Copying from NvBufferTransform directly to output_plane fd

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
1

Hi im trying to color convert a video stream and encode it with x264. The code works if I copy the data after NvBufferTransform with NvBufferMap and then from that buffer to the output_plan of the encoder. Since this operation takes quite some time, I was wondering if I can color convert the image directly into the output_plane fd of the encoder. A shortend version of the programm looks like:

 NvBuffer* buffer;
 ctx.enc->output_plane.dqBuffer(v4l2_buf, &buffer, NULL, 10);
 int fd = buffer->planes[0].fd;
 int ret = NvBufferTransform(tctx.in_dmabuf_fd, fd, &tctx.transform_params); 
 ret = ctx.enc->output_plane.qBuffer(v4l2_buf, NULL);

The qBuffer functions blocks after around 10 calls which indicates that the encoder is not encoding the image. What am I’m doing wrong?

Best
Michael

2

Hi,
For using hardware encoder, you can set output plane to DMA buffer mode and call NvBufferTransform () to copy data into the buffers. Please refer to 01_video_encode sample.

3

The issue was that bytes_used need to be set in the output_plane. Otherwise the encoder does not start. However I found that the fastest way of color converting images is width kernels. NvBufferTransform is quite slow compared to that.