翻译I am building a music player based on gstreamer-0.10. I am able to play the successfully , but I have issues when I change the state of the pipeline. I have posted the code to initialize and start the pipeline below :
void start_gstreamer() { gst_init(0,NULL);//call to initialise gstreamer time_val=0;//set to default value volume = 1.0;//set volume to default value player = gst_element_factory_make ("playbin2", "player");//get pipeline equalizer = gst_element_factory_make ("equalizer-10bands", "equalizer");//get the 10band equalizer convert = gst_element_factory_make ("audioconvert", "convert"); sink = gst_element_factory_make ("autoaudiosink", "audio_sink");//get the audio-sink if (!equalizer || !convert || !sink)//check is all elements were created { g_printerr ("Not all elements could be created.\n"); //return -1; } //int i=0; /* Create the sink bin, add the elements and link them */ bin = gst_bin_new ("audio_sink_bin");//get new bin gst_bin_add_many (GST_BIN (bin), equalizer, convert, sink, NULL);//add elements to bin if(!(gst_element_link_many (equalizer, convert, sink, NULL)))//link all elements g_print("Could not link all elements\n"); pad = gst_element_get_static_pad (equalizer, "sink");//set equalizer to sink ghost_pad = gst_ghost_pad_new ("sink", pad);//get a ghost pad to sink gst_pad_set_active (ghost_pad, TRUE); gst_element_add_pad (bin, ghost_pad);//add ghost pad to the bin gst_object_unref (pad);//unreference pad gst_element_set_state (player, GST_STATE_READY);//set pipeline to ready state //gst_element_set_state (player, GST_STATE_PAUSED); /* Configure the equalizer */ g_object_set (G_OBJECT (equalizer), "band0",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band1",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band2",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band3",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band4",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band5",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band6",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band7",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band8",(gdouble) 0.0, NULL); g_object_set (G_OBJECT (equalizer), "band9",(gdouble) 0.0, NULL); /* Set playbin2's audio sink to be our sink bin */ g_object_set (GST_OBJECT (player), "audio-sink", bin, NULL); }The above code will initialize the gstreamer pipeline. I am using playbin2.
void start_playbin (char *gargv1) { time_t rawtime; struct tm * timeinfo; static gboolean i=TRUE; gchar* uri;//to hold the path temporarily gchar* dname;//to hold the directory name time ( &rawtime ); timeinfo = localtime ( &rawtime ); printf ( "START:%s\n", asctime (timeinfo) ); uri = (gchar *)g_malloc( sizeof("file://") + strlen(gargv1) + 1);//get complete path strcpy(uri,"file://"); strcat(uri,gargv1);//add path with the file path dname = g_uri_escape_string(uri,G_URI_RESERVED_CHARS_ALLOWED_IN_PATH,TRUE); g_free(uri); uri = dname; g_object_set(player,"uri",uri,NULL);//set file path for playback in the pipeline g_print("\n\nPlaying %s\n", gargv1); g_free(uri);//free path /* start playback */ gst_element_set_state (GST_ELEMENT (player), GST_STATE_READY);//set pipeline to ready state if(i==TRUE) { unsigned int count=0; while(gst_element_set_state (GST_ELEMENT (player), GST_STATE_PLAYING)!=GST_STATE_CHANGE_SUCCESS); //g_print("here:%d\n",count++); i=FALSE; } else play_playbin();//start playback bus = gst_pipeline_get_bus(GST_PIPELINE(player));//get bus reference gst_bus_add_watch(bus,(GstBusFunc)cb_message,player);//add bus to be monitored by process events g_object_unref(bus);//unreference bus time ( &rawtime ); timeinfo = localtime ( &rawtime ); printf ( "AFTER START:%s\n", asctime (timeinfo) ); }I had to use the if(i == TRUE) condition just because the pipeline doesn't change the state for the first time.
void stop_playbin() { if(gst_element_set_state (GST_ELEMENT (player), GST_STATE_NULL)!=GST_STATE_CHANGE_SUCCESS) g_print("Playbin could not be stopped\n"); //g_assert(gst_element_set_state (GST_ELEMENT (player),GST_STATE_NULL)==GST_STATE_CHANGE_SUCCESS); } void pause_playbin() { if(gst_element_set_state (GST_ELEMENT (player), GST_STATE_PAUSED)!=GST_STATE_CHANGE_SUCCESS) g_print("Playbin could not be paused\n"); //g_assert(gst_element_set_state (GST_ELEMENT (player), GST_STATE_PAUSED)==GST_STATE_CHANGE_SUCCESS);}
void play_playbin() { if(gst_element_set_state (GST_ELEMENT (player), GST_STATE_PLAYING)!=GST_STATE_CHANGE_SUCCESS) g_print("Playbin could not be played\n"); //g_assert(gst_element_set_state (GST_ELEMENT (player),GST_STATE_PLAYING)==GST_STATE_CHANGE_SUCCESS); }The above function perform play,pause and Stop function respectively. The problem is, when I send the path of the file to the function start_playbin() I cannot change the path of the file after setting the pipeline only to ready. I have to make it 1) Ready 2)Pause or Play(cannot set state) 3)stop and then Play(set state success) the song.
Please help me. I don't get any errors if I set the pipeline to only ready but the program hangs. What could be the problem? Is there any specific sequence to be followed to setup a pipeline and set the path of the file?