Thank you, I’ve looked at gst-dsexample plugin and deepstream-opencv-test sample app, it all works great.
Then I’ve tried to map and read\write NvBufSurface in a python plugin using ctypes mappings, since I couldn’t find a way to get NvBufSurface bindings object from Gst.Buffer, but wasn’t able to successfully sync surface for CPU
Here’s my plugin code
_GST_PADDING = 4
_NVBUF_MAX_PLANES = 4
class _GstMapInfo(ctypes.Structure):
_fields_ = [
("memory", ctypes.c_void_p),
("flags", ctypes.c_int),
("data", ctypes.POINTER(ctypes.c_ubyte)),
("size", ctypes.c_size_t),
("maxsize", ctypes.c_size_t),
("user_data", ctypes.c_void_p * 4),
("_gst_reserved", ctypes.c_void_p * _GST_PADDING)
]
class _NvBufSurfaceMappedAddr(ctypes.Structure):
_fields_ = [
('addr', ctypes.c_void_p * _NVBUF_MAX_PLANES),
('eglImage', ctypes.c_void_p),
("_reserved", ctypes.c_void_p * _GST_PADDING)
]
class _NvBufSurfacePlaneParams(ctypes.Structure):
_fields_ = [
('num_planes', ctypes.c_uint32),
('width', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
('height', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
('pitch', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
('offset', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
('psize', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
('bytesPerPix', ctypes.c_uint32 * _NVBUF_MAX_PLANES),
("_reserved", ctypes.c_void_p * (_GST_PADDING * _NVBUF_MAX_PLANES))
]
class _NvBufSurfaceParams(ctypes.Structure):
_fields_ = [
('width', ctypes.c_uint32),
('height', ctypes.c_uint32),
('pitch', ctypes.c_uint32),
('colorFormat', ctypes.c_int),
('layout', ctypes.c_int),
('bufferDesc', ctypes.c_uint64),
('dataSize', ctypes.c_uint32),
('dataPtr', ctypes.c_void_p),
('planeParams', _NvBufSurfacePlaneParams),
('mappedAddr', _NvBufSurfaceMappedAddr),
("_reserved", ctypes.c_void_p * _GST_PADDING)
]
class _NvBufSurface(ctypes.Structure):
_fields_ = [
('gpuId', ctypes.c_uint32),
('batchSize', ctypes.c_uint32),
('numFilled', ctypes.c_uint32),
('isContiguous', ctypes.c_bool),
('memType', ctypes.c_int),
('surfaceList', ctypes.POINTER(_NvBufSurfaceParams)),
("_gst_reserved", ctypes.c_void_p * _GST_PADDING)
]
_GST_MAP_INFO_POINTER = ctypes.POINTER(_GstMapInfo)
_libgst = ctypes.CDLL("libgstreamer-1.0.so.0")
_libgst.gst_buffer_map.argtypes = [ctypes.c_void_p, _GST_MAP_INFO_POINTER, ctypes.c_int]
_libgst.gst_buffer_map.restype = ctypes.c_bool
_libgst.gst_buffer_unmap.argtypes = [ctypes.c_void_p, _GST_MAP_INFO_POINTER]
_libgst.gst_buffer_unmap.restype = None
_libnvbufsurface = ctypes.CDLL('libnvbufsurface.so')
_libnvbufsurface.NvBufSurfaceMap.argtypes = [
ctypes.POINTER(_NvBufSurface),
ctypes.c_int, # index Index of a buffer in the batch (frame_meta.batch_id), -1 for all
ctypes.c_int, # plane Index of a plane in the buffer (0?), -1 for all
ctypes.c_int # NvBufSurfaceMemMapFlags type, 0 READ, 1 WRITE, 2 READ_WRITE
]
_libnvbufsurface.NvBufSurfaceMap.restype = ctypes.c_int # 0 if successful, or -1 otherwise
_libnvbufsurface.NvBufSurfaceSyncForCpu.argtypes = [
ctypes.POINTER(_NvBufSurface),
ctypes.c_int, # index Index of a buffer in the batch (frame_meta.batch_id), -1 for all
ctypes.c_int, # plane Index of a plane in the buffer (0?), -1 for all
]
_libnvbufsurface.NvBufSurfaceSyncForCpu.restype = ctypes.c_int # 0 if successful, or -1 otherwise
class SurfTest(GstBase.BaseTransform):
GST_PLUGIN_NAME = 'surf'
__gstmetadata__ = (
'test',
'test',
'test',
'test')
__gsttemplates__ = (
Gst.PadTemplate.new('src', Gst.PadDirection.SRC, Gst.PadPresence.ALWAYS, Gst.Caps.new_any()),
Gst.PadTemplate.new('sink', Gst.PadDirection.SINK, Gst.PadPresence.ALWAYS, Gst.Caps.new_any())
)
def do_transform_ip(self, buffer):
map_info = _GstMapInfo()
res = _libgst.gst_buffer_map(hash(buffer), map_info, Gst.MapFlags.READ)
Gst.log(f'gst buffer map {res}') # prints True
nvbuf_surf_p = ctypes.cast(map_info.data, ctypes.POINTER(_NvBufSurface))
nvbuf_surf = nvbuf_surf_p.contents
Gst.log(f'surface mem type {nvbuf_surf.memType}') # prints 3
batch_meta = pyds.gst_buffer_get_nvds_batch_meta(hash(buffer))
l_frame = batch_meta.frame_meta_list
while l_frame is not None:
try:
frame_meta = pyds.NvDsFrameMeta.cast(l_frame.data)
except StopIteration:
break
nvbuf_surf_params = nvbuf_surf.surfaceList[frame_meta.batch_id]
nvbuf_surf_mappedaddr = nvbuf_surf_params.mappedAddr
if nvbuf_surf_mappedaddr.addr[0] is None:
res = _libnvbufsurface.NvBufSurfaceMap(nvbuf_surf_p, frame_meta.batch_id, 0, 2)
Gst.log(f'NvBufSurfaceMap {res}') # prints 0
if res == 0:
res = _libnvbufsurface.NvBufSurfaceSyncForCpu(nvbuf_surf_p, frame_meta.batch_id, 0)
Gst.log(f'sync for cpu {res}') # prints -1
try:
l_frame = l_frame.next
except StopIteration:
break
_libgst.gst_buffer_unmap(hash(buffer), map_info)
return Gst.FlowReturn.OK
And my run command
GST_DEBUG=python:6 gst-launch-1.0 \
uridecodebin uri=file:///opt/app/data/sample_720p.mp4 \
! nvvideoconvert nvbuf-memory-type=3 \
! video/x-raw\(memory:NVMM\), format=RGBA \
! m.sink_0 nvstreammux name=m batch-size=1 width=1280 height=720 nvbuf-memory-type=3 \
! surf \
! fakesink sync=false
I understand this is hardly a supported case, but if there’s any advice I’d very much appreciate it.