Is it possible for two processes to access the webcam at the same time?












12















I would like to try using Cheese in Google+ Hangouts, and similar configurations, and I would like to know if it is possible for the webcam to be used by two processes to have access to the webcam at the same time. I have not tried it as yet, but before I do, I figured I would ask.



So, is it possible?






video webcam







share|improve this question





























    12















    I would like to try using Cheese in Google+ Hangouts, and similar configurations, and I would like to know if it is possible for the webcam to be used by two processes to have access to the webcam at the same time. I have not tried it as yet, but before I do, I figured I would ask.



    So, is it possible?






    video webcam







    share|improve this question



























      12












      12








      12


      4






      I would like to try using Cheese in Google+ Hangouts, and similar configurations, and I would like to know if it is possible for the webcam to be used by two processes to have access to the webcam at the same time. I have not tried it as yet, but before I do, I figured I would ask.



      So, is it possible?






      video webcam







      share|improve this question
















      I would like to try using Cheese in Google+ Hangouts, and similar configurations, and I would like to know if it is possible for the webcam to be used by two processes to have access to the webcam at the same time. I have not tried it as yet, but before I do, I figured I would ask.



      So, is it possible?






      video webcam




      video webcam






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Aug 6 '14 at 16:38







      RolandiXor

















      asked Jul 19 '12 at 21:46









      RolandiXor♦RolandiXor

      44.8k26140231




      44.8k26140231






















          4 Answers
          4






          active

          oldest

          votes


















          5





          +100









          Well I just tried. Interesting results.



          I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.



          Results:



          You can't use the same webcam on 2 things at once.



          Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).



          enter image description here



          You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).



          enter image description here



          Hangouts (Not working) + Cheese (Working)



          enter image description here



          Hangouts (Working on it's own).



          enter image description here



          Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...



          enter image description here



          I even tried making a symbolic link to /dev/video0 and saving it in /dev as video2. That didn't work.



          I also can't run 2 cheese processes at once.



          A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.



          enter image description here



          If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.






          share|improve this answer


























          • Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

            – RolandiXor♦
            Aug 6 '14 at 19:07













          • @Mew That was my last attempt at getting it to work :)

            – Tim
            Aug 9 '14 at 18:25











          • @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

            – Isiah Meadows
            Aug 12 '14 at 6:38






          • 1





            @impinball nope, just found it an interesting question!

            – Tim
            Aug 12 '14 at 7:41



















          12














          Happily, now, YES!



          There is currently a project on GitHub that can show not only two, but an infinite (limited only by system capacity) number of video devices from a single source.



          The project is called v4l2loopback. (Check the link and scroll down to view the README for instructions.)



          You can install v4l2loopback by cloning its GitHub and running these commands:



          $ git clone https://github.com/umlaeute/v4l2loopback.git
          
$ cd v4l2loopback
          
$ make
          
$ sudo make install


          Examples



          For samples on how to use it with GStreamer, FFmpeg, MPlayer, and Skype, check their small wiki. Hopefully you could find the right settings to fit your needs.



          Enjoy tweaking around!






          share|improve this answer





















          • 1





            Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

            – Isiah Meadows
            Aug 12 '14 at 6:30











          • Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

            – Tim
            Aug 12 '14 at 7:46






          • 2





            I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

            – RolandiXor♦
            Aug 12 '14 at 8:20






          • 1





            This is now actually part of ubuntu - no need for git.

            – nbubis
            Nov 12 '18 at 14:06



















          2














          The answer is no with a maybe... The Library, "Video 4 Linux" detects whether a device is being used, and will not initiate. However; if you wish to download libv4l-dev and edit it manually, you can edit the code to get rid of this check and then just recompile it. I imagine you could get this to work, but it would be extremely unstable. May be worth checking out though.



          TLDR: Anything is possible if you are a programmer with some elbow grease handy. Don't want to go that far? Then no; its not possible.






          share|improve this answer

































            0














            Based on @The Eye answer



            I first installed gstreamer packages on Ubuntu 18.04
            https://gstreamer.freedesktop.org/documentation/installing/on-linux.html



            $ git clone https://github.com/umlaeute/v4l2loopback.git
            
$ cd v4l2loopback
            
$ make
            
$ sudo make install


            I got warning message as here on Ubuntu 18.04 LTS https://github.com/umlaeute/v4l2loopback/issues/139 (but it didn't prevent me from loading v4l2loopback driver)



            $ sudo depmod -a


            I just have 1 webcam on my laptop /dev/video0 and I wanted to get 2 streams from the same hardware. Based on https://github.com/umlaeute/v4l2loopback/blob/master/README.md



            $ modprobe v4l2loopback devices=2


            There should now be /dev/video1 and /dev/video2 created assuming /dev/video0 was the only video device.



            Now I run the following in one terminal window



            gst-launch-1.0 v4l2src device=/dev/video0 ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2


            I open 2 more tabs



            In the first tab



            gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


            In the second tab



            gst-launch-1.0 v4l2src device=/dev/video2 ! videoconvert ! ximagesink


            Now one should see 2 video streams



            UPDATE



            Even if I use the same /dev/video1 device multiple times it all gives me that many stream. example.



            In the first tab



            gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


            In the second tab



            gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


            In the third tab



            gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


            gives me three streams.






            share|improve this answer


























            • BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

              – enthusiasticgeek
              Feb 7 at 22:09














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            4 Answers
            4






            active

            oldest

            votes








            4 Answers
            4






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            5





            +100









            Well I just tried. Interesting results.



            I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.



            Results:



            You can't use the same webcam on 2 things at once.



            Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).



            enter image description here



            You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).



            enter image description here



            Hangouts (Not working) + Cheese (Working)



            enter image description here



            Hangouts (Working on it's own).



            enter image description here



            Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...



            enter image description here



            I even tried making a symbolic link to /dev/video0 and saving it in /dev as video2. That didn't work.



            I also can't run 2 cheese processes at once.



            A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.



            enter image description here



            If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.






            share|improve this answer


























            • Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

              – RolandiXor♦
              Aug 6 '14 at 19:07













            • @Mew That was my last attempt at getting it to work :)

              – Tim
              Aug 9 '14 at 18:25











            • @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

              – Isiah Meadows
              Aug 12 '14 at 6:38






            • 1





              @impinball nope, just found it an interesting question!

              – Tim
              Aug 12 '14 at 7:41
















            5





            +100









            Well I just tried. Interesting results.



            I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.



            Results:



            You can't use the same webcam on 2 things at once.



            Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).



            enter image description here



            You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).



            enter image description here



            Hangouts (Not working) + Cheese (Working)



            enter image description here



            Hangouts (Working on it's own).



            enter image description here



            Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...



            enter image description here



            I even tried making a symbolic link to /dev/video0 and saving it in /dev as video2. That didn't work.



            I also can't run 2 cheese processes at once.



            A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.



            enter image description here



            If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.






            share|improve this answer


























            • Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

              – RolandiXor♦
              Aug 6 '14 at 19:07













            • @Mew That was my last attempt at getting it to work :)

              – Tim
              Aug 9 '14 at 18:25











            • @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

              – Isiah Meadows
              Aug 12 '14 at 6:38






            • 1





              @impinball nope, just found it an interesting question!

              – Tim
              Aug 12 '14 at 7:41














            5





            +100







            5





            +100



            5




            +100





            Well I just tried. Interesting results.



            I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.



            Results:



            You can't use the same webcam on 2 things at once.



            Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).



            enter image description here



            You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).



            enter image description here



            Hangouts (Not working) + Cheese (Working)



            enter image description here



            Hangouts (Working on it's own).



            enter image description here



            Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...



            enter image description here



            I even tried making a symbolic link to /dev/video0 and saving it in /dev as video2. That didn't work.



            I also can't run 2 cheese processes at once.



            A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.



            enter image description here



            If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.






            share|improve this answer















            Well I just tried. Interesting results.



            I have got skype and cheese and webcam toy and hangouts (which all do work) and tried them together.



            Results:



            You can't use the same webcam on 2 things at once.



            Cheese (Working) + Webcam Toy (Not working) + Skype (Small, top right. Not working).



            enter image description here



            You can use 2 webcams on 2 things though. (Cheese + Webcam Toy).



            enter image description here



            Hangouts (Not working) + Cheese (Working)



            enter image description here



            Hangouts (Working on it's own).



            enter image description here



            Cheese broken when I opened Hangouts first. It did the same with the others, but my internet is too slow to upload every single screenshot (and I doubt you'd appreciate 30+ screenshots)...



            enter image description here



            I even tried making a symbolic link to /dev/video0 and saving it in /dev as video2. That didn't work.



            I also can't run 2 cheese processes at once.



            A picture of my garden, to cheer you up, as the answer is no. It is very cool at the moment: I can swing (on the swing) and jump off and land in the paddling pool. Taken with cheese.



            enter image description here



            If you had to, I would advise making it full screen and doing 2 screen recordings. I doubt that would work for what you want though.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Aug 6 '14 at 18:46

























            answered Aug 6 '14 at 18:35









            TimTim

            20.1k1586141




            20.1k1586141













            • Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

              – RolandiXor♦
              Aug 6 '14 at 19:07













            • @Mew That was my last attempt at getting it to work :)

              – Tim
              Aug 9 '14 at 18:25











            • @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

              – Isiah Meadows
              Aug 12 '14 at 6:38






            • 1





              @impinball nope, just found it an interesting question!

              – Tim
              Aug 12 '14 at 7:41



















            • Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

              – RolandiXor♦
              Aug 6 '14 at 19:07













            • @Mew That was my last attempt at getting it to work :)

              – Tim
              Aug 9 '14 at 18:25











            • @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

              – Isiah Meadows
              Aug 12 '14 at 6:38






            • 1





              @impinball nope, just found it an interesting question!

              – Tim
              Aug 12 '14 at 7:41

















            Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

            – RolandiXor♦
            Aug 6 '14 at 19:07







            Thanks! This is concise and tells me what I need to know. Nice garden btw! The bounty will be awarded when the timeout expires (21 hrs to go). Then I will delete this comment.

            – RolandiXor♦
            Aug 6 '14 at 19:07















            @Mew That was my last attempt at getting it to work :)

            – Tim
            Aug 9 '14 at 18:25





            @Mew That was my last attempt at getting it to work :)

            – Tim
            Aug 9 '14 at 18:25













            @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

            – Isiah Meadows
            Aug 12 '14 at 6:38





            @Tim The next answer is exactly what you're looking for if you came here because you need a way to do that.

            – Isiah Meadows
            Aug 12 '14 at 6:38




            1




            1





            @impinball nope, just found it an interesting question!

            – Tim
            Aug 12 '14 at 7:41





            @impinball nope, just found it an interesting question!

            – Tim
            Aug 12 '14 at 7:41













            12














            Happily, now, YES!



            There is currently a project on GitHub that can show not only two, but an infinite (limited only by system capacity) number of video devices from a single source.



            The project is called v4l2loopback. (Check the link and scroll down to view the README for instructions.)



            You can install v4l2loopback by cloning its GitHub and running these commands:



            $ git clone https://github.com/umlaeute/v4l2loopback.git
            
$ cd v4l2loopback
            
$ make
            
$ sudo make install


            Examples



            For samples on how to use it with GStreamer, FFmpeg, MPlayer, and Skype, check their small wiki. Hopefully you could find the right settings to fit your needs.



            Enjoy tweaking around!






            share|improve this answer





















            • 1





              Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

              – Isiah Meadows
              Aug 12 '14 at 6:30











            • Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

              – Tim
              Aug 12 '14 at 7:46






            • 2





              I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

              – RolandiXor♦
              Aug 12 '14 at 8:20






            • 1





              This is now actually part of ubuntu - no need for git.

              – nbubis
              Nov 12 '18 at 14:06
















            12














            Happily, now, YES!



            There is currently a project on GitHub that can show not only two, but an infinite (limited only by system capacity) number of video devices from a single source.



            The project is called v4l2loopback. (Check the link and scroll down to view the README for instructions.)



            You can install v4l2loopback by cloning its GitHub and running these commands:



            $ git clone https://github.com/umlaeute/v4l2loopback.git
            
$ cd v4l2loopback
            
$ make
            
$ sudo make install


            Examples



            For samples on how to use it with GStreamer, FFmpeg, MPlayer, and Skype, check their small wiki. Hopefully you could find the right settings to fit your needs.



            Enjoy tweaking around!






            share|improve this answer





















            • 1





              Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

              – Isiah Meadows
              Aug 12 '14 at 6:30











            • Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

              – Tim
              Aug 12 '14 at 7:46






            • 2





              I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

              – RolandiXor♦
              Aug 12 '14 at 8:20






            • 1





              This is now actually part of ubuntu - no need for git.

              – nbubis
              Nov 12 '18 at 14:06














            12












            12








            12







            Happily, now, YES!



            There is currently a project on GitHub that can show not only two, but an infinite (limited only by system capacity) number of video devices from a single source.



            The project is called v4l2loopback. (Check the link and scroll down to view the README for instructions.)



            You can install v4l2loopback by cloning its GitHub and running these commands:



            $ git clone https://github.com/umlaeute/v4l2loopback.git
            
$ cd v4l2loopback
            
$ make
            
$ sudo make install


            Examples



            For samples on how to use it with GStreamer, FFmpeg, MPlayer, and Skype, check their small wiki. Hopefully you could find the right settings to fit your needs.



            Enjoy tweaking around!






            share|improve this answer















            Happily, now, YES!



            There is currently a project on GitHub that can show not only two, but an infinite (limited only by system capacity) number of video devices from a single source.



            The project is called v4l2loopback. (Check the link and scroll down to view the README for instructions.)



            You can install v4l2loopback by cloning its GitHub and running these commands:



            $ git clone https://github.com/umlaeute/v4l2loopback.git
            
$ cd v4l2loopback
            
$ make
            
$ sudo make install


            Examples



            For samples on how to use it with GStreamer, FFmpeg, MPlayer, and Skype, check their small wiki. Hopefully you could find the right settings to fit your needs.



            Enjoy tweaking around!







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Aug 12 '14 at 4:55

























            answered Aug 11 '14 at 8:29









            The EyeThe Eye

            33127




            33127








            • 1





              Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

              – Isiah Meadows
              Aug 12 '14 at 6:30











            • Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

              – Tim
              Aug 12 '14 at 7:46






            • 2





              I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

              – RolandiXor♦
              Aug 12 '14 at 8:20






            • 1





              This is now actually part of ubuntu - no need for git.

              – nbubis
              Nov 12 '18 at 14:06














            • 1





              Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

              – Isiah Meadows
              Aug 12 '14 at 6:30











            • Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

              – Tim
              Aug 12 '14 at 7:46






            • 2





              I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

              – RolandiXor♦
              Aug 12 '14 at 8:20






            • 1





              This is now actually part of ubuntu - no need for git.

              – nbubis
              Nov 12 '18 at 14:06








            1




            1





            Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

            – Isiah Meadows
            Aug 12 '14 at 6:30





            Virtual devices is one of the areas where Linux (and *nix, for that matter) shines. It is more complicated on Windows to even write a basic tee utility that doesn't wait for stdin to finish feeding it stuff. I wouldn't be surprised if this actually uses a binary equivalent to tee with more scalable support under the hood.

            – Isiah Meadows
            Aug 12 '14 at 6:30













            Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

            – Tim
            Aug 12 '14 at 7:46





            Whilst this does answer the question, it would be preferable to include parts of the link here, and provide the link for reference, so that we have some examples - e.g. make 2 devices from 1. What are the options for that? And is it possible (as said in the OP's requirements) to use with Google hangouts? I also just tested it with Skype and it doesn't seem to work. We are now version 4.3 not 4.0...

            – Tim
            Aug 12 '14 at 7:46




            2




            2





            I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

            – RolandiXor♦
            Aug 12 '14 at 8:20





            I'll have to check this out when my other system gets back. I'll probably give an additional bounty.

            – RolandiXor♦
            Aug 12 '14 at 8:20




            1




            1





            This is now actually part of ubuntu - no need for git.

            – nbubis
            Nov 12 '18 at 14:06





            This is now actually part of ubuntu - no need for git.

            – nbubis
            Nov 12 '18 at 14:06











            2














            The answer is no with a maybe... The Library, "Video 4 Linux" detects whether a device is being used, and will not initiate. However; if you wish to download libv4l-dev and edit it manually, you can edit the code to get rid of this check and then just recompile it. I imagine you could get this to work, but it would be extremely unstable. May be worth checking out though.



            TLDR: Anything is possible if you are a programmer with some elbow grease handy. Don't want to go that far? Then no; its not possible.






            share|improve this answer






























              2














              The answer is no with a maybe... The Library, "Video 4 Linux" detects whether a device is being used, and will not initiate. However; if you wish to download libv4l-dev and edit it manually, you can edit the code to get rid of this check and then just recompile it. I imagine you could get this to work, but it would be extremely unstable. May be worth checking out though.



              TLDR: Anything is possible if you are a programmer with some elbow grease handy. Don't want to go that far? Then no; its not possible.






              share|improve this answer




























                2












                2








                2







                The answer is no with a maybe... The Library, "Video 4 Linux" detects whether a device is being used, and will not initiate. However; if you wish to download libv4l-dev and edit it manually, you can edit the code to get rid of this check and then just recompile it. I imagine you could get this to work, but it would be extremely unstable. May be worth checking out though.



                TLDR: Anything is possible if you are a programmer with some elbow grease handy. Don't want to go that far? Then no; its not possible.






                share|improve this answer















                The answer is no with a maybe... The Library, "Video 4 Linux" detects whether a device is being used, and will not initiate. However; if you wish to download libv4l-dev and edit it manually, you can edit the code to get rid of this check and then just recompile it. I imagine you could get this to work, but it would be extremely unstable. May be worth checking out though.



                TLDR: Anything is possible if you are a programmer with some elbow grease handy. Don't want to go that far? Then no; its not possible.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited Aug 6 '14 at 18:59









                Tim

                20.1k1586141




                20.1k1586141










                answered Aug 6 '14 at 18:58









                AkivaAkiva

                4,7721446100




                4,7721446100























                    0














                    Based on @The Eye answer



                    I first installed gstreamer packages on Ubuntu 18.04
                    https://gstreamer.freedesktop.org/documentation/installing/on-linux.html



                    $ git clone https://github.com/umlaeute/v4l2loopback.git
                    
$ cd v4l2loopback
                    
$ make
                    
$ sudo make install


                    I got warning message as here on Ubuntu 18.04 LTS https://github.com/umlaeute/v4l2loopback/issues/139 (but it didn't prevent me from loading v4l2loopback driver)



                    $ sudo depmod -a


                    I just have 1 webcam on my laptop /dev/video0 and I wanted to get 2 streams from the same hardware. Based on https://github.com/umlaeute/v4l2loopback/blob/master/README.md



                    $ modprobe v4l2loopback devices=2


                    There should now be /dev/video1 and /dev/video2 created assuming /dev/video0 was the only video device.



                    Now I run the following in one terminal window



                    gst-launch-1.0 v4l2src device=/dev/video0 ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2


                    I open 2 more tabs



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video2 ! videoconvert ! ximagesink


                    Now one should see 2 video streams



                    UPDATE



                    Even if I use the same /dev/video1 device multiple times it all gives me that many stream. example.



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the third tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    gives me three streams.






                    share|improve this answer


























                    • BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                      – enthusiasticgeek
                      Feb 7 at 22:09


















                    0














                    Based on @The Eye answer



                    I first installed gstreamer packages on Ubuntu 18.04
                    https://gstreamer.freedesktop.org/documentation/installing/on-linux.html



                    $ git clone https://github.com/umlaeute/v4l2loopback.git
                    
$ cd v4l2loopback
                    
$ make
                    
$ sudo make install


                    I got warning message as here on Ubuntu 18.04 LTS https://github.com/umlaeute/v4l2loopback/issues/139 (but it didn't prevent me from loading v4l2loopback driver)



                    $ sudo depmod -a


                    I just have 1 webcam on my laptop /dev/video0 and I wanted to get 2 streams from the same hardware. Based on https://github.com/umlaeute/v4l2loopback/blob/master/README.md



                    $ modprobe v4l2loopback devices=2


                    There should now be /dev/video1 and /dev/video2 created assuming /dev/video0 was the only video device.



                    Now I run the following in one terminal window



                    gst-launch-1.0 v4l2src device=/dev/video0 ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2


                    I open 2 more tabs



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video2 ! videoconvert ! ximagesink


                    Now one should see 2 video streams



                    UPDATE



                    Even if I use the same /dev/video1 device multiple times it all gives me that many stream. example.



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the third tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    gives me three streams.






                    share|improve this answer


























                    • BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                      – enthusiasticgeek
                      Feb 7 at 22:09
















                    0












                    0








                    0







                    Based on @The Eye answer



                    I first installed gstreamer packages on Ubuntu 18.04
                    https://gstreamer.freedesktop.org/documentation/installing/on-linux.html



                    $ git clone https://github.com/umlaeute/v4l2loopback.git
                    
$ cd v4l2loopback
                    
$ make
                    
$ sudo make install


                    I got warning message as here on Ubuntu 18.04 LTS https://github.com/umlaeute/v4l2loopback/issues/139 (but it didn't prevent me from loading v4l2loopback driver)



                    $ sudo depmod -a


                    I just have 1 webcam on my laptop /dev/video0 and I wanted to get 2 streams from the same hardware. Based on https://github.com/umlaeute/v4l2loopback/blob/master/README.md



                    $ modprobe v4l2loopback devices=2


                    There should now be /dev/video1 and /dev/video2 created assuming /dev/video0 was the only video device.



                    Now I run the following in one terminal window



                    gst-launch-1.0 v4l2src device=/dev/video0 ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2


                    I open 2 more tabs



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video2 ! videoconvert ! ximagesink


                    Now one should see 2 video streams



                    UPDATE



                    Even if I use the same /dev/video1 device multiple times it all gives me that many stream. example.



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the third tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    gives me three streams.






                    share|improve this answer















                    Based on @The Eye answer



                    I first installed gstreamer packages on Ubuntu 18.04
                    https://gstreamer.freedesktop.org/documentation/installing/on-linux.html



                    $ git clone https://github.com/umlaeute/v4l2loopback.git
                    
$ cd v4l2loopback
                    
$ make
                    
$ sudo make install


                    I got warning message as here on Ubuntu 18.04 LTS https://github.com/umlaeute/v4l2loopback/issues/139 (but it didn't prevent me from loading v4l2loopback driver)



                    $ sudo depmod -a


                    I just have 1 webcam on my laptop /dev/video0 and I wanted to get 2 streams from the same hardware. Based on https://github.com/umlaeute/v4l2loopback/blob/master/README.md



                    $ modprobe v4l2loopback devices=2


                    There should now be /dev/video1 and /dev/video2 created assuming /dev/video0 was the only video device.



                    Now I run the following in one terminal window



                    gst-launch-1.0 v4l2src device=/dev/video0 ! tee name=t ! queue ! v4l2sink device=/dev/video1 t. ! queue ! v4l2sink device=/dev/video2


                    I open 2 more tabs



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video2 ! videoconvert ! ximagesink


                    Now one should see 2 video streams



                    UPDATE



                    Even if I use the same /dev/video1 device multiple times it all gives me that many stream. example.



                    In the first tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the second tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    In the third tab



                    gst-launch-1.0 v4l2src device=/dev/video1 ! videoconvert ! ximagesink


                    gives me three streams.







                    share|improve this answer














                    share|improve this answer



                    share|improve this answer








                    edited Feb 7 at 22:25

























                    answered Feb 7 at 17:42









                    enthusiasticgeekenthusiasticgeek

                    1116




                    1116













                    • BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                      – enthusiasticgeek
                      Feb 7 at 22:09





















                    • BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                      – enthusiasticgeek
                      Feb 7 at 22:09



















                    BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                    – enthusiasticgeek
                    Feb 7 at 22:09







                    BTW if one's webcam has audio then filter audio devices using the command pactl list | grep -A2 'Source #' then use that device in the following pipeline (can run multiple instances of pipeline too) gst-launch-1.0 pulsesrc device=alsa_input.<name of device> ! autoaudiosink

                    – enthusiasticgeek
                    Feb 7 at 22:09




















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