yuv420 format for nvhost-msenc

Autonomous Machines Jetson & Embedded Systems Jetson TX2
#1

All,
I’m using the hardware video encoder to encode h264 video. My source is YUV420, with seperate Y U and V planes.
The resolution of this video is 1280x720, meaning my buffer sizes should be 921600 for y, and 230400 for U and V.

The resultant (encoded) video doesn’t look right. the Y channel seems to be just fine, but the colors are off. There’s a big green bar at the bottom of the video that seems to indicate my chroma samples aren’t correct.

When i look at the buffers that are mapped for my output planes, the U and V buffers are 276480 bytes wide, which is 1.2 times the size that I expect. I think that the extra space at the end of the buffer means that I’ve got my formatting wrong.

Have I missed something? I’m having trouble understanding why these buffers aren’t the size that I expect.

Thanks for any Insight.

#2

Hi wdouglass,
Do you run gstreamer or MMAPIs? Is BSP r28.1?

#3

I’m using the mmapis. Specifically, i’m using the v4l extensions. No gstreamer.

#4

Also, the firmware came from Jetpack 3.2, so it’s version 28.2.

#5

The buffer is with alignment so you have to check pitch, width, and height.

#6

I used the ‘bytesperline’ member of the v4l2_format structure to get pitch. Works great, that’s what I was missing.

Thanks so much!