V4L2-library

v4l2-library@linuxtv.org

82 discussions

Sensor driver development
by Anton Pryima 26 Mar '25

26 Mar '25

Hello, I need to develop a camera sensor driver for the specific rockchip platform. I’ve already done a big part, but now I’m faced with an issue: [ 92.374493] rkisp rkisp-vir0: link validation failed for ‘rockchip-csi2-dphy0’:1 -> ‘rkisp-csi-subdev’:0, error -32 I don't have much experience working with V4L2 stack. Can you help me and advise where I should dig in? I feel that possibly something wrong with the DT entry for this device, but I did my, based on the working one, so I assume that the bus configuration should be ok. If you need any more data on my issue, please let me know. Best regards, Anton

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Macro Silicon M2106
by gert.cauwenberg＠telenet.be 29 Feb '20

29 Feb '20

Hello, About a year ago a page about a new Easycap variant was added to the wiki - [ https://linuxtv.org/wiki/index.php/Talk:Easycap | https://linuxtv.org/wiki/index.php/Talk:Easycap ] Has anybody been working on this? I just bought a video grabber - and it seems to be one of those... Sold as BASETech BR116, but lsusb lists it as ID 534d:0021 MACROSILICON AV TO USB2.0 Thanks,

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RPI 3 64bit (aarch64) image cropped
by david bensoussan 13 Apr '18

13 Apr '18

Hello, I'm currently working with a RPI 3 in 64 bit os. I have the issue that the image captured is cropped. I don't know where it comes from but I'm exploring all possibilities. Note that it works perfectly on a 32 bits os with same versions of v4l, kernel, libc and everything. The system is generated with Yocto so I'm 100% sure the versions don't change. I don't think the kernel plays a big role here and my knowledge about it is not significant enough to dig into the image capture calls easily. I tried using musl instead of libc but results are similar. I don't need to enable quirks to fetch the image when using it but the cropped image is exactly the same. Here is the system configuration: * Kernel 4.9.52 * v4l 1.14.2 * usb camera with uvcvideo driver Would you know how I could know V4l is not causing such issue? Regards, David Bensoussan, Synapticon GmbH -- *David bensoussan* Roboticist / Embedded Software Engineer ------------------------------ *Synapticon* | Robotic Control Systems Mobile: 004915779804515 / 0033659971070

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Requesting I420 results in broken picture
by Przemek Gajos 22 Jul '17

22 Jul '17

Dear all, I am a v4l2 capture driver developer and I have encountered a problem when requesting I420 pixel format with: gst-launch-1.0 v4l2src device=/dev/video4 ! video/x-raw, format=I420, width=1920, height=1080, framerate=30/1 ! autovideosink The above pipeline results in broken picture (see attached). Note that my driver does not support I420 and what I see requested from the driver is YUYV (0x56595559) so I think there is a conversion done in libv4l2. I first wrote to GStreamer and got an answer confirming it: the emulation is done in libv4l2. Can there be a bug while converting YUYV to I420 in libv4l2? Requesting other formats which driver supports (no v4l2 emulation involved) results in the correct captured image (see attached). Best regards, Przemek Przemek Gajos Software Engineer [Datapath]<http://www.datapath.co.uk/> Bemrose House, Bemrose Park, Wayzgoose Drive, Derby, DE21 6XQ, United Kingdom T:+44 (0)1332 294 441 | www.datapath.co.uk<http://www.datapath.co.uk> [cid:image231efd.JPG@19d9246f.4a977e7b]<http://ow.ly/a4cH300zbGd> Datapath Ltd. Registered Number: 1609392. Registered in England at Bemrose House, Bemrose Park, Wayzgoose Drive, Derby. DE21 6XQ.

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STK1160 Sharpness
by Барт Гопник 09 Nov '14

09 Nov '14

Hi! (Not sure this is right mailing list to asking this question...) I have 05e1:0408 USB ID STK1160 chip GM7113 (SAA7113 clone) video processor device. Is there way to control for sharpness improvement via STK1160 driver? SAA7113 Data Sheet says that control for sharpness via I2C-bus subaddress 09H. Brightness, saturation, contrast, hue, etc. work perfectly. Is it implemented control for sharpness in the diver? Or at least, is it possible to implement it? The sharpness controlled for my webcam is perfectly, but I can't conrol sharpness for my EasyCap STK1160 device and I think the problem is in STK1160 driver. I carefully looked through all the source codes of the driver and found no references of sharpness. I can control brightness, saturation, etc., but I can't control sharpness. Hope for your help. Thanks in advance!

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FourCC support
by Monica, Agnes 23 Jul '14

23 Jul '14

Hi , One of drivers which we are developing supports formats like sYcc , AdobeRGB and AdobeYCC601 which was added recently in HDMI spec1.4. So can you please tell me how will these formats be supported by fmt. Regards, Monica

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Valgrind error
by João M. S. Silva 20 Jan '14

20 Jan '14

Hi, I faced the Valgrind error described in https://bugs.launchpad.net/ubuntu/+source/libv4l/+bug/432477 and reported it: https://bugs.kde.org/show_bug.cgi?id=330180 But then I also tried v4l version 1.0.1 and it seems to me that the above mentioned error was corrected, but another exists: ==15368== Syscall param ioctl(generic) points to uninitialised byte(s) ==15368== at 0x439EFB7: syscall (syscall.S:30) ==15368== by 0x4488F52: dev_ioctl (libv4lconvert.c:43) ==15368== by 0x44A0BF1: v4lcontrol_create (libv4lcontrol.c:591) ==15368== by 0x44897FF: v4lconvert_create_with_dev_ops (libv4lconvert.c:217) ==15368== by 0x4037BDF: v4l2_fd_open (libv4l2.c:666) ==15368== by 0x42CB904: (below main) (libc-start.c:260) ==15368== Address 0xbe8c5bc4 is on thread 1's stack ==15368== Uninitialised value was created by a stack allocation ==15368== at 0x44A0161: v4lcontrol_create (libv4lcontrol.c:566) ==15368== ==15368== Syscall param ioctl(generic) points to uninitialised byte(s) ==15368== at 0x439EFB7: syscall (syscall.S:30) ==15368== by 0x4488F52: dev_ioctl (libv4lconvert.c:43) ==15368== by 0x44A02D9: v4lcontrol_create (libv4lcontrol.c:630) ==15368== by 0x44897FF: v4lconvert_create_with_dev_ops (libv4lconvert.c:217) ==15368== by 0x4037BDF: v4l2_fd_open (libv4l2.c:666) ==15368== by 0x42CB904: (below main) (libc-start.c:260) ==15368== Address 0xbe8c6018 is on thread 1's stack ==15368== Uninitialised value was created by a stack allocation ==15368== at 0x44A0161: v4lcontrol_create (libv4lcontrol.c:566) Is this correct? Thanks. -- João M. S. Silva

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RDS help needed
by Matthias Bock 01 May '12

01 May '12

Hi there! I hacked a RDS TMC-message receiver to work on the serial port. http://www.matthiasbock.net/wiki/?title=Kategorie:GNS_TrafficBox_FM9_RDS_TM… According to http://linuxtv.org/wiki/index.php/Radio_Data_System_(RDS) already several different receivers are available for usage with Linux but development of the RDS message daemon, that would be required to collect, decode and distribute the RDS messages to client applications http://rdsd.berlios.de/ kindof stucked, didn't progress since 2009 (!) The available SVN sources only support SAA6588-based RDS receivers. Is RDS support still an important task to someone on this list ? Is there someone, who would consider assisting me a little in writing some documentation on the RDS daemon project, some code maybe, lateron some linux kernel modules ? Cheers! Matthias

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modprobe uvcvideo fail
by Benoît Guillaume 18 Apr '12

18 Apr '12

Hello I try to install uvcvideo on PlugComputer's Stratus (ARMv5) with kernel : Linux debian 2.6.31.8-IONICS-STRB0-1011-1. 0-0.0 #2 PREEMPT Mon Nov 22 13:37:25 PHT 2010 armv5tel GNU/Linux after few adjustment the compilation of media_build works, the install too, but when i try to activate the module i get an error debian:/mnt/clef/root# modprobe uvcvideo > WARNING: Error inserting videobuf2_memops > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/video/videobuf2-memops.ko): > Invalid module format > WARNING: Error inserting videobuf2_vmalloc > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/video/videobuf2-vmalloc.ko): > Invalid module format > WARNING: Error inserting media > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/media.ko): > Invalid module format > WARNING: Error inserting videodev > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/video/videodev.ko): > Invalid module format > WARNING: Error inserting videobuf2_core > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/video/videobuf2-core.ko): > Invalid module format > FATAL: Error inserting uvcvideo > (/lib/modules/2.6.31.8-IONICS-STRB0-1011-1.0-0.0/kernel/drivers/media/video/uvc/uvcvideo.ko): > Invalid module format > and in dmesg > videobuf2_memops: version magic '2.6.31.8 mod_unload modversions ARMv5 ' > should be '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > videobuf2_vmalloc: version magic '2.6.31.8 mod_unload modversions ARMv5 ' > should be '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > media: version magic '2.6.31.8 mod_unload modversions ARMv5 ' should be > '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > videodev: version magic '2.6.31.8 mod_unload modversions ARMv5 ' should be > '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > videobuf2_core: version magic '2.6.31.8 mod_unload modversions ARMv5 ' > should be '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > uvcvideo: version magic '2.6.31.8 mod_unload modversions ARMv5 ' should be > '2.6.31.8-IONICS-STRB0-1011-1.0-0.0 preempt mod_unload ARMv5 ' > if i force with modprobe-f uvcvideo, i don't have the dmesg message but i still have the warning & fatal I don't think is revelant but the webcam i have to test is : > Bus 001 Device 003: ID 046d:08c5 Logitech, Inc. QuickCam Pro 5000 > For the build i use the guide line of : http://git.linuxtv.org/media_build.git Before lunch build i had to prepare the kernel : > cd /mnt/clef/root/KERNEL-LINUX2.6.31.8-IONICS-STRB0-1011-1.0-0.0-s > make oldconfig > make prepare > make scripts > Do i miss something ? Thanks for you help. ps: sorry for my english, i'm french -- Benoît GUILLAUME Ingénieur d'application Office : +33(0) 4 70 59 18 11 <http://yansys-medical.fr/> YANSYS SAS BIOPARC-VICHY 03270 HAUTERIVE

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uvcvideo at ARM9
by Aspect 27 Oct '10

27 Oct '10

Hello, I'm taku_s. Sorry, If I'v wroton wrong. so I weak English. I want to use uvcvideo at ARM9 processer. First I downloaded v4l-dvb-abd3aac6644e.tar.gz. and conpiled at i386. It is successed. Next I made link. # cd /lib/modules/2.6.26-2-686/ # ln -s /home/arm/linux-2.6.26 ./build I edited Makefile KSR := ../atmark-dist/linux-2.6.x MAKEARCH = $(MAKE) ARCH=arm CROSS_COMPILE=arm-linux- all: install: $(MAKEARCH) -C $(BUILD_DIR) install And $ make all So I hav error /home/arm/v4l-dvb-abd3aac6644e/v4l/cx18-alsa-main.c: In function 'cx18_alsa_exit': /home/arm/v4l-dvb-abd3aac6644e/v4l/cx18-alsa-main.c:293: error: 'pci_bus_type' undeclared (first use in this function) /home/arm/v4l-dvb-abd3aac6644e/v4l/cx18-alsa-main.c:293: error: (Each undeclared identifier is reported only once /home/arm/v4l-dvb-abd3aac6644e/v4l/cx18-alsa-main.c:293: error: for each function it appears in.) make[3]: *** [/home/arm/v4l-dvb-abd3aac6644e/v4l/cx18-alsa-main.o] Error 1 make[2]: *** [_module_/home/arm/v4l-dvb-abd3aac6644e/v4l] Error 2 make[2]: Leaving directory `/home/arm/linux-2.6.26-at4-ep93xx-port-pre2' I want just v4l1-compt.ko,v4l2-common.ko,uvcvideo.ko. How can I get their.

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