Cannot see the v4l2loopback using google-chrome or chromium

[thierryg]

Hi,

While the v4l2loopback is loaded i can play normaly with using ffmpeg/ffplay/vlc/... but when i start the google-chrome browser (or even chromium), i can only see my physical local webcam not my loopbak one.

I have see the following issue : https://code.google.com/p/chromium/issues/detail?id=142568

It explain that chomium filter the loopback webcam from the v4l2 device listing.

Is there someone that have made it works in this case?

Thanks for any reply but i haven't seen any previous issue on your bugtracker.

Regards

Thierry GAYET

[umlaeute]

since 0.7.0 (hey, 0.8.0 was released more than a year ago!!) the driver supports an exclusive_caps option that makes it compatible with chrome (as is documented in the NEWS file).

enable it:

# insmod v4l2loopback exclusive_caps=1

the newly created device will announce output capabilities only (so ordinary webcam applications (including chrome) won't see it. as soon as you have attached a producer to the device, it will start announcing capture capabilities only, so chrome (and other braindead applications) will see it)

[umlaeute]

btw, the issue is a duplicate of #40

[thierryg]

Hi, thanks for your previous reply. I have seen the bug #40 but it was not working for me.

Here is all the process i have followed for my test ; tell me is something is missing :

1. Build :

make clean && make

1. Check parameters :

modinfo v4l2loopback
filename: /lib/modules/3.13.0-37-generic/extra/v4l2loopback.ko
license: GPL
author: Vasily Levin, IOhannes m zmoelnig zmoelnig@iem.at,Stefan Diewald,Anton Novikov
description: V4L2 loopback video device
srcversion: DD5EF63321657CC1C01E35A
depends: videodev
vermagic: 3.13.0-37-generic SMP mod_unload modversions
parm: debug:debugging level (higher values == more verbose) (int)
parm: max_buffers:how many buffers should be allocated (int)
parm: max_openers:how many users can open loopback device (int)
parm: devices:how many devices should be created (int)
parm: video_nr:video device numbers (-1=auto, 0=/dev/video0, etc.) (array of int)
parm: card_label:card labels for every device (array of charp)
parm: exclusive_caps:whether to announce OUTPUT/CAPTURE capabilities exclusively or not (array of bool)
parm: max_width:maximum frame width (int)
parm: max_height:maximum frame height (int)

1. Unload previous :

rmmod -r v4l2loopback
or
modprove -r v4l2loopback

1. Load the current drivers :

sudo su
modprobe videodev
insmod ./v4l2loopback.ko devices=1 video_nr=2 exclusive_caps=1

1. Check configuration

tree /sys/module/v4l2loopback/
/sys/module/v4l2loopback/
├── coresize
├── holders
├── initsize
├── initstate
├── notes
├── parameters
│   ├── debug
│   ├── exclusive_caps
│   ├── max_buffers
│   ├── max_height
│   ├── max_openers
│   ├── max_width
│   └── video_nr
├── refcnt
├── sections
│   ├── __bug_table
│   ├── __mcount_loc
│   └── __param
├── srcversion
├── taint
└── uevent

4 directories, 17 files

cat /sys/module/v4l2loopback/parameters/exclusive_caps

Y,Y,Y,Y,Y,Y,Y,Y

ls -al /dev/video*

crw-rw----+ 1 root video 81, 0 janv. 17 15:59 /dev/video0

ffmpeg -f v4l2 -list_formats all -i /dev/video0

ffmpeg version 1.2.6-7:1.2.6-1trusty1 Copyright (c) 2000-2014 the FFmpeg developers
built on Apr 26 2014 18:52:58 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --arch=amd64 --disable-stripping --enable-avresample --enable-pthreads --enable-runtime-cpudetect --extra-version='7:1.2.6-1trusty1' --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis --enable-libvpx --enable-zlib --enable-gpl --enable-postproc --enable-libcdio --enable-x11grab --enable-libx264 --shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static
libavutil 52. 18.100 / 52. 18.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 53. 5.103 / 53. 5.103
libavfilter 3. 42.103 / 3. 42.103
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[video4linux2,v4l2 @ 0x1d682c0] Not a video capture device.
/dev/video0: No such device

I need to inject a video for a local streaming that i will see as buildin video camera using chrome.

It works really fine with firefox not google-chrome yet.

1. Check with google-chrome :

Url for the test : https://opentokrtc.com/

The result is that i don't see the cam.

Thanks a lot for any other idea

[thierryg]

Hi, thanks for your previous reply. I have seen the bug #40
#40 but it was not working
for me.

Here is all the process i have followed for my test ; tell me is something
is missing :

1. Build :

make clean && make

1. Check parameters :

modinfo v4l2loopback
filename: /lib/modules/3.13.0-37-generic/extra/v4l2loopback.ko
license: GPL
author: Vasily Levin, IOhannes m zmoelnig zmoelnig@iem.at,Stefan
Diewald,Anton Novikov
description: V4L2 loopback video device
srcversion: DD5EF63321657CC1C01E35A
depends: videodev
vermagic: 3.13.0-37-generic SMP mod_unload modversions
parm: debug:debugging level (higher values == more verbose) (int)
parm: max_buffers:how many buffers should be allocated (int)
parm: max_openers:how many users can open loopback device (int)
parm: devices:how many devices should be created (int)
parm: video_nr:video device numbers (-1=auto, 0=/dev/video0, etc.) (array
of int)
parm: card_label:card labels for every device (array of charp)
parm: exclusive_caps:whether to announce OUTPUT/CAPTURE capabilities
exclusively or not (array of bool)
parm: max_width:maximum frame width (int)
parm: max_height:maximum frame height (int)

1. Unload previous :

rmmod -r v4l2loopback
or
modprove -r v4l2loopback

1. Load the current drivers :

sudo su
modprobe videodev
insmod ./v4l2loopback.ko devices=1 video_nr=2 exclusive_caps=1

1. Check configuration

tree /sys/module/v4l2loopback/
/sys/module/v4l2loopback/
├── coresize
├── holders
├── initsize
├── initstate
├── notes
├── parameters
│ ├── debug
│ ├── exclusive_caps
│ ├── max_buffers
│ ├── max_height
│ ├── max_openers
│ ├── max_width
│ └── video_nr
├── refcnt
├── sections
│ ├── __bug_table
│ ├── __mcount_loc
│ └── __param
├── srcversion
├── taint
└── uevent

4 directories, 17 files
cat /sys/module/v4l2loopback/parameters/exclusive_caps

Y,Y,Y,Y,Y,Y,Y,Y
ls -al /dev/video*

crw-rw----+ 1 root video 81, 0 janv. 17 15:59 /dev/video0
ffmpeg -f v4l2 -list_formats all -i /dev/video0

ffmpeg version 1.2.6-7:1.2.6-1trusty1 Copyright (c) 2000-2014 the FFmpeg
developers
built on Apr 26 2014 18:52:58 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --arch=amd64 --disable-stripping --enable-avresample
--enable-pthreads --enable-runtime-cpudetect
--extra-version='7:1.2.6-1trusty1' --libdir=/usr/lib/x86_64-linux-gnu
--prefix=/usr --enable-bzlib --enable-libdc1394 --enable-libfreetype
--enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame
--enable-librtmp --enable-libopencv --enable-libopenjpeg --enable-libopus
--enable-libpulse --enable-libschroedinger --enable-libspeex
--enable-libtheora --enable-vaapi --enable-vdpau --enable-libvorbis
--enable-libvpx --enable-zlib --enable-gpl --enable-postproc
--enable-libcdio --enable-x11grab --enable-libx264
--shlibdir=/usr/lib/x86_64-linux-gnu --enable-shared --disable-static
libavutil 52. 18.100 / 52. 18.100
libavcodec 54. 92.100 / 54. 92.100
libavformat 54. 63.104 / 54. 63.104
libavdevice 53. 5.103 / 53. 5.103
libavfilter 3. 42.103 / 3. 42.103
libswscale 2. 2.100 / 2. 2.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 2.100 / 52. 2.100
[video4linux2,v4l2 @ 0x1d682c0] Not a video capture device.
/dev/video0: No such device

I need to inject a video for a local streaming that i will see as buildin
video camera using chrome. for that stuff i am using ffmpeg :

ffmpeg -f mjpeg -i http://: -f v4l2 /dev/video2

It works really fine with firefox not google-chrome yet.

1. Check with the latest release of google-chrome :

Url for the test : https://opentokrtc.com/

The result is that i don't see the cam.

Thanks a lot for any other idea

Regards

Thierry GAYET
Mobile : +33.663.849.589
Skype : terranova44 / tux35220
Member of the GNU/Linux Fundation :
https://www.linuxfoundation.org/users/thierryg35
www.nextinnovation.org
www.apprendreindonesien.com

2015-01-16 21:56 GMT+01:00 umläute notifications@github.com:

since 0.7.0 (hey, 0.8.0 was released more than a year ago!!) the driver
supports an exclusive_caps option that makes it compatible with chrome
(as is documented in the NEWS file).

enable it:

insmod v4l2loopback exclusive_caps=1

the newly created device will announce output capabilities only (so
ordinary webcam applications (including chrome) won't see it. as soon as
you have attached a producer to the device, it will start announcing
capture capabilities only, so chrome (and other braindead
applications) will see it)

—
Reply to this email directly or view it on GitHub
#78 (comment)
.

[umlaeute]

can i remove one of the two last comments (they seem to be identical apart from formatting)?

[umlaeute]

so the error you get is basically:

$ ffmpeg -f v4l2 -list_formats all -i /dev/video0
 [...]
 [video4linux2,v4l2 @ 0x1d682c0] Not a video capture device.
 /dev/video0: No such device

which is very much expected: ffmpeg tries to capture (read) from the device. but if yo uare using the exclusive_caps option, then you can only capture if you have started a producer (writer) beforehand.

what you should do is (in the given order=:

• load the v4l2loopback module

• start a producer, like

  $ gst-launch-0.10 -v videotestsrc ! "video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)I420" ! v4l2sink device=/dev/video0

• start a consumer, like

  $ ffmpeg -f v4l2 -list_formats all -i /dev/video0

[camwhite]

This has appeared for me after upgrading to 18.04 LTS. Anyone have any ideas on a fix?

[chdsbd]

@camwhite Did you resolve this issue? I think I may have just run into this, but it could just be a misconfiguration on my part. I can open the virtual devices in VLC, but Chrome doesn't provide any options.

[adrianimajion]

I am also encountering this problem, and following @umleaute 's directions did not resolve it. The virtual device is visible in other applications like mplayer, but not in Chrome stable or Chromium.

@camwhite and @chdsbd , were either of you able to resolve? If not can we re-open this issue?