def update_video_loader(self,
file_path=None,
device=None,
backend_factory=None,
backend_opts=None):
if backend_factory is not None:
self.backend_factory = backend_factory
if device is not None:
self.device = device
if file_path is not None:
self.file_path = file_path
if backend_opts is not None:
self.backend_opts = backend_opts
if not self.file_path:
return
try:
if self.backend_factory is not None:
tvl.set_backend_factory(self.device.type, self.backend_factory)
vl = tvl.VideoLoader(self.file_path,
self.device,
backend_opts=self.backend_opts)
self.video_thread.set_video_loader(vl)
self.spn_frame_index.configure(to=vl.n_frames - 1)
self.title(self.file_path.name)
except Exception:
print(f'Failed to load video: {self.file_path:s}')
traceback.print_exc()
def read_sequential(video_file, device, **backend_opts):
n_frames = 40
n_trials = 1
vl = tvl.VideoLoader(video_file, device, torch.float32, backend_opts)
# Read one frame to get any initialisation out of the way.
vl.read_frame()
t1 = time.time()
for _ in range(n_trials):
frames = list(vl.read_frames(n_frames))
assert len(frames) == n_frames
t2 = time.time()
return (n_trials * n_frames) / (t2 - t1)
def read_random(video_file, device, **backend_opts):
n_frames = 5
n_trials = 8
vl = tvl.VideoLoader(video_file, device, torch.float32, backend_opts)
# Read one frame to get any initialisation out of the way.
vl.read_frame()
vl.seek(0)
t1 = time.time()
for _ in range(n_trials):
frames = list(vl.select_frames(np.arange(n_frames) * 10))
assert len(frames) == n_frames
t2 = time.time()
return (n_trials * n_frames) / (t2 - t1)
def test_vl_read_frame(dummy_backend):
vl = tvl.VideoLoader('', dummy_backend.device)
assert vl.read_frame() == dummy_backend.frames[0]
def test_vl_select_frames_mixed(dummy_backend, mocker):
vl = tvl.VideoLoader('', dummy_backend.device)
mocked_seek = mocker.patch.object(vl, 'seek_to_frame')
list(vl.select_frames([1, 2, 10, 12]))
assert mocked_seek.mock_calls == [call(1), call(10)]
def test_vl_select_frames_random(dummy_backend, mocker):
vl = tvl.VideoLoader('', dummy_backend.device)
mocked_seek = mocker.patch.object(vl, 'seek_to_frame')
list(vl.select_frames([5, 45, 25]))
# When frame indices are sparse, multiple seeks should occur
assert mocked_seek.mock_calls == [call(5), call(25), call(45)]
def test_vl_select_frames_sequental(dummy_backend, mocker):
vl = tvl.VideoLoader('', dummy_backend.device)
mocked_seek = mocker.patch.object(vl, 'seek_to_frame')
list(vl.select_frames([24, 26, 25]))
# When frame indices are dense, only one seek should occur
mocked_seek.assert_called_once_with(24)
def test_vl_remaining_frames(dummy_backend):
vl = tvl.VideoLoader('', dummy_backend.device)
vl.read_frame()
assert list(vl.remaining_frames()) == dummy_backend.frames[1:]
def test_vl_read_all_frames(dummy_backend):
vl = tvl.VideoLoader('', dummy_backend.device)
assert list(vl.read_all_frames()) == dummy_backend.frames
def test_vl_read_frame(dummy_backend_factory_cpu):
vl = tvl.VideoLoader('', dummy_backend_factory_cpu.device)
assert vl.read_frame() == dummy_backend_factory_cpu.frames[0]