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Video technology has exploded in the past several years: Video capability is now a standard feature on most high-end mobile phones, and a menagerie of other inexpensive video devices now inhabit the high-tech landscape. But eye-witness footage alone does not make for a compelling film. The new legions of camera users need editing tools to cut out the rough parts and assemble the snippets into polished products. No fewer than nine free video editing programs vie for the favor of Linux-conscious filmmakers. All these tools are capable of editing videos, arranging them into a new work of art, and furnishing them with effects.

The proprietary but free Lightworks joined the lineup at the start of 2014. In this article, I explore the crowded field of Linux video editing alternatives, including Cinelerra, Flowblade, Kdenlive, Kino, Lightworks, LiVES, OpenShot, Pitivi, and Shotcut. Most of these tools are guided by the methods of professional video editing programs like Adobe Premiere Pro: You drag and drop movie snippets on a timeline to create your video, and when you're finished editing, you export the video into a new file.

Cinelerra

Adam Williams attaches great importance to a stable program. He therefore updates his video editing program Cinelerra [1] only once a year, and each version has only a few new features. Williams's website provides an archive with a binary version for the 64-bit version of Ubuntu 14.04, whereas users of other distributions have to compile the source text themselves.

Cinelerra opens several windows on startup (Figure 1): One presents a preview of the finished film, a second provides the timeline, and a third provides rudimentary media management and allows access to all effects. Although Cinelerra might have opened an HD video in the distributed AVCHD format during our test, it only displayed a purple screen. A Ogg video, on the other hand, did not cause any problems.

Figure 1: Cinelerra takes up a lot of space on the desktop with its numerous windows.

Cinelerra can import videos not only from the hard drive but also from an analog TV card, a webcam, a DVB card, or a Video4Linux device. The editing program even films the screen and creates a screencast very quickly. Cinelerra beams imported clips directly into the timeline. You can edit the film snippets precisely in the viewer window. Alternatively, you can conveniently telescope the clip on the timeline at its ends using the mouse.

Apart from that, editing clips in the timeline is a cumbersome process: First, you have to switch to the appropriate select and edit mode, then select the area to be removed with the mouse, and finally edit out this piece by clicking on the appropriate button. Cinelerra always applies actions to all currently active tracks. If you do not take care, you can easily edit two video clips at the same time by accident.

In the current version 4.6, Cinelerra can split the timeline into two independent areas, which proves to be especially useful in complex projects. The illustration in the timeline can only be made slightly smaller, which results in constant scrolling even with small projects. Nevertheless, you can mark selections that start up much like a bookmark.

To apply an effect, first mark the section in which you want it to take effect. Then, drag the desired effect from the Resources window onto the corresponding video track. Each effect appears below the clip as a bar. You can switch the effect on and off via small symbols and open its settings.

These settings appear in a separate window and consist entirely of slide controls. As soon as you drag them, you can see the effects directly in the preview. Cinelerra supports keyframes allowing effects to transition. The compositing window helps with picture-in-picture effects: Not only does it display videos from the timeline, it can also change their size using its tools and move them to the virtual screen.

Cinelerra does not provide any templates for exporting the final video; instead, you need to adjust the output format correctly yourself, along with the compression process. This includes parameters such as the bit rate, the color model, or iframe padding with MPEG compression. On a brighter note, Cinelerra can distribute the finished, edited films to several computers on a network for processing.

Flowblade

The video editing program Flowblade [2] is written in Python and is based on the free Media Lovin' Toolkit (MLT) multimedia framework. It comes up with an equally stylish and tidy user interface on startup (Figure  2). The preview is in the top right area, and the timeline is at the bottom.

Figure 2: Crossfades are clearly visible in Flowblade.

Unlike its competitors, Flowblade can create and manage multiple independent timelines or sequences. Unlike its competitor Lightworks, you cannot nest sequences. Additionally, a sequence always only offers precisely nine tracks. When creating a new sequence, you also need to decide how many of these tracks will house movies and how much audio material to record. The Flowblade developers set arbitrary limits for both.

The main window shows an area with several tabs at top left. The first offers a small Media management function that lets you import clips and then drag and drop them into the timeline. By default, Flowblade stores the clips with no gaps. If that is not what you want, you need to reposition the clip with the appropriate tool. Flowblade offers several different cutting tools, one of which can even move (roll) a cut-over point. However, because of this diversity, you should always check to see which tool is currently enabled.

You can cut clips directly in the timeline using the appropriate tool. Alternatively, you can move the film snippet into the preview window by double-clicking and edit it there using the appropriate buttons. Professionals can also display a vector scope and an RGB parade via the preview image. These two special modes give you an insight into the video's color composition and color balance.

Flowblade has Compositors and Filters in other tabs. The filter effects always affect an entire clip. Compositors, on the other hand, mix two video tracks and create crossfades or picture-in-picture effects. Unlike filters, a compositor's settings can be controlled using keyframes. You can determine these key points on a separate timeline in the compositor's settings. Conveniently, Flowblade synchronizes the time bar in this timeline with its counterpart in the timeline window; thus, the keyframes can be set with frame accuracy.

You can create titles in a small wizard. The wizard shows the movie from the timeline in the background, so you can place the titles exactly. The wizard even allows several text levels which, however, cannot be faded in and out individually. You can control the sound using a virtual audio mixer. If desired, Flowblade adds a watermark to the movie; you would need to call an effect to do this in any of the competitors.

Switch to the Render tab to export the edited film. You can choose a suitable format from the numerous templates. If you know a bit about the process of compression, you also have the option to pass in a few parameters to FFmpeg, which handles the actual coding.

Kdenlive

Toward the end of last year, the project manager and the lead programmer suddenly disappeared from Kdenlive [3]. As a result, further development froze for several months. However, the project picked up pace again in March thanks to several committed helpers. The bugfix version 0.9.8, which the developers used to provide binary packages for several major distributions, appeared in May. Compiling the video editing program from sources is extremely complex because of the numerous dependencies. Just like Flowblade, Kdenlive is essentially based on MLT.

The Kdenlive user interface frightens off some newcomers with a mass of tabs and small icons (Figure 3). The main menu appears overloaded because of its many features. Imported media end up at the top left in a small media management area. The currently selected effect's settings appear just to the right. The area to the far right provides a preview of the finished video.

Figure 3: Each area of Kdenlive's main window can be scaled, undocked, and repositioned individually.

You can click to open clips in the preview and then cut them there. However, this process is a little intricate because of the small buttons. That said, you can control Kdenlive almost completely using keyboard shortcuts. A timeline with several video and audio tracks is at the bottom of the window; Kdenlive provides several different editing and insertion modes. However, when editing with the mouse, make sure you aim precisely – or for more precision, use keyboard shortcuts.

You can use any number of effects on one clip and there is also an extensive selection of color corrections. The appropriate settings are simplified by special views such as a histogram or RGB Parade. The effects can be reviewed precisely using keyframes; you can only create crossfades in Kdenlive using the mouse. To change the length of the crossfade, you need to squeeze the much-too-small bars inserted by Kdenlive using the mouse. Because the height of the video and audio tracks cannot be increased, this process can be a trying experience on large displays.

If necessary, you can tap into the Openclipart library, the Archive.org video library, and the FreeSound audio library directly from Kdenlive. You can add titles or a slide show to the project using other wizards. If desired, Kdenlive will help you record a stop-motion cartoon. You only need to pick a suitable template ("profile") when either creating a new project or exporting it later. Experts can also adjust the video format and the compression themselves. On request, the wizard will also output the film directly as a DVD.