ref: f74bff74f6c3961eb4e3b73cd38a4aff71aff5f4
dir: /dnn/training_tf2/fec_packets.py/
import numpy as np
def write_fec_packets(filename, packets, rates=None):
""" writes packets in binary format """
assert np.dtype(np.float32).itemsize == 4
assert np.dtype(np.int16).itemsize == 2
# derive some sizes
num_packets = len(packets)
subframes_per_packet = packets[0].shape[-2]
num_features = packets[0].shape[-1]
# size of float is 4
subframe_size = num_features * 4
packet_size = subframe_size * subframes_per_packet + 2 # two bytes for rate
version = 1
# header size (version, header_size, num_packets, packet_size, subframe_size, subrames_per_packet, num_features)
header_size = 14
with open(filename, 'wb') as f:
# header
f.write(np.int16(version).tobytes())
f.write(np.int16(header_size).tobytes())
f.write(np.int16(num_packets).tobytes())
f.write(np.int16(packet_size).tobytes())
f.write(np.int16(subframe_size).tobytes())
f.write(np.int16(subframes_per_packet).tobytes())
f.write(np.int16(num_features).tobytes())
# packets
for i, packet in enumerate(packets):
if type(rates) == type(None):
rate = 0
else:
rate = rates[i]
f.write(np.int16(rate).tobytes())
features = np.flip(packet, axis=-2)
f.write(features.astype(np.float32).tobytes())
def read_fec_packets(filename):
""" reads packets from binary format """
assert np.dtype(np.float32).itemsize == 4
assert np.dtype(np.int16).itemsize == 2
with open(filename, 'rb') as f:
# header
version = np.frombuffer(f.read(2), dtype=np.int16).item()
header_size = np.frombuffer(f.read(2), dtype=np.int16).item()
num_packets = np.frombuffer(f.read(2), dtype=np.int16).item()
packet_size = np.frombuffer(f.read(2), dtype=np.int16).item()
subframe_size = np.frombuffer(f.read(2), dtype=np.int16).item()
subframes_per_packet = np.frombuffer(f.read(2), dtype=np.int16).item()
num_features = np.frombuffer(f.read(2), dtype=np.int16).item()
dummy_features = np.zeros((1, subframes_per_packet, num_features), dtype=np.float32)
# packets
rates = []
packets = []
for i in range(num_packets):
rate = np.frombuffer(f.read(2), dtype=np.int16).item
rates.append(rate)
features = np.reshape(np.frombuffer(f.read(subframe_size * subframes_per_packet), dtype=np.float32), dummy_features.shape)
packet = np.flip(features, axis=-2)
packets.append(packet)
return packets