[gst-devel] How do I clean a pipeline to start/stop it several times?

[Stefan Kost]

ldac schrieb:
>     Hi all,
> 
> I have programmed a C application where I capture video, then I encode 
> it, and finally I stream it using an udpsink element. It works, but if I 
> stop the pipeline (sending it EOS) and then start it again, I get old 
> video, when it should be alive. How can I clean absolutely the pipeline 
> to avoid this?
> 
>     My code is something like this:
>    
>         ...
>         // Create the elements
>         pipeline = gst_pipeline_new( "pipe" );
>         video_src = gst_element_factory_make( "mfw_v4lsrc", 
> "video-source" );
>         video_enc = gst_element_factory_make( "mfw_vpuencoder", 
> "video-encoder" );
>         sink = gst_element_factory_make( "udpsink", "sink" );
>         // Add the elements to the pipeline
>         gst_bin_add_many( GST_BIN( pipeline ), video_src, video_enc, 
> sink, NULL );
>         gst_element_link_with_filter( video_src, video_enc, &settings );
>         gst_element_link( video_enc, sink );
>         ...
>         // Start/Stop the video stream
>         while ( 1 )
>         {
>              if ( do_stream )  
>              {
>                  gst_element_set_state( pipeline, GST_STATE_PLAYING );
>                  g_main_loop_run( loop );
>                  gst_element_set_state( pipeline, GST_STATE_NULL );
>              }
>              else
>                 sleep( 1 );
>         }
>         ...
> 
>     Another function changes the variable 'do_stream' to true/false, and 
> send also the EOS signal to the pipeline when required.
> 
>     So, specifically, my question is: What do I clean my pipeline when 
> stopped to start again with the buffers and everything clean? Do I have 
> to delete the pipeline object and do I have to create and link all the 
> pipeline again?

You need to talk to the vendor of mfw_v4lsrc, mfw_vpuencoder to get confirmation
from them that their elements are reusable (that is they correcly cleanup their
state in state_changed()).

Stefan


> 
>     Thank you very much.
>     All the best.
>     LD.
> 
> 
> 
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