How to Reduce Latency in AWS Transcribe Batch Processing

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If you’re trying to decide between different ways to transcribe audio with Amazon Transcribe, here’s what you need to know about the two main methods: batch and streaming.

Batch transcription is straightforward; it processes audio files that you upload and then gives you a written transcript once the entire file has been processed. This method works well because it uses the full audio context, which helps improve the accuracy of the transcription. It’s asynchronous, so you send in your file and wait for the result later.

Streaming transcription, on the other hand, is meant for real-time situations. It processes live audio as you speak and provides partial results quickly, updating with final transcripts as more audio comes in. This type is great for use cases like live captions or monitoring ongoing calls, where low-latency results are important. However, streaming expects audio to be generated in real time, not pre-recorded.

If you’re working with a short, pre-recorded audio clip, like a 1-minute file, streaming may not give you a big performance boost. Since streaming is built for live input, using it for a pre-recorded file is like trying to force it to work as if the audio is being generated live. This means it might not process as quickly as expected, mainly because it’s not designed for that use case.

To get the best results and optimize performance, consider these tips if you choose streaming:

– Use PCM-encoded audio whenever possible
– Keep your audio stream as close to real-time as you can
– Break the audio into chunks between 50 and 200 milliseconds for better latency
– Keep chunk sizes consistent
– Make sure to specify the correct number of audio channels
– Record at a sampling rate of 16,000 Hz for a good mix of quality and data size

Remember, the processing time can vary depending on factors like audio format, content, language, and other details. For a short, pre-recorded file like yours, batch transcription might actually be a better fit. It can analyze the entire audio at once, which often results in more accurate transcriptions.

If you want more tailored advice or support, it’s a good idea to review your AWS Support options to get guidance specific to your setup and needs.