When working with Speech Studio in Azure AI Speech (for example, to build a custom speech model for recognition or training purposes), you must provide speech samples along with their transcripts.
Requirements for Uploading Speech Samples:
Audio File Format
The supported format is .wav (PCM, 16-bit, 16 kHz or 8 kHz mono).
Other formats like .wma , .flac , or .mp3 are not accepted for training custom models.
Batch Upload via .zip
Audio files must be placed in a .zip archive.
The .zip file must also include a transcription file (usually a .txt or .json file) that maps the spoken audio in each .wav file to the correct text.
Transcript Format
Transcripts must be plain text, not Microsoft Word documents.
The transcript must align correctly with each audio file to ensure the Speech service learns from accurate mappings.
Option Analysis
A). Combine into one .wma file
Incorrect. .wma is not supported. Also, Speech Studio expects multiple .wav samples, not one big file.
B). Upload a .zip file containing .wav files + transcript
Correct. This is the officially supported method for uploading training data into a Speech Studio project.
C). Upload .flac files with Word transcript
Incorrect. .flac is not supported. Transcripts must be plain text, not Word files.
D). Upload individual .wma files
Incorrect. .wma is not supported.
The answer: B. Upload a .zip file that contains a collection of audio files in the .wav format and a corresponding text transcript file.
Microsoft References
Prepare training data for Custom Speech
Speech Studio - Data Requirements