Created attachment 250435 [details] [review]
patch to fix this problem

If there are no frame delimiter at the end of stream. You will see this bug.
Root cause:
If the input adapter is emptied. GstVideoDecoder will not call subclass's parser at EOS reached.So last frame is buffered in output adapter.   it never get a chance to send last frame to our decoder.

record bytes count in output adapter can fix this.

Hi, actually the real root cause was in the GstVideoDecoder base class implementation. Depending on the stream, it would not submit the expect EOS message.

I have to review your patch again, but it looks like an acceptable workaround.

For instance, could you please test with ffdec_h264 for example, or more precisely avdec_h264 for current 1.0 builds? Thanks. i.e. if both vaapidecode and avdec_h264 miss the last frame, and both are using GstVideoDecoder base class, then this means the issue was in there.

Note: I know gstreamer-libav was ported to the GstVideoDecoder infrastructure, but I have not checked whether this actually was released for GStreamer 1.0.x. Will check later, or you could have a look while doing the test.

Hi Gwenole:
Yes. I have tried avdec_h264. It's no such problem. you can install gstreamer ppa and take a look.
https://wiki.ubuntu.com/Novacut/GStreamer1.0 
No. Actually, the GstVideoDecoder have accepted EOS. So it called gst_video_decoder_drain_out.
In our case the gst_adapter_available(priv->input_adapter)  will return 0.
Since we take all slices from last frame to output_adapter.We never get a chance to call decoder_class->parse (dec, priv->current_frame,
            priv->input_adapter, TRUE); 




static GstFlowReturn
gst_video_decoder_drain_out (GstVideoDecoder * dec, gboolean at_eos)
{
  GstVideoDecoderClass *decoder_class = GST_VIDEO_DECODER_GET_CLASS (dec);
  GstVideoDecoderPrivate *priv = dec->priv;
  GstFlowReturn ret = GST_FLOW_OK;

  GST_VIDEO_DECODER_STREAM_LOCK (dec);

  if (dec->input_segment.rate > 0.0) {
    /* Forward mode, if unpacketized, give the child class
     * a final chance to flush out packets */
    if (!priv->packetized) {
      while (ret == GST_FLOW_OK && gst_adapter_available (priv->input_adapter)) {
        if (priv->current_frame == NULL)
          priv->current_frame = gst_video_decoder_new_frame (dec);

        ret = decoder_class->parse (dec, priv->current_frame,
            priv->input_adapter, TRUE);
      }
    }
  } else {
    /* Reverse playback mode */
    ret = gst_video_decoder_flush_parse (dec, TRUE);
  }

  if (at_eos) {
    if (decoder_class->finish)
      ret = decoder_class->finish (dec);
  }

  GST_VIDEO_DECODER_STREAM_UNLOCK (dec);

  return ret;
}

Fixed in git master branch. Thanks.

Additional changes:
- Renamed bytes_added_to_frame to current_frame_size ;
- Reset current_frame_size to zero on parse error so that we are sure to have valid data when the frame is submitted to the decoder in _finish().

commit 111d7d4fa4b2ced74d29d70887b63f2d39cae7d3
Author: Guangxin.Xu <Guangxin.Xu@intel.com>
Date:   Tue Jul 30 14:05:39 2013 +0800

    vaapidecode: submit the last frame from output adapter to decoder.
    
    If there is no frame delimiter at the end of the stream, e.g. no
    end-of-stream or end-of-sequence marker, and that the current frame
    was fully parsed correctly, then assume that last frame is complete
    and submit it to the decoder.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705123
    
    Signed-off-by: Guangxin.Xu <Guangxin.Xu@intel.com>
    Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>