Rendering Video Tracks in KDEnlive
Once you have edited you video so that it looks exactly as you want in the Project Monitor window, the last stage is to render it into the final display file format. KDenlive supports an impressive number of file formats straight out of the box - including MP4 and full HD video (-in both PAL and NTSC).
The good news is that KDenlive does all the hard work for you - with the user just selecting the desired format and clicking the "render" button.
Once you are happy with your video, simply left-click the "Render" button:
The rendering dialogue box will display:
The defaults are normally fine - and you can go ahead and just the select the desired category (-on the left) and format (-on the right) and click the "Render to File" button. However, if you going to be doing a lot of editing, it can be worthwhile tuning some of the the following properties:
Destination: directory/folder to write the output file to
Output file: the output filename
Format: set to NTSC (USA) or PAL (Europe)
Encoder Threads: if you have a multi-core processor you can tell KDenlive to use multiple threads (1 per core) to render the file quicker
Render to File: set this to render in the background whilst KDenlive is running
Full Project / Selected Zone: when working on large project, it can sometimes be helpful to make a test rendering of part of a video to check it, rather than render the whole project (-which would probably take a lot longer). Use these radio buttons to toggle accordingly
Generate Script: set this to create a script that you can from the command line to render the file outside of KDenlive
The picture below shows the rendering dialogue box displaying the PAL HDV (High Definition Video) formats. Once you have set the rendering parameters as desired, click on the "Render to File" button:
Note: the "2 pass" options generally produce better quality output (-and the same file size) as their standard siblings, but take twice as long to render
The picture below shows the rendering in progress:
Note: the rendering takes place in the background, so you can continue to edit in KDenlive whilst it is running!
Once completed, the rendering dialogue will show the progress as 100% - and you will see the output file created (-where you specified) on disc:
Note: if you find that a track is missing from the rendered output then check the imported clip is in a supported format
Here is a brief table of the relative rendering times, file size and quality for the 15 second audio-visual project shown below:
The benchmarking machine used a 3.0GHz Athlon II processor with 2Gb of 1333MHz DDR3 RAM, using a single thread (core) for rendering. The formats are shown in order of increasing quality:
|Category||Format||Time (min:sec)||File Size||Quality|
|MPEG-4||200k 2 pass||2:00||1.1Mb||*+|
|MPEG-4||25000k 2 pass||2:20||10.9Mb||**+|
|HDV||720p 25fps 2 pass||2:00||13.2Mb||***+|
|HDV||1080p 50fps 2 pass||2:11||15.8Mb||****+|
The preceding table should give you an indication of the relative times to render various file formats. Please note that a larger project will take considerably longer than the timings shown above.
KDenlive does provide a number of recommended options for displaying your videos on the Web. These can be accessed by setting the "Destination" field to "Web sites" in the Render window:
Obviously, you can publish many formats to the Web, so KDenlive has just grouped the common ones together as a shortcut and to aid the less experienced web-publisher.