request: zoomable waveform

[Nick]

It would be very useful if the range viewed by the waveform was user-configurable in easy discrete steps. So that you can zoom in and out. A good use case: if you have a very long track and want to see what happens in the next four bars, then the next 32, then the next 64, and then go back to watching only one or two bars at a time. I know this sort of overlaps with having an overview waveform available, but sometimes it's just too small to see the details of what is coming up.

[Sean M. Pappalardo (pegasus-renegadetech)]

Wouldn't changing the size of the overview waveform in the skin help? Like make it the full width of the main waveform, putting each under the respective deck.

Or have it be the full height of the display and put it next to each of the channel strips (if it can be oriented vertically, that is.)

[Nick (kousu)]

No I meant configurable -at runtime-, so that you can look ahead or
back as needed.

I saw someone using this in VirtualDJ to great effect.

[RJ Skerry-Ryan (rryan)]

http://www.youtube.com/watch?v=tIFh27mfcjg

You can see this feature at 0:19. Is this really that useful? Isn't it what the waveform overviews are for? It might be interesting to try a skin with much bigger overview waveforms...

[jus (jus)]

For reference, some work on this has already be done by shanxS. https://bugs.launchpad.net/mixxx/+bug/325377

[shanxS (shanx-shashank)]

Updated patch for zoomable waveform against trunk #2969.

Regards

[shanxS (shanx-shashank)]

Just for record:
- new CO added called "zoom_waveform"
- right click resets the zoom
- currents zoom changes only by mouse wheel movement captured in WGLWaveformViewer::eventFilter
- Default value is 0 and range is form [-0.8, 0.8]
- Neagtive values means zoom in and vice versa

[Owen Williams (ywwg)]

I implemented this too over the weekend -- My patch isn't any better, I'm really just providing it for reference. One thing I noticed was that as the waveform is zoomed out there are issues with beatmarkers not rendering throughout the waveform and preroll markers causing slow render time. You'll see some simple conditionals that turn off beatmarkers and preroll markers when the zoom level pulls out.

I also made the zoom range much wider. Specifically, I want to be able to zoom way in so I can align the beatgrid precisely. I had to increase the subpixels_per_second size to make this work. I'd suggest that in the official patch we increase that number slightly (maybe not as much as I did) and allow for large amounts of zoom.

[Sean M. Pappalardo (pegasus-renegadetech)]

Can we just make the pre-roll markers (and other non-music data) disregard the zoom level when rendering so they're always the same size?

[Owen Williams (ywwg)]

Yes, that's possible. I tried to do it but had trouble getting the graphics to draw in the right location (finding the right x value for head of track, etc) so I gave up. The code for drawing them is a little confusing.

[shanxS (shanx-shashank)]

I just observed one very obvious flaw in my implementation - that range of zooming is being checked in the function that sets it
i.e., WGLWaveformViewer::eventFilter() sets the zooming limits.
While the better approach will be to check the range centrally, somewhere in ratecontrol.cpp or enginemaster.

Also,
1. as Owen mentioned - increase zooming more and
2. as Sean pointed out, pre-roll markers (and other non-music data) should disregard the zoom level when rendering so they're always the same size.

I'll include all above changes in next patch.

Few more things I would like to discuss:
I noticed some talks regarding +/- buttons on waveform for zooming, is that on hit list too ?
If yes, I'll be needing some help with making pixmaps of '+' and '-' for different skins.

I would also suggest disabling zooming with pitch slider (as Jus mentioned in https://bugs.launchpad.net/mixxx/+bug/325377/comments/22).

[RJ Skerry-Ryan (rryan)]

FYI -- no need to update all the skins. All you need to do from the feature
perspective is make the functionality possible and give a proof of concept
(e.g. by re-using an existing +/- graphic from the pitch bend buttons) and
by providing a simple skin.xml example that puts the buttons in the skin.
Jus or another person on the art team (we can dream, right? ;) ) will
update the skins.

On Mon, Nov 28, 2011 at 5:20 PM, Owen Williams <email address hidden> wrote:

> Yes, that's possible. I tried to do it but had trouble getting the
> graphics to draw in the right location (finding the right x value for
> head of track, etc) so I gave up. The code for drawing them is a little
> confusing.
>
> --
> You received this bug notification because you are a member of Mixxx
> Development Team, which is subscribed to Mixxx.
> https://bugs.launchpad.net/bugs/367151
>
> Title:
> request: zoomable waveform
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mixxx/+bug/367151/+subscriptions
>

[shanxS (shanx-shashank)]

This patch is against r2970.
Apart from improving my implementation in WGLWaveformViewer::eventFilter(), changes are as follows

1. Increased zooming
2. Pre-roll doesn't zoom any more
3. Pitch slider doesn't affect zoom
4. new COs for adding '+' and '-' zooming buttons on skin
    - new COs are 'zoom_waveform_in' and 'zoom_waveform_out' for zoom in and zoom out resp.
    - I am also attaching a dummy skin.xml from Deree 1280x800 WXGA which uses these new COs to control zooming from
      Raise/Lower pitch buttons on Channel 1

[shanxS (shanx-shashank)]

Dummy skin.xml from Deree 1280x800 WXGA which uses Raise/Lower pitch buttons on Channel 1 for waveform zooming.
Edited lines are 2918 to 2957

[Sean M. Pappalardo (pegasus-renegadetech)]

ShanxS's latest patch tests good for me. Nice work!! And nice touch on the right-clicking returning to default zoom!

Just a few recommendations:
1) Switch the direction of the mouse wheel zoom to match Firefox's: wheel up/forward zooms in, wheel down/backward zooms out.
2) Only return to default zoom when the right mouse button is released and only if it had been pressed for less than 150ms or so. The reason is that we're going to add back the jog behavior (that was on the left mouse button in 1.9) to the right button in 1.10, and we don't want to reset the user's zoom level every time they want to jog.
3) Can you make the skin buttons zoom a much larger amount? The user should only have to click no more than 6 times to go from full zoom-out to full zoom-in. (They can use the wheel for finer control.)

[shanxS (shanx-shashank)]

Thanks for feedback Sean !
I am working on your recommendations and will soon upload a new patch with these changes.

regards

[RJ Skerry-Ryan (rryan)]

vRince has added zooming to his rewrite of the Mixxx waveforms -- thanks for working on this shanx and sorry your work was deprecated!

[Thomas Vincent (vrince)]

Buttons in skins are not available in the waveform-2.0 branch I'll try to use patches in this tread to introduce it.

[Thomas Vincent (vrince)]

"waveform_zoom" ControlPotmeter are declared by every WWaveformViewer present in a skin (one per group).
Those potmeters should be accessible like any other ControlObject.
User can sync them vis pref ui.

[jus (jus)]

Could you please give an working example for use in skin.xml?
I tried to use Channel 1 pitch slider in LateNight1280x800-WXGA from your branch for waveform zoom , around line 2375 but all i got was a segfault.

<SliderComposed>
 <Tooltip>...</Tooltip>
 <Style>...</Style>
 <Handle>knob_pitch1.png</Handle>
 <Slider>slider_pitch1.png</Slider>
 <Pos>3,7</Pos>
 <Horizontal>false</Horizontal>
 <Connection>
  <ConfigKey>[Channel1],waveform_zoom</ConfigKey>
  <EmitOnDownPress>false</EmitOnDownPress>
 </Connection>
</SliderComposed>

[Thomas Vincent (vrince)]

Ok that sucks ...
Could you attach the modified skin you made so that I can reproduce the crash ?

[jus (jus)]

Changed only line 2365 in LateNight1280x800-WXGA/skin.xml
from
ConfigKey>[Channel1],rate</ConfigKey>
to
ConfigKey>[Channel1],waveform_zoom</ConfigKey>

My specs:
MacOSX 10.6.8 waveform2.0 r2751
Display type: Simple ( cause filtered GL/GLSL do not work, will file separate bug )
FPS: 30

Crash occurs as soon as i try to move the waveform zoom slider.

[Thomas Vincent (vrince)]

Ok I tried, no crash for me but nothing append with the rate slider.
When I replace a knob for example <ConfigKey>[Channel1],pregain</ConfigKey> ~line 4227 it works.
Except that the for steps (min 1, max 4, big/small step 1) are not linearly triggered.

[jus (jus)]

After some more testing: waveform_zoom works for me only with knobs like in your example, but not with sliders and buttons.

* Imo a knob is the most impractical control for this purpose. More practical world be sliders or buttons. Also this would allow to map zoom-in /zoom-out easily to the keyboard for mouse free operation which is preferable while performing.
* We should extend our zoom range. It is fair to say that there are good use cases for zooming in more closely ( e.g. when preparing tracks, setting cuepoints) and zooming far out (e.g. when waveform widget is relatively small because of screen size)
Xwax allows to zoom x10 / ÷10 which is very handy sometimes and many competitors do it in a similar way (some use steps of two).
* Imo It is absolutely fine that waveform_zoom works not seamless but in steps.

The crash i mentioned in #21 was unrelated to waveform_zoom (see lp:979925).

[Thomas Vincent (vrince)]

Normally ControlPotmeter seems to automaticaly comes with controls to set up/down value step by step.
They are named "waveform_zoom_up" "waveform_zoom_down" ...
I tried to use them but it's does not work for the moment.

The skin parser creates the associate buttons (I used <ConfigKey>[Channel1],rate_perm_up</ConfigKey>) before the waveform viewers, and potmeter controls are created on WWaveformViewer constructor. I guess I have to find a better place to create the waveform_zoom controls.

I can easly extend zoom range, but at at some point zooming in will not add details about the audio visualization. At zoom 100% we already display all the information we have in the waveform data.

[Thomas Vincent (vrince)]

Commit fix in waveform-2.0 branch I tested it with zoom in/out button.
Entend zoom range 1:1 -> 1:6.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/5155