All Boards Creating App Video

Document created by jesseg Employee on Aug 6, 2012Last modified by Jodi Paul on Apr 17, 2013
Version 3Show Document
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Instead to use gst-launch to play your audio/video media you can create an application do to that.

 

 

This application was tested in iMX27ADS but should to work on iMX27PDK

 

 

First execute LTIB (./ltib -c) and select these packages: all gstreamer plugin, alsa-utils and libmad.

Create your file code (i.e.: playvideo.c):

#include <gst/gst.h>

#include <glib.h> #include <string.h>



static GstElement *source, *demuxer, *vdqueue, *adqueue, *vdsink, *adsink, *decvd, *decad;

void on_pad_added (GstElement *element, GstPad *pad)
{
        g_debug ("Signal: pad-added");
        GstCaps *caps;
        GstStructure *str;

        caps = gst_pad_get_caps (pad);
        g_assert (caps != NULL);
        str = gst_caps_get_structure (caps, 0);
        g_assert (str != NULL);

        if (g_strrstr (gst_structure_get_name (str), "video")) {
                g_debug ("Linking video pad to dec_vd");
                // Link it actually
                GstPad *targetsink = gst_element_get_pad (decvd, "sink");
                g_assert (targetsink != NULL);
                gst_pad_link (pad, targetsink);
                gst_object_unref (targetsink);
        }

        if (g_strrstr (gst_structure_get_name (str), "audio")) {
                g_debug ("Linking audio pad to dec_ad");
                // Link it actually
                GstPad *targetsink = gst_element_get_pad (decad, "sink");
                g_assert (targetsink != NULL);
                gst_pad_link (pad, targetsink);
                gst_object_unref (targetsink);
        }

        gst_caps_unref (caps);
}

static gboolean
bus_call (GstBus    *bus,
          GstMessage *msg,
          gpointer    data)
{
  GMainLoop *loop = (GMainLoop *) data;

  switch (GST_MESSAGE_TYPE (msg)) {

    case GST_MESSAGE_EOS:
      g_print ("End of stream\n");
      g_main_loop_quit (loop);
      break;

    case GST_MESSAGE_ERROR: {
      gchar  *debug;
      GError *error;

      gst_message_parse_error (msg, &error, &debug);
      g_free (debug);

      g_printerr ("Error: %s\n", error->message);
      g_error_free (error);

      g_main_loop_quit (loop);
      break;
    }
    default:
      break;
  }

  return TRUE;
}

int
main (int  argc,
      char *argv[])
{
  GMainLoop *loop;

  GstElement *pipeline;
  GstBus *bus;

  /* Initialisation */
  gst_init (&argc, &argv);

  loop = g_main_loop_new (NULL, FALSE);


  /* Check input arguments */
  if (argc != 2) {
    g_printerr ("Usage: %s <Video H264 filename>\n", argv[0]);
    return -1;
  }


  /* Create gstreamer elements */
  pipeline      = gst_pipeline_new ("media-player");
  source        = gst_element_factory_make ("filesrc","file-source");
  demuxer      = gst_element_factory_make ("mfw_mp4demuxer","avi-demuxer");
  decvd        = gst_element_factory_make ("mfw_vpudecoder", "video-decoder");
  decad        = gst_element_factory_make ("mad", "mp3-decoder");
  vdsink        = gst_element_factory_make ("mfw_v4lsink",    "video-sink");
  vdqueue      = gst_element_factory_make ("queue",            "video-queue");
  adqueue      = gst_element_factory_make ("queue",            "audio-queue");
  adsink        = gst_element_factory_make ("fakesink",        "audio-sink");

  g_object_set (decvd, "codec-type", "std_avc", NULL);

  if (!pipeline || !source || !demuxer || !decvd || !decad || !vdsink || !vdqueue || !adqueue || !adsink) {
    g_printerr ("One element could not be created. Exiting.\n");
    return -1;
  }

  /* Set up the pipeline */

  /* we set the input filename to the source element */
  g_object_set (G_OBJECT (source), "location", argv[1], NULL);

  /* we add a message handler */
  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  gst_bus_add_watch (bus, bus_call, loop);
  gst_object_unref (bus);

  /* we add all elements into the pipeline */
  /* file-source | ogg-demuxer | vorbis-decoder | converter | alsa-output */
  gst_bin_add_many (GST_BIN (pipeline),
                    source, demuxer, decvd, decad, adqueue, vdqueue, vdsink, adsink,  NULL);

  /* we link the elements together */
  /* file-source -> ogg-demuxer ~> vorbis-decoder -> converter -> alsa-output */
  gst_element_link (source, demuxer);
  gst_element_link (decvd, vdqueue);
  gst_element_link (vdqueue, vdsink);
  //gst_element_link (decad, adqueue);
  gst_element_link (adqueue, adsink);

  g_signal_connect (demuxer, "pad-added", G_CALLBACK (on_pad_added), NULL);

  /* note that the demuxer will be linked to the decoder dynamically.
    The reason is that Ogg may contain various streams (for example
    audio and video). The source pad(s) will be created at run time,
    by the demuxer when it detects the amount and nature of streams.
    Therefore we connect a callback function which will be executed
    when the "pad-added" is emitted.*/

  /* Set the pipeline to "playing" state*/
  g_print ("Now playing: %s\n", argv[1]);
  gst_element_set_state (pipeline, GST_STATE_PLAYING);


  /* Iterate */
  g_print ("Running...\n");
  g_main_loop_run (loop);


  /* Out of the main loop, clean up nicely */
  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;
}

Create a directory inside your ltib directory to compile your source code:

$ mkdir ~/your-ltib-dir/rpm/BUILD/gst

 

Enter on LTIB shell mode:

$ ./ltib -m shell

 

Entering ltib shell mode, type 'exit' to quit

LTIB>

 

Enter in your application dir:

LTIB> cd rpm/BUILD/gst/

 

Compile your application:

LTIB> gcc -Wall $(pkg-config --cflags --libs gstreamer-0.10) playvideo.c -o playvideo

 

If everything worked file you will get a "playvideo" arm binary:

LTIB> file playvideo

playvideo: ELF 32-bit LSB executable, ARM, version 1 (SYSV), for GNU/Linux 2.6.14, dynamically linked (uses shared libs), not stripped

 

Now just copy it to ~/your-ltib-dir/rootfs/home.

 

Start your board using this rootfs and execute:

root@freescale ~$ cd /home/

root@freescale /home$ ./playvideo your-file-h264-mp3.avi

Now playing: your-file-h264-mp3.avi

Running...

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