Media Tool: Managing Media Handles

This tutorial demonstrates how you can create, set, and get media handles.

Warm-up

Become familiar with the Media Tool API basics by learning about:

• Managing the Media Format Handle

  Create, set, and get the <media_format_h> handle.

• Managing the Media Packet Handle

  Create, set, and get the <media_packet_h> handle.

Managing the Media Format Handle

To manage the media format handle:

1. To use the media format handle of the Media Tool API (in mobile and wearable applications), include the <media_format.h> header file in your application:

   #include <media_format.h>
   

2. Define a handle for media_format_h and pass it to the media_format_create() function, which returns the handle. Set the video (or audio) information with the media_format_set_video_info() function.

   media_format_h format;
   if (media_format_create(&format) == MEDIA_FORMAT_ERROR_NONE)     
   {
      if (media_format_set_video_info(format, MEDIA_FORMAT_H264_HP, 480, 640, 10000000, 15000000) != MEDIA_FORMAT_ERROR_NONE)
      {             
         printf("media_format_set_video_info failed!");         
      }
   }
   else
   {         
      printf("media_format_create() failed!");     
   }

3. To get video format information, use the media_format_get_video_info() function:

   media_format_h fmt;
   
   media_format_mimetype_e mime;
   int w;
   int h;
   int avg_bps;
   int max_bps;
    
   if (media_format_get_video_info(fmt, &mimetype, &w, &h, &avg_bps, &max_bps) == MEDIA_PACKET_ERROR_NONE)
   {
      printf("media_format_get_video_info success! width = %d, height = %d", w, h);
   }
   else
   {
      print("media_format_get_video is failed...");
   }

Managing the Media Packet Handle

To manage the media packet handle:

1. To use the media packet handle of the Media Tool API (in mobile and wearable applications), include the <media_packet.h> header file in your application:

   #include <media_packet.h>
   

2. Define a handle for media_packet_h and pass it to a creation function with an existing media_format_h handle.

   To reuse the packet handle, set the return value as MEDIA_PACKET_REUSE of int (*media_packet_finalize_cb) and use media_format_unref(media_format_h fmt) after creating the handle.

   The following creation functions are available:

   • Create a handle and allocate a buffer into the heap or TBM surface with the media_packet_create_alloc() function:

     {
        media_format_h fmt;
        media_packet_h packet;
      
        media_format_create(&fmt);
        media_format_set_video_info(fmt, MEDIA_FORMAT_H264_HP, 480, 640, 10000000, 15000000);
      
        media_packet_create_alloc (fmt, _finalize_callback, fcb_data, &packet);
        media_format_unref(fmt);
     }
      
     int _finalize_callback(media_packet_h packet, int err, void* userdata)
     {
        return MEDIA_PACKET_REUSE;
     }

   • Create only a handle with the media_packet_create() function:

     {
        media_format_h fmt;
        media_packet_h packet;
      
        media_format_create(&fmt);
        media_format_set_video_info(fmt, MEDIA_FORMAT_H264_HP, 480, 640, 10000000, 15000000);
      
        media_packet_create (fmt, _finalize_callback, fcb_data, &packet);
        media_format_unref(fmt);
     }
     int _finalize_callback(media_packet_h packet, int err, void* userdata)
     {
        return MEDIA_PACKET_FINALIZE;
     }
     
     

   • Create a handle and store the TBM surface data with the media_packet_create_from_tbm_surface() function:

     {
        media_format_h fmt;
        media_packet_h packet;
     
        media_format_create(&fmt);
        media_format_set_video_info(fmt, MEDIA_FORMAT_RGBA, 128, 128, 2000000, 15000000);
     
        media_packet_create_from_tbm_surface (fmt, surface, _finalize_callback, fcb_data, &packet);
        media_format_unref(fmt);
     }
     int _finalize_callback(media_packet_h packet, int err, void* userdata)
     {
        return MEDIA_PACKET_FINALIZE;
     }
     
     

3. Set and get the metadata with the media packet handle:

   int ret = MEDIA_PACKET_ERROR_NONE;
   
   // format1 already exists
    
   media_packet_create_alloc(format1, NULL, NULL, &packet);
    
   ret = media_packet_set_duration(packet, duration);
    
   // After media_packet_get_format(), use media_format_unref()
   media_format_h tmp;
   media_packet_get_format(packet, &tmp);
   media_format_unref(tmp);
    
   // Set previously created format2 to packet
   // After media_packet_set_format(), use media_format_unref()
   media_packet_set_format(packet, format2);
    
   // Packet format is format2. If format2 ref_count is 1, format2 is free
   // If format2 ref_count is bigger than 1, it is not free
   media_packet_destroy(packet);