gstreamer shmsrc interface

[mattes]

I getting my feet wet with gstreamer. Looks pretty cool.

I have an app that already captures and overlays video frames.
I like to import these frames into gstreamer using the shmsrc
interface.

Is there some test code/sample available I could use as a starter kit?
Something that outlines what needs to be done to satisfy the needs of shmsrc:

  e.g.   gst-launch shmsrc socketpath=mydata ! video/x-raw-yuv,witdh=320,height=240 ! ...

Unfortunately nothing popped up searching/googl'ing the net'z.

Mat



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[Olivier Crête-3]

Hi,

On Wed, 2011-06-22 at 11:02 -0700, mattes wrote:

> I getting my feet wet with gstreamer. Looks pretty cool.
>
> I have an app that already captures and overlays video frames.
> I like to import these frames into gstreamer using the shmsrc
> interface.
>
> Is there some test code/sample available I could use as a starter kit?
> Something that outlines what needs to be done to satisfy the needs of shmsrc:
>
>   e.g.   gst-launch shmsrc socketpath=mydata ! video/x-raw-yuv,witdh=320,height=240 ! ...
>
> Unfortunately nothing popped up searching/googl'ing the net'z.

Basically, that's it. I should really write some doc.

Short example:

$ gst-launch -v videotestsrc ! 'video/x-raw-yuv, width=320, height=240,
framerate=15/1,  format=(fourcc)YUY2' ! shmsink socket-path=/tmp/test
shm-size=10000000 wait-for-connection=0
$ gst-launch shmsrc socket-path=/tmp/test is-live=1 ! video/x-raw-yuv,
width=320, height=240, framerate=15/1,  'format=(fourcc)YUY2' !
xvimagesink

- The default shm-size is too small for video, don't be afraid to make
it larger, maybe I should change the default..
- It seems that wait-for-connection mode is broken (oops)

That said, if both ends are inside the same program, you should be using
appsrc/appsink instead. The shm stuff is only meant for IPC, also, you
can integrate shmpipe.[ch] inside your own application if you don't want
to have GStreamer on both sides (but there is no API guarantee and no
communication compatibility guarantees for future releases).


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Olivier Crête
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[Tristan Matthews-2]

2011/6/22 mattes <[hidden email]>:

>
> I getting my feet wet with gstreamer. Looks pretty cool.
>
> I have an app that already captures and overlays video frames.
> I like to import these frames into gstreamer using the shmsrc
> interface.
>
> Is there some test code/sample available I could use as a starter kit?
> Something that outlines what needs to be done to satisfy the needs of shmsrc:
>
>  e.g.   gst-launch shmsrc socketpath=mydata ! video/x-raw-yuv,witdh=320,height=240 ! ...
>
> Unfortunately nothing popped up searching/googl'ing the net'z.

I made this example a little while ago:
https://github.com/tmatth/gst-prototypes/tree/master/shm

Hope it's of some use.

-T

>
> Mat
>
>
>
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web: http://tristanswork.blogspot.com
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[mattes]

> That said, if both ends are inside the same program, you should be using appsrc/appsink instead.
> The shm stuff is only meant for IPC, also, you can integrate shmpipe.[ch] inside your own application
> if you don't want to have GStreamer on both sides (but there is no API guarantee and no communication
> compatibility guarantees for future releases).

My app is an existing C application that captures and massages video frames.  It is not based on
gstreamer. I want to extend the functionality of the current app and import the video frames into
gstreamer.

I was following some hints mentioned in shmpipe.h, which leaves room for interpretation on how things
and what order they need to be done. Ran into some issues. That's why I was interested in a small test
app, (hopefully something not gstreamer based).

Though, I think, I figured a couple of things out.

At least I can feed and visualize frames now in gstreamer doing this:

  gst-launch shmsrc socket-path=/tmp/mxtdata !
video/x-raw-yuv,width=320,height=240,framerate=5/1,format='(fourcc)YV12' ! xvimagesink

thanx for the input



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[Martin Bisson]

My 2 cents:

If you want to send your images (from your existing non-GStreamer
application) to GStreamer within the same application/process, use
appsource as an interface to send your images to a GStreamer pipeline.  
If you want your application to remain a stand-alone application with no
"explicit" link to GStreamer, you can use shm stuff and launch the
GStreamer pipeline (using shmsrc) in a totally different process, with
the caveats mentionned by Olivier.

Mart


On 23/06/2011 8:04 PM, mattes wrote:

>> That said, if both ends are inside the same program, you should be using appsrc/appsink instead.
>> The shm stuff is only meant for IPC, also, you can integrate shmpipe.[ch] inside your own application
>> if you don't want to have GStreamer on both sides (but there is no API guarantee and no communication
>> compatibility guarantees for future releases).
> My app is an existing C application that captures and massages video frames.  It is not based on
> gstreamer. I want to extend the functionality of the current app and import the video frames into
> gstreamer.
>
> I was following some hints mentioned in shmpipe.h, which leaves room for interpretation on how things
> and what order they need to be done. Ran into some issues. That's why I was interested in a small test
> app, (hopefully something not gstreamer based).
>
> Though, I think, I figured a couple of things out.
>
> At least I can feed and visualize frames now in gstreamer doing this:
>
>    gst-launch shmsrc socket-path=/tmp/mxtdata !
> video/x-raw-yuv,width=320,height=240,framerate=5/1,format='(fourcc)YV12' ! xvimagesink
>
> thanx for the input
>
>
>
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

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