cv::cudacodec::VideoReader unable to Play rtsp stream - c++

Question

System information
OpenCV => 3.3.0
Operating System / Platform => Ubuntu 16.04, x86_64
Compiler => gcc version 5.4.1 20160904
Cuda => 8.0
Nvidia card => GTX 1080 Ti
ffmpeg details
libavutil 55. 74.100 / 55. 74.100
libavcodec 57.103.100 / 57.103.100
libavformat 57. 77.100 / 57. 77.100
libavdevice 57. 7.101 / 57. 7.101
libavfilter 6.100.100 / 6.100.100
libswscale 4. 7.103 / 4. 7.103
libswresample 2. 8.100 / 2. 8.100
Detailed description
i am trying to play a rtsp stream using cudacodec::VideoReader
Rtsp Stream Details ( from vlc )
this stream plays fine in vlc and cv::VideoCapture but when i try to play it in cudacodec::VideoReader i get a error saying:
OpenCV Error: Gpu API call (CUDA_ERROR_FILE_NOT_FOUND [Code = 301]) in CuvidVideoSource, file /home/deep/Development/libraries/opencv/opencv/modules/cudacodec/src/cuvid_video_source.cpp, line 66
OpenCV Error: Assertion failed (init_MediaStream_FFMPEG()) in FFmpegVideoSource, file /home/deep/Development/libraries/opencv/opencv/modules/cudacodec/src/ffmpeg_video_source.cpp, line 101
Steps to reproduce
#include <iostream>
#include "opencv2/opencv_modules.hpp"
#if defined(HAVE_OPENCV_CUDACODEC)
#include <opencv2/core.hpp>
#include <opencv2/cudacodec.hpp>
#include <opencv2/highgui.hpp>
int main(int argc, const char* argv[])
{
const std::string fname = "rtsp://admin:admin#192.168.1.13/media/video2";
cv::namedWindow("GPU", cv::WINDOW_NORMAL);
cv::cuda::GpuMat d_frame;
cv::Ptr<cv::cudacodec::VideoReader> d_reader = cv::cudacodec::createVideoReader(fname);
for (;;)
{
if (!d_reader->nextFrame(d_frame))
break;
cv::Mat frame;
d_frame.download(frame);
cv::imshow("GPU", frame);
if (cv::waitKey(3) > 0)
break;
}
return 0;
}
#else
int main()
{
std::cout << "OpenCV was built without CUDA Video decoding support\n" << std::endl;
return 0;
}
#endif
I tried debugging it using GDB and saw that in ffmpeg_video_source.cpp bool init_MediaStream_FFMPEG() directly returns without checking the if condition.
GDB output
cv::cudacodec::detail::FFmpegVideoSource::FFmpegVideoSource
(this=0x402a20 <_start>, fname=...) at /home/deep/Development/libraries/opencv/opencv/modules/cudacodec/src/ffmpeg_video_source.cpp:98
98 cv::cudacodec::detail::FFmpegVideoSource::FFmpegVideoSource(const String& fname) :
(gdb) n
99 stream_(0)
(gdb) n
101 CV_Assert( init_MediaStream_FFMPEG() );
(gdb) s
(anonymous namespace)::init_MediaStream_FFMPEG () at /home/deep/Development/libraries/opencv/opencv/modules/cudacodec/src/ffmpeg_video_source.cpp:94
94 return initialized;
(gdb) display initialized
4: initialized = false
(gdb) s
95 }
UPDATE:
I have solved the problem. solution link

Answer 1

In the solution provided here the problem was related to the pixel format detected by ffmpeg.
In order to check your rtsp pixel format you can use ffprobe.
Then inside your cap_ffmpeg_impl.hpp you should add the case related to your pixel format like
case AV_PIX_FMT_YUV420P:
case AV_PIX_FMT_YUVJ420P:
*chroma_format = ::VideoChromaFormat_YUV420;
break;
And then rebuild opencv.