Linux/TMS320DM8168: About cropping and scaling using V4L2 capture API

Kiet Phi77

Intellectual 410 points

Part Number: TMS320DM8168
Other Parts Discussed in Thread: TVP5150, TVP7002

Tool/software: Linux

Hi,

Could anyone confirm me about cropping ability of V4L2 capture driver.

I capture frame (720x576) from /dev/video0 and want to crop a region 640x480.

struct v4l2_crop crop;
crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
crop.c.left = 0;
crop.c.top = 0;
crop.c.width = 640;
crop.c.height = 480;

ret = ioctl(fd, VIDIOC_S_CROP, &crop);

VIDIOC_S_CROP return -1. In ti81xxvin_main.c, function vidioc_s_crop failed because interlaced format is not supported.

static int vidioc_s_crop(struct file *file, void *priv,
		struct v4l2_crop *crop)
{
 //..................
 if (params->interlaced) {
	mutex_unlock(&buf_obj->buf_lock);
	return -EINVAL; // FUNCTION RETURNS AT HERE
 }

}

I think V4L2 capture driver in EZSDK doesn't support cropping and scaling.

I want to cropping frame and do some image processing. Could anybody suggest me some tips !

Many thanks !

over 6 years ago

0 Margarita Gashova over 6 years ago

TI__Guru* 80190 points

Hello,

Please check this guide:
processors.wiki.ti.com/.../TI81XX_PSP_VIDEO_CAPTURE_Driver_User_Guide

You could check saLoopBackScale demo also.

BR
Margarita

0 Kiet Phi77 over 6 years ago in reply to Margarita Gashova

Intellectual 410 points

Hi,
I have modified saLoopbackScale with my decoder (tvp5150, 720x576, YUYV). This demo also failed at ioctl VIDIOC_S_CROP
if (ioctl(capt.fd, VIDIOC_S_CROP, &capt.crop)) {
printf("Setting format failed\n");
exit(2);
}

I have read "TI81XX PSP VIDEO CAPTURE Driver User Guide" carefully. I also check source code of function vidioc_s_crop in ti81xxvin_main.c, it failed because it only supports progressive format.

0 Margarita Gashova over 6 years ago in reply to Kiet Phi77

TI__Guru* 80190 points

Hello,

As you could check in the video capture user guide cropping and scaling are supported for progressive input.
Please check Features chapter :
*Supports scaling and cropping for YUV formats (downscaling and progressive inputs only)

BR
Margarita

0 Kiet Phi77 over 6 years ago in reply to Margarita Gashova

Intellectual 410 points

Thank you very much !
I don't know much about interlaced and progressive format.I only know about 3 common pixel formats as below:
+ V4L2_PIX_FMT_YUYV: YUV422 interleaved
+ V4L2_PIX_FMT_RGB24: 24 bit RGB interleaved
+ V4L2_PIX_FMT_NV12: YUV420 semi planar (I use this format for passing to OMX H264 encoder)
I have tried with above formats, but function ioctl VIDIOC_S_CROP still returns failed.
Could you give me more details about setting format?

0 Margarita Gashova over 6 years ago in reply to Kiet Phi77

TI__Guru* 80190 points

Hello,

Please check these threads they could be in help:
e2e.ti.com/.../868884
e2e.ti.com/.../613773

BR
Margarita

0 Kiet Phi77 over 6 years ago in reply to Margarita Gashova

Intellectual 410 points

Thank you very much !

I can crop and scale image with tvp7002 (720p and 1080p). With PAL input, I use tvp5150, probably it doesn't support progressive format.

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Linux/TMS320DM8168: About cropping and scaling using V4L2 capture API