Unable to collect data from sensors from source build on Linux, V_0_9_11

Hi, Everyone!

I successfully wrote a simple python script that collected data from vehicle sensors(various types), and, using the package build (0_9_10), recorded data from all of these sensors to the file system, no problem.

Now I have gotten a source build of carla (0_9_11), am running it via “make launch” and am trying to run the very same client script to record sensor data to files and no cigar. I get a series of blank files written instead of data.

I am able to spawn vehicles, no problem… so the connection to send commands to the server seems to be working just fine. But… when I try to collect data, the client does not seem to be able to receive data from the server. I see the following error on the server side:

ERROR: Invalid session: no stream available with id 2
(an unending series of these errors)

From the client side, I see:
CameraF.listen(lambda image: image.save_to_disk(’/home/…/rgbCamF/FRONT_%.6d.jpg’ %image.frame))
Runtime Error: cannot write jpeg file: upstream error

(and an unending series of these errors also)

Has anyone seen this, and does anyone know how to fix it?

Any idea why I can send commands to the server, but not receive data back?

Any idea why I would be able to collect data via the package version of the server, but not via a native source build?

Help is greatly appreciated! Apologies - I’m a newbie in this space.


Hi, can you show the python file you are trying to run?

Thanks! See test script here at the link below. I have defined a number of sensors but shut off recording for all but one RGB camera in the front of the vehicle.

This successfully runs from the package distribution on 0.9.10. But, from the default source build for 0.9.11, it writes blank files.

I am able to spawn vehicles into my 0.9.11 source build, no problem. It is the connection for data collection that is blocked.

Short data collection script:


@yap9996 Hello! At least part of the problem is that the 0.9.11 source build cannot handle writing jpeg files. I had no issues writing jpg files in 0.9.10, and did not immediately suspect an issue with jpg. I don’t yet know why writing jpg doesn’t work in 0.9.11, whether something changed to affect this in the source, some incompatibility on my system, etc. The short term solution is writing images with an extension of png instead of jpg. I don’t have a preference for my application, but someone might. Maybe someone on the Carla team could check this out?