Warn when v4l2_buffer::bytesused has an unexpected value

For uncompressed formats in capture devices, the v4l2_buffer::bytesused
field should have the same value as the v4l2_pix_format::sizeimage field
reported by the VIDIOC_G_FMT ioctl.

Print a warning on VIDIOC_DQBUG when the values don't match.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/yavta.c b/yavta.c
index 4c0d97b..3d42915 100644
--- a/yavta.c
+++ b/yavta.c
@@ -42,6 +42,7 @@ struct device
 	enum v4l2_memory memtype;
 	unsigned int nbufs;
 	unsigned int bufsize;
+	unsigned int imagesize;
 	void **mem;
 };
 
@@ -186,6 +187,8 @@ static int video_get_format(struct device *dev)
 		return ret;
 	}
 
+	dev->imagesize = fmt.fmt.pix.bytesperline ? fmt.fmt.pix.sizeimage : 0;
+
 	printf("Video format: %c%c%c%c (%08x) %ux%u\n",
 		(fmt.fmt.pix.pixelformat >> 0) & 0xff,
 		(fmt.fmt.pix.pixelformat >> 8) & 0xff,
@@ -765,6 +768,11 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 				buf.m.userptr = (unsigned long)dev->mem[i];
 		}
 
+		if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE &&
+		    dev->imagesize != 0	&& buf.bytesused != dev->imagesize)
+			printf("Warning: bytes used %u != image size %u\n",
+			       buf.bytesused, dev->imagesize);
+
 		size += buf.bytesused;
 
 		gettimeofday(&ts, NULL);