Archive:Kdenlive/Manual/Capturing

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Capturing

Kdenlive provides functionality for capturing video from external devices - Firewire, FFmpeg, Screen Grab and Blackmagic.

You configure video capturing from Settings -> Configure Kdenlive -> Capture (more on this here).

You define the location your captures will end up using Settings -> Configure Kdenlive -> Environment -> Default Folders (more on this here).

To execute a video capture select the Record Monitor and choose the capture device from the drop down in the bottom right.

Firewire

This captures video from sources connected via a firewire (also known as - IEEE 1394 High Speed Serial Bus) card and cable.

Capture options are

DV RAW
DV AVI Type 1
DV AVI Type 2
HDV

The first three are quality wise the same (exactly the same DV 25Mb/s standard definition codec), just packed differently into the file. Type 2 seems to be the most widely supported by other applications.

The raw format contains just the plain video frames (with audio interleaved) without any additional information . Raw is useful for some Linux software. Files in this format can also be played with Windows QuickTime when renamed to file.dv .

AVI files may contain multiple streams. Typically, they include one video and one audio stream. The native DV stream format already includes the audio interleaved into its video stream. A type 1 DV AVI file only includes one DV video stream where the audio must be extracted from the DV video stream. A type 2 DV AVI file includes a separate audio stream in addition to the audio data already interleaved in the DV video stream. Therefore, the type 2 DV AVI file is redundant and consumes more space.

HDV is a high-definition format used on tape-based HD camcorders.

This functionality uses dvgrab

FFmpeg

I believe this captures video from an installed Web Cam using Video4Linux2.

Screen Grab

This captures video of the PC screen. In version 0.9.2 it uses recordMyDesktop to do the capture. There is an open defect with this functionality in ver 0.9.2 - See bug tracker ID 2643.

In version 0.9.3 the Screen grab is done by the ffmpeg functionality instead. For screen capture to work in ver 0.9.3 the version of ffmpeg installed needs to have been compiled with the --enable-x11grab option. Ubuntu comes with an ffmpeg compiled with this option.

To check on your linux distro type "ffmpeg -version" in a terminal and look for --enable-x11grab in the reported configuration info. ^[1]

If you are capturing screen and using the X246 with audio settings and you get a crash as shown in the screen shot ...

... then consider creating a profile for audio capture where -acodec pcm_s16le is replaced by -acodec libvorbis -b 320k. See Configure Kdnelive

Blackmagic

This is for capturing from Blackmagics decklink video capture cards (AFAIK). Not sure how stable this code is at the moment. See defect 2130.

Footnotes

↑ There are two branches of ffmpeg now a Libav branch and a ffmpeg.org branch. The ffmpeg version from the later reports the configuration when you run with "ffmpeg -version". The Libav version does not. So this method to check for the --enable-x11grab does not work if you have libav version of ffmpeg.

[1] There are two branches of ffmpeg now a Libav branch and a ffmpeg.org branch. The ffmpeg version from the later reports the configuration when you run with "ffmpeg -version". The Libav version does not. So this method to check for the --enable-x11grab does not work if you have libav version of ffmpeg.

[1]