Do you need audio recording transcription services? Any type of audio recording can be transcribed. However, not all file types are created equal.
Some audio files are easier to send, receive, and play. Since we started this business in 2010, we’ve realized that some files are clearer, but others require less disk space at the expense of lower quality. Suppose you are considering purchasing a recording device. In that case, it is essential to know the file type in which the audio files are recorded, as this may significantly impact your preferred quality.
If you want to send your files to an audio recording transcription services company, knowing what audio file type your sound files are in will help the file transfer process go much smoothly.
Today, we’ll discuss the various standard audio file formats, as well as a few lesser-known file types.
In This Article, You’ll Know How:
- Standard audio formats, such as WAV, MP3, AAC, and WMA, differ in quality, file size, and compatibility — factors that impact transcription accuracy and ease of transfer.
- Lesser-used formats such as FLAC, OGG, AIFF, AU, DSS, and DCT may suit specific needs, but compatibility should be confirmed with your transcription provider.
- Choosing the correct file type can improve turnaround time, reduce costs, and help ensure the highest quality of transcription.
Waveform Audio File Format (.wav)
The Waveform Audio File Format, commonly known as .wav, is the gold standard in audio file formats. The format is very accessible — it is easy to download and access. Furthermore, the file format is compatible with most, if not all, available media players on the market. It is used in professional audio applications, such as music production, sound editing, and audio archiving. Furthermore, .wav files can store audio in various formats, including uncompressed (PCM) and compressed formats like Microsoft ADPCM and GSM 6.10.
One of the best features of the file type is that they are lossless, meaning the audio quality is preserved just as the recording device captured it. As a result, .wav files are ideal for sensitive transcription jobs, such as those in law enforcement and legal transcription for court cases. No compression is applied, and this means that .wav files have higher bitrates, which can occupy significantly more disk space than other formats.
File transfer processes that have capped file sizes, like emails, typically cannot handle .wav file transfers. However, they can be saved on CDs or flash drives. Some transcription service providers have secure sites to accommodate the upload and transfer of .wav files.
MPEG-1 Audio Layer 3 (.mp3)
MPEG-1 Audio Layer 3, commonly referred to as .mp3, is another widely used file format for audio recordings. The .mp3 format is part of the MPEG-1 standards and builds upon its functionality by compressing audio files while maintaining reasonable quality. Reasonable quality can be relative, though, as we need to consider the original file’s recording quality. The file type is usually smaller than .wav as it discards some audio data considered less essential for human perception.
Once cut out of the file, the data is lost, a process known as lossy compression, which can be adjusted to result in better audio quality at the cost of larger file sizes.
That said, .mp3 files are very popular, especially when sharing smaller files like music and other sound bites. They are easy to download and occupy little space, making them ideal for music players and other recording devices. Similar to .wav, .mp3 can also be used for legal recordings such as trial transcription.
However, the file type may not be the best option for those seeking the highest quality of their recorded audio files for transcription, as it can impact transcription accuracy.
Advanced Audio Coding (.aac)
AAC stands for Advanced Audio Coding and is a standardized audio compression format designed to produce high-quality audio while maintaining relatively small file sizes. AAC files have better compression, meaning they can maintain audio quality and fidelity better than MP3 files at lower bitrates and with minimal space requirements. Advanced Audio Codec was built upon the MPEG-2 and MPEG-4 standards, making it the successor to the .mp3 file format.
The .aac file format inherits the broad compatibility and accessibility of .mp3. The file type supports different profiles and levels, allowing for flexibility. These profiles offer various features and capabilities, such as support for multichannel audio and higher bitrates. This means that .aac can also be used for high-quality audio recording, making it great for recording audio files for later transcription. Notably, .aac is the default audio format for iTunes, iPhones, and other Apple devices.
Windows Media Audio (.wma)
The .wma file format, which stands for Windows Media Audio, was developed by Microsoft as part of the Windows Media framework. Windows Media Audio is designed to compete with other popular audio formats, such as MP3 and AAC.
The Windows Media Audio format uses the same compression algorithm as .mp3, which means that any data compressed or removed is permanently deleted. Microsoft launched the file format with compatibility in mind for its product lines; however, it has not achieved the same widespread use as .mp3 files, although its use has increased over the years.
WMA files are even smaller and more compressed than MP3s, making them another good option if upload or download time is a concern. However, the format does offer the same balance by allowing adjustments to bitrates based on disk space.
There are different versions of .wav files, such as WMA Pro, which utilizes higher bitrates to achieve higher-quality audio, and WMA Lossless, which functions similarly to a .wav file with no compression.
Though not always the case, .wma files are often incompatible with non-Windows-based computers or non-Microsoft devices and programs. The Windows Media Audio format also supports Digital Rights Management (DRM), which provides providers with enhanced access to their audio files and enables them to limit playback and block copying, among other features. The adjustable audio quality and relatively small file sizes might be a valid choice for businesses looking to have their audio recordings transcribed, especially if time and disk space are important considerations.
Free Lossless Audio Codec (.flac)
FLAC is a lossless compression format that reduces the size of audio files without compromising the original audio quality. This makes it a preferred format for audiophiles and those who want to preserve the highest possible audio fidelity. .flac is an open-source audio compression codec widely supported by major platforms. Another benefit of using .flac is its ability to carry metadata, which allows for more file organization options; however, this functionality stores artist names, album titles, track titles, and other data. As far as transcription is concerned, .flac files offer little benefits over other lossless compression formats like .wav and .wma.
Lesser-used File Types
The widespread use of audio files has led to the development of different file types and formats. However, some of these formats may not be as widely compatible as the ones we’ve previously discussed.
OGG Vorbis (.ogg)
The OGG Container refers to the free, open-container format developed by the Xiph.Org Foundation that can be used for various types of media data, including audio and video streams. Meanwhile, the Vorbis Codec is the standalone compression standard typically used with the OGG standard. This means that audio files compressed using the Vorbis Codec result in .ogg files. Compared to .mp3 files, .ogg files are smaller with lower bitrates while maintaining quality.
Musical Instrument Digital Interface (.midi)
MIDI (Musical Instrument Digital Interface) files don’t contain actual audio data. Instead, they consist of instructions that tell synthesizers or MIDI-compatible devices how to produce music. In short, MIDI files are sets of commands that instruct musical instruments on how to play, which makes them incompatible with audio recordings for transcription purposes.
Audio Interchange File Format (.aif / .aifc / .aiff)
AIFF is an uncompressed audio file format, meaning it retains the total quality of the original audio recording, similar to a .wav file. Apple Inc. developed the AIFF format for storing high-quality audio on Macintosh and other Apple platforms. Despite that, the format can be used in Windows systems.
Sun Audio File Format (.au / .snd / .ulaw)
.au, which simply stands for “audio,” is a file format developed by Sun Microsystems. As the name suggests, .au is a simple, standard, uncompressed audio format mainly used in Unix- or Linux-based operating systems. Some programs on Microsoft platforms can also open .au files.
Digital Recorder-Specific Files
Many digital audio recorders also have their own specific file formats. Olympus digital audio recorders utilize the company’s proprietary Digital Speech Standard files in their devices, and the file extensions for these files are typically .dss. DSS is commonly used in professional settings where transcription services are involved, and some transcription software supports DSS files directly. DSS uses high compression, meaning smaller file sizes but commensurately lower audio quality.
Then there are.dct files, which several different brands of audio recorders utilize. Any audio recording transcription services company should be able to easily accommodate these files.
Here’s a side-by-side comparison of everything we covered:
| File Format | Compression Type | Key Advantages | Key Disadvantages | Common Uses / Notes |
| WAV (.wav) | Lossless (uncompressed or compressed PCM, ADPCM, GSM 6.10) | Highest audio quality; widely compatible; ideal for transcription and professional audio | Very large file sizes; hard to send via email | Music production, audio archiving, legal/law enforcement transcription |
| MP3 (.mp3) | Lossy | Small file size; widely supported; adjustable quality vs. size | Loses some audio data; quality depends on bitrate | Music sharing, portable players, general audio |
| AAC (.aac) | Lossy (more efficient than MP3) | Better quality than MP3 at lower bitrates; Apple default format; flexible profiles | Still lossy; slightly less universal than MP3 | iTunes, iPhones, streaming, high-quality small files |
| WMA (.wma) | Lossy (Pro, Lossless variants available) | Smaller than MP3; adjustable bitrate; DRM support | Limited compatibility outside Microsoft ecosystem | Windows devices, business audio sharing |
| FLAC (.flac) | Lossless compressed | Maintains full audio quality; smaller than WAV; metadata support | Larger than lossy formats; little benefit over other lossless formats for transcription | Archiving, audiophiles |
| OGG Vorbis (.ogg) | Lossy | Smaller than MP3 at similar quality; open-source | Less universally supported | Streaming, open media projects |
| MIDI (.midi) | N/A (no audio, only instructions) | Tiny file sizes; music notation/control | No actual audio; unsuitable for transcription | Music production, instrument control |
| AIFF (.aif/.aifc/.aiff) | Lossless uncompressed | High quality; cross-platform | Large file sizes | Apple music storage, professional audio |
| AU (.au/.snd/.ulaw) | Uncompressed | Simple; used in Unix/Linux | Large sizes; less common | Unix/Linux audio |
| DSS (.dss) | Lossy | Small size; designed for transcription | Lower audio quality | Professional dictation devices |
| DCT (.dct) | Variable (device-specific) | Supported by many transcription services | Quality/compatibility varies | Various digital recorders |
Conclusion
Transcription service providers often accommodate a wide variety of file formats, and there are several methods for converting files into more common extensions. However, the best way to ensure fast and efficient transcription is to contact the company and inquire if your file format is supported.
Not sure if we’ll support your file type? Please give us a call, and we’ll be happy to discuss how to proceed. Our real human agents will address any concerns that arise during the transcription process.
With competitive pricing, we guarantee an accuracy rate of >99% and the confidentiality of your data. Aside from that, our transcripts are legally admissible, which means you can use them in court as part of a reference or evidence, should it be needed.
If you still don’t believe us, have a look at our client testimonials and see what they say:
Ditto Transcripts is a Denver, Colorado-based transcription company that provides fast, accurate and affordable transcription services for individuals and companies of all sizes. Call (720) 287-3710 today for a free quote.