Why would videoencoder handle_frame only ever be called once?

[Graham Leggett]

Hi all,

I am trying to convert a video frame into text metatdata (printing the time), and have created a videoencoder element in an effort to do this.

I have implemented a set_format() and handle_frame() function, and they are called as below. set_format is called once, and handle_frame() is called once, and then nothing follows. There are no warnings, and no errors.

I am expecting handle_frame() to be called once per frame, is this correct?

Redistribute latency...
0:00:09.027681221 29059   0x22b8f0 DEBUG            xxx gstxxx.c:258:gst_xxx_set_format:<xxx0> set_format
0:00:09.028384236 29059   0x22b8f0 DEBUG            xxx gstxxx.c:313:gst_xxx_handle_frame:<xxx0> handle_frame
************ handle_frame
[New Thread 0x69379470 (LWP 29083)]

I am currently creating a 64 byte buffer and writing it as follows. This is wired into filesink, which then creates a zero byte file and I never see any data written. Can anyone see where I am going wrong?

static GstFlowReturn
gst_xxx_handle_frame (GstVideoEncoder * encoder,
    GstVideoCodecFrame * frame)
{
  Gstxxx *xxx = GST_xxx (encoder);
  GstVideoFrame vframe;
  GstMemory *output_mem;
  GstMapInfo output_map;
  static GstAllocationParams params = { 0, 7, 0, 0, };
  gsize desired_size;

  GST_DEBUG_OBJECT (xxx, "handle_frame");

  if (!gst_video_frame_map (&vframe,
          &xxx->input_state->info, frame->input_buffer, GST_MAP_READ))
    goto invalid_frame;

  desired_size = 64;

  output_mem = gst_allocator_alloc (NULL, desired_size, &params);
  gst_memory_map (output_mem, &output_map, GST_MAP_READWRITE);

  output_map.data[0] = 'f';
  output_map.data[1] = 'o';
  output_map.data[2] = 'o';
  output_map.data[3] = '\n';

  output_map.data[4] = 0;

  gst_memory_unmap (output_mem, &output_map);
  frame->output_buffer = gst_buffer_new ();
  gst_buffer_copy_into (frame->output_buffer, frame->input_buffer,
      GST_BUFFER_COPY_METADATA, 0, -1);
  gst_buffer_append_memory (frame->output_buffer, output_mem);
  output_mem = NULL;

  gst_video_frame_unmap (&vframe);


printf("************ handle_frame\n");

  GST_VIDEO_CODEC_FRAME_SET_SYNC_POINT (frame);

  return gst_video_encoder_finish_frame (GST_VIDEO_ENCODER (xxx),
      frame);

//  return GST_FLOW_OK;

invalid_frame:
  {
    GST_WARNING_OBJECT (xxx, "invalid frame received");
    return gst_video_encoder_finish_frame (encoder, frame);
  }
}

Regards,
Graham
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