[maemo-developers] problem with playing wav file

[From: Stefan Kost]

Ganesh Kundapur schrieb:
> Hi,
>   I'm able to play the wav file by using gst-launch as fallows
> 
> gst-launch-0.10  filesrc location=~/songs/4voice.wav ! wavparse ! 
> audioconvert ! alsasink
> Setting pipeline to PAUSED ...
> Pipeline is PREROLLING ...
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> New clock: GstAudioSinkClock
> Caught interrupt -- handling interrupt.
> Interrupt: Setting pipeline to PAUSED ...
> Execution ended after 1914601000 ns.
> Setting pipeline to PAUSED ...
> Setting pipeline to READY ...
> Setting pipeline to NULL ...
> FREEING pipeline ...
> 
> 
> I modified the helloworld code to play the wav as
> 1. I created "waveparse" in place of oggdemux and vorbis  parser elements
> 2. Added filesrc, waveparse and alsasink to the pipeline and linked.
> 
> --
> int
> main ( int argc, char *argv[] )
> {
>         GMainLoop *loop;
>         GstBus *bus;
> 
>         gst_init ( &argc, &argv );
>         loop = g_main_loop_new ( NULL, FALSE );
> 
>          pipeline = gst_pipeline_new ( "audio-player" );
>         source = gst_element_factory_make ( "filesrc", "file-source" );
>         //parser = gst_element_factory_make ( "oggdemux", "ogg-parser" );
>         parser = gst_element_factory_make ( "wavparse", "wave-parser" );
>         //decoder = gst_element_factory_make ( "vorbisdec", 
> "vorbis-decoder" );
>         conv = gst_element_factory_make ( "audioconvert", "converter" );
>         sink = gst_element_factory_make ( "alsasink", "alsa-output" );
> 
>         if ( !pipeline || !source || !parser || !conv || !sink ) {
>                 g_print ( "One element could not be created\n" );
>                 return -1;
>         }
> 
>         g_object_set (G_OBJECT (source), "location", argv[1], NULL );
> 
>         bus = gst_pipeline_get_bus ( GST_PIPELINE ( pipeline ) );
>         gst_bus_add_watch ( bus, bus_call, loop );
>         gst_object_unref ( bus );
> 
>         gst_bin_add_many ( GST_BIN ( pipeline), source, parser,
>                            conv, sink, NULL );
> 
>         //gst_element_link ( source, parser );
>         gst_element_link_many ( source, parser, conv, sink, NULL );
>         g_signal_connect ( parser, "pad-added", G_CALLBACK ( new_pad ), 
> NULL );

This is the problem:
gst_element_link ( source, parser );
gst_element_link ( conv, sink );
g_signal_connect ( parser, "pad-added", G_CALLBACK ( new_pad ),  conv );

in new_pad() callback link the new pad you receive to the sink-pad of conv.

Stefan

> 
>         g_print ( "Setting to Playing\n" );
>         gst_element_set_state ( pipeline, GST_STATE_PLAYING );
>         g_print ( "Running\n" );
>         g_main_loop_run ( loop );
> 
>         g_print ( "Returned, stopping playback\n" );
>         gst_element_set_state ( pipeline, GST_STATE_NULL );
>         g_print ( "Deleting pipeline\n" );
> 
>         gst_object_unref ( GST_OBJECT ( pipeline ) );
> 
>         return 0;
> }
> --
> 
> 
> When i tried to run the fallowing code, i'm getting fallowing errors
> --
> ./a.out ~/songs/4voice.wav
> Setting to Playing
> Running
> Dynamic pad created, linking parser/decoder
> 
> (a.out:20136): GStreamer-CRITICAL **: gst_element_get_static_pad: 
> assertion `GST_IS_ELEMENT (element)' failed
> 
> (a.out:20136): GStreamer-CRITICAL **: gst_pad_link_prepare: assertion 
> `GST_IS_PAD (sinkpad)' failed
> 
> (a.out:20136): GStreamer-CRITICAL **: gst_object_unref: assertion 
> `object != NULL' failed
> Error: Internal data flow error.
> Returned, stopping playback
> Deleting pipeline
> --
> 
> Somebody already posted the similar problem in the mailing list ( 
> http://lists.maemo.org/pipermail/maemo-developers/2006-August/023007.html 
> ), but solution is not mentioned over there.
> 
> It would be of great help if somebody look into this.
> 
> Thanks,
> Ganesh
> 
> 
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