I’m trying to use the latency measurement functionality from the deepstream-app sample.
When my source is a video file, it works correctly. The frame number increases, and the latency is computed correctly.
If I use a camera source the reported frame number is stuck at 0, and the per-frame latency isn’t calculated correctly. See console output below. I’ve tried a V4L2 camera, and an source using the Aravis library. Both give the same result.
I confirmed that my source is setting the GstBuffer offset correctly when it is pushed onto the pipeline, but by the time nvds_measure_buffer_latency() gets called, the value of buffer->offset is -1.
It seems some other element in the deepstream pipeline is clobbering the buffer offset for a camera source. I’m not sure where. Is there somewhere else deepstream_app.c:latency_measurement_buf_prob() can get the frame number from such as some NVDS metadata?
Console output below showing frame_num = 0, frame latency miscalculated. The frame latency shown in the video overlay is the same (incorrect).
DeepStream version is 4.0.2, running on a TX2.
************BATCH-NUM = 199************** Comp name = src_bin_muxer source_id = 0 pad_index = 0 frame_num = 0 in_system_timestamp = 1583457792462.908936 out_system_timestamp = 1583457792463.787109 component_latency = 0.878174 Comp name = primary_gie_classifier in_system_timestamp = 1583457792463.978027 out_system_timestamp = 1583457792502.768066 component latency= 38.790039 Comp name = tiled_display_tiler in_system_timestamp = 1583457792503.020996 out_system_timestamp = 1583457792504.729004 component latency= 1.708008 Comp name = nvosd0 in_system_timestamp = 1583457792505.832031 out_system_timestamp = 1583457792507.922119 component latency= 2.090088 Source id = 0 Frame_num = 0 Frame latency = 1583457792509.444092 (ms) ************BATCH-NUM = 200************** Comp name = src_bin_muxer source_id = 0 pad_index = 0 frame_num = 0 in_system_timestamp = 1583457792498.487061 out_system_timestamp = 1583457792499.410889 component_latency = 0.923828 Comp name = primary_gie_classifier in_system_timestamp = 1583457792499.604980 out_system_timestamp = 1583457792539.282959 component latency= 39.677979 Comp name = tiled_display_tiler in_system_timestamp = 1583457792539.616943 out_system_timestamp = 1583457792541.226074 component latency= 1.609131 Comp name = nvosd0 in_system_timestamp = 1583457792542.456055 out_system_timestamp = 1583457792544.235107 component latency= 1.779053 Source id = 0 Frame_num = 0 Frame latency = 1583457792545.691895 (ms)