wenet/dataset/kaldi_io.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright 2014-2016  Brno University of Technology (author: Karel Vesely)
# Licensed under the Apache License, Version 2.0 (the "License")

import numpy as np
import sys, os, re, gzip, struct

#################################################
# Adding kaldi tools to shell path,

# Select kaldi,
if not 'KALDI_ROOT' in os.environ:
    # Default! To change run python with 'export KALDI_ROOT=/some_dir python'
    os.environ['KALDI_ROOT'] = '/mnt/matylda5/iveselyk/Tools/kaldi-trunk'

# Add kaldi tools to path,
os.environ['PATH'] = os.popen(
    'echo $KALDI_ROOT/src/bin:$KALDI_ROOT/tools/openfst/bin:$KALDI_ROOT/src/fstbin/:$KALDI_ROOT/src/gmmbin/:$KALDI_ROOT/src/featbin/:$KALDI_ROOT/src/lm/:$KALDI_ROOT/src/sgmmbin/:$KALDI_ROOT/src/sgmm2bin/:$KALDI_ROOT/src/fgmmbin/:$KALDI_ROOT/src/latbin/:$KALDI_ROOT/src/nnetbin:$KALDI_ROOT/src/nnet2bin:$KALDI_ROOT/src/nnet3bin:$KALDI_ROOT/src/online2bin/:$KALDI_ROOT/src/ivectorbin/:$KALDI_ROOT/src/lmbin/'
).readline().strip() + ':' + os.environ['PATH']


#################################################
# Define all custom exceptions,
class UnsupportedDataType(Exception):
    pass


class UnknownVectorHeader(Exception):
    pass


class UnknownMatrixHeader(Exception):
    pass


class BadSampleSize(Exception):
    pass


class BadInputFormat(Exception):
    pass


class SubprocessFailed(Exception):
    pass


#################################################
# Data-type independent helper functions,


def open_or_fd(file, mode='rb'):
    """ fd = open_or_fd(file)
   Open file, gzipped file, pipe, or forward the file-descriptor.
   Eventually seeks in the 'file' argument contains ':offset' suffix.
  """
    offset = None
    try:
        # strip 'ark:' prefix from r{x,w}filename (optional),
        if re.search('^(ark|scp)(,scp|,b|,t|,n?f|,n?p|,b?o|,n?s|,n?cs)*:',
                     file):
            (prefix, file) = file.split(':', 1)
        # separate offset from filename (optional),
        if re.search(':[0-9]+$', file):
            (file, offset) = file.rsplit(':', 1)
        # input pipe?
        if file[-1] == '|':
            fd = popen(file[:-1], 'rb')  # custom,
        # output pipe?
        elif file[0] == '|':
            fd = popen(file[1:], 'wb')  # custom,
        # is it gzipped?
        elif file.split('.')[-1] == 'gz':
            fd = gzip.open(file, mode)
        # a normal file...
        else:
            fd = open(file, mode)
    except TypeError:
        # 'file' is opened file descriptor,
        fd = file
    # Eventually seek to offset,
    if offset != None: fd.seek(int(offset))
    return fd


# based on '/usr/local/lib/python3.4/os.py'
def popen(cmd, mode="rb"):
    if not isinstance(cmd, str):
        raise TypeError("invalid cmd type (%s, expected string)" % type(cmd))

    import subprocess, io, threading

    # cleanup function for subprocesses,
    def cleanup(proc, cmd):
        ret = proc.wait()
        if ret > 0:
            raise SubprocessFailed('cmd %s returned %d !' % (cmd, ret))
        return

    # text-mode,
    if mode == "r":
        proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
        threading.Thread(target=cleanup,
                         args=(proc, cmd)).start()  # clean-up thread,
        return io.TextIOWrapper(proc.stdout)
    elif mode == "w":
        proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE)
        threading.Thread(target=cleanup,
                         args=(proc, cmd)).start()  # clean-up thread,
        return io.TextIOWrapper(proc.stdin)
    # binary,
    elif mode == "rb":
        proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
        threading.Thread(target=cleanup,
                         args=(proc, cmd)).start()  # clean-up thread,
        return proc.stdout
    elif mode == "wb":
        proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE)
        threading.Thread(target=cleanup,
                         args=(proc, cmd)).start()  # clean-up thread,
        return proc.stdin
    # sanity,
    else:
        raise ValueError("invalid mode %s" % mode)


def read_key(fd):
    """ [key] = read_key(fd)
   Read the utterance-key from the opened ark/stream descriptor 'fd'.
  """
    key = ''
    while 1:
        char = fd.read(1).decode("latin1")
        if char == '': break
        if char == ' ': break
        key += char
    key = key.strip()
    if key == '': return None  # end of file,
    assert (re.match('^\S+$', key) != None)  # check format (no whitespace!)
    return key


#################################################
# Integer vectors (alignments, ...),


def read_ali_ark(file_or_fd):
    """ Alias to 'read_vec_int_ark()' """
    return read_vec_int_ark(file_or_fd)


def read_vec_int_ark(file_or_fd):
    """ generator(key,vec) = read_vec_int_ark(file_or_fd)
   Create generator of (key,vector<int>) tuples, which reads from the ark file/stream.
   file_or_fd : ark, gzipped ark, pipe or opened file descriptor.

   Read ark to a 'dictionary':
   d = { u:d for u,d in kaldi_io.read_vec_int_ark(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        key = read_key(fd)
        while key:
            ali = read_vec_int(fd)
            yield key, ali
            key = read_key(fd)
    finally:
        if fd is not file_or_fd: fd.close()


def read_vec_int_scp(file_or_fd):
    """ generator(key,vec) = read_vec_int_scp(file_or_fd)
   Returns generator of (key,vector<int>) tuples, read according to kaldi scp.
   file_or_fd : scp, gzipped scp, pipe or opened file descriptor.

   Iterate the scp:
   for key,vec in kaldi_io.read_vec_int_scp(file):
     ...

   Read scp to a 'dictionary':
   d = { key:vec for key,mat in kaldi_io.read_vec_int_scp(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        for line in fd:
            (key, rxfile) = line.decode().split(' ')
            vec = read_vec_int(rxfile)
            yield key, vec
    finally:
        if fd is not file_or_fd: fd.close()


def read_vec_int(file_or_fd):
    """ [int-vec] = read_vec_int(file_or_fd)
   Read kaldi integer vector, ascii or binary input,
  """
    fd = open_or_fd(file_or_fd)
    binary = fd.read(2).decode()
    if binary == '\0B':  # binary flag
        assert (fd.read(1).decode() == '\4')
        # int-size
        vec_size = np.frombuffer(fd.read(4), dtype='int32',
                                 count=1)[0]  # vector dim
        # Elements from int32 vector are sored in tuples: (sizeof(int32), value),
        vec = np.frombuffer(fd.read(vec_size * 5),
                            dtype=[('size', 'int8'), ('value', 'int32')],
                            count=vec_size)
        assert (vec[0]['size'] == 4)  # int32 size,
        ans = vec[:]['value']  # values are in 2nd column,
    else:  # ascii,
        arr = (binary + fd.readline().decode()).strip().split()
        try:
            arr.remove('[')
            arr.remove(']')  # optionally
        except ValueError:
            pass
        ans = np.array(arr, dtype=int)
    if fd is not file_or_fd: fd.close()  # cleanup
    return ans


# Writing,
def write_vec_int(file_or_fd, v, key=''):
    """ write_vec_int(f, v, key='')
   Write a binary kaldi integer vector to filename or stream.
   Arguments:
   file_or_fd : filename or opened file descriptor for writing,
   v : the vector to be stored,
   key (optional) : used for writing ark-file, the utterance-id gets written before the vector.

   Example of writing single vector:
   kaldi_io.write_vec_int(filename, vec)

   Example of writing arkfile:
   with open(ark_file,'w') as f:
     for key,vec in dict.iteritems():
       kaldi_io.write_vec_flt(f, vec, key=key)
  """
    fd = open_or_fd(file_or_fd, mode='wb')
    if sys.version_info[0] == 3: assert (fd.mode == 'wb')
    try:
        if key != '':
            fd.write(
                (key +
                 ' ').encode("latin1"))  # ark-files have keys (utterance-id),
        fd.write('\0B'.encode())  # we write binary!
        # dim,
        fd.write('\4'.encode())  # int32 type,
        fd.write(struct.pack(np.dtype('int32').char, v.shape[0]))
        # data,
        for i in range(len(v)):
            fd.write('\4'.encode())  # int32 type,
            fd.write(struct.pack(np.dtype('int32').char, v[i]))  # binary,
    finally:
        if fd is not file_or_fd: fd.close()


#################################################
# Float vectors (confidences, ivectors, ...),


# Reading,
def read_vec_flt_scp(file_or_fd):
    """ generator(key,mat) = read_vec_flt_scp(file_or_fd)
   Returns generator of (key,vector) tuples, read according to kaldi scp.
   file_or_fd : scp, gzipped scp, pipe or opened file descriptor.

   Iterate the scp:
   for key,vec in kaldi_io.read_vec_flt_scp(file):
     ...

   Read scp to a 'dictionary':
   d = { key:mat for key,mat in kaldi_io.read_mat_scp(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        for line in fd:
            (key, rxfile) = line.decode().split(' ')
            vec = read_vec_flt(rxfile)
            yield key, vec
    finally:
        if fd is not file_or_fd: fd.close()


def read_vec_flt_ark(file_or_fd):
    """ generator(key,vec) = read_vec_flt_ark(file_or_fd)
   Create generator of (key,vector<float>) tuples, reading from an ark file/stream.
   file_or_fd : ark, gzipped ark, pipe or opened file descriptor.

   Read ark to a 'dictionary':
   d = { u:d for u,d in kaldi_io.read_vec_flt_ark(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        key = read_key(fd)
        while key:
            ali = read_vec_flt(fd)
            yield key, ali
            key = read_key(fd)
    finally:
        if fd is not file_or_fd: fd.close()


def read_vec_flt(file_or_fd):
    """ [flt-vec] = read_vec_flt(file_or_fd)
   Read kaldi float vector, ascii or binary input,
  """
    fd = open_or_fd(file_or_fd)
    binary = fd.read(2).decode()
    if binary == '\0B':  # binary flag
        # Data type,
        header = fd.read(3).decode()
        if header == 'FV ': sample_size = 4  # floats
        elif header == 'DV ': sample_size = 8  # doubles
        else: raise UnknownVectorHeader("The header contained '%s'" % header)
        assert (sample_size > 0)
        # Dimension,
        assert (fd.read(1).decode() == '\4')
        # int-size
        vec_size = np.frombuffer(fd.read(4), dtype='int32',
                                 count=1)[0]  # vector dim
        # Read whole vector,
        buf = fd.read(vec_size * sample_size)
        if sample_size == 4: ans = np.frombuffer(buf, dtype='float32')
        elif sample_size == 8: ans = np.frombuffer(buf, dtype='float64')
        else: raise BadSampleSize
        return ans
    else:  # ascii,
        arr = (binary + fd.readline().decode()).strip().split()
        try:
            arr.remove('[')
            arr.remove(']')  # optionally
        except ValueError:
            pass
        ans = np.array(arr, dtype=float)
    if fd is not file_or_fd: fd.close()  # cleanup
    return ans


# Writing,
def write_vec_flt(file_or_fd, v, key=''):
    """ write_vec_flt(f, v, key='')
   Write a binary kaldi vector to filename or stream. Supports 32bit and 64bit floats.
   Arguments:
   file_or_fd : filename or opened file descriptor for writing,
   v : the vector to be stored,
   key (optional) : used for writing ark-file, the utterance-id gets written before the vector.

   Example of writing single vector:
   kaldi_io.write_vec_flt(filename, vec)

   Example of writing arkfile:
   with open(ark_file,'w') as f:
     for key,vec in dict.iteritems():
       kaldi_io.write_vec_flt(f, vec, key=key)
  """
    fd = open_or_fd(file_or_fd, mode='wb')
    if sys.version_info[0] == 3: assert (fd.mode == 'wb')
    try:
        if key != '':
            fd.write(
                (key +
                 ' ').encode("latin1"))  # ark-files have keys (utterance-id),
        fd.write('\0B'.encode())  # we write binary!
        # Data-type,
        if v.dtype == 'float32': fd.write('FV '.encode())
        elif v.dtype == 'float64': fd.write('DV '.encode())
        else:
            raise UnsupportedDataType(
                "'%s', please use 'float32' or 'float64'" % v.dtype)
        # Dim,
        fd.write('\04'.encode())
        fd.write(struct.pack(np.dtype('uint32').char, v.shape[0]))  # dim
        # Data,
        fd.write(v.tobytes())
    finally:
        if fd is not file_or_fd: fd.close()


#################################################
# Float matrices (features, transformations, ...),


# Reading,
def read_mat_scp(file_or_fd):
    """ generator(key,mat) = read_mat_scp(file_or_fd)
   Returns generator of (key,matrix) tuples, read according to kaldi scp.
   file_or_fd : scp, gzipped scp, pipe or opened file descriptor.

   Iterate the scp:
   for key,mat in kaldi_io.read_mat_scp(file):
     ...

   Read scp to a 'dictionary':
   d = { key:mat for key,mat in kaldi_io.read_mat_scp(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        for line in fd:
            (key, rxfile) = line.decode().split(' ')
            mat = read_mat(rxfile)
            yield key, mat
    finally:
        if fd is not file_or_fd: fd.close()


def read_mat_ark(file_or_fd):
    """ generator(key,mat) = read_mat_ark(file_or_fd)
   Returns generator of (key,matrix) tuples, read from ark file/stream.
   file_or_fd : scp, gzipped scp, pipe or opened file descriptor.

   Iterate the ark:
   for key,mat in kaldi_io.read_mat_ark(file):
     ...

   Read ark to a 'dictionary':
   d = { key:mat for key,mat in kaldi_io.read_mat_ark(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        key = read_key(fd)
        while key:
            mat = read_mat(fd)
            yield key, mat
            key = read_key(fd)
    finally:
        if fd is not file_or_fd: fd.close()


def read_mat(file_or_fd):
    """ [mat] = read_mat(file_or_fd)
   Reads single kaldi matrix, supports ascii and binary.
   file_or_fd : file, gzipped file, pipe or opened file descriptor.
  """
    fd = open_or_fd(file_or_fd)
    try:
        binary = fd.read(2).decode()
        if binary == '\0B':
            mat = _read_mat_binary(fd)
        else:
            assert (binary == ' [')
            mat = _read_mat_ascii(fd)
    finally:
        if fd is not file_or_fd: fd.close()
    return mat


def _read_mat_binary(fd):
    # Data type
    header = fd.read(3).decode()
    # 'CM', 'CM2', 'CM3' are possible values,
    if header.startswith('CM'): return _read_compressed_mat(fd, header)
    elif header == 'FM ': sample_size = 4  # floats
    elif header == 'DM ': sample_size = 8  # doubles
    else: raise UnknownMatrixHeader("The header contained '%s'" % header)
    assert (sample_size > 0)
    # Dimensions
    s1, rows, s2, cols = np.frombuffer(fd.read(10),
                                       dtype='int8,int32,int8,int32',
                                       count=1)[0]
    # Read whole matrix
    buf = fd.read(rows * cols * sample_size)
    if sample_size == 4: vec = np.frombuffer(buf, dtype='float32')
    elif sample_size == 8: vec = np.frombuffer(buf, dtype='float64')
    else: raise BadSampleSize
    mat = np.reshape(vec, (rows, cols))
    return mat


def _read_mat_ascii(fd):
    rows = []
    while 1:
        line = fd.readline().decode()
        if (len(line) == 0): raise BadInputFormat  # eof, should not happen!
        if len(line.strip()) == 0: continue  # skip empty line
        arr = line.strip().split()
        if arr[-1] != ']':
            rows.append(np.array(arr, dtype='float32'))  # not last line
        else:
            rows.append(np.array(arr[:-1], dtype='float32'))  # last line
            mat = np.vstack(rows)
            return mat


def _read_compressed_mat(fd, format):
    """ Read a compressed matrix,
      see: https://github.com/kaldi-asr/kaldi/blob/master/src/matrix/compressed-matrix.h
      methods: CompressedMatrix::Read(...), CompressedMatrix::CopyToMat(...),
  """
    assert (format == 'CM ')  # The formats CM2, CM3 are not supported...

    # Format of header 'struct',
    global_header = np.dtype([('minvalue', 'float32'), ('range', 'float32'),
                              ('num_rows', 'int32'), ('num_cols', 'int32')
                              ])  # member '.format' is not written,
    per_col_header = np.dtype([('percentile_0', 'uint16'),
                               ('percentile_25', 'uint16'),
                               ('percentile_75', 'uint16'),
                               ('percentile_100', 'uint16')])

    # Mapping for percentiles in col-headers,
    def uint16_to_float(value, min, range):
        return np.float32(min + range * 1.52590218966964e-05 * value)

    # Mapping for matrix elements,
    def uint8_to_float_v2(vec, p0, p25, p75, p100):
        # Split the vector by masks,
        mask_0_64 = (vec <= 64)
        mask_193_255 = (vec > 192)
        mask_65_192 = (~(mask_0_64 | mask_193_255))
        # Sanity check (useful but slow...),
        # assert(len(vec) == np.sum(np.hstack([mask_0_64,mask_65_192,mask_193_255])))
        # assert(len(vec) == np.sum(np.any([mask_0_64,mask_65_192,mask_193_255], axis=0)))
        # Build the float vector,
        ans = np.empty(len(vec), dtype='float32')
        ans[mask_0_64] = p0 + (p25 - p0) / 64. * vec[mask_0_64]
        ans[mask_65_192] = p25 + (p75 - p25) / 128. * (vec[mask_65_192] - 64)
        ans[mask_193_255] = p75 + (p100 - p75) / 63. * (vec[mask_193_255] -
                                                        192)
        return ans

    # Read global header,
    globmin, globrange, rows, cols = np.frombuffer(fd.read(16),
                                                   dtype=global_header,
                                                   count=1)[0]

    # The data is structed as [Colheader, ... , Colheader, Data, Data , .... ]
    #                         {           cols           }{     size         }
    col_headers = np.frombuffer(fd.read(cols * 8),
                                dtype=per_col_header,
                                count=cols)
    data = np.reshape(np.frombuffer(fd.read(cols * rows),
                                    dtype='uint8',
                                    count=cols * rows),
                      newshape=(cols, rows))  # stored as col-major,

    mat = np.empty((cols, rows), dtype='float32')
    for i, col_header in enumerate(col_headers):
        col_header_flt = [
            uint16_to_float(percentile, globmin, globrange)
            for percentile in col_header
        ]
        mat[i] = uint8_to_float_v2(data[i], *col_header_flt)

    return mat.T  # transpose! col-major -> row-major,


def write_ark_scp(key, mat, ark_fout, scp_out):
    mat_offset = write_mat(ark_fout, mat, key)
    scp_line = '{}\t{}:{}'.format(key, ark_fout.name, mat_offset)
    scp_out.write(scp_line)
    scp_out.write('\n')


# Writing,
def write_mat(file_or_fd, m, key=''):
    """ write_mat(f, m, key='')
  Write a binary kaldi matrix to filename or stream. Supports 32bit and 64bit floats.
  Arguments:
   file_or_fd : filename of opened file descriptor for writing,
   m : the matrix to be stored,
   key (optional) : used for writing ark-file, the utterance-id gets written before the matrix.

   Example of writing single matrix:
   kaldi_io.write_mat(filename, mat)

   Example of writing arkfile:
   with open(ark_file,'w') as f:
     for key,mat in dict.iteritems():
       kaldi_io.write_mat(f, mat, key=key)
  """
    mat_offset = 0
    fd = open_or_fd(file_or_fd, mode='wb')
    if sys.version_info[0] == 3: assert (fd.mode == 'wb')
    try:
        if key != '':
            fd.write(
                (key +
                 ' ').encode("latin1"))  # ark-files have keys (utterance-id),
        mat_offset = fd.tell()
        fd.write('\0B'.encode())  # we write binary!
        # Data-type,
        if m.dtype == 'float32': fd.write('FM '.encode())
        elif m.dtype == 'float64': fd.write('DM '.encode())
        else:
            raise UnsupportedDataType(
                "'%s', please use 'float32' or 'float64'" % m.dtype)
        # Dims,
        fd.write('\04'.encode())
        fd.write(struct.pack(np.dtype('uint32').char, m.shape[0]))  # rows
        fd.write('\04'.encode())
        fd.write(struct.pack(np.dtype('uint32').char, m.shape[1]))  # cols
        # Data,
        fd.write(m.tobytes())
    finally:
        if fd is not file_or_fd: fd.close()
    return mat_offset


#################################################
# 'Posterior' kaldi type (posteriors, confusion network, nnet1 training targets, ...)
# Corresponds to: vector<vector<tuple<int,float> > >
# - outer vector: time axis
# - inner vector: records at the time
# - tuple: int = index, float = value
#


def read_cnet_ark(file_or_fd):
    """ Alias of function 'read_post_ark()', 'cnet' = confusion network """
    return read_post_ark(file_or_fd)


def read_post_ark(file_or_fd):
    """ generator(key,vec<vec<int,float>>) = read_post_ark(file)
   Returns generator of (key,posterior) tuples, read from ark file.
   file_or_fd : ark, gzipped ark, pipe or opened file descriptor.

   Iterate the ark:
   for key,post in kaldi_io.read_post_ark(file):
     ...

   Read ark to a 'dictionary':
   d = { key:post for key,post in kaldi_io.read_post_ark(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        key = read_key(fd)
        while key:
            post = read_post(fd)
            yield key, post
            key = read_key(fd)
    finally:
        if fd is not file_or_fd: fd.close()


def read_post(file_or_fd):
    """ [post] = read_post(file_or_fd)
   Reads single kaldi 'Posterior' in binary format.

   The 'Posterior' is C++ type 'vector<vector<tuple<int,float> > >',
   the outer-vector is usually time axis, inner-vector are the records
   at given time,  and the tuple is composed of an 'index' (integer)
   and a 'float-value'. The 'float-value' can represent a probability
   or any other numeric value.

   Returns vector of vectors of tuples.
  """
    fd = open_or_fd(file_or_fd)
    ans = []
    binary = fd.read(2).decode()
    assert (binary == '\0B')
    # binary flag
    assert (fd.read(1).decode() == '\4')
    # int-size
    outer_vec_size = np.frombuffer(fd.read(4), dtype='int32',
                                   count=1)[0]  # number of frames (or bins)

    # Loop over 'outer-vector',
    for i in range(outer_vec_size):
        assert (fd.read(1).decode() == '\4')
        # int-size
        inner_vec_size = np.frombuffer(
            fd.read(4), dtype='int32',
            count=1)[0]  # number of records for frame (or bin)
        data = np.frombuffer(fd.read(inner_vec_size * 10),
                             dtype=[('size_idx', 'int8'), ('idx', 'int32'),
                                    ('size_post', 'int8'),
                                    ('post', 'float32')],
                             count=inner_vec_size)
        assert (data[0]['size_idx'] == 4)
        assert (data[0]['size_post'] == 4)
        ans.append(data[['idx', 'post']].tolist())

    if fd is not file_or_fd: fd.close()
    return ans


#################################################
# Kaldi Confusion Network bin begin/end times,
# (kaldi stores CNs time info separately from the Posterior).
#


def read_cntime_ark(file_or_fd):
    """ generator(key,vec<tuple<float,float>>) = read_cntime_ark(file_or_fd)
   Returns generator of (key,cntime) tuples, read from ark file.
   file_or_fd : file, gzipped file, pipe or opened file descriptor.

   Iterate the ark:
   for key,time in kaldi_io.read_cntime_ark(file):
     ...

   Read ark to a 'dictionary':
   d = { key:time for key,time in kaldi_io.read_post_ark(file) }
  """
    fd = open_or_fd(file_or_fd)
    try:
        key = read_key(fd)
        while key:
            cntime = read_cntime(fd)
            yield key, cntime
            key = read_key(fd)
    finally:
        if fd is not file_or_fd: fd.close()


def read_cntime(file_or_fd):
    """ [cntime] = read_cntime(file_or_fd)
   Reads single kaldi 'Confusion Network time info', in binary format:
   C++ type: vector<tuple<float,float> >.
   (begin/end times of bins at the confusion network).

   Binary layout is '<num-bins> <beg1> <end1> <beg2> <end2> ...'

   file_or_fd : file, gzipped file, pipe or opened file descriptor.

   Returns vector of tuples.
  """
    fd = open_or_fd(file_or_fd)
    binary = fd.read(2).decode()
    assert (binary == '\0B')
    # assuming it's binary

    assert (fd.read(1).decode() == '\4')
    # int-size
    vec_size = np.frombuffer(fd.read(4), dtype='int32',
                             count=1)[0]  # number of frames (or bins)

    data = np.frombuffer(fd.read(vec_size * 10),
                         dtype=[('size_beg', 'int8'), ('t_beg', 'float32'),
                                ('size_end', 'int8'), ('t_end', 'float32')],
                         count=vec_size)
    assert (data[0]['size_beg'] == 4)
    assert (data[0]['size_end'] == 4)
    ans = data[['t_beg',
                't_end']].tolist()  # Return vector of tuples (t_beg,t_end),

    if fd is not file_or_fd: fd.close()
    return ans


#################################################
# Segments related,
#


# Segments as 'Bool vectors' can be handy,
# - for 'superposing' the segmentations,
# - for frame-selection in Speaker-ID experiments,
def read_segments_as_bool_vec(segments_file):
    """ [ bool_vec ] = read_segments_as_bool_vec(segments_file)
   using kaldi 'segments' file for 1 wav, format : '<utt> <rec> <t-beg> <t-end>'
   - t-beg, t-end is in seconds,
   - assumed 100 frames/second,
  """
    segs = np.loadtxt(segments_file, dtype='object,object,f,f', ndmin=1)
    # Sanity checks,
    assert (len(segs) > 0)  # empty segmentation is an error,
    assert (len(np.unique([rec[1] for rec in segs])) == 1
            )  # segments with only 1 wav-file,
    # Convert time to frame-indexes,
    start = np.rint([100 * rec[2] for rec in segs]).astype(int)
    end = np.rint([100 * rec[3] for rec in segs]).astype(int)
    # Taken from 'read_lab_to_bool_vec', htk.py,
    frms = np.repeat(
        np.r_[np.tile([False, True], len(end)), False],
        np.r_[np.c_[start - np.r_[0, end[:-1]], end - start].flat, 0])
    assert np.sum(end - start) == np.sum(frms)
    return frms