Transcription Services

The Best File Formats for Transcription Services

By Thomas Carter on January, 31 2019
Thomas Carter

Choosing a file format for an audio transcription can be a daunting task if this is your first time using transcription services. Fears around compatibility, audio quality and upload speeds can leave those without a background in technology feeling hesitant and unsure.

I am not gonna tell you that file formats don’t matter … But, they don’t really matter. So, relax. If you already have an audio file, you will be able to find someone who can transcribe it. Most transcription companies are willing to accommodate a range of file formats for audio transcription services. If you are starting from scratch, your file format choice isn’t going to make or break your ability to get a high-quality, accurate transcription.

With that said, information is power and there are subtle differences worth understanding that might improve your transcription service experience and the transcription process. In this post, we’re going to take a look at the best file formats for transcription services and explain the small differences that could end up having an impact on the quality of your results.

Audio File Formats That Work Best For Transcription Services

First, let’s explain the three main categories of audio files:

  • Uncompressed (PCM, WAV) - Uncompressed audio is, as the name suggests, not tampered with in any way. These files are made from sound waves that are captured and converted to a digital format with zero processing. This delivers the highest-quality audio file possible, only limited by the quality of the microphone used. The caveat is that, as an uncompressed audio format, the files take up a lot of disk space. That means slow upload times and unwieldy storage.

  • Lossy (MP3, WMA, AAC) - Lossy file formats are very popular due to their smaller file size, making them easier to transfer between devices and networks. However, it comes at the sacrifice of audio quality and fidelity. In most cases, it’s difficult to hear the differences between a high-quality lossy recording and an uncompressed one, but there are times when audio can be compressed too much and you’ll start to hear artefacts in the audio. You also have less data to play with if you need to enhance a recording with audio quality damaged by background noise or other factors.

  • Lossless (FLAC, WMA, ALC) - Lastly, we have lossless formats. These use a method that reduces the file size of the original audio without any loss in quality. This usually takes a bit more time to convert, and the files remain much larger than their lossy counterparts. But, the file sizes are smaller than raw uncompressed audio while still retaining the same clear quality. This can seem like a perfect middle ground. However, if you are going to run into compatibility issues, it will be with lossless audio files. They are the least common, least supported solution that may force you to limit your transcription company choices.   

In general, the audio file format that you use isn’t going to be much of a problem as long as the audio is clear. An uncompressed file will still be no good if there are other noises covering up the speech to be transcribed, and a low-quality MP3 recording can work fine if it’s just one person in a quiet room. The bottom line is that the nature of your recording is more important than the file type to getting a good result from quality transcription services. But, if you know that your audio quality will be poor, choosing an uncompressed format will improve your ability to clean up the audio after the fact. This can be particularly important when using speech to text automatic transcription software. But, under most circumstances, the small file size of lossy formats will serve you just as well and be easier to use. The compatibility issues with lossless files probably aren’t worth the trouble.     

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Video File Formats That Work Best For Transcription Services

Digital video files are generally much larger, and this is where compression starts to make a huge difference. In most cases, video cameras will typically render video in MOV, MP4 or AVI format. These are the most typical video camera formats, but high-end cameras may produce proprietary formats such as R3D from RED digital cameras or ARRIRAW which is produced by the ARRI group.

If you’re simply recording on a phone, then the most typical format will be an MP4. If you’re downloading videos that have already been uploaded, then you’ll typically see MP4 or FLV formats especially if they can be viewed online. However, if you’re using high-end video camera equipment, then you may need to process and convert the file formats with professional-grade tools before they can be uploaded.

We would recommend MP4, FLV or AVI as the go-to choice for uploading video files to be transcribed. If you are using an Apple device, then it will most likely produce QuickTime (MOV) files that will also work.

Because many cameras have built-in microphones that are subpar in quality, it may be rather difficult to hear any speech that has to be transcribed. If you’re recording video, make sure you do not accidentally cover the microphone, and attempt to be as silent as possible so that it does not cover up the sound of the speaker. If possible, connect an external microphone for better quality and reduced background noise.

In short, video file formats generally don’t make a huge difference on the quality of the audio, but the devices used to record the video could introduce quality concerns. File size is the major inherent factor when it comes to video files. The best choice is broadly impacted by the length of your recording and the amount of data you are capable of storing and uploading.  


You have been reading about the best file formats to use for transcription services. If you want to learn more about how to get the best transcription service for your transcription needs, we have written an Ultimate Guide to Transcription Services that covers everything from turnaround times and transcription rates to speech to text software and the importance of SSL encryption — making the use of transcription services for the first time as easy as possible.

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