Trouble with replaying recorded sensor data


I am having trouble understanding the replay function. I have recorded a sample stream of data camera+lidar which was stored on my external SSD. I want to replay all of the sensor data with the replayer with the --rig flag. Which JSON file should I choose in order to replay all of the data at once, and not only individual sensors? I have tried the following:

  1. ./replayer --rig /path/to/last_record/config/NAME-virtual.json
    –> this gives me errors saying that it cannot find .h264 and .bin files for cam+lidar, even if I point to the correct files with --camera and --lidar flag

  2. ./replayer --rig /path/to/last_record/recorder1.0-NAME.json
    –> also gives errors ‘nlohmann::detail::type_error’

  3. I copied NAME-virtual.json into last_record directory and then ./replayer --rig /path/to/last_record/NAME-virtual.json
    –> this works! But this can clearly not be right, right?

Maybe I overlooked something in the docs, but could someone please advise me on how replayer is to be used?


Dear cschro,

This is my condition to record from sensors.
External storage path : /media/nvidia/AAA
Recorded files path : /media/nvidia/AAA/dw_2019_09_20xxx
release.json file location : /media/nvidia/AAA/dw_2019_09_20xxx

./replay --rig=/media/nvidia/AAA/dw_2019_09_20xxx/release.json

So could you please try to run the replayer tool referring to the above? Thanks.

Hi Steve,

I do not have a JSON-file NAME.json (in your case Name=“release”) in the directory of the recording. This is located in the config/ folder in the same directory. If I launch ./replayer with --rig=NAME.json, it will only launch the sensors attached to the platform and live broadcast. It will not replay recorded data. The only way I cam replay recorded data is by copying NAME-virtual.json from the config/ directory one dir up directly into the recording folder.

This seems like a path problem. The NAME-virtual.sjon file should not be located in the config/ folder or otherwise reference the recorded data one dir up.

Clostest to your suggestion is the option you see below. My json is called “sensortests.json” and the recording tool outputs a “recorder1.0-sensortests.json” into the recording folder. When I launch with this file, the following error occurs:

./replayer --rig=/media/absolut/SensorData/dw_2017_07_04_08:15:13_000000_sensortests_e7dca0f2-6090-11e7-bd32-00044bcbcb32/recorder1.0-sensortests.json
[23-09-2019 14:49:09] Platform: Detected Generic x86 Platform
[23-09-2019 14:49:09] Initialize DriveWorks SDK v2.0.2081
[23-09-2019 14:49:09] Release build with GNU 4.9.4 from heads/buildbrain-branch-0-g36b127f
[23-09-2019 14:49:09] TimeSource: monotonic epoch time offset is 1569242752492591
[23-09-2019 14:49:09] Platform: number of GPU devices detected 1
[23-09-2019 14:49:09] Platform: currently selected GPU device discrete ID 0
[23-09-2019 14:49:09] SDK: Resources mounted from …/…/data/
[23-09-2019 14:49:09] Initialize DriveWorks VisualizationSDK v2.0.2081
[23-09-2019 14:49:09] Initialize DriveWorksGL SDK v2.0.2081
[23-09-2019 14:49:09] GL-SDK: initialize OpenGL
[23-09-2019 14:49:09] Loading rig file: /media/absolut/SensorData/dw_2017_07_04_08:15:13_000000_sensortests_e7dca0f2-6090-11e7-bd32-00044bcbcb32/recorder1.0-sensortests.json
terminate called after throwing an instance of ‘nlohmann::detail::type_error’
what(): [json.exception.type_error.302] type must be number, but is string
Aborted (core dumped)

Dear cschro,

Thank you for your update.
Sorry it is my fault.
You’re right. release.json file is in /media/nvidia/AAA/dw_2019_09_20xxx/config.

Hi Steve,

when I choose --rig=NAME.json, this will only start replayer with live broadcast of attached sensors. I have to use --rig=NAME-virtual.json to replay sensor data, after I copied the file over from config/ one dir up.

So just to confirm, this seems to be the “right” way? A fix would then be appreciated in upcoming releases, copying before replay isn’t that big of a deal but still shouldn’t be mandatory.


Dear cschro,

Thank you for your verification.
I will check this with our team. Thanks.

Hello this is Minjun,

Can you told me what do you use the sample code to record a camera and lidar?

I want to record these sensors at same time with time sync

Dear Minjun,
Did you check our recorder tool. Please check