FFmpegDemuxer: no AVFormatContext provided #104

Decoding on GPU 0
Can't open data/test.mp4: Invalid data found when processing input
Traceback (most recent call last):
  File "test_video.py", line 56, in <module>
    nvDec = nvc.PyNvDecoder(path + video_name, 0)
ValueError: FFmpegDemuxer: no AVFormatContext provided.`

cmake ..   -DFFMPEG_DIR:PATH="$PATH_TO_FFMPEG"   -DVIDEO_CODEC_SDK_DIR:PATH="$PATH_TO_SDK"  
 DGENERATE_PYTHON_BINDINGS:BOOL="1"   -DCMAKE_INSTALL_PREFIX:PATH="$INSTALL_PREFIX"
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- The CUDA compiler identification is NVIDIA 10.2.89
-- Check for working CUDA compiler: /usr/local/cuda-10.2/bin/nvcc
-- Check for working CUDA compiler: /usr/local/cuda-10.2/bin/nvcc -- works
-- Detecting CUDA compiler ABI info
-- Detecting CUDA compiler ABI info - done
**-- Searching for FFmpeg libs in /opt/FFmpeg/build_x64_release_shared/lib**
**-- Searching for FFmpeg headers in /opt/FFmpeg/build_x64_release_shared/include**
**-- Searching for Video Codec SDK headers in /opt/Video_Codec_SDK_9.1.23/include folder**
-- Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython3.6m.so (found suitable version "3.6.9", minimum required is "3.5") 
-- Found PythonInterp: /usr/bin/python3.6 (found version "3.6.9") 
-- Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython3.6m.so
-- pybind11 v2.3.dev0
-- Performing Test HAS_FLTO
-- Performing Test HAS_FLTO - Success
-- LTO enabled
-- Configuring done
-- Generating done
-- Build files have been written to: /home/luhang/VideoProcessingFramework-master/build

$ ffmpeg -version
ffmpeg version 4.3.git Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
configuration: --prefix=/home/luhang/FFmpeg-master/build_x64_release_shared --disable-static --disable-stripping --disable-doc --enable-shared
libavutil      56. 58.100 / 56. 58.100
libavcodec     58.105.100 / 58.105.100
libavformat    58. 54.100 / 58. 54.100
libavdevice    58. 11.101 / 58. 11.101
libavfilter     7. 87.100 /  7. 87.100
libswscale      5.  8.100 /  5.  8.100
libswresample   3.  8.100 /  3.  8.100

~/VideoProcessingFramework-master/install/bin$ python SampleDecode.py 0 ./test.mp4 out
This sample decodes input video to raw NV12 file on given GPU.
Usage: SampleDecode.py $gpu_id $input_file $output_file.
Decoding on GPU 0
Can't open ./zidane_LR.mp4: Invalid data found when processing input
Traceback (most recent call last):
  File "SampleDecode.py", line 55, in <module>
    decode(gpuID, encFilePath, decFilePath)
  File "SampleDecode.py", line 22, in decode
    nvDec = nvc.PyNvDecoder(encFilePath, gpuID)
ValueError: FFmpegDemuxer: no AVFormatContext provided.