# How to specify a single camera for detection when using multi source input? **URL:** \ **Category:** DeepStream SDK\ **Created:** [April 8, 2021, 11:55pm UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623 "2021-04-08T23:55:35Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![linyeglasses](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@linyeglasses](https://forums.developer.nvidia.com/u/linyeglasses)\ **Post date:** [April 8, 2021, 11:55pm UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623/1 "2021-04-08T23:55:35Z")
\*\*• Hardware Platform (Jetson / GPU) \*\* Jetson Xavier NX **• DeepStream Version** 5.0.1 **• TensorRT Version** come with jetpack **• JetPack Version (valid for Jetson only)** 4.5 **• Issue Type( questions, new requirements, bugs)** New requirement **• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)** Hi, I’m new to gstreamer and deepstream. I have an application that requires multiple source inputs. So i started with the python app ‘image-data multi stream example’ provided by deepstream. This app do detection on all the camera inputs. Is there a way to specify only one or some of them do the detection, while all inputs include the one used for detection are collected by nvmultistreamtiler linked later in the pipeline? Also, I tried to use two pipelines to meet the requirement, one follows the single camera (camera 0) pipeline to detect objects, and an another pipeline that receives multiple camera inputs (camera 0,1,2…) with no detection but a nvmultistreamtiler to link them. It works fine when I execute them separately. However, when executing two pipelines in the same script, it gives me error when building the second pipeline: ``` Starting pipeline Unable to set device in gst_nvstreammux_change_state Unable to set device in gst_nvstreammux_change_state Decodebin child added: decodebin0 ``` I guess the two nvsteammux for two pipeline are having a conflict? is there a workaround? Thanks ---
**Author:** ![kayccc](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/kayccc/32/14043_2.png) [@kayccc](https://forums.developer.nvidia.com/u/kayccc)\ **Post date:** [April 9, 2021, 12:33am UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623/2 "2021-04-09T00:33:30Z")
Please provide complete information as applicable to your setup. **• Hardware Platform (Jetson / GPU)** **• DeepStream Version** **• JetPack Version (valid for Jetson only)** **• TensorRT Version** **• NVIDIA GPU Driver Version (valid for GPU only)** **• Issue Type( questions, new requirements, bugs)** **• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)** **• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)** ---
**Author:** ![linyeglasses](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@linyeglasses](https://forums.developer.nvidia.com/u/linyeglasses)\ **Post date:** [April 9, 2021, 12:44am UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623/4 "2021-04-09T00:44:38Z")
Sorry, just added it. ---
**Author:** ![bcao](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/bcao/32/14043_2.png) [@bcao](https://forums.developer.nvidia.com/u/bcao)\ **Post date:** [April 20, 2021, 6:54am UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623/5 "2021-04-20T06:54:25Z")
**There is no update from you for a period, assuming this is not an issue any more. Hence we are closing this topic. If need further support, please open a new one. Thanks** Hey customer, > [@linyeglasses](#): > > This app do detection on all the camera inputs. Is there a way to specify only one or some of them do the detection, while all inputs include the one used for detection are collected by nvmultistreamtiler linked later in the pipeline? May I know why you need to do inference on on or some of the sources, so what you need to do for other sources ? > [@linyeglasses](#): > > Also, I tried to use two pipelines to meet the requirement, one follows the single camera (camera 0) pipeline to detect objects, and an another pipeline that receives multiple camera inputs (camera 0,1,2…) with no detection but a nvmultistreamtiler to link them. It works fine when I execute them separately. However, when executing two pipelines in the same script, it gives me error when building the second pipeline: Could you share more details about your pipeline and Enable more log via setting GST\_DEBUG=n (where n maybe 3 or 4) ---
**Author:** ![TomNVIDIA](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/tomnvidia/32/14181_2.png) [@TomNVIDIA](https://forums.developer.nvidia.com/u/TomNVIDIA)\ **Post date:** [October 12, 2021, 4:14pm UTC](https://forums.developer.nvidia.com/t/how-to-specify-a-single-camera-for-detection-when-using-multi-source-input/174623/7 "2021-10-12T16:14:28Z")