docs/random/example

   1 OUTDATED, methods have different names now
   2 ------------------------------------------
   3
   4
   5 Here's a pipeline that does audio/video MPEG streams with a queue on
   6 either side of each decompressor, for a total of 5 threads (read/split,
   7 decode audio, decode video, play audio, play video):
   8
   9 NOTES: mpegsplit is the intelligence in this pipeline, providing an IDL
  10 that allows one to connect things to a GUI.
  11
  12 Pipeline(mpegplay)
  13         Thread(reader)
  14                 Element(:disk_async_src) [StreamerAsyncSrc]
  15                         OutPad(disk1)
  16                 Element(:mpegsplit)
  17                         InPad(disk1)
  18                         OutPad(audio1)
  19                         OutPad(video1)
  20
  21         Queue(audioQ1)
  22                 InPad(audio1)
  23                 OutPad(audio2)
  24         Thread(audiodecode)
  25                 Element(:mpeg_audio_decode) [StreamerVideoFilter]
  26                         InPad(audio2)
  27                         OutPad(audio3)
  28         Queue(audioQ2)
  29                 InPad(audio3)
  30                 OutPad(audio4)
  31         Thread(audioplay)
  32                 Element(:audio_play) [StreamerAudioSink]
  33                         InPad(audio4)
  34
  35         Queue(videoQ1)
  36                 InPad(video1)
  37                 OutPad(video2)
  38         Thread(videodecode)
  39                 Element(:mpeg_video_decode) [StreamerVideoFilter]
  40                         InPad(video2)
  41                         OutPad(video3)
  42         Queue(videoQ2)
  43                 InPad(video3)
  44                 OutPad(video4)
  45         Thread(videoplay)
  46                 Element(:video_play) [StreamerVideoSink]
  47                         InPad(video4)
  48
  49
  50 A simpler pipeline that just does MPEG videos:
  51
  52 Pipeline(mpegplay)
  53         Thread(reader)
  54                 Element(:disk_async_src) [GstAsyncSrc]
  55                         OutPad(disk1)
  56                 Element(:mpeg_control)
  57                         InPad(disk1)
  58                         OutPad(video1)
  59                 Element(:mpeg_video_decode) [GstVideoFilter]
  60                         InPad(video1)
  61                         InPad(video2)
  62         Queue(queue)
  63                 InPad(video2)
  64                 OutPad(video3)
  65         Thread(play)
  66                 Element(:video_play) [GstVideoSink]
  67                         InPad(video3)
  68
  69 The code for the above looks roughly like:
  70
  71 /* all the objects we're worried about */
  72 GstPipeline *mpegplay;
  73 GstThread *reader;
  74 GstSrc *disk_src;
  75 GstControl *mpeg_control;
  76 GstFilter *mpeg_video_decode;
  77 GstQueue *queue;
  78 GstThread *play;
  79 GstSink *video_play;
  80
  81 /*** first we create all of the objects ***/
  82
  83 mpegplay = gst_pipeline_new();
  84 reader = gst_thread_new();
  85 disk_src = gst_async_disk_src_new("filename.mpg");
  86 mpeg_control = gst_mpeg_control_new();
  87 mpeg_video_decode = gst_mpeg_video_decode_new();
  88 queue = gst_queue_new();
  89 play = gst_thread_new();
  90 video_play = gst_video_sink_new();
  91
  92
  93 /*** now we start to create the pipeline ***/
  94
  95 /* first set up the reader thread */
  96 gst_bin_add(reader,disk_src);
  97 gst_object_connect(disk_src,"out",mpeg_control,"in");
  98 gst_object_connect(mpeg_control,"out",mpeg_audio_decode,"in");
  99 gst_bin_ghost_pad(reader,mpeg_audio_decode,"out");
 100
 101 /* then set up the player thread */
 102 gst_bin_add(play,audio_play);
 103 gst_bin_ghost_pad(play,audio_play,"in");
 104
 105 /* now plug them all into the main pipeline */
 106 gst_bin_add(mp3play,reader);
 107 gst_object_connect(reader,"out",queue,"in");
 108 gst_object_connect(queue,"out",play,"in");