Opencv s native colour space bgr is known to ffmpeg and if you allocate you own mat then the memory layout is continuous.
Opencv mat type conversion.
The second thing to notice is the switch statement in the cv mat to qimage conversion cvmattoqimage because both opencv and qt provide multiple data.
Anyone who knows how to deal with the p.
The colour conversion is done by ffmpeg rather than by opencv.
To convert from cv mat to qimage you could try to use the qimage uchar data int width int height format format constructor as follows mat is a cv mat.
Qimage img uchar mat data mat cols mat rows qimage format rgb32.
It seems that the smart pointer could work in this case.
The first thing to note is that the cv mat to qpixmap conversion cvmattoqpixmap at the bottom of this section simply relies on cvmattoqimage and uses qt s qpixmap fromimage to return a qpixmap so that s pretty straightforward.
While mat is sufficient in most cases mat can be more convenient if you use a lot of element access operations and if you know matrix type at the compilation time.
I want to read the image by opencv and i faced the problem to transform the type of cv mat to matrix rgb pixel.
Say i have gpumat 512 512 cv 32fc2 and i want to convert it to float2 which has 512 512 elements.
Your input video can be encoded in a variety of colour spaces and memory layouts and ffmpeg has all the information needed to do the best conversion.
Hi the dnn imagenet ex cpp example in line 141 load image as a matrix rgb pixel.
The reason is i want to write my own kernel outside cv gpu modules.