v4l2src: Ignore non-increasing sequence number

With older kernel, older driver or just broken drivers, the sequence number
may not be increasing. This simply ignore the sequence in this case. This
would otherwise miss-leading large amount of lost frame being reported.

Fixes #729

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/598>

diff --git a/sys/v4l2/gstv4l2src.c b/sys/v4l2/gstv4l2src.c
index 5ebac9e..c523701 100644 (file)
--- a/sys/v4l2/gstv4l2src.c
+++ b/sys/v4l2/gstv4l2src.c
@@ -978,7 +978,9 @@ retry:
   /* use generated offset values only if there are not already valid ones
    * set by the v4l2 device */
   if (!GST_BUFFER_OFFSET_IS_VALID (*buf)
-      || !GST_BUFFER_OFFSET_END_IS_VALID (*buf)) {
+      || !GST_BUFFER_OFFSET_END_IS_VALID (*buf)
+      || GST_BUFFER_OFFSET (*buf) <=
+      (v4l2src->offset - v4l2src->renegotiation_adjust)) {
     GST_BUFFER_OFFSET (*buf) = v4l2src->offset;
     GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset + 1;
     if (!half_frame || !v4l2src->next_offset_same)