Hi dk1900,
It is a SW issue and it should be number of B frames. Please rebuild libgstomx.so by referring to the following sample(hack to have two B frames between P frames):
--- a/omx/gstomxh264enc.c
+++ b/omx/gstomxh264enc.c
@@ -735,6 +735,7 @@ gst_omx_set_avc_encoder_property (GstOMXVideoEnc * enc)
OMX_IndexParamVideoAvc, &oH264Type);
if (eError == OMX_ErrorNone) {
oH264Type.nBFrames = self->no_BFrames;
+ oH264Type.nBFrames = 2;
oH264Type.nSliceHeaderSpacing = self->slice_header_spacing;
oH264Type.eProfile = self->profile;