VPX Mercalli V4 plugin - how to stabilize GoPro video - chest harness

browj2 wrote on 8/7/2018, 10:38 AM

I have been trying to stabilize some video clips filmed with a GoPro Hero 5 Black, mounted on a chest harness. Other than left-right movements, there is some roll and some up and down as I'm walking. I see a very nice job done on this on the proDAD site for "Runner's cam chest-mounted shakes removed" - link to YT video:

My clips are walking, so I don't have near the same problem, but it is similar.

I watched various tutorials on Mercalli V4 on the proDADUSA YT site:

https://www.youtube.com/user/proDADUSA/videos

including one for using the plugin with Vegas - similar to that for VPX, but did not find a tutorial for video taken using a chest mount, like the one above or less drastic.

I tried many combinations, including first using the CMOS Fixr, as per one of the tutorials, followed by Merc V4. I managed to get one result that was not too bad (I should have kept the settings), and many that were improvements on the original, but not even as good as my best shot at it. In Edit mode, I used the sliders, with the Chart on - extra large - for Pan, then Roll. Played with the Borders depending on where the problems showed up, etc.

Has anyone successfully stabilized something like this? How? Parameters?

Here is a link on DropBox to an mxv file of the original clip. I used this in my tests.

https://www.dropbox.com/s/n66xnzfsz3m5gzd/GoPr0650.mxv?dl=0

In the image below, I have Mercalli open, Chart open on roll, and you can see the vertical red lines in the chart of the preview window. To remove these problem areas, the Border slider has to be increased. This is just for illustration in case you've never seen these tools.

Below is my best shot at stabilizing. Watch the electric pole. It's quite stable - at least it does not lean to the left and right, but I still have some up and down if you watch the sidewalk.

Once I get good parameters, I should be able to use them for many walking video clips.

Thanks,

John CB

Comments

johnebaker wrote on 8/7/2018, 12:49 PM

Hi John

Try these settings:

Camera:

Sports cam
Keep camera dynamic - off
Avoid border - on set to 70%

Movement tab

Pan shot smoothing 22%
Roll compensate - on set to 76%

Border tab

Best border
Scale 71%
Dynamic scale 85%

Perspective tab

Zoom compensate - on set to 20%

HTH

John EB

browj2 wrote on 8/7/2018, 3:21 PM

@johnebaker

Hi John,

Thanks for trying this out and the details. I get a very slight improvement using your values over what I had, but still have some bouncing up and down from walking.

I tried a few more test, adjusting up both Pan and Roll and then Avoid Border to get rid of the red lines. Still get some bobbling, but less.

The tutorial that I watched suggested (from memory):

Universal camera
Use CMOS first then uncheck Rolling shutter
Keep Camera Dynamic - on
Used Camera Optics - select the camera setting from the list - I took GoPro Hero 4 medium, as no Hero 5 with Linear
Perspective - Zoom off

so this is somewhat different. Adjusting the Pan and Roll do not show the same things in the graphs as per the tutorial.

Questions:

Why Sports Cam? The manual says, "The Stabi-Cam Sports Cam is used if you are recording images with many movements (e.g. an action-riddled camera drive). Here, only the extreme disquiet in the video will be stabilized." I want more than extreme disquiet to be corrected. However, I presume that shutting off "Keep camera dynamic" overrides this and gives more stabilization?
Avoid Border - how did you determine 70? The manual says, "If you remove nearly all undesired movements that are signaled by a Pan diagram, move the slider only as far as you need to go in the field Avoid Border in order to maintain the original resolution in the stabilized result as much as possible." When I look at the charts, I can reduce the avoid border down to about 26%, with Pan at 22% and Roll at 76%.
Under Border tab, Best Border, moving the Scale to 71 also moves the slider under Avoid Border to 71. Did you mean 70?
Just to make sure that I understand the coordinate system, X is the horizonal axis, so tilting the camera up and down would be about the X-axis, Y is vertical, so panning left and right would be about the Y-axis, Z-axis is out of the plane towards you, so tilting the camera left and right would be about the Z-axis. Correct? If so, then Pan is Y-axis and Roll is Z-axis. What compensates for tilting up and down (X-axis) which seems to be the only problem that I have left?
Just to confirm, are you using Version 4.0.467.1?

I have been through most of the Mercalli manual several times. I am lost in much of the Workshops - Stabilization part. More explanation would have helped.

In the charts for Forensic view, there is no grid or border shown, as indicated in the manual and as in the tutorial for Vegas. A bug, I presume?

Thanks,

John CB

johnebaker wrote on 8/7/2018, 5:12 PM

Hi John

. . . . do not show the same things in the graphs as per the tutorial . . . .

Same here - I find the graphs to be poor.

. . . . Why Sports Cam? . . . .

Experience from stabilisation my skiing videos both from my old Contour HD and my Sony sportscams.

. . . . Avoid Border - how did you determine 70? . . . .

By shifting the slider while watching the effect on the image until there was no more change visible.

. . . .Under Border tab, Best Border, moving the Scale to 71 also moves the slider under Avoid Border to 71. Did you mean 70? . . . .

Yes, misread the number from my notes (rather scribbled).

. . . . Just to make sure that I understand the coordinate system . . . .

The perspective adjustments work as you describe.

. . . . What compensates for tilting up and down (X-axis) which seems to be the only problem that I have left? . . . .

The movements in your video appear to be vertical/horizontal, rather than tilting in the x and y axis, there is no option to adjust the strength of the Shift correction applied, however I suspect the Avoid border option may have some influence on this.

. . . . are you using Version 4.0.467.1? . . . .

V4.0 (467) - no .1 !

. . . . In the charts for Forensic view . . .

How are you getting into this view?

HTH

John EB

browj2 wrote on 8/7/2018, 7:23 PM

Hi John,

I just checked, mine is definitely 4.0.467.1 so I may have something slightly newer than you.

Forensic view

There are 2 places, but first, you may want to view this proDAD tutorial at about 3 minutes in:

As indicated in the tutorial, click on the Border tab, and change from Best border to Forensic View in the pop-down. The manual states, " In the Forensic View the display is zoomed out and has no limits. By zooming into a scene, the effected correction is easier to evaluate with Mercalli. The slider Scale will support you with Zoom IN/OUT."

The other place, and I haven't checked out what happens, is under Camera - select Forensic Camera. The manual states:

"The Stabi-Cam Forensic Camera stabilizes very strongly to show the differences. This is the general opportunity to get into the forensic view; here, the correction affected by Mercalli can be better evaluated by means of the Stabilizr."

Here is the image with Border, Forensic View turned on and Video Color Filling checked:

Here is the graph shown in the tutorial:

We dont get the graphical overlay.

John CB