Function

This program is a simple editor for manipulating label files. Typical examples of its use might be to merge a sequence of labels into a single composite label or to expand a set of labels into a context sensitive set. HLED works by reading in a list of editing commands from an edit script file and then makes an edited copy of one or more label files. For multiple level files, edit commands are applied to the current level which is initially the first (i.e. 1). Other levels may be edited by moving to the required level using the ML Move Level command.

Each edit command in the script file must be on a separate line. The first two-letter mnemonic on each line is the command name and the remaining letters denote labels^17.8. The commands supported may be divided into two sets. Those in the first set are used to edit individual labels and they are as follows

CH X A Y B

Change Y in the context of A_B to X. A and/or B may be a * to match any context, otherwise they must be defined by a DC command (see below). A block of consecutive CH commands are effectively executed in parallel so that the contexts are those that exist before any of the commands in the block are applied.

DC A B C ..

define the context A as the set of labels B, C, etc.

DE A B ..

Delete any occurrences of labels A or B etc.

FI A Y B

Find Y in the context of A_B and count the number of occurrences.

ME X A B ..

Merge any sequence of labels A B C etc. and call the new segment X.

ML N

Move to label level N.

RE X A B ..

Replace all occurrences of labels A or B etc. by the label X.

The commands in the second set perform global operations on whole transcriptions. They are as follows.

DL [N]

Delete all labels in the current level. If the optional integer arg is given, then level N is deleted.

EX

Expand all labels either from words to phones using the first pronunciation from a dictionary when it is specified on the command line otherwise expand labels of the form A_B_C_D_... into a sequence of separate labels A B C D ..... This is useful for label formats which include a complete orthography as a single label or for creating a set of sub-word labels from a word orthography for a sub-word based recogniser. When a label is expanded in this way, the label duration is divided into equal length segments. This can only be performed on the root level of a multiple level file.

FG X

Mark all unlabelled segments of the input file of duration greater than $T_g$ msecs with the label X. The default value for $T_g$ is 50000.0 (=5msecs) but this can be changed using the -g command line option. This command is mainly used for explicitly labelling inter-word silences in data files for which only the actual speech has been transcribed.

IS A B

Insert label A at the start of every transcription and B at the end. This command is usually used to insert silence labels.

IT

Ignore triphone contexts in CH and FI commands.

LC [X]

Convert all phoneme labels to left context dependent. If X is given then the first phoneme label a becomes X-a otherwise it is left unchanged.

NB X

The label X (typically a short pause) should be ignored at word boundaries when using the context commands LC, RC and TC.

RC [X]

Convert all phoneme labels to right context dependent. If X is given then the last phoneme label z becomes z+X otherwise it is left unchanged.

SB X

Define the label X to be a sentence boundary marker. This label can then be used in context-sensitive change commands.

SO

Sort all labels into time order.

SP

Split multiple levels into multiple alternative label lists.

TC [X[Y]

] Convert all phoneme labels to Triphones, that is left and right context dependent. If X is given then the first phoneme label a becomes X-a+b otherwise it is left unchanged. If Y is given then the last phoneme label z becomes y-z+Y otherwise if X is given then it becomes y-z+X otherwise it is left unchanged.

WB X

Define X to be an inter-word label. This command affects the operation of the LC, RC and TC commands. The expansion of context labels is blocked wherever an inter-word label occurs.

The source and target label file formats can be defined using the -G and -P command line arguments. They can also be set using the configuration variables SOURCELABEL and TARGETLABEL. The default for both cases is the HTK format.