Pitch of second frame

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hi,

I’ve an incoming video sample described by a structure of type CUeglFrame with the following values:

width: 640
height: 480
planeCount: 3
frame type: pitch
numChannels: 1
pitch: 768
CUeglColorFormat: 0 => CU_EGL_COLOR_FORMAT_YUV420_PLANAR
depth: 0
CUarray_format: 1

my problem is which pitch I must use for the second and third planes ( U and V in YUV420 ). The data structure provides the pitch for the first plane in field CUeglFrame->pitch, but not the ones for remainders.

Using try&test, it seems the correct value is 512, that I suppose is the width (640) divided by 2 (because in YUV420 chroma planes has half width) and ceil rounded to 256, 640/2=320 => 512.

Googling, the only information I’ve found is this phrase (from here):

Note that in case of multiplanar *eglFrame, pitch of only first plane (unsigned int cudaEglPlaneDesc::pitch) is to be considered by the application.

Thanks

3

Hi,
If your buffer is NvBuffer, you can call NvBufferGetParams to get pitch of U and V planes. Looks like in CUeglFrame, it contains only pitch of first plane.

4

Yes, the result of the NvBufferGetParams contains an array of pitchs with the expected value 512 for the second and third plane. Thanks for the suggestion.

I wonder why CUeglFrame doesn’t contains an array instead of only the first element. Moreover, the cited phrase is misleading.