[aravis] timestamping gstreamer buffers
- From: Patrick Doyle <wpdster@xxxxxxxxx>
- To: aravis@xxxxxxxxxxxxx
- Date: Mon, 14 Apr 2014 13:07:38 -0400
Is this a bug in the code, or in my understanding:
According to gst-inspect-1.0 aravissrc:
do-timestamp : Apply current stream time to buffers
flags: readable, writable
Boolean. Default: false
I was expecting that, when do-timestamp is true, aravissrc would grab
the timestamp field from the GigEVision packet and stuff it in into
the timestamp field of the gstreamer buffer.
But when I look in gstaravis.c, I see (note the "!" in the first if statement):
if (!gst_base_src_get_do_timestamp(GST_BASE_SRC(push_src))) {
if (gst_aravis->timestamp_offset == 0) {
gst_aravis->timestamp_offset = arv_buffer->timestamp_ns;
gst_aravis->last_timestamp = arv_buffer->timestamp_ns;
}
GST_BUFFER_PTS (*buffer) = arv_buffer->timestamp_ns -
gst_aravis->timestamp_offset;
GST_BUFFER_DURATION (*buffer) = arv_buffer->timestamp_ns -
gst_aravis->last_timestamp;
gst_aravis->last_timestamp = arv_buffer->timestamp_ns;
}
which looks like it fills in the GST_BUFFER_PTS when do-timestamp is
false. Am I misunderstanding the timestamp notion in gstreamer? Or
is this simply a typo in the code?
(Unfortunately, this doesn't explain the weird latency issues I'm
seeing with my Blackfly camera, but it does explain weird, sub
milliscecond frame durations when I put the stream through a queue
element).
--wpd
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