# Python GStreamer HW decoding from RTSP not working **URL:** \ **Category:** Jetson Nano\ **Created:** [September 13, 2019, 1:18pm UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661 "2019-09-13T13:18:49Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![simone.rinaldi](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@simone.rinaldi](https://forums.developer.nvidia.com/u/simone.rinaldi)\ **Post date:** [September 13, 2019, 1:18pm UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/1 "2019-09-13T13:18:49Z")
Hi all, I’m trying to capture frames from RTSP stream using GStreamer in order to access HW decoding but it seems not working. I compiled Opencv 4.0 using this script: [https://github.com/AastaNV/JEP/blob/master/script/install\_opencv4.0.0\_Nano.sh](https://github.com/AastaNV/JEP/blob/master/script/install_opencv4.0.0_Nano.sh) required cause original Opencv installed in jetson nano distro returns an error using GST pipeline as input Now using this simple code: ```auto import cv2 import gi gi.require_version('Gst', '1.0') if __name__ == ' __main__': gst = "rtspsrc location=rtsp://admin:Password@192.168.0.200:554/ latency=200 ! queue ! rtph264depay ! h264parse ! queue ! h264parse ! omxh264dec ! videoconvert ! appsink" cap = cv2.VideoCapture(gst) if not cap.isOpened(): print("capture failed") exit() while True: ret, frame = cap.read() if ret: frame = cv2.resize(frame, (1280,720)) # I know it could increase CPU usage but also removing it doesn't change cv2.imshow('frame', frame) if (cv2.waitKey(1) & 0xFF == ord('q')): break; cap.release() cv2.destroyAllWindows() ``` If I check CPU utilization with top command I get: 160-190% but if I launch: ```auto gst-launch-1.0 rtspsrc location=rtsp://admin:Password@192.168.0.200:554 latency=200 ! queue ! rtph264depay ! h264parse ! queue ! h264parse ! omxh264dec ! nveglglessink -e ``` I have a CPU utilization of: 34% So seems that using gst-launch-1.0 HW decoding works but not using Python and opencv. Python building result: ```auto >>> import cv2 >>> print cv2.getBuildInformation() General configuration for OpenCV 4.0.0 ===================================== Version control: unknown Extra modules: Location (extra): /home/viper/opencv-4.0.0/opencv_contrib-4.0.0/modules Version control (extra): unknown Platform: Timestamp: 2019-09-13T09:09:00Z Host: Linux 4.9.140-tegra aarch64 CMake: 3.10.2 CMake generator: Unix Makefiles CMake build tool: /usr/bin/make Configuration: RELEASE CPU/HW features: Baseline: NEON FP16 required: NEON disabled: VFPV3 C/C++: Built as dynamic libs?: YES C++ Compiler: /usr/bin/c++ (ver 7.4.0) C++ flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG C++ flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wno-narrowing -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG C Compiler: /usr/bin/cc C flags (Release): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -O3 -DNDEBUG -DNDEBUG C flags (Debug): -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-narrowing -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUG Linker flags (Release): Linker flags (Debug): ccache: NO Precompiled headers: YES Extra dependencies: m pthread cudart_static -lpthread dl rt nppc nppial nppicc nppicom nppidei nppif nppig nppim nppist nppisu nppitc npps cublas cufft -L/usr/local/cuda/lib64 -L/usr/lib/aarch64-linux-gnu 3rdparty dependencies: OpenCV modules: To be built: aruco bgsegm bioinspired calib3d ccalib core cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev datasets dnn dnn_objdetect dpm face features2d flann freetype fuzzy gapi hdf hfs highgui img_hash imgcodecs imgproc java_bindings_generator line_descriptor ml objdetect optflow phase_unwrapping photo plot python2 python3 python_bindings_generator reg rgbd saliency shape stereo stitching structured_light superres surface_matching text tracking video videoio videostab xfeatures2d ximgproc xobjdetect xphoto Disabled: world Disabled by dependency: - Unavailable: cnn_3dobj cvv java js matlab ovis sfm ts viz Applications: apps Documentation: NO Non-free algorithms: NO GUI: GTK+: YES (ver 2.24.32) GThread : YES (ver 2.56.4) GtkGlExt: NO VTK support: NO Media I/O: ZLib: /usr/lib/aarch64-linux-gnu/libz.so (ver 1.2.11) JPEG: /usr/lib/aarch64-linux-gnu/libjpeg.so (ver 80) WEBP: build (ver encoder: 0x020e) PNG: /usr/lib/aarch64-linux-gnu/libpng.so (ver 1.6.34) TIFF: build (ver 42 - 4.0.9) JPEG 2000: build (ver 1.900.1) OpenEXR: build (ver 1.7.1) HDR: YES SUNRASTER: YES PXM: YES PFM: YES Video I/O: DC1394: NO FFMPEG: YES avcodec: YES (ver 57.107.100) avformat: YES (ver 57.83.100) avutil: YES (ver 55.78.100) swscale: YES (ver 4.8.100) avresample: YES (ver 3.7.0) GStreamer: base: YES (ver 1.14.5) video: YES (ver 1.14.5) app: YES (ver 1.14.5) riff: YES (ver 1.14.5) pbutils: YES (ver 1.14.5) v4l/v4l2: linux/videodev2.h Parallel framework: pthreads Trace: YES (built-in) Other third-party libraries: Lapack: NO Eigen: YES (ver 3.3.4) Custom HAL: YES (carotene (ver 0.0.1)) Protobuf: build (3.5.1) NVIDIA CUDA: YES (ver 10.0, CUFFT CUBLAS) NVIDIA GPU arch: 53 NVIDIA PTX archs: OpenCL: YES (no extra features) Include path: /home/viper/opencv-4.0.0/opencv-4.0.0/3rdparty/include/opencl/1.2 Link libraries: Dynamic load Python 2: Interpreter: /usr/bin/python2.7 (ver 2.7.15) Libraries: /usr/lib/aarch64-linux-gnu/libpython2.7.so (ver 2.7.15+) numpy: /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.13.3) packages path: lib/python2.7/dist-packages Python 3: Interpreter: /usr/bin/python3 (ver 3.6.8) Libraries: /usr/lib/aarch64-linux-gnu/libpython3.6m.so (ver 3.6.8) numpy: /usr/local/lib/python3.6/dist-packages/numpy/core/include (ver 1.17.1) packages path: lib/python3.6/dist-packages Python (for build): /usr/bin/python2.7 Java: ant: NO JNI: NO Java wrappers: NO Java tests: NO Install to: /usr/local ----------------------------------------------------------------- ``` Any idea? I don’t really know how to quit from this condition… ---
**Author:** ![simone.rinaldi](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@simone.rinaldi](https://forums.developer.nvidia.com/u/simone.rinaldi)\ **Post date:** [September 13, 2019, 1:25pm UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/2 "2019-09-13T13:25:01Z")
If I change line 8 to: ```auto cap = cv2.VideoCapture("rtsp://admin:Password@192.168.0.200:554/") ``` Visualization seems less fluid but CPU utilization drops down to 60-70% ---
**Author:** ![DaneLLL](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/danelll/32/14043_2.png) [@DaneLLL](https://forums.developer.nvidia.com/u/DaneLLL)\ **Post date:** [September 16, 2019, 3:52am UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/3 "2019-09-16T03:52:30Z")
Hi, The working pipeline should be ```auto gst = "rtspsrc location=rtsp://admin:Password@192.168.0.200:554/ latency=200 ! queue ! rtph264depay ! queue ! h264parse ! omxh264dec ! nvvidconv ! video/x-raw,format=BGRx ! videoconvert ! video/x-raw,format=BGR ! appsink" ``` Please run ‘sudo tegrastats’ to check CPU usage. And ‘sudo jetson\_clocks’ to run in max performance. ---
**Author:** ![simone.rinaldi](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@simone.rinaldi](https://forums.developer.nvidia.com/u/simone.rinaldi)\ **Post date:** [September 17, 2019, 6:59am UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/4 "2019-09-17T06:59:33Z")
> [@DaneLLL](#): > > Hi, > The working pipeline should be > > ```auto > gst = "rtspsrc location=rtsp://admin:Password@192.168.0.200:554/ latency=200 ! queue ! rtph264depay ! queue ! h264parse ! omxh264dec ! nvvidconv ! video/x-raw,format=BGRx ! videoconvert ! video/x-raw,format=BGR ! appsink" > > ``` > > Please run ‘sudo tegrastats’ to check CPU usage. And ‘sudo jetson\_clocks’ to run in max performance. Thank you! I’m trying to undestand GStreamer but is very complex compared to FFMPEG. ---
**Author:** ![caruofc](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@caruofc](https://forums.developer.nvidia.com/u/caruofc)\ **Post date:** [December 16, 2020, 5:29am UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/5 "2020-12-16T05:29:27Z")
Hi, I have been trying different ideas but can’t figure out how to get smooth motion display from gstreamer output. I tried the gst suggested by @DaneLLL as well. I am using Python with openCV 4.5 compiled with CUDA, tried both nvv4l2decoder and omxh264dec. None of them is giving me a smooth motion video. It seems the openCV call read() in the loop after cv2.VideoCapture() takes periodically longer time and that is why the display showing periodic jerking. I tried placing queue in several places and lastly as suggested by @DaneLLL. My platform is a Nano running JP4.4. Any help would be greatly appreciated. Thanks in advance. ---
**Author:** ![caruofc](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@caruofc](https://forums.developer.nvidia.com/u/caruofc)\ **Post date:** [December 16, 2020, 6:28am UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/6 "2020-12-16T06:28:43Z")
Found the solution. Taking the latency off, solved my problem. ---
**Author:** ![nadeemm](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/nadeemm/32/367020_2.png) [@nadeemm](https://forums.developer.nvidia.com/u/nadeemm)\ **Post date:** [October 14, 2021, 9:59pm UTC](https://forums.developer.nvidia.com/t/python-gstreamer-hw-decoding-from-rtsp-not-working/81661/7 "2021-10-14T21:59:34Z")
Closed on October 14, 2021, 9:59pm UTC