Sending timestamp metadata from C++ to Python

[Wilkins White]

Found this in the logs:

0:00:13.756895364 11417   0x55ae8c7540 WARN ipcpipelinecomm 
gstipcpipelinecomm.c:483:build_meta:<ipcpipelinesink0> Ignoring GstMeta 
type GstReferenceTimestampMetaAPI

Looks like ipcpipelinesink does ignore GstReferenceTimestampMetaAPI, 
I'll have to do some more research

On 8/27/20 5:42 PM, Wilkins White wrote:
> I would like to send metadata, specifically GstReferenceTimestampMeta, from
> my C/C++ application to a Python application. It seems like I should be able
> to accomplish this with `appsrc ! ipcpipelinesink` and `ipcpipelinesrc !
> appsink` but the metadata isn't showing up on the Python side.  Am I missing
> something obvious, or will metadata not travel through
> ipcpipelinesink/ipcpipelinesrc?
>
> On my C++ application I am loading an appsrc with data from a CUDA pipeline
> which feeds an ipcpipelinesink. I am using
> `gst_buffer_add_reference_timestamp_meta` to add the reference timestamp for
> when the frame was captured. I was able to read the value back using
> `gst_buffer_get_reference_timestamp_meta` so I know it is there.
>
>      // Allocate a new GstBuffer
>      GstBuffer *gstbuf = gst_buffer_new_allocate(nullptr, buffer_size,
> nullptr);
>
>      // Add reference timestamp to metadata
>      GstClockTime timestamp = static_cast<uint64_t>(ctx->m_frame.m_ts);
>
>      GstCaps *reference =
> gst_caps_from_string("timestamp/x-metavision-stream");
>
>      gst_buffer_add_reference_timestamp_meta(
>          gstbuf, reference, timestamp, GST_CLOCK_TIME_NONE);
>
>      // Set pipeline timestamp
>      if(ctx->m_init_ts == 0)
>          ctx->m_init_ts = timestamp;
>
>      gstbuf->pts = timestamp - ctx->m_init_ts; // ns
>      gstbuf->dts = gstbuf->pts;
>
>      // Map GstBuffer (output)
>      GstMapInfo map;
>      memset(&map, 0, sizeof(GstMapInfo));
>      gst_buffer_map(gstbuf, &map, GST_MAP_WRITE);
>
>      // Copy NvBuffer to GstBuffer
>      ...
>
>      // Unmap
>      gst_buffer_unmap(gstbuf, &map);
>
>      // Push buffer
>      gst_app_src_push_buffer(GST_APP_SRC(ctx->m_appsrc), gstbuf);
>
> On the Python side I create an ipcslavepipeline with an ipcpipelinesrc
> feeding an appsink. Caps are negotiated properly and I am able to convert
> the Gst.Buffer into a numpy array, but
> `Gst.Buffer.buf.get_reference_timestamp_meta` is returning None:
>
>      buf = sample.get_buffer()
>
>      reference = Gst.Caps.from_string('timestamp/x-metavision-stream')
>      ts_meta = buf.get_reference_timestamp_meta(reference) #
> Gst.ReferenceTimestampMeta
>      print(ts_meta) # None
>
> Am I barking up the wrong tree here? I would appreciate any input.
>
>
>
>
> --
> Sent from: http://gstreamer-devel.966125.n4.nabble.com/
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
-- 
Nova Dynamics <http://www.novadynamics.com> 	

*Wilkins White* *| * /Firmware Engineer/ *| * ww at novadynamics.com 
<mailto:ww at novadynamics.com>
517 N 19th St, Philomath, OR *| * 503.805.0762 <tel:+15038050762>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20200828/77eec6a7/attachment.htm>