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Run batch operations with the Speech CLI

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Common tasks when using the Speech service, are batch operations. In this article, you learn how to do batch speech to text (speech recognition), batch text to speech (speech synthesis) with the Speech CLI. Specifically, you learn how to:

  • Run batch speech recognition on a directory of audio files
  • Run batch speech synthesis by iterating over a .tsv file

Batch speech to text (speech recognition)

The Speech service is often used to recognize speech from audio files. In this example, you learn how to iterate over a directory using the Speech CLI to capture the recognition output for each .wav file. The --files flag is used to point at the directory where audio files are stored, and the wildcard *.wav is used to tell the Speech CLI to run recognition on every file with the extension .wav. The output for each recognition file is written as a tab separated value in speech_output.tsv.

Note

The --threads argument can be also used in the next section for spx synthesize commands, and the available threads will depend on the CPU and its current load percentage.

spx recognize --files C:\your_wav_file_dir\*.wav --output file C:\output_dir\speech_output.tsv --threads 10

Here's an example of the output file structure.

audio.input.id	recognizer.session.started.sessionid	recognizer.recognized.result.text
sample_1	07baa2f8d9fd4fbcb9faea451ce05475	A sample wave file.
sample_2	8f9b378f6d0b42f99522f1173492f013	Sample text synthesized.

Batch text to speech (speech synthesis)

The easiest way to run batch text to speech is to create a new .tsv (tab-separated-value) file, and use the --foreach command in the Speech CLI. You can create a .tsv file using your favorite text editor, for this example, let's call it text_synthesis.tsv:

Important

When copying the contents of this text file, make sure that your file has a tab not spaces between the file location and the text. Sometimes, when copying the contents from this example, tabs are converted to spaces causing the spx command to fail when run.

audio.output	text
C:\batch_wav_output\wav_1.wav	Sample text to synthesize.
C:\batch_wav_output\wav_2.wav	Using the Speech CLI to run batch-synthesis.
C:\batch_wav_output\wav_3.wav	Some more text to test capabilities.

Next, you run a command to point to text_synthesis.tsv, perform synthesis on each text field, and write the result to the corresponding audio.output path as a .wav file.

spx synthesize --foreach in @C:\your\path\to\text_synthesis.tsv

This command is the equivalent of running spx synthesize --text "Sample text to synthesize" --audio output C:\batch_wav_output\wav_1.wav for each record in the .tsv file.

A couple things to note:

  • The column headers, audio.output and text, correspond to the command-line arguments --audio output and --text, respectively. Multi-part command-line arguments like --audio output should be formatted in the file with no spaces, no leading dashes, and periods separating strings, for example, audio.output. Any other existing command-line arguments can be added to the file as more columns using this pattern.
  • When the file is formatted in this way, no other arguments are required to be passed to --foreach.
  • Ensure to separate each value in the .tsv with a tab.

However, if you have a .tsv file like the following example, with column headers that do not match command-line arguments:

wav_path    str_text
C:\batch_wav_output\wav_1.wav	Sample text to synthesize.
C:\batch_wav_output\wav_2.wav	Using the Speech CLI to run batch-synthesis.
C:\batch_wav_output\wav_3.wav	Some more text to test capabilities.

You can override these field names to the correct arguments using the following syntax in the --foreach call. This command makes the same call as before.

spx synthesize --foreach audio.output;text in @C:\your\path\to\text_synthesis.tsv

Next steps