[Ffmpeg-devel] Streaming from camera segfaults on Ubuntu Dapper

Timo Rantalaiho Timo.Rantalaiho
Mon Oct 30 12:44:32 CET 2006

Hello Luca,

> better look at this driver. You are using a Logitech Quickcam 8000,
> right? Which driver are you using? (Which kernel version are you using?
> What's the driver's name? Is it in upstream kernel, or did you have to
> recompile it? In the second case, where can the driver be downloaded
> from? )

Yep, Logitech Quickcam 8000, kernel is stock from Ubuntu

  Linux toro 2.6.15-27-686 #1 SMP PREEMPT Sat Sep 16 02:13:27 UTC 2006 i686 GNU/Linux

and the driver as well. I think it's called pwc (Philips webcam):

thrantal at toro:~/downloads/ffmpeg$ lsmod | grep v4l
v4l2_common             6080  1 pwc
thrantal at toro:~/downloads/ffmpeg$ lsmod | grep pwc
pwc                    90932  0
videodev               10144  1 pwc
v4l2_common             6080  1 pwc
usbcore               139172  8 snd_usb_audio,snd_usb_lib,hci_usb,pwc,usbhid,ehci_hcd,uhci_hcd
thrantal at toro:~/downloads/ffmpeg$ grep -i pwc /var/log/dmesg
[17179587.284000] pwc Philips webcam module version 10.0.7-unofficial loaded.
[17179587.284000] pwc Supports Philips PCA645/646, PCVC675/680/690, PCVC720[40]/730/740/750 & PCVC830/840.
[17179587.284000] pwc Also supports the Askey VC010, various Logitech Quickcams, Samsung MPC-C10 and MPC-C30,
[17179587.284000] pwc the Creative WebCam 5 & Pro Ex, SOTEC Afina Eye and Visionite VCS-UC300 and VCS-UM100.
[17179587.284000] pwc Trace options: 0x00a1
[17179587.284000] pwc Logitech QuickCam 4000 Pro USB webcam detected.
[17179587.284000] pwc Registered as /dev/video0.

Now I notice that in fact it claims to be QuickCam 4000.
In images.google.com, the 4000 and 8000 seem identical, so I
cannot tell for sure :) I just had the idea that we before
had QuickCam 4000 and then it was upgraded to 8000, but that
was years ago...

> I do not know ffserver very much, but I think the problem here is that
> the selected bitrate is too low (maybe the bitrate is ok for a 320x280
> picture, but 640x480 is too large for this bitrate). Try increasing the
> bitrate.

Yep, I increased the bitrate to 200 and the picture got a 
bit better, but nevertheless there was a lot of errors and
a lot of lag.

> Anyway, I want to make v4l2.c work with your setup... I hope you'll be
> able to grab at 320x240 in a short time.

Gee, thanks! I'll stay tuned :)

Best wishes,


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