Regression in V4L (Bug #2084)

Added by Philippe FOUBERT over 12 years ago. Updated about 12 years ago.

Status:Done Start date:2012-06-25
Priority:Normal Due date:
Assignee:Andrey Kamaev % Done:

0%
Category:highgui-camera
Target version:2.4.4
Affected version:branch '2.4' Operating System:
Difficulty: HW Platform:
Pull request:

Description

Philippe FOUBERT wrote (see bug Bug #1988) :

[...] regression in highgui [....]

Suspected origin:

On some Linux OS (such as Fedora 16), V4L2 is available but V4L1 is not anymore available. Reading the OpenCV 2.4.0 source code, it seems that V4L2 (HAVE_CAMV4L2 define) is only compiled if V4L1 (HAVE_CAMV4L define) is also available (it was not the case in OpenCV 2.3.1).

Work around that can be checked:

I have not enought time to check it more seriously in the next days but a workaround could be to add the V4L1 header "videodev.h" (file which is tested in CMakeList.txt to define HAVE_CAMV4L) to your system include folder (it can for example be taken from QT SDK).

I have been able to confirm what I told: there is a regression in the way cap_v4l is built. On an operating system where V4L1 is not any more supported, OpenCV doesn't let us use V4L2.

A temporary work around (which has been sucessfully tested) is to add the old V4L1 header file on the operating system.

Philippe

patch-modules_highgui_src_cap_v4l.cpp (12.3 kB) Patrick Welche, 2012-07-12 06:38 pm

Related issues

related to Patch #2360: NetBSD video support / decouple V4L2 from V4L Done 2012-09-17

Associated revisions

Revision 5327482b
Added by Roman Donchenko about 11 years ago

Merge pull request #2084 from ilya-lavrenov:cont

History

#1
Updated by Patrick Welche over 12 years ago

I had hit this - attached is a patch "in progress" just in case it helps.

The patch makes HAVE_CAMV4L independent of HAVE_CAMV4L2 with a mess of preprocessor directives. It may make more sense to split this into a cap_v4l1.cpp and cap_v4l2.cpp and compile the correct one using cmake... It also means that cap_libv4l.cpp would no longer be required?

  • File patch-modules_highgui_src_cap_v4l.cpp added

#2
Updated by Patrick Welche over 12 years ago

I should have said - the patch was against the 2.4.1 tar file.

#3
Updated by Andrey Kamaev over 12 years ago

  • Category changed from highgui-images to highgui-camera

#4
Updated by Patrick Welche over 12 years ago

I think the patches in issue 2360 should deal with this one.

#5
Updated by Andrey Kamaev about 12 years ago

Fixes for #2360 are pushed to 2.4. So I'm closing this bug as fixed.

  • Affected version set to branch '2.4'
  • Target version deleted ()
  • Status changed from Open to Done
  • Assignee changed from Vadim Pisarevsky to Andrey Kamaev

#6
Updated by Kirill Kornyakov about 12 years ago

  • Target version set to 2.4.4

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