Good example to show usage of tee
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Good example to show usage of tee
 
Administrator
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Hi,
I'm a gstreamer newbie. I'm writing my own application where in I read from a 1920x1080 YUV file, resize it into different dimensions namely 1280x720, 800x480 and 640x360 and then encode each of these resolutions. I want to connect "filesrc" to 3 different resizer element. I know this is possible using a tee element. However, I have not been able to find a good example which demonstrates one such usage. Please throw some light on this Regards, Baby Octopus |
Re: Good example to show usage of tee
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Here's an example:
gst-launch filesrc location=source.file ! tee name=tp \ tp. ! queue ! filesink location=destination1.file \ tp. ! queue ! filesink location=destination2.file The queues are to prevent deadlocking. On 7 November 2012 14:01, Baby Octopus <[hidden email]> wrote: Hi, _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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In reply to this post by Baby Octopus
On Wed, 2012-11-07 at 06:01 -0800, Baby Octopus wrote:
> I'm a gstreamer newbie. I'm writing my own application where in I read from > a 1920x1080 YUV file, resize it into different dimensions namely 1280x720, > 800x480 and 640x360 and then encode each of these resolutions. I want to > connect "filesrc" to 3 different resizer element. I know this is possible > using a tee element. However, I have not been able to find a good example > which demonstrates one such usage. Please throw some light on this gst-launch-1.0 v4l2src ! tee name=t \ t. ! queue ! videoscale ! video/x-raw,width=640,height=480 ! \ videoconvert ! autovideosink t. ! queue ! videoscale ! video/x-raw,width=360,height=240 ! \ videoconvert ! autovideosink -v (if you're still on 0.10, replace videoconvert with ffmpegcolorspace and gst-launch-1.0 with gst-launch-0.10). The same should work with different inputs as well of course, and you can add more t. ! queue ! ... branches. Cheers -Tim _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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Administrator
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In reply to this post by Atish Nazir
Thank you Atish. But I'm not using gst-launch. I'm developing my own application usging gstreamer APIs. Would have been good if there was some demo which shows how to do this in source code
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Re: Good example to show usage of tee
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I find gst_parse_launch useful for quick prototyping tasks:
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstParse.html Alternatively you'll need to look up the tutorials on creating pipelines, connecting elements and the such like. On 7 November 2012 15:31, Baby Octopus <[hidden email]> wrote: Thank you Atish. But I'm not using gst-launch. I'm developing my own _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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Administrator
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Hi Atish,
Thanks for your suggestion. I see gst_launch_parse takes in commandline string and then creates a pipeline based on this, which actually simplifies my task. But all I want to know is, is this the right way to create a pipeline even when you are creating a product of your own, which you will market? Can I create any possible pipeline using gst_parse_launch(or gst-launch) ? Regards, Baby Octopus |
Re: Good example to show usage of tee
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On 11/09/2012 12:44 AM, Baby Octopus wrote:
> Hi Atish, > > Thanks for your suggestion. I see gst_launch_parse takes in commandline > string and then creates a pipeline based on this, which actually simplifies > my task. But all I want to know is, is this the right way to create a > pipeline even when you are creating a product of your own, which you will > market? Can I create any possible pipeline using gst_parse_launch(or > gst-launch) ? I would expect that you want to manually build the pipes. Often with complex pipes you need to attach to signals/events and doing so requires knowing the element etc.. which is easier if you instantiated it directly than searching through a pipeline for a matching element... -- Nathanael d. Noblet t 403.875.4613 _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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Administrator
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Hi Nathanael,
I agree that for complicated pipeline handling is difficult but not impossible. All I want to know is that if there is something which I will not be able to do using command line options Regards, BO |
Re: Good example to show usage of tee
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On Saturday, November 10, 2012 05:10:30 Baby Octopus wrote:
> Hi Nathanael, > > I agree that for complicated pipeline handling is difficult but not > impossible. All I want to know is that if there is something which I will > not be able to do using command line options > Play video full screen. -- Remco Treffkorn (RT445) HAM DC2XT [hidden email] (831) 685-1201 _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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In reply to this post by Nathanael D. Noblet
On 09/11/12 16:53, Nathanael D. Noblet wrote:
> On 11/09/2012 12:44 AM, Baby Octopus wrote: >> Thanks for your suggestion. I see gst_launch_parse takes in commandline >> string and then creates a pipeline based on this, which actually >> simplifies >> my task. But all I want to know is, is this the right way to create a >> pipeline even when you are creating a product of your own, which you will >> market? Can I create any possible pipeline using gst_parse_launch(or >> gst-launch) ? > > I would expect that you want to manually build the pipes. Often with > complex pipes you need to attach to signals/events and doing so requires > knowing the element etc.. which is easier if you instantiated it > directly than searching through a pipeline for a matching element... I disagree. With complex pipes I think parse_launch becomes even more helpful as it becomes harder to visualise what the pipeline actually contains, particularly with teeing and muxing, etc. You can use gst_bin_get_by_name to easily retrieve the elements. This has been a curiosity of mine for a while, what is the reason that the examples don't use parse_launch more often. For example, Christian Schaller's recent blog post "GStreamer, Python and videomixing"[1] "manually" constructs a Gstreamer pipeline over several lines. This compares to this parse_launch equivalent: gst.parse_launch('v4l2src ! video/x-raw,width=320,height=240 ! videoconvert ! textoverlay ! videobox border-alpha=0 top=0 left=-320 ! mixer.' 'v4l2src ! video/x-raw,width=320,height=240 ! theoraenc ! rtptheorapay ! rtptheoradepay ! theoradec ! videoconvert ! mixer.' 'videomixer name=mixer ! videoconvert ! xvimagesink') Christian clearly knows far more about gstreamer and has more experience than I do so I'm left wondering what it is that I've missed that means that those many lines would be preferable to the above. Anyone? [1]: http://blogs.gnome.org/uraeus/2012/11/08/gstreamer-python-and-videomixing/ This transmission contains information that may be confidential and contain personal views which are not necessarily those of YouView TV Ltd. YouView TV Ltd (Co No:7308805) is a limited liability company registered in England and Wales with its registered address at YouView TV Ltd, 3rd Floor, 10 Lower Thames Street, London, EC3R 6YT. For details see our web site at http://www.youview.com _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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On 11/12/2012 09:30 AM, William Manley wrote:
> On 09/11/12 16:53, Nathanael D. Noblet wrote: >> On 11/09/2012 12:44 AM, Baby Octopus wrote: >>> Thanks for your suggestion. I see gst_launch_parse takes in commandline >>> string and then creates a pipeline based on this, which actually >>> simplifies >>> my task. But all I want to know is, is this the right way to create a >>> pipeline even when you are creating a product of your own, which you >>> will >>> market? Can I create any possible pipeline using gst_parse_launch(or >>> gst-launch) ? >> >> I would expect that you want to manually build the pipes. Often with >> complex pipes you need to attach to signals/events and doing so requires >> knowing the element etc.. which is easier if you instantiated it >> directly than searching through a pipeline for a matching element... > > I disagree. With complex pipes I think parse_launch becomes even more > helpful as it becomes harder to visualise what the pipeline actually > contains, particularly with teeing and muxing, etc. You can use > gst_bin_get_by_name to easily retrieve the elements. How do you know what the element's named? Also what happens if there are multiple of the same type of element, how will your code know which one you are looking for? -- Nathanael d. Noblet t 403.875.4613 _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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On 13/11/12 16:06, Nathanael D. Noblet wrote:
> On 11/12/2012 09:30 AM, William Manley wrote: >> On 09/11/12 16:53, Nathanael D. Noblet wrote: >>> On 11/09/2012 12:44 AM, Baby Octopus wrote: >>>> Thanks for your suggestion. I see gst_launch_parse takes in commandline >>>> string and then creates a pipeline based on this, which actually >>>> simplifies >>>> my task. But all I want to know is, is this the right way to create a >>>> pipeline even when you are creating a product of your own, which you >>>> will >>>> market? Can I create any possible pipeline using gst_parse_launch(or >>>> gst-launch) ? >>> >>> I would expect that you want to manually build the pipes. Often with >>> complex pipes you need to attach to signals/events and doing so requires >>> knowing the element etc.. which is easier if you instantiated it >>> directly than searching through a pipeline for a matching element... >> >> I disagree. With complex pipes I think parse_launch becomes even more >> helpful as it becomes harder to visualise what the pipeline actually >> contains, particularly with teeing and muxing, etc. You can use >> gst_bin_get_by_name to easily retrieve the elements. > > How do you know what the element's named? By setting its 'name' attribute. > Also what happens if there are > multiple of the same type of element, how will your code know which one > you are looking for? > Once you set the 'name' attribute for each of them, you know their names. GStreamer won't let you set the same name for more multiple elements. Cheers, Kris _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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On 11/13/2012 10:54 AM, Krzysztof Konopko wrote:
> On 13/11/12 16:06, Nathanael D. Noblet wrote: >> On 11/12/2012 09:30 AM, William Manley wrote: >>> On 09/11/12 16:53, Nathanael D. Noblet wrote: >>>> On 11/09/2012 12:44 AM, Baby Octopus wrote: >>>>> Thanks for your suggestion. I see gst_launch_parse takes in commandline >>>>> string and then creates a pipeline based on this, which actually >>>>> simplifies >>>>> my task. But all I want to know is, is this the right way to create a >>>>> pipeline even when you are creating a product of your own, which you >>>>> will >>>>> market? Can I create any possible pipeline using gst_parse_launch(or >>>>> gst-launch) ? >>>> >>>> I would expect that you want to manually build the pipes. Often with >>>> complex pipes you need to attach to signals/events and doing so requires >>>> knowing the element etc.. which is easier if you instantiated it >>>> directly than searching through a pipeline for a matching element... >>> >>> I disagree. With complex pipes I think parse_launch becomes even more >>> helpful as it becomes harder to visualise what the pipeline actually >>> contains, particularly with teeing and muxing, etc. You can use >>> gst_bin_get_by_name to easily retrieve the elements. >> >> How do you know what the element's named? > > By setting its 'name' attribute. > >> Also what happens if there are >> multiple of the same type of element, how will your code know which one >> you are looking for? >> > > Once you set the 'name' attribute for each of them, you know their > names. GStreamer won't let you set the same name for more multiple elements. So I guess then you would be putting the name into your gst_parse_launch string? Or are you iterating over all elements in a pipe and giving them names? Also when you use bins like encodebin or decodebin getting the child seems harder to me, as does setting some of the settings... Just my opinion though. I've only been using gstreamer for a year or two. -- Nathanael d. Noblet t 403.875.4613 _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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On 13/11/12 21:34, Nathanael D. Noblet wrote:
> On 11/13/2012 10:54 AM, Krzysztof Konopko wrote: >> On 13/11/12 16:06, Nathanael D. Noblet wrote: >>> On 11/12/2012 09:30 AM, William Manley wrote: >>>> On 09/11/12 16:53, Nathanael D. Noblet wrote: >>>>> On 11/09/2012 12:44 AM, Baby Octopus wrote: >>>>>> Thanks for your suggestion. I see gst_launch_parse takes in >>>>>> commandline >>>>>> string and then creates a pipeline based on this, which actually >>>>>> simplifies >>>>>> my task. But all I want to know is, is this the right way to create a >>>>>> pipeline even when you are creating a product of your own, which you >>>>>> will >>>>>> market? Can I create any possible pipeline using gst_parse_launch(or >>>>>> gst-launch) ? >>>>> >>>>> I would expect that you want to manually build the pipes. Often with >>>>> complex pipes you need to attach to signals/events and doing so >>>>> requires >>>>> knowing the element etc.. which is easier if you instantiated it >>>>> directly than searching through a pipeline for a matching element... >>>> >>>> I disagree. With complex pipes I think parse_launch becomes even more >>>> helpful as it becomes harder to visualise what the pipeline actually >>>> contains, particularly with teeing and muxing, etc. You can use >>>> gst_bin_get_by_name to easily retrieve the elements. >>> >>> How do you know what the element's named? >> >> By setting its 'name' attribute. >> >>> Also what happens if there are >>> multiple of the same type of element, how will your code know which one >>> you are looking for? >>> >> >> Once you set the 'name' attribute for each of them, you know their >> names. GStreamer won't let you set the same name for more multiple >> elements. > > So I guess then you would be putting the name into your gst_parse_launch > string? Exactly. >Or are you iterating over all elements in a pipe and giving them > names? Also when you use bins like encodebin or decodebin getting the > child seems harder to me, as does setting some of the settings... Just > my opinion though. I've only been using gstreamer for a year or two. > Here's how I do it. error = NULL; pipeline = gst_parse_launch (" videotestsrc name=src" " ! mpeg2enc name=enc" " ! mpegtsmux name=mux" " ! filesink name=sink", &error); ... sink = gst_bin_get_by_name (GST_BIN (pipeline), "sink"); if (!sink) { g_printerr ("Failed to get sink element by name\n"); return EXIT_FAILURE; } g_object_set (G_OBJECT (sink), "location", savefile, NULL); gst_object_unref (sink); ... Referring to elements by name is quite handy although I can imagine it's not ideal in every situation. Getting objects "by name" is a quite common concept along with "by index" and "by object/reference" in systems where elements form some sort of hierarchy (or a graph in general). So it's nothing special about GStreamer or GLib. Kris _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
Re: Good example to show usage of tee
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In reply to this post by William Manley
On 12 Nov 2012, at 16:30, William Manley wrote:
> This has been a curiosity of mine for a while, what is the reason that > the examples don't use parse_launch more often. The "GStreamer SDK" tutorials, at least, seem to recommend using "gst_parse_launch"[1]: Please note that gst-launch is primarily a debugging tool for developers. You should not build applications on top of it. Instead, use the gst_parse_launch() function of the GStreamer API as an easy way to construct pipelines from pipeline descriptions. ...although they introduce it rather late (in the 10th tutorial, after using gst_element_factory_make etc in all the previous tutorials). Subsequent tutorials ([2], [3]) do use "gst_parse_launch". [1] http://docs.gstreamer.com/display/GstSDK/Basic+tutorial+10%3A+GStreamer+tools [2] http://docs.gstreamer.com/display/GstSDK/Basic+tutorial+12%3A+Streaming [3] http://docs.gstreamer.com/display/GstSDK/Basic+tutorial+13%3A+Playback+speed _______________________________________________ gstreamer-devel mailing list [hidden email] http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel |
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