As of version 14.03.26, audio cross-fades and video transitions have been added. Even though some other video editors also do it this way, it may be different for some. So, we made a tutorial to help get you started.
A very brief textual explanation is that you overlap adjacent clips on the same track either by drag-n-drop or by trimming. By default this creates a video dissolve with audio cross-fade. To change that, select the transition on the Timeline and view Properties to make a video wipe or to manually control the audio mix. Custom wipes can be provided by a grayscale image, and there are links to locations where you can get wipes that others have created in the FAQ.
This new feature does support GPU processing if your system supports that. However, while making this addition, GPU processing broke on Mac OS X in version 14.03.25, fixed in version 14.03.27.
There are still some sharp edges on this new feature that we will continue to improve. For example, currently Shotcut lets you (re)size the transition when there are not enough excess frames in the “handles” before the in point and after the out point of your shots. We need to add some limiters on the actions around that.
Fade in and out filters have been added as of version 14.03.01. There are 2 video filters - Fade From Black and Fade To Black - plus 2 new audio filters: Fade In and Fade Out. The video filters support GPU processing if you can use that.
As you can see in the screenshot, fade conrols are available on the shots directly on the timeline making it very easy and convenient to add the filters and adjust audio+video in a tandem/ganged fashion. Simply move the mouse pointer to the top-left corner or top-right corner of a particular shot to make a pulsating circle appear. Then, click and drag the circle control horizontally to drag-out a fade rectangle. But that does not mean you have to use the timeline to utilize these new filters. If you are simply working with a clip or playlist project, you can still apply and use these filters.
And before you ask, no, this update does not include or support cross-fading audio or cross-dissolving video. That is coming next.
Now, as of version 14.02.18, the clip rectangle aligns to the track, and there is snapping that can be toggled. Instead of an append-only operation, there are now overwrite (default) and insert (ripple) operations. Overwrite has been corrected to support overwriting multiple shots and gaps along with its corresponding undo action. Lastly, there is optional scrubbing in the program viewer while dragging.
As of v14.02.12, GPU processing works again in Windows! Of course, you need a video card and driver that supports at least OpenGL version 3.2. This has only been tested on systems with NVIDIA, but it should work with other providers.
Also, as v14.02.13, drag-n-drop of shots from either the Playlist or the Source player into the timeline is working now on Windows and OS X. (Previously, it only worked on Linux.) This is very basic at the moment by only letting you append a shot to a track, but it was necessary to get it working across platforms before enhancing it.
Thanks to contributing developers, Stabilize and Normalize filters are improved as of version 14.02.11. Normalize is now based on EBU R128 technology provided through libebur. This gives better results because R128 is based on perceived loudness instead of RMS or peak volume. Stabilize is using the latest and greatest version of vid.stab making it faster and yielding better quality results.