Preview window visibility option for blank sections

Using version 19.10.20
MacOS Catalina

Part of the current work flow employs an automated process which creates an mlt file with blanks (candidates cuts) within the playlist that are not always perfect, so manual editing is required to move the blank start/stop edge to determine if the blank created is accurate, then undo or readjust the blank edge. To solve this, toggle the video preview window on videos with playlists containing blank lengths where the video preview will still display the video information when the play head is positioned within a blank space. Which brings the question of how does one observe, especially at low timeline zoom, if the playhead is resting on video or blank space if they both present the same way in the preview. This could be solved with shortcut keys; snap playhead to blank space start, and snap playhead to blank space end. Further, snap to blank edge would also allow for faster movement through the timeline. Even without the transparent/opaque blank space preview option, the snap to blank edge would mitigate excessive scrolling and/or timeline zoom/unzoom to find the next blank transition.

If I’m understanding your request correctly, I think this can already be done on Windows with the Alt+Left Arrow and Alt+Right Arrow shortcut keys. Presumably, there are equivalent shortcut keys for macOS. These shortcuts are called “Seek Next Edit” and “Seek Previous Edit” on the Shotcut Keyboard Shortcuts reference page:

Austin, yes that was what I was getting at and your contribution solves that portion of the suggestion. In testing a 3.5 hour transport stream file with 43 blanks, it performs equally at full time line zoom as it does at minimal zoom. Further, instead of one key directionally seeking the end of blanks and the other key seeking the beginning of blanks as I had indicated, it seeks directionally to every transition regardless of type, which is equally as useable. On the macOS keyboard, the shortcut is also Alt+Arrow but Apple keyboard users may think of it as option+Arrow. Thank you for your comment.

What you write here is meaningless to me. I have no idea why are you using playlist with blanks instead of timeline with clips. It sounds like whatever you are trying to achieve is not what Shotcut was designed for, and you are asking for a feature for your custom usage, which will not be accepted.

I had a hunch I may be asking for something outside the design scope as well as use paradigm. I don’t know much about video editors, but I like your org’s work. The design approach to my mlt creator was to emulate an mlt file created via shotcut manually which presents similar to of that of the previous editor I was using - kind of reverse-engineering. I see now it would have been wiser to first ask a question along the lines of what are best practices when creating a timeline with clips of one video showing sequentially wanted spans as well as flagging potentially undesired time spans. Thanks for taking the time to consider the suggestion and provide comments. If anyone can provide examples of a better mlt file model, such as one reflecting your suggestion of a timeline with clips, that would kindly and humbly appreciated.


Another idea which may help you with low timeline zooms.
Open a video waveform view.
When the playhead is over any video, there will be some waveform displayed and nothing when it’s over a blank cut.

You can learn and observe how to create a timeline MLT. For the quoted need above, given what Shotcut does today, I would use the <property name="shotcut:caption"> XML element aka. clip name, which is editable now as of v20.02 to perhaps say something in ALL CAPS so it is easy to spot in the Playlist or on the Timeline. For what you ask - to show video in a blank space - is impossible: there is no video to show. In case you are trying to do something like automatic advertisement removal, I would go ahead and remove the ad and not try to represent it flagged in the playlist or timeline. One can easily assume that any break is where there was an ad, visit that area, and easily adjust by trimming.

Dan, agreed all around. The original mlt-xml playlist property list structure alternated between producer and blank length properties where the blank length entries represented ‘cut’ candidates on the Shotcut timeline. The proposed solution is to alter the mlt file structure by adding new producers with shotcut:caption properties to indicate a cut as per your suggestion, then replacing the playlist id: blank length property entries with the new producer entries representing cut candidates. This leaves the playlist property list consisting of producers only, which are presented on the timeline as a sequential series of clips. The shotcut:caption worked fairly well, but wasn’t always visible; it seems to depend upon the zoom level and cut clip length.

To clarify, when I first mentioned playlist, I was referring to the xml property, not the Shotcut gui playlist window, which may have caused some confusion - Currently using timeline and preview only.

As an adjunct to shotcut:caption, a Text:Simple filter (shotcut:filter>dynamicText<) was added to the new ‘cut’ producer instances, making it very obvious in the preview window when a cut candidate clip is under the playhead.

The MLT configuration solves both the ‘blank visibility’ concern (misinformed design) and provides clear indication as to what clip is a cut candidate and what is not, especially under the playhead.

As far a workflow: Shotcut opens the draft MLT xml file (created from a MLT creator script referencing a cut list/EDL) for review. Once the clips have been vetted/adjusted, the cut candidate clips are deleted from the timeline, project saved, leaving the MLT project file playlist property containing only the desired producers/clips, ready for upstream processing.

Further, the Seek Edit keyboard shortcuts are valuable to this use case; using 360p preview scaling and cmd-mouse-scroll to zoom the timeline further enhance the workflow efficiency.

27-inch Apple Thunderbolt, (half the screen for Shotcut) driven by a 2012 MacBook Pro & seeing few performance issues when working with 8GB transport stream files.

Thank you again for your expertise and insights.

Thanks, Paul2. I abandon using blanks for this particular use case, but appreciate the comments just the same.