I want to capture video from my laptop's webcam directly to kdenlive.

The webcam works out of the box in Skype, as USB2.0 UVC VGA WebCam (/dev/video0).

However when I try to setup the Capture device in kdenlive, the drop-down menu is empty (in the wizard, and in Configure->Capture->FFmpeg->Detected devices). I had /dev/video0 by default in "Video device", which is correct but doesn't help.

I can't seem to run ffmpeg from a terminal (not found), although the wizard says FFmpeg & ffplay are installed. I tried installing it but found no ffmpeg to install via apt-get.
Screen grab works fine.

Since the webcam seems to be USB, here comes the device's lusb -v: http://pastebin.com/Fhm6v9xm

I have seen this: viewtopic.php?f=19&t=120937&p=310358&hilit=webcam#p310358 . No on/off button, and as I said it works with skype.

Why doesn't my device show up? Do I need to do something with Video4Linux2? Is FFmpeg the right input to use?

I can't seem to run ffmpeg from a terminal (not found), although the wizard says FFmpeg & ffplay are installed. I tried installing it but found no ffmpeg to install via apt-get.

Go to Settings->Configure Kdenlive->Environment to see where Kdenlive thinks FFMpeg is living at.

Sorry, I don't have much help though for the webcam...

If your system doesn't have ffmpeg it may instead have avconv - so you may want to try manually running that instead.

Thanks for the help. Kdenlive was indeed setup to use /usr/bin/avconv instead of ffmpeg.
I could test avconv and catpure from my webcam with:

Code: Select all

avconv -f video4linux2 -r 10 -i /dev/video0 test.avi

This got me a video file, nice.
Now I don't know how to make avconv work in kdenlive, any help for this next step? I tried to enter the whole command (with these options) in the Preferences, and I got a number of frames then a freeze. The latency was big too.

You might want to check the rate Kdenlive was trying to capture at - if it is trying to capture faster than your computer/camera can handle, then it could be causing problems such as the lag you experienced.

bcooksley wrote:You might want to check the rate Kdenlive was trying to capture at - if it is trying to capture faster than your computer/camera can handle, then it could be causing problems such as the lag you experienced.

I tried to change the "-r" option to 24, that didn't help. How can I check the rate that kdenlive is trying to capture at?

I don't if that's interesting, here comes what the terminal shows me:

Code: Select all

gauthier@dorian ~ $ kdenlive
ERROR: Could not load classifier cascade /usr/share/opencv/haarcascades/haarcascade_frontalface_alt2.xml
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
[video4linux2 @ 0xb9128ca0] Estimating duration from bitrate, this may be inaccurate
[mpeg2video @ 0xa7f2d020] MPEG1/2 does not support 15/1 fps
[mpeg @ 0xa7f004e0] VBV buffer size not set, muxing may fail
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
kdenlive(1570)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:


Also, the "Capture" of the settings still has "Detected devices" empty, as well as "Capture format", and the settings "Size", "Frame rate" seem to have default values which I can't change (320x200, 15/1, ...).

Hmm, the options being disabled and the device not found is possibly indicative of why it is having capture problems...
What is the output of "solid-hardware list" on your system?

So, it looks like it starts with some errors, but these seem to be about power.

Code: Select all

$ solid-hardware list
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
udi = '/org/kde/solid/udev/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input3'
udi = '/org/kde/solid/udev/sys/devices/LNXSYSTM:00/device:00/PNP0C0C:00/input/input2'
udi = '/org/kde/solid/udev/sys/devices/LNXSYSTM:00/device:00/PNP0C0D:00/input/input0'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1b.0/sound/card0/hwC0D0'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1b.0/sound/card0/pcmC0D0c'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1b.0/sound/card0/pcmC0D0p'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1b.0/sound/card0/controlC0'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/bcma0:0/net/wlan0'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1c.2/0000:02:00.0/net/eth0'
udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-6/1-6:1.0/video4linux/video0'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS0'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS1'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS10'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS11'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS12'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS13'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS14'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS15'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS16'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS17'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS18'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS19'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS2'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS20'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS21'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS22'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS23'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS24'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS25'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS26'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS27'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS28'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS29'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS3'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS30'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS31'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS4'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS5'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS6'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS7'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS8'
udi = '/org/kde/solid/udev/sys/devices/platform/serial8250/tty/ttyS9'
udi = '/org/kde/solid/udev/sys/devices/virtual/net/lo'
udi = '/org/kde/solid/udev/sys/devices/virtual/sound/seq'
udi = '/org/kde/solid/udev/sys/devices/virtual/sound/timer'
udi = '/org/freedesktop/UDisks2/block_devices/sda1'
udi = '/org/freedesktop/UDisks2/block_devices/sda3'
udi = '/org/freedesktop/UDisks2/block_devices/loop4'
udi = '/org/freedesktop/UDisks2/block_devices/sda4'
udi = '/org/freedesktop/UDisks2/block_devices/loop7'
udi = '/org/freedesktop/UDisks2/block_devices/loop1'
udi = '/org/freedesktop/UDisks2/block_devices/loop6'
udi = '/org/freedesktop/UDisks2/block_devices/loop5'
udi = '/org/freedesktop/UDisks2/block_devices/loop3'
udi = '/org/freedesktop/UDisks2/block_devices/loop2'
udi = '/org/freedesktop/UDisks2/block_devices/ram9'
udi = '/org/freedesktop/UDisks2/block_devices/ram8'
udi = '/org/freedesktop/UDisks2/block_devices/loop0'
udi = '/org/freedesktop/UDisks2/block_devices/ram6'
udi = '/org/freedesktop/UDisks2/block_devices/ram5'
udi = '/org/freedesktop/UDisks2/block_devices/ram4'
udi = '/org/freedesktop/UDisks2/block_devices/ram3'
udi = '/org/freedesktop/UDisks2/block_devices/ram2'
udi = '/org/freedesktop/UDisks2/block_devices/ram1'
udi = '/org/freedesktop/UDisks2/block_devices/ram0'
udi = '/org/freedesktop/UDisks2/block_devices/sda'
udi = '/org/freedesktop/UDisks2/block_devices/ram15'
udi = '/org/freedesktop/UDisks2/block_devices/ram14'
udi = '/org/freedesktop/UDisks2/block_devices/ram13'
udi = '/org/freedesktop/UDisks2/block_devices/ram12'
udi = '/org/freedesktop/UDisks2/block_devices/ram11'
udi = '/org/freedesktop/UDisks2/block_devices/ram10'
udi = '/org/freedesktop/UDisks2/block_devices/sda2'
udi = '/org/freedesktop/UDisks2/block_devices/ram7'
udi = '/org/freedesktop/UDisks2/block_devices/sda6'
udi = '/org/freedesktop/UDisks2/block_devices/sda5'
udi = '/org/freedesktop/UDisks2/drives/ST9250315AS_5VCKFWHL'
udi = '/org/freedesktop/UPower'
udi = '/org/freedesktop/UPower/devices/battery_BAT0'
udi = '/org/freedesktop/UPower/devices/line_power_AC0'
udi = '/org/kde/fstab'

There is a:

Code: Select all

udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-6/1-6:1.0/video4linux/video0'

something wrong here?

Maybe of interest: I am running kdenlive on Peppermint Linux.

Okay, so the KDE hardware framework (Solid) is aware of your webcam - the above output is what I was expecting. I'm not sure why Kdenlive wouldn't be able to detect it. Perhaps MLT or another framework is responsible for retrieving the list of devices? This would require knowledge of how this specific part of Kdenlive works unfortunately..

ghostwail wrote:

bcooksley wrote:You might want to check the rate Kdenlive was trying to capture at - if it is trying to capture faster than your computer/camera can handle, then it could be causing problems such as the lag you experienced.

I tried to change the "-r" option to 24, that didn't help. How can I check the rate that kdenlive is trying to capture at?

I don't if that's interesting, here comes what the terminal shows me:

Code: Select all

gauthier@dorian ~ $ kdenlive
ERROR: Could not load classifier cascade /usr/share/opencv/haarcascades/haarcascade_frontalface_alt2.xml
QWidget::insertAction: Attempt to insert null action
QWidget::insertAction: Attempt to insert null action
[video4linux2 @ 0xb9128ca0] Estimating duration from bitrate, this may be inaccurate
[mpeg2video @ 0xa7f2d020] MPEG1/2 does not support 15/1 fps
[mpeg @ 0xa7f004e0] VBV buffer size not set, muxing may fail
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QDBusObjectPath)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QDBusObjectPath)
kdenlive(1570)/kdecore (KConfigSkeleton) KCoreConfigSkeleton::writeConfig:


Also, the "Capture" of the settings still has "Detected devices" empty, as well as "Capture format", and the settings "Size", "Frame rate" seem to have default values which I can't change (320x200, 15/1, ...).

Hi,

It seems that your Kdenlive package is not build with libv4l2 support.
Can you provide details on your distro, packages origin and version?