h264 encode fail when enable b frame and use vaapih264enc+h265pase+filesink.

root@T:~# gst-launch-1.0 videotestsrc num-buffers=30 ! vaapih264enc max-bframes=2 ! h264parse ! filesink location=a.h264

Setting pipeline to PAUSED ... Pipeline is PREROLLING ... Got context from element 'vaapiencodeh264-0': gst.vaapi.Display=context, gst.vaapi.Display=(GstVaapiDisplay)"(GstVaapiDisplayX11)\ vaapidisplayx11-0"; ERROR: from element /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Internal data stream error. Additional debug info: gstbasesrc.c(3064): gst_base_src_loop (): /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: streaming stopped, reason not-negotiated (-4) ERROR: pipeline doesn't want to preroll. Setting pipeline to NULL ... Freeing pipeline ...

If remove h264pase in cmdline, then it works well.