VisionLabs/torch-opencv

What does the following error message mean?

yxchng opened this issue · 4 comments

yxchng commented

OpenCV Error: Assertion failed (image->depth == 8) in writeFrame, file /home/yxchng/OpenCV/modules/videoio/src/cap_ffmpeg.cpp, line 272

I follow the VideoWriter example but I couldnt save a video. Instead I got the above error.

shrubb commented

It's an error similar to this one. Be careful about image depth (RGB or grayscale) and the type of video codec you use. Try different options.

yxchng commented

@shrubb I tried using XVID, MPEG, H264. All don't work. Image depth is rgb.

If i can do imwrite why i cant do videowriter.write?

shrubb commented

Because OpenCV works this way -- every function has constraints on the types of input matrices (images). imwrite has nothing to do with VideoWriter.write, they are completely different functions with different constraints.

Image depth can't be RGB. This is the channel layout. Depth is the number of bits per pixel. As far as I remember, VideoWriter typically requires 8 bit per channel pixel. So it should work with ByteTensors.