How to capture a yuv frame from h.264 stream

glenne glenne at
Tue Nov 7 00:29:19 UTC 2017

Here is my current iteration code and an attempt to get an image.  My stream
is "videotestsrc ! autovideosink enable-last-buffer=true"

Unfortunately, I always get NULL for from_sample after calling g_object_get. 
Do I have an error in my
use of item or does autovideosink not pass on the enable-last-buffer setting
to the sink?

static void take_pic(CustomData *data) {
    GstIterator *sink_iterator =
    GValue item = G_VALUE_INIT;
    while (gst_iterator_next (sink_iterator, &item) == GST_ITERATOR_OK)

    GstElement *sink = GST_ELEMENT(g_value_get_object (&item));
    g_object_get (sink, "last-sample", &from_sample, (char*)NULL);
    if (from_sample == NULL) {
        GST_ERROR ("Error getting last sample form sink");

  GError *err = NULL;
  GstCaps *caps = gst_caps_from_string ("image/jpeg");
  GstSample *to_sample = gst_video_convert_sample (from_sample, caps,

    if (to_sample == NULL) {
        GST_ERROR ("Error converting video sample");

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