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# Author: Mainak Jas
#
# License: BSD (3-clause)
import re
import copy
import time
import threading
import warnings
import numpy as np
from ..io.constants import FIFF
from ..io.meas_info import Info
from ..utils import logger
from ..externals.FieldTrip import Client as FtClient
def _buffer_recv_worker(ft_client):
"""Worker thread that constantly receives buffers."""
try:
for raw_buffer in ft_client.iter_raw_buffers():
ft_client._push_raw_buffer(raw_buffer)
except RuntimeError as err:
# something is wrong, the server stopped (or something)
ft_client._recv_thread = None
print('Buffer receive thread stopped: %s' % err)
class FieldTripClient(object):
""" Realtime FieldTrip client
Parameters
----------
info : dict | None
The measurement info read in from a file. If None, it is guessed from
the Fieldtrip Header object.
host : str
Hostname (or IP address) of the host where Fieldtrip buffer is running.
port : int
Port to use for the connection.
wait_max : float
Maximum time (in seconds) to wait for Fieldtrip buffer to start
tmin : float | None
Time instant to start receiving buffers. If None, start from the latest
samples available.
tmax : float
Time instant to stop receiving buffers.
buffer_size : int
Size of each buffer in terms of number of samples.
verbose : bool, str, int, or None
Log verbosity see mne.verbose.
"""
def __init__(self, info=None, host='localhost', port=1972, wait_max=30,
tmin=None, tmax=np.inf, buffer_size=1000, verbose=None):
self.verbose = verbose
self.info = info
self.wait_max = wait_max
self.tmin = tmin
self.tmax = tmax
self.buffer_size = buffer_size
self.host = host
self.port = port
self._recv_thread = None
self._recv_callbacks = list()
def __enter__(self):
# instantiate Fieldtrip client and connect
self.ft_client = FtClient()
# connect to FieldTrip buffer
logger.info("FieldTripClient: Waiting for server to start")
start_time, current_time = time.time(), time.time()
success = False
while current_time < (start_time + self.wait_max):
try:
self.ft_client.connect(self.host, self.port)
logger.info("FieldTripClient: Connected")
success = True
break
except:
current_time = time.time()
time.sleep(0.1)
if not success:
raise RuntimeError('Could not connect to FieldTrip Buffer')
# retrieve header
logger.info("FieldTripClient: Retrieving header")
start_time, current_time = time.time(), time.time()
while current_time < (start_time + self.wait_max):
self.ft_header = self.ft_client.getHeader()
if self.ft_header is None:
current_time = time.time()
time.sleep(0.1)
else:
break
if self.ft_header is None:
raise RuntimeError('Failed to retrieve Fieldtrip header!')
else:
logger.info("FieldTripClient: Header retrieved")
self.info = self._guess_measurement_info()
self.ch_names = self.ft_header.labels
# find start and end samples
sfreq = self.info['sfreq']
if self.tmin is None:
self.tmin_samp = max(0, self.ft_header.nSamples - 1)
else:
self.tmin_samp = int(round(sfreq * self.tmin))
if self.tmax != np.inf:
self.tmax_samp = int(round(sfreq * self.tmax))
else:
self.tmax_samp = np.iinfo(np.uint32).max
return self
def __exit__(self, type, value, traceback):
self.ft_client.disconnect()
def _guess_measurement_info(self):
"""
Creates a minimal Info dictionary required for epoching, averaging
et al.
"""
if self.info is None:
warnings.warn('Info dictionary not provided. Trying to guess it '
'from FieldTrip Header object')
info = Info() # create info dictionary
# modify info attributes according to the FieldTrip Header object
info['nchan'] = self.ft_header.nChannels
info['sfreq'] = self.ft_header.fSample
info['ch_names'] = self.ft_header.labels
info['comps'] = list()
info['projs'] = list()
info['bads'] = list()
# channel dictionary list
info['chs'] = []
for idx, ch in enumerate(info['ch_names']):
this_info = dict()
this_info['scanno'] = idx
# extract numerical part of channel name
this_info['logno'] = int(re.findall('[^\W\d_]+|\d+', ch)[-1])
if ch.startswith('EEG'):
this_info['kind'] = FIFF.FIFFV_EEG_CH
elif ch.startswith('MEG'):
this_info['kind'] = FIFF.FIFFV_MEG_CH
elif ch.startswith('MCG'):
this_info['kind'] = FIFF.FIFFV_MCG_CH
elif ch.startswith('EOG'):
this_info['kind'] = FIFF.FIFFV_EOG_CH
elif ch.startswith('STI'):
this_info['kind'] = FIFF.FIFFV_STIM_CH
elif ch.startswith('ECG'):
this_info['kind'] = FIFF.FIFFV_ECG_CH
elif ch.startswith('MISC'):
this_info['kind'] = FIFF.FIFFV_MISC_CH
# Fieldtrip already does calibration
this_info['range'] = 1.0
this_info['cal'] = 1.0
this_info['ch_name'] = ch
this_info['coil_trans'] = None
this_info['loc'] = None
this_info['eeg_loc'] = None
if ch.startswith('EEG'):
this_info['coord_frame'] = FIFF.FIFFV_COORD_HEAD
elif ch.startswith('MEG'):
this_info['coord_frame'] = FIFF.FIFFV_COORD_DEVICE
else:
this_info['coord_frame'] = FIFF.FIFFV_COORD_UNKNOWN
if ch.startswith('MEG') and ch.endswith('1'):
this_info['unit'] = FIFF.FIFF_UNIT_T
elif ch.startswith('MEG') and (ch.endswith('2')
or ch.endswith('3')):
this_info['unit'] = FIFF.FIFF_UNIT_T_M
else:
this_info['unit'] = FIFF.FIFF_UNIT_V
this_info['unit_mul'] = 0
info['chs'].append(this_info)
else:
info = copy.deepcopy(self.info)
return info
def get_measurement_info(self):
"""Returns the measurement info.
Returns
-------
self.info : dict
The measurement info.
"""
return self.info
def register_receive_callback(self, callback):
"""Register a raw buffer receive callback.
Parameters
----------
callback : callable
The callback. The raw buffer is passed as the first parameter
to callback.
"""
if callback not in self._recv_callbacks:
self._recv_callbacks.append(callback)
def unregister_receive_callback(self, callback):
"""Unregister a raw buffer receive callback."""
if callback in self._recv_callbacks:
self._recv_callbacks.remove(callback)
def _push_raw_buffer(self, raw_buffer):
"""Push raw buffer to clients using callbacks."""
for callback in self._recv_callbacks:
callback(raw_buffer)
def start_receive_thread(self, nchan):
"""Start the receive thread.
If the measurement has not been started, it will also be started.
Parameters
----------
nchan : int
The number of channels in the data.
"""
if self._recv_thread is None:
self._recv_thread = threading.Thread(target=_buffer_recv_worker,
args=(self, ))
self._recv_thread.daemon = True
self._recv_thread.start()
def stop_receive_thread(self, stop_measurement=False):
"""Stop the receive thread
Parameters
----------
stop_measurement : bool
Also stop the measurement.
"""
if self._recv_thread is not None:
self._recv_thread.stop()
self._recv_thread = None
def iter_raw_buffers(self):
"""Return an iterator over raw buffers
Returns
-------
raw_buffer : generator
Generator for iteration over raw buffers.
"""
iter_times = zip(range(self.tmin_samp, self.tmax_samp,
self.buffer_size),
range(self.tmin_samp + self.buffer_size,
self.tmax_samp, self.buffer_size))
for ii, (start, stop) in enumerate(iter_times):
# wait for correct number of samples to be available
self.ft_client.wait(stop, np.iinfo(np.uint32).max,
np.iinfo(np.uint32).max)
# get the samples
raw_buffer = self.ft_client.getData([start, stop]).transpose()
yield raw_buffer
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