Not able to read Video from Capture Card with GPU (Unsupported Format) while Reading with CPU works fine

[cudawarped]

As mentioned in

VideoCapture from camera with CAP_PROP_FORMAT -1 (raw) and DSHOW/FFMPEG/windows

I performed a quick test and it appears that you can retrieve the raw encoded MJPEG data from directshow using CAP_FFMPEG if you slightly modify the source and link OpenCV against libavdevice. You need to add avdevice_register_all(); to void CvCapture_FFMPEG::init() and #include <libavdevice/avdevice.h>. Unfortunatley this means you need to build OpenCV against FFMPEG libs and not use the precompiled dll - opencv_videoio_ffmpegxxx_64.dll. Once the modification is in place you simply ne…

1. You need to specify the device name given in device manager, i.e. “HD Webcam”, not the index as you would when using the Direct Show backend (CAP_DSHOW).

@cudawarped

VideoCapture cap(“video=<NAME_FROM_DEVICE_MANAGER>”);

2. You need to build against FFmpeg not use the pre-built binaries, these won’t include any changes you made to cap_ffmpeg_impl.hpp.

@data

    FFMPEG:                      YES (prebuilt binaries)
      avcodec:                   YES (58.134.100)
      avformat:                  YES (58.76.100)
      avutil:                    YES (56.70.100)
      swscale:                   YES (5.9.100)