commit 6b09409845d60d60d99b6ba471dc6955753f173e
author milind-u <milind.upadhyay@gmail.com> Mon Jan 09 19:26:12 2023 -0800
committer milind-u <milind.upadhyay@gmail.com> Tue Jan 10 19:02:33 2023 -0800
tree a02c40e7339a7d5050291a3715978f3b1c6952c4
parent ac402e946a7a4acdae4afdf2a972beb1823374c9

Correctly initialize legacy v4l2 reader image size

Fixes v4l2 crash for raspberry pis.

Signed-off-by: milind-u <milind.upadhyay@gmail.com>
Change-Id: I6aaee295af7dadda01ad5470a8af596473425749

frc971/vision/v4l2_reader.cc

diff --git a/frc971/vision/v4l2_reader.cc b/frc971/vision/v4l2_reader.cc
index e549ae5..e30fa34 100644
--- a/frc971/vision/v4l2_reader.cc
+++ b/frc971/vision/v4l2_reader.cc
@@ -285,18 +285,21 @@
   memset(&format, 0, sizeof(format));
   format.type = multiplanar() ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE
                               : V4L2_BUF_TYPE_VIDEO_CAPTURE;
-  format.fmt.pix.width = cols_;
-  format.fmt.pix.height = rows_;
+
+  constexpr int kWidth = 640;
+  constexpr int kHeight = 480;
+  format.fmt.pix.width = kWidth;
+  format.fmt.pix.height = kHeight;
   format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
   // This means we want to capture from a progressive (non-interlaced)
   // source.
   format.fmt.pix.field = V4L2_FIELD_NONE;
   PCHECK(Ioctl(VIDIOC_S_FMT, &format) == 0);
-  CHECK_EQ(static_cast<int>(format.fmt.pix.width), cols_);
-  CHECK_EQ(static_cast<int>(format.fmt.pix.height), rows_);
+  CHECK_EQ(static_cast<int>(format.fmt.pix.width), kWidth);
+  CHECK_EQ(static_cast<int>(format.fmt.pix.height), kHeight);
   CHECK_EQ(static_cast<int>(format.fmt.pix.bytesperline),
-           cols_ * 2 /* bytes per pixel */);
-  CHECK_EQ(format.fmt.pix.sizeimage, ImageSize());
+           kWidth * 2 /* bytes per pixel */);
+  CHECK_EQ(format.fmt.pix.sizeimage, ImageSize(kHeight, kWidth));
 
   StreamOn();
 }

frc971/vision/v4l2_reader.h

diff --git a/frc971/vision/v4l2_reader.h b/frc971/vision/v4l2_reader.h
index 334ad81..85ca475 100644
--- a/frc971/vision/v4l2_reader.h
+++ b/frc971/vision/v4l2_reader.h
@@ -61,7 +61,10 @@
 
   // TODO(Brian): This concept won't exist once we start using variable-size
   // H.264 frames.
-  size_t ImageSize() const { return rows_ * cols_ * 2 /* bytes per pixel */; }
+  size_t ImageSize() const { return ImageSize(rows_, cols_); }
+  static size_t ImageSize(int rows, int cols) {
+    return rows * cols * 2 /* bytes per pixel */;
+  }
 
   const aos::ScopedFD &fd() { return fd_; };
 
@@ -132,10 +135,6 @@
 class V4L2Reader : public V4L2ReaderBase {
  public:
   V4L2Reader(aos::EventLoop *event_loop, const std::string &device_name);
-
- private:
-  const int rows_ = 480;
-  const int cols_ = 640;
 };
 
 // Rockpi specific v4l2 reader.  This assumes that the media device has been