Copying buffer data

[Ozhmegov]

Hi everyone,
   I'm creating a new buffer in my gstreamer's plugins and then I don't
touch that buffer. However, data of old buffer appears in new one. How does
old buffer appear in new one?
Here my C code:

static GstFlowReturn
gst_coder_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
  Gstcoder *filter;

  filter = GST_CODER (parent);
  g_print ("%d x %d\n",filter->width,filter->height);
  g_print ("Have data of size %" G_GSIZE_FORMAT" bytes!\n",
gst_buffer_get_size (buf));
   
   
  gint sz = 0;
  if ((sz = gst_buffer_get_size(buf)) != 0)
  {
   * //info stores properties about buffer*
    GstMapInfo info;
    gst_buffer_map (buf, &info, GST_MAP_WRITE);

    *//create template var buffer*
    GstBuffer *buffer = gst_buffer_new_allocate(NULL, sz, NULL);
    GstMapInfo info1;
    gst_buffer_map (buffer, &info1, GST_MAP_WRITE);

   
    gst_buffer_unmap (buf, &info);
    gst_buffer_unref (buf);
    gst_buffer_unmap (buffer, &info1);
       
    return gst_pad_push (filter->srcpad, buffer);
  }
  GST_WARNING ("zero sized buffer");
  return gst_pad_push (filter->srcpad, buf);
}

I'd appreciate any advice.  Thanks

gstcoder.c
gstcoder.h


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[Yasushi SHOJI-2]

Hi,

On Fri, Sep 29, 2017 at 9:52 PM, Ozhmegov <[hidden email]> wrote:
>    I'm creating a new buffer in my gstreamer's plugins and then I don't
> touch that buffer. However, data of old buffer appears in new one. How does
> old buffer appear in new one?

I'm not quite sure what you mean.  What appears where?
Do you have a complete minimal example which we can compile and try?

>     GstBuffer *buffer = gst_buffer_new_allocate(NULL, sz, NULL);

If you mean by the buffer has old contents right after the allocation,
that's how heap memory (g_slice_alloc / malloc) works in C.

https://stackoverflow.com/a/8029624/640650
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[Nicolas Dufresne-5]

Le vendredi 29 septembre 2017 à 05:52 -0700, Ozhmegov a écrit :
>    I'm creating a new buffer in my gstreamer's plugins and then I don't
> touch that buffer. However, data of old buffer appears in new one. How does
> old buffer appear in new one?
> Here my C code:

For performance reason, a heap being asked for a buffer with the size
of a previously released buffer, will likely return you the same
buffer. Also, for performance reason, we don't clear the buffers. You
application will need to handle that if it wanted an zero-ed out
buffer.

Nicolas
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[Ozhmegov]

Hi,

Thank you for replies

I posted my coder.c and coder.h files (see above). I understood my mistakes.




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