If you shoot a video and want to edit it in Linux, you might get confused by the sheer number of free editing programs. The web pages for these programs contain information about a multitude of features and functions. Some free programs even attract the attention of professional filmmakers.

This article compares the features and the performance of several open source video editing programs. For testing, we selected Cinelerra, Flowblade, Kdenlive, Kino, LiVES, and Shotcut, together with the proprietary but free Lightworks. Most of these programs follow the lead of Adobe Premiere Pro, a professional video editing program, in terms of how they work. Film snippets are assembled via drag and drop onto a time line and then exported as a new file.

Cinelerra

Developer Adam Williams places a lot of emphasis on the value of stable software. Therefore, he updates the video editing program Cinelerra [1] just once a year, making only a few changes each time. Williams offers an archive with a binary version for the 64-bit version of Cinelerra for Ubuntu 14.04 on his homepage. However, users of other distributions will need to compile the source code.

Once Cinelerra starts up, it opens several windows (Figure 1). The first of these windows displays a preview of the completed film. The second window contains the time line, and the third offers rudimentary media management and access to all effects. Cinelerra 4.6.1 proved extremely picky about the type of video file it handles. For example, the program refused to open HD videos in the widely used AVCHD format, nor would it open videos in Ogg format. And, just one of the many MPEG4 videos in the MOV container opened without any problem.

Figure 1: Cinelerra requires a considerable amount of space on the desktop because of its numerous windows.

Cinelerra can load videos from the hard drive and also import videos from an analog TV card, webcam, DVB card, and Video4Linux device. If desired, the software also records the output of a display screen and thus quickly creates a screencast. Cinelerra immediately transfers imported clips to the time line. By switching into the viewer window, you can edit the film snippets with absolute precision. Alternatively, you can use the mouse to move the ends of snippets together on the time line as desired.

Basically, however, editing clips in the time line is cumbersome. First, you have to switch into the appropriate select and edit mode, use the mouse to select the area you wish to cut, and then, finally, click on the correct button to remove the area. Cinelerra always applies operations to all currently active tracks. Therefore, you must be careful to avoid accidentally editing two video clips simultaneously.

In the current version 4.6.1, Cinelerra can divide the time line into two independent areas. This approach is helpful to those working on complex projects. The representation on the time line can only be marginally reduced. This limitation results in constant scrolling even with smaller projects; however, you can set markers that act much like bookmarks.

To apply an effect, you should first mark the area of the clip for including the effect. Then, drag the desired effect from the Resources window to the corresponding video track. Each effect will appear below the clip as a bar. By clicking on the small symbols found with the bar, you can quickly switch the effect on and off and also open its settings.

The settings for effects appear in a separate window and consist entirely of sliders. As soon as these sliders are positioned, you'll see an immediate impact on the preview. Cinelerra supports key frames that let you adjust the effects over time. The compositing window is the helper for picture-in-picture effects. This window displays the output of the time line and has tools to let you modify the size of the video output and drag it onto the virtual screen.

Cinelerra does not offer templates for exporting a completed video. Instead, you are responsible for selecting the correct output format and the appropriate compression method. Making the right selection involves accounting for bitrate, color model, and the I-frame interval for MPEG compression. However, Cinelerra does have the capability to distribute the processing of the finished film to multiple computers in the network.

Flowblade

Flowblade [2] is a video editing program written in Python that is based on the MLT multimedia framework (see the box entitled MLT). Version 1.4 was the most current version of Flowblade when this article went to press. At the time, the developers were only offering the program as a DEB package for Ubuntu versions 16.04, 15.10, and 14.10, as well as Debian 8. Users working with other distributions were responsible for resolving Flowblade's multiple dependencies on their own. In testing Flowblade, we were able to download and decompress the Flowblade source code archive and then start the flowblade script.

After starting flowblade, you are presented with an elegant and orderly user interface (Figure 2). The preview is found at the upper right, and the time line is located at the lower edge. Unlike many of its competitors, Flowblade can generate and manage multiple independent time lines or sequences. Although Lightworks lets its users nest sequences, Flowblade does not. Moreover, each of the Flowblade sequences offers only nine tracks. When generating a new sequence, the user will need to determine how many of these tracks will have videos, and how many of them will record audio material. The Flowblade developers specified these limits arbitrarily.

Figure 2: Unlike its competitors, Flowblade makes it easy to recognize cross-fades.

To the upper left of the main window are several tabs. The first tab offers a small media-management function that lets you import clips and then drag and drop them into the time line. The function does not work smoothly, and its use is not intuitive. Depending on the track and the clips already on the time line, Flowblade adds the video snippet to another clip, edits the new video, or moves the videos that follow. Beginning users, in particular, will need to reposition the clips with the appropriate tools until becoming more proficient. Flowblade offers several different editing tools, one of which can even move or roll a cut-over point. Given the large tool set, you'll need to remember which tool is currently active.

You can cut clips directly in the time line. Alternatively, you can double-click to move the film snippet into the preview window in order to cut it with the help of appropriate buttons. Experienced users may want to display a vector scope and an RGB parade. These two special modes provide a look at the color composition and color balance of the video. To assemble video clips precisely, all editing programs have time lines with various zoom levels. In Flowblade, you control the zoom level by turning the mouse wheel or using the somewhat inconvenient menu options. The track height is not adjustable. On larger monitors especially, this action changes the rectangles of the clips into narrow lines.

Flowblade offers compositors and filters on other tabs. Filters involve effects that always apply to the entire clip. Compositors, however, mix two video tracks, creating cross-fades or picture-in-picture effects. Unlike the settings for filters, compositor settings are controlled via keyframes. You can specify the starting and ending points on a separate time bar in the compositor settings. Flowblade conveniently synchronizes the time needle on the time bar with its counterpart on the time line.

A wizard is available for creating titles. The window for the wizard displays the video from the time line in the background, letting you position text with a high degree of precision. The wizard even permits multiple layers of text. However these layers cannot be displayed or hidden separately. A virtual mixer console lets you modulate the sound. If desired, Flowblade adds a watermark to the video; competing programs do not offer this convenience.

To export the film after editing, you switch to the Render tab. This tab offers numerous format templates. Users familiar with video compression methods can supply additional parameters to Ffmpeg, which is responsible for the video coding.

Kdenlive

The extremely powerful Kdenlive [3] video editing program has become an official part of the KDE applications. The applications in this collection are always bundled into a new version. By the time this article went to press, Kdenlive 15.12.1 was a part of the KDE applications 15.12. Additionally, Kdenlive is based on the modern KDE Frameworks 5, which also uses the desktop environment Plasma 5. Therefore, to use the video editing program, the distribution must have these components as well as Qt 5.

The Kdenlive developers have put binary packages for several large distributions on their home page. However, they have skimped on the package for Ubuntu. All of the symbols are missing on the user interface, which makes the editing program impossible to use. Compiling Kdenlive from the source code is extremely cumbersome because of numerous dependencies. As with Flowblade, Kdenlive is based on the multimedia framework MLT. Nonetheless, Kdenlive is found in the repositories for all of the large distributions.

The user interface may be overpowering for newcomers because of the multitude of tabs and small symbols (Figure 3). The main menu with its numerous functions looks overloaded. Imported media land at the upper right in a small media manager. To the right are the settings for the most recently selected effects. The area outside and to the right shows previews of the completed video.

Figure 3: You can scale, unlock, and reposition the individual areas of the main window in Kdenlive.

You can open clips in the preview with a mouse click and cut them there. However, precise cuts are difficult because of the somewhat awkward buttons. Even so, Kdenlive can be controlled almost entirely via keyboard shortcuts. A time line with numerous video and audio tracks sits at the lower edge of the window. Kdenlive offers several different editing and insertion modes, but it is not possible to move or roll a cutting point.

You can apply arbitrarily many effects to a clip, and Kdenlive offers extensive color correction. Special views like a histogram or an RGB parade make adjustments easier, and you can control effects precisely via keyframes. To modify the length of the cross-fades, you can move bars, inserted for this purpose, together via the mouse. Kdenlive also lets you adjust the height of the track – in contrast to Flowblade.

If necessary, you can also access the open clip art library, the archive.org-video library, and the FreeSound audio library from Kdenlive. Using other wizards, you can quickly add a title or slideshow to a project. All you need is a suitable template or profile for specifying a new project or exporting it later. Expert users have the option of setting the video format and the compression method. If desired, the wizard can output the film directly as a DVD.

Kino

Development of the Kino editing program actually stopped in 2009. Even so, Kino is still found in the repositories for current distributions. The application only processes video material in DV format, which dates back to amateur cameras used in the mid-1990s (Figure 4).

Figure 4: Kino is a relatively ancient program that is limited to use with videos in a standard format.

The user interface lists all imported videos on the left side. The videos play back from top to bottom. You can change the sequence via drag and drop. Kino recognizes scene changes when videos are imported and automatically separates the material into corresponding clips. The large preview in the middle of the window shows the completed film. Kino even offers a shuttle slider. The farther you push the slider to the right, the faster the preview will play.

Processing steps are selected via the tabs on the right side. Use the cut tab at the beginning and end of the clip, and add effects with the FX tab. However, the possibilities are restricted; you can only apply one effect and one cross-fade to each clip.

Kino prefers to output the results of user efforts in DV format. Kino also lets you generate other formats with suitable external programs. For example, you can generate MPEG files for a DVD.

Lightworks

The commercial version of the Lightworks editing program has played a role in the production of well known films such as The King's Speech and Pulp Fiction . A free version of Lightworks is also available from EditShare.

You can download Lightworks Free free of charge, but you must register with EditShare after starting the program. The free version only produces videos in MPEG4 format. Also, some functions are missing right from the start, including support for 3D videos and team-editing functions.

Lightworks Pro has a complete set of functions you can purchase for around EUR338. Alternatively, you can choose a rental payment option of EUR20 per month. An annual subscription costs EUR135. Regardless of the choice of payment, the pro version is always activated via the Internet.

The manufacturer offers the Linux version as a DEB package for Ubuntu, Lubuntu, Xubuntu as of version 14.04, and Linux Mint 17. Beginning with version 20 of Fedora, the software is offered as an RPM package. For proprietary graphics card drivers, Lightworks strongly recommends Nvidia or AMD. Problems can occur during video processing when using free drivers.

Lightworks takes up the entire screen when it starts (Figure 5). You can minimize the main window. Lightworks remembers the visual arrangement of the subwindows as part of a saved project. Editing functions can be activated through one of the following: using small symbols found along the edges of the window, via the context menu invoked by pressing the right mouse button, or using keyboard shortcuts. You can enlarge the elements of the user interface in the basic settings, permitting operations on high-definition monitors.

Figure 5: Lightworks users must juggle numerous windows, even when working on smaller projects.

Lightworks lets you group loaded clips into bins. Filters can be created and added only to those clips displaying specified characteristics. This lets you maintain an overview even when numerous film snippets are involved. Lightworks opens a clip in a separate preview window, letting you perform editing operations with just a few mouse clicks. The results can then be moved to one of several time lines that Lightworks can manage. Time lines can be nested, so you can put together a film out of several sequences. You can scale the tracks in the time line for easy editing on a high-definition monitor. Lightworks offers many cutting tools, including tools allowing you to retroactively move or roll the cut points.

Lightworks also stands out for its extensive color correction. You can work in an HSV model and also fade in vectorscope and waveform representations to check on results. The effects that come from the manufacturer will satisfy even the professional film editor. Along with the standard effects, such as color correction, the program also offers split screen and bluebox effects. Keyframes are used for modifying the settings for effects over time. A suitable effect is used to generate titles. Two additional effects handle screen credits that run either horizontally or vertically across the image.

A special view lets you interconnect several effects. Each effect will appear as a small box with input and output ports, which are then connected together via virtual cables. If desired, Lightworks can easily merge scenes shot with multiple cameras via the multi-cam feature.

LiVES

LiVES [6] is primarily intended for video jockeys and video artists, who produce their videos during the course of an event. As a result, LiVES assigns effects and clips to individual keys. A simple press on a key suffices to invoke a film or apply an effect. Lives lets you use a keyboard, joystick, or Midi controller as a control device. Moreover, the program can stream clips over a network to other LiVES installations and record the video produced during an event.

Almost as an afterthought, LiVES works as a typical editing program. The clip editor shown in Figure 6 lets you first cut individual film clips and then apply effects. Afterward, you can switch into multi-track mode to assemble the edited clips into a complete movie. Although the version of LiVES offered in the Ubuntu 15.10 software center crashed multiple times during testing, the package offered by the Packman repository for openSUSE Leap functioned perfectly.

Figure 6: The LiVES user interface is extremely cluttered and cumbersome to use.

LiVES imports files from the hard drive. It also digitalizes videos from webcams and analog TV cards, records DVDs, and downloads clips from YouTube. However, LiVES converts each of the videos it loads into a series of PNG images. Converting the videos to PNGs makes it easier to apply effects when using the video for an event, but the video occupies considerably more space on the hard disk. A one-minute video in standard definition takes up almost 1.6GB. After about one hour of trying, we interrupted the import of 10 seconds of a commercially available AVCHD video. During the load process, LiVES completely consumed all CPU time for the test computer. With other video formats, the program occasionally displayed distorted images.

LiVES lets you control playback using keyboard shortcuts, buttons in the main menu, and in the Play menu. To cut a clip, move the white bars together and mark the area for removal. This process could hardly be more complicated. As a result, frame-perfect cuts are possible only with extremely short clips.

The upper left area of the multi track mode displays a small preview. All of the available effects sit to the right of the preview area, along with a list of imported videos. Arrange these imported videos using drag and drop on the time line in the lower area of the window.

Cross-fades are very difficult to create. After marking the correct track, you must specify the area for the cross-fade to occur, which is done by joining a gray bar above the time line in a suitable fashion. Then, a cross-fade effect is moved to the time line. This causes a settings window for the effect to open. Heights for the tracks on the timeline should not be modified; otherwise, they turn into narrow bands on high-definition monitors.

The effects come from the Frei0r collection, which should please the intended target group because of the availability of drastic distortion effects like the whirlpool. The title generator looks like the console for a space ship. Slider bars are used to set the length, position, and color for the text you wish to display.

To output the film you create, first convert it into an individual clip, then switch back into the clip editor and export from there. The scope of functions that LiVES offers can be expanded via a plugin interface.

Shotcut

Shotcut [7] developers release new versions of the software right on time every month. At the time I wrote this article, version 16.01 was the most recent version (Figure 7). The developers offer a precompiled version of Shotcut on their homepage. You can download the archive for Linux, decompress it, and then start the shotcut script in the Shotcut.app directory.

Figure 7: The main window.

Shotcut uses MLT to process videos in the background. It can also utilize the graphics card for processing; however, the developers report that this feature is still experimental. Shotcut starts up with a window that is practically empty. As soon as the user opens a video, Shotcut plays it, acting much like a video player. Two white triangles that sit on the ends of a time line are the only indication of the video editing functionality of the program. Moving the triangles cuts the beginning and end of a clip. With this method, it is very difficult to make precision cuts.

The view menu option lets you display tabs on the left-hand side of the window. These tabs have additional tools, including a group of effects referred to as filters in Shotcut. Filters always apply to the finished clip currently opened. As a rule, these filters offer few options. Moreover, the filters are difficult to adjust because of the small size of the slider bar. Nonetheless, Shotcut displays the effects in the preview. If necessary, the user can save settings already applied as a template and later quickly call the template to apply the effects to another video.

If effects have already been applied to a clip, you can add the clip to the playback list. Shotcut plays the list starting from top to bottom, thereby playing a completed movie. To retroactively edit a clip from the playback list, open the clip in the preview by clicking on the hamburger symbol, and then click on Open as a clip . This process is somewhat cumbersome.

An alternative to the playback list is to start with an empty time line. As soon as a video is moved onto the line, Shotcut automatically creates an accompanying track. Any additional tracks must be explicitly added by the user. The clips latch onto important points like the time needle or the end of another clip. The height of the track cannot change, only the time resolution.

Trimming a clip involves using the mouse to move the ends of the clip onto the timeline. However, you are flying blind during this task because the preview only shows the position of the time needle. Shotcut currently has just one cutting tool; it separates the clip that has been marked at the point at which the time needle is positioned. You can simulate cross-fades with the help of the Video fade out filter and Video fade in .

To export the film after editing, open the suitable tab and select one of the numerous templates. Professional film editors can perform additional fine-tuning. If desired, Shotcut can stream the video to a "Melted" server, which refers to the Melted video server. This industrial-strength media player for television broadcasting is the original use case and application for the MLT framework.

Conclusion

In spite of similarities in operating concepts and user interfaces, the video editing programs described in this article are intended for specific user groups with different backgrounds and demands.

Beginners and those users who occasionally produce films should take a look at Shotcut and Flowblade. Shotcut deserves special attention for a user interface that the developers have reduced to the essentials and that only displays tools if explicitly requested. Users who want to do more than assemble clips one after another must reckon with cumbersome operation on both Shotcut and Flowblade.

Cinelerra, Kdenlive, and Lightworks are clearly intended for advanced users and professionals. Cinelerra comes across as outmoded, but users who can handle the somewhat awkward operation are rewarded with a broad range of functions that make even compositings possible. Kdenlive has also grown into a function monster over the years. However, it still cannot compete with Adobe Premiere Pro. In spite of some clumsy controls, Kdenlive does offer keyboard shortcuts – most of which work well.

Lightworks Free is actually a test version for its fee-based counterpart. You can only use Lightworks Free for producing videos because export functions come with the Lightworks Pro package. Even experienced film editors will need some time to accustom themselves to the free version. However, professionals will find that Lightworks Pro is a solid and well-made tool.

Kino is primarily intended for beginning film editors who want to post-process old videos in DV format. Even though Kino development has stopped the Kino video editor continues to run without a hitch. LiVES is probably best suited to artists, provided they do not get discouraged by the extremely confusing controls.