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Last active December 5, 2022 11:45
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Utility functions to check for corruption in tfrecord files
import tensorflow as tf
def validate_dataset(filenames, reader_opts=None):
Attempt to iterate over every record in the supplied iterable of TFRecord filenames
:param filenames: iterable of filenames to read
:param reader_opts: (optional) tf.python_io.TFRecordOptions to use when constructing the record iterator
i = 0
for fname in filenames:
print('validating ', fname)
record_iterator = tf.python_io.tf_record_iterator(path=fname, options=reader_opts)
for _ in record_iterator:
i += 1
except Exception as e:
print('error in {} at record {}'.format(fname, i))
# The code below here uses the crcmod package to implement an alternative method which is able to print out
# if it finds a bad record and attempt to keep going. If the corruption in your file is just flipped bits this may be helpful.
# If the corruption is added or deleted bytes this will probably crash and burn.
import struct
from crcmod.predefined import mkPredefinedCrcFun
_crc_fn = mkPredefinedCrcFun('crc-32c')
def calc_masked_crc(data):
crc = _crc_fn(data)
return (((crc >> 15) | (crc << 17)) + 0xa282ead8) & 0xFFFFFFFF
def validate_dataset_slower(filenames):
total_records = 0
total_bad_len_crc = 0
total_bad_data_crc = 0
for f_name in filenames:
i = 0
print('validating ', f_name)
with open(f_name, 'rb') as f:
len_bytes =
while len(len_bytes) > 0:
# tfrecord format is a wrapper around protobuf data
length, = struct.unpack('<Q', len_bytes) # u64: length of the protobuf data (excluding the header)
len_crc, = struct.unpack('<I', # u32: masked crc32c of the length bytes
data = # protobuf data
data_crc, = struct.unpack('<I', # u32: masked crc32c of the protobuf data
if len_crc != calc_masked_crc(len_bytes):
print('bad crc on len at record', i)
total_bad_len_crc += 1
if data_crc != calc_masked_crc(data):
print('bad crc on data at record', i)
total_bad_data_crc += 1
i += 1
len_bytes =
print('checked', i, 'records')
total_records += i
print('checked', total_records, 'total records')
print('total with bad length crc: ', total_bad_len_crc)
print('total with bad data crc: ', total_bad_data_crc)
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Note that if you need to check compressed files with validate_dataset_slower you'll need to modify this code or decompress the files manually first

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Thanks, very helpful! I used validate_dataset to check for corrupted tfrecords (compressed using GZIP), and it found it.

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lkhphuc commented Jul 11, 2022

For the lost soul that still wander here in 2022, use at line 14 instead.

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robmoore commented Dec 2, 2022

Also, if your files are compressed, you'll need to pass in"GZIP") to validate_dataset.

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