Timeouts about librealsense HOT 6 CLOSED

This is a somewhat tricky issue. The behavior of rs_wait_for_frames(...) is to block until a coherent frameset is available. However, there are also a class of hardware errors which prevent further streaming and which are only portably detectable by the fact that new frames stop arriving over the UVC connection, so rs_wait_for_frames(...) is also responsible for detecting this scenario and raising an error in that case.

The timing and synchronization code is due for a bit of an overhaul, though, and if there's interest, we could add a second method (rs_check_for_frames(...), perhaps?) with a user specifiable timeout and a return value to indicate if new data is available.

As an aside, if you have a use case that seems to be frequently triggering the timeout, please open it as a second issue, and we'll see if we can do something to improve the reliability of streaming for that use case.

from librealsense.

I thought it might be tricky with multiple streams from multiple devices (/dev/videoX) etc.

I was mostly worried about while(true) loops in wait_all_streams consuming CPU core looping, either until next frame (15-30 ms) or in error condition until 5 second timeout, but it seems not that bad - I suppose thanks to the atomics in triple_buffer.

BTW are the sensors (RGB/Depth) in F200/R200 hardware synchronized? Either by sharing pixel clock or exposure timestamped to a common HW timer? I see something related in stream_buffer::frame::timestamp so I was hopeful that the cameras have proper timing, not like Kinect with two separate free running sensors.

from librealsense.

Both F200 and R200 have internal sync mechanism to trigger the sensors on a common clock. These are exposed to software via frame-counters, and we provide matched frame sets in librealsense. The SR300 has a revised timing architecture (via frame metadata in the UVC protocol) that provides additional timing information, and we'll expose that as a feature when SR300 reaches general availability.

from librealsense.

Awesome, that's proper camera engineering right there :) If only these cameras had GPIO trigger in/out to synchronize other things as well (think IMU, robot's odometry etc).

from librealsense.

👍 for trigger I/O (or at least for a hint on where to solder :-)

from librealsense.

Trigger IO would be awesome; please?

from librealsense.