. Again, the hits should start failing when you strike and the note gem has barely left the target. If the hit window is not centered as I've described, then go back and adjust the Lag Compensation settings manually to shift the hit window in the proper direction (leave the A/V offset as is).

That's basically it. Right now I consider this method to be foolproof. It may feel a little weird at first as I had trained myself to play the game and was unconsciously compensating for the game's improper calibration. But now I'm able to hit notes on target with the music and it "feels" right. Better yet, the hits line up with the chart on the screen.

Hope this helps everyone! Happy plastic rocking!
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  #2  
Old 04-13-2008, 09:17 AM
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mooremwm mooremwm is online now
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Cool thanks for the very informative post. I'm curious though, do webcams have a faster framerate than your average point-n-shoot digital camera's video function? I don't have a webcam but my point-n-shoot does 30 fps, which in theory should get us to within 33ms of actual sync (or is my theory wrong or decimal place in the wrong spot?).

Also, I wonder if it would be easier to take one video (or a few small video clips) at a bunch of different delays while making notes on which part is which delay setting, then analysing frame-by-frame which one is closest so you don't have to go back and repeat all those steps over.

Also, thanks for the tip about not looking at the sliding thing in the second part. I think I was doing it all wrong and trying to time it visually instead of timing it to the sound. They really should have made that more clear in the instructions!

P.S. Wouldn't it be nice to be able to save profiles of the different calibration settings for when switching between TVs or locations? I suppose we could just write down the settings for each theatre system, but it would be nice to not have to manually set this every time.
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Old 04-13-2008, 09:55 AM
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davidshek davidshek is online now
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Quote:
Originally Posted by mooremwm View Post
Also, I wonder if it would be easier to take one video (or a few small video clips) at a bunch of different delays while making notes on which part is which delay setting, then analysing frame-by-frame which one is closest so you don't have to go back and repeat all those steps over.
Well sure, that would definitely be easier. Try to set it by eye/ear first, and then take a video of that. Then also take videos of each setting +5, +10, +15, +20 from where your eye/ear put it, and the equivalent negative values too.

Unless your eyes and ears are WAY off, one of those 9 videos should be spot on
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Old 04-13-2008, 10:05 AM
ReverseEngineer ReverseEngineer is online now
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This is a pretty helpful thread, nice.
I've done the eye-closing thing from the start, once I realized that it was measuring controller-to-console lag. the A/V lag doesn't bother me too much if it's close, because I'm usually playing to the music anyway.
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Old 04-13-2008, 11:03 AM
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v1g1lance1 v1g1lance1 is offline
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Funny to see this post, I was just thinking about doing this with my video camera. It has a 120 FPS function that this would be perfect for!
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  #6  
Old 04-13-2008, 06:59 PM
rkuo rkuo is offline
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Quote:
Originally Posted by mooremwm View Post
Cool thanks for the very informative post. I'm curious though, do webcams have a faster framerate than your average point-n-shoot digital camera's video function? I don't have a webcam but my point-n-shoot does 30 fps, which in theory should get us to within 33ms of actual sync (or is my theory wrong or decimal place in the wrong spot?).

Also, I wonder if it would be easier to take one video (or a few small video clips) at a bunch of different delays while making notes on which part is which delay setting, then analysing frame-by-frame which one is closest so you don't have to go back and repeat all those steps over.

Also, thanks for the tip about not looking at the sliding thing in the second part. I think I was doing it all wrong and trying to time it visually instead of timing it to the sound. They really should have made that more clear in the instructions!

P.S. Wouldn't it be nice to be able to save profiles of the different calibration settings for when switching between TVs or locations? I suppose we could just write down the settings for each theatre system, but it would be nice to not have to manually set this every time.
Some webcams can record at 60fps and it will help a little bit more with the calibration. At 30 fps you can still figure out by looking at individual frames when the target gets "hit" by looking at the motion between each frame.

Really, you can use any camera to do this if you can get the video onto your computer, I just used a webcam because they're already attached to your computer.

Recording one long video with different A/V settings makes a lot of sense. You could calibrate in one pass by doing that, yes.
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Old 04-14-2008, 11:09 AM
kaiserkreb kaiserkreb is offline
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Quote:
3. You will receive a result which should be positive...something like 30 ms, in my case, with my drum kit. If you have a negative number, you really screwed up as that would mean your inputs are arriving at the console before you enter them.
Actually, all that it would mean if you received a negative number is that the hit detection window was adjusted the opposite direction to make up for the notes appearing sooner than later from whatever it is by default. At least that's how I understood it.
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Old 04-14-2008, 12:32 PM
1980s_Guy 1980s_Guy is offline
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I wouldn't call this foolproof exactly, because:
a) As mentioned, most webcams and video cameras record at 30fps, limiting your accuracy to 33ms
b) Even if you can record at a higher framerate, there's no guarantee that the audio and video recorded by your camera are in sync. If it's a webcam with the audio running through your soundcard, I wouldn't be surprised if there was 50-100ms of lag between the audio and video.
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Old 04-14-2008, 02:49 PM
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Your math is correct: you need a camera with at least 200fps to get 5ms resolution, and as a practical matter you need double that to definitively resolve which frame is closer where the sound comes in between two frames.

The 120fps mode gets you 8 1/3 ms resolution, so it would at least be useful for narrowing it down to one of two settings--you can play-test both of them to pick one.

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