Scrolling Waveforms blog post #314
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wip wip
m0dB
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Hi Maarten, have you considered to add some author metadata to the config file? This will make it possible to add a tagline and associate your name with your GitHub user. It works like this: https://github.com/mixxxdj/website/blob/website/pelicanconf.py#L190-L195 |
m0dB
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Co-authored-by: ronso0 <[email protected]>
Co-authored-by: ronso0 <[email protected]>
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| The Mixxx scrolling waveforms are drawn with a number of overlapping layers: The beat grid, the looping-, intro- and outro-ranges, the markers, the end-of-track indication, and the actual waveform. Originally these layers were rendered with a combination of Qt (QPainter) and Legacy OpenGL calls, on the now deprecated QGLWidget. Profiling showed that this combination was a performance bottleneck, particularly on macOS. With the rewrite, all these layers are now using Modern OpenGL, with hardware accelerated GLSL shaders. The different waveform types (Simple, Filtered, HSV, RGB and RGB L/R) all come with a GLSL implementation. In addition to the waveforms, the spinny widgets and VU-meters have been rewritten with the same approach. | ||
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| Visually the new waveforms follow the design of the legacy waveforms, with some minor tweaks, note for example the semi-transparently filled triangles pre- and post track. What has been improved is the layout of the markers layers: Overlapping markers (multiple markers at the same beat grid location) which would previously obfuscate each other, are now automatically placed at an increasing / decreasing vertical position. |
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The writting is really good, but I would recommend to insert two detail screenshots showing:
- the pre-track triangles
- the stacked markers
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The beatgrid in the triangle screenshot has an offset. Could you adjust this?
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I replaced it with a different screenshot. Is this better?
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right now this is quite a lot of text. I think a little sign-posting in the form of subheadings would not also make the text look nicer but also easier to read/navigate. |
Co-authored-by: ronso0 <[email protected]>
Co-authored-by: ronso0 <[email protected]>
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I have made the changes suggested here, as well as some restructuring suggested by @ywwg , starting with less technical talk for normal users and moving the technical details to the end. |
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great! i'd appreciate a last review from a native speaker (@ywwg maybe?). |
JoergAtGithub
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@m0dB There` is a review of a native speaker on Zulip https://mixxx.zulipchat.com/#narrow/stream/248802-website/topic/Native.20Englisch.20speaker.20needed.2C.20to.20check.20blog.20post |
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I think this is ready for publication. What do you think is the best time to do that? Immediately / shortly after the 2.4 release announcement? |
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I don't suppose we can do scheduled posts? :). Let's not forget about this |
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I think if this ready now, why not publish now as a teaser for the upcoming 2.4 release? |
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Yes, this is ready. I think posting now as a "teaser" is fine, as long as 2.4 is truly about to be released 😅 |
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yeah, I'll leave that decision up to people more involved in the release process right now. @daschuer @ywwg @JoergAtGithub |
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What do you think would be a good moment to publish this? |
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If nobody objects, I will merge this tonight! |
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Though that's a rather short time to raise an objection. Don't wanna complciat things but if you mean it there should be a fair chance to catch this note in time. |
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LGTM already.
If you wish the PLL section can be have some more details. See discussion in https://mixxx.zulipchat.com/#narrow/stream/247620-development-help/topic/vSync
- PLL: no improvement for Linux/Windows
- Not related to audio performance
- Free = for debug only.
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| ## New display synchronization mode | ||
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| Finally, a last minute addition is an alternative mode to synchronise the scrolling waveform animation with the display refresh rate, using a so-called phase-locked-loop (PLL). This mechanism attempts to track the actual refresh rate and timing of the display automatically. On particular hardware, the default periodic timer-based approach can result in jitter and frame drops, and the PLL may give better results. The PLL has been made the default on macOS. See [instructions to change the V-Sync mode](https://github.com/mixxxdj/mixxx/wiki/Changing-the-VSync-Mode-for-Scrolling-Waveforms) if you want to try which mode works best for you. |
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| Finally, a last minute addition is an alternative mode to synchronise the scrolling waveform animation with the display refresh rate, using a so-called phase-locked-loop (PLL). This mechanism attempts to track the actual refresh rate and timing of the display automatically. On particular hardware, the default periodic timer-based approach can result in jitter and frame drops, and the PLL may give better results. The PLL has been made the default on macOS. See [instructions to change the V-Sync mode](https://github.com/mixxxdj/mixxx/wiki/Changing-the-VSync-Mode-for-Scrolling-Waveforms) if you want to try which mode works best for you. | |
| To avoid micro jitter, it is required to display the rendered picture in the right moment. This is achieved by synchronising the scrolling waveform animation with the display refresh rate. As a last minute addition an alternative mode to using a so-called phase-locked-loop (PLL) has been introduced. This mechanism attempts to track the actual refresh rate and timing of the display automatically. On particular hardware, the default periodic timer-based approach can result in jitter and frame drops, and the PLL may give better results. The PLL has been made the default on macOS other targets did not show an improvement. See [instructions to change the V-Sync mode](https://github.com/mixxxdj/mixxx/wiki/Changing-the-VSync-Mode-for-Scrolling-Waveforms) if you want to try which mode works best for you. This setting does not effect the audio control performance. |
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OT: PLL shows also improvements on Windows, but does not work on every system - might be graphic driver related. |
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the only note I have is that the first heading is "REWRITE" and looks a bit weird on the news page:
maybe call that section "Starting From Scratch" ? |
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or otherwise move the 'more...' break |
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I'll merge this tomorrow so as not to double-up with the flatpak blog post |
Is that possible? |
I don't think so, not without hacking the news template or bending over otherwise. I think the general issue is (for me) that first-level headings are too dominant, their font size is about twice as that of the paragraphs. No idea how to work around that. |
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I'll make the first paragraph a bit longer! |
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Let's merge this now! Thank you Marten! |
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| ## Some technical insights | ||
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| Mixxx uses the Qt software framework for its user interface. Originally the layers that form the scrolling waveform display were rendered on the now deprecated QGLWidget through a combination of 'QPainter' and Legacy OpenGL function calls. Profiling showed that this combination was a performance bottleneck, particularly on macOS. |
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| Mixxx uses the Qt software framework for its user interface. Originally the layers that form the scrolling waveform display were rendered on the now deprecated QGLWidget through a combination of 'QPainter' and Legacy OpenGL function calls. Profiling showed that this combination was a performance bottleneck, particularly on macOS. | |
| Mixxx uses the Qt software framework for its user interface. Originally the layers that form the scrolling waveform display were rendered on the now deprecated `QGLWidget` through a combination of `QPainter` and legacy OpenGL function calls. Profiling showed that this combination was a performance bottleneck, particularly on macOS. |
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| With the rewrite, all the layers mentioned above are now implemented using Modern OpenGL code: All different waveform types, i.e, Simple, Filtered, HSV, RGB and RGB L/R, are now hardware accelarated using GLSL shaders. In addition to the waveforms, the spinny widgets and VU-meters code has been revised with the same approach. | ||
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| The deprecated QGLWidget has been replaced by a custom solution using a QOpenGLWindow inside a QWidget using the createWindowContainer() call. Qt also offers QOpenGLWidget to replace QGLWidget, but the QOpenGLWindow solution resulted in better performance and integrated better with the existing source code. This change will also facilitate the migration to Qt 6, planned for Mixxx 2.5. |
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| The deprecated QGLWidget has been replaced by a custom solution using a QOpenGLWindow inside a QWidget using the createWindowContainer() call. Qt also offers QOpenGLWidget to replace QGLWidget, but the QOpenGLWindow solution resulted in better performance and integrated better with the existing source code. This change will also facilitate the migration to Qt 6, planned for Mixxx 2.5. | |
| The deprecated `QGLWidget` has been replaced by a custom solution using a `QOpenGLWindow` inside a `QWidget` using the `createWindowContainer()` call. Qt also offers `QOpenGLWidget` to replace `QGLWidget`, but the `QOpenGLWindow` solution resulted in better performance and integrated better with the existing source code. This change will also facilitate the migration to Qt 6, planned for Mixxx 2.5. |
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| One of the major improvements of Mixxx 2.4 is a revision of the scrolling waveform implementation, to achieve smoother animation at a higher frame rate (60 fps), with less frame-drops and lower CPU load. | ||
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| ## Rewrite |
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Not sure, do we really need this headline? It looks bad in the news section of the homepage.
I think we can either drop this headline, make the paragraph before the headline longer so that it gets pushed out of the excerpt or specify an excerpt explicitly in the metadata.
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Oops, forgot to submit my review. Sorry. |
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The blogpost doen't appear on our website. Has anybody an idea why? |
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yes, its still a draft, I assume because its not automatically been removed because the title wasn't prefixed with XXXX-XX-XX. |
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fixed by manual commit |
https://deploy-preview-314--mixxx-website.netlify.app/news/2023-08-15-improved-waveforms/