libv4l: Only allow supported destination formats when doing processing

From: Hans de Goede <hdegoede@redhat.com>

Only report / allow supported destination formats in enum_fmt / try_fmt /
g_fmt / s_fmt when processing, rotating or flipping.

Priority: normal

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
index de8b608f9..b09ffc582 100644
--- a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
+++ b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
@@ -339,3 +339,8 @@ int v4lcontrol_get_ctrl(struct v4lcontrol_data *data, int ctrl)
 
   return 0;
 }
+
+/* See the comment about this in libv4lconvert.h */
+int v4lcontrol_needs_conversion(struct v4lcontrol_data *data) {
+  return data->flags || data->controls;
+}
diff --git a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
index 344e68055..28308bc55 100644
--- a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
+++ b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
@@ -39,6 +39,11 @@ void v4lcontrol_destroy(struct v4lcontrol_data *data);
 /* Functions used by v4lprocessing to get the control state */
 int v4lcontrol_get_flags(struct v4lcontrol_data *data);
 int v4lcontrol_get_ctrl(struct v4lcontrol_data *data, int ctrl);
+/* Check if we must go through the conversion path (and thus alloc conversion
+   buffers, etc. in libv4l2). Note this always return 1 if we *may* need
+   rotate90 / flipping / processing, as if we actually need this may change
+   on the fly while the stream is active. */
+int v4lcontrol_needs_conversion(struct v4lcontrol_data *data);
 
 /* Functions used by v4lconvert to pass vidioc calls from libv4l2 */
 int v4lcontrol_vidioc_queryctrl(struct v4lcontrol_data *data, void *arg);