I have a simple script to read mp4 file like this.
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/videoio/videoio.hpp>
int main()
{
cv::VideoCapture file("test.mp4");
cv::Mat frame;
while (true)
{
file.read(frame);
cv::imshow("Preview", frame);
cv::waitKey(42);
}
file.release();
return 0;
}
This works fine. But when I integrate this script into another project I'm working on. The the image frame shows in wrong aspect ratio.
Correct (Side by Side):
Wrong (Only show one side and aspect ratio is wrong):
I'm running on Windows VS2019. I have remove all other script in my exists project, just leave the above. The only different I can think of is the includes and linker setting. I use ceres, glog, d3d11, realsense2, VTK, pcl, eigen3, OpenXR in the project. Does any of that effects what OpenCV behave? Or what might be the problem?
- I've already try setting the frame width and height for VideoCapture and it's not working.
- I've test both OpenCV 4.1 and 4.6.
- When accessing frame.cols, frame.rows, I got the correcy resolution.
UPDATE
The metadata of the file I'm trying to read is as below. This is a side by side 3D video. It also can display correctly in player such as VLC.
mediainfo test.mp4
General
Complete name : test.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 181 MiB
Duration : 31 s 339 ms
Overall bit rate : 48.4 Mb/s
Writing application : Lavf58.20.100
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.1
Format settings : CABAC / 1 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 31 s 317 ms
Bit rate : 48.0 Mb/s
Width : 3 840 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Original display aspect ratio : 3.556
Frame rate mode : Variable
Frame rate : 60.000 FPS
Minimum frame rate : 59.920 FPS
Maximum frame rate : 60.080 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.193
Stream size : 179 MiB (99%)
Title : SStar Video
Codec configuration box : avcC
Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 31 s 339 ms
Bit rate mode : Constant
Bit rate : 140 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 534 KiB (0%)
Title : SStar Audio
Default : Yes
Alternate group : 1