Types of digital files for Audio Transcription

There are a variety of recording systems available, suitable for dictation recording the conference. If you already have a mechanism for digital recording, there's a good chance that there is a wide variety of different file types for different purposes. This article aims to discuss these different types and suggest the right one for you, depending on the circumstances. If you are still considering which digital recording device to purchase, then you have the opportunity to consider the types of files that will produce before buying.

If you do not know what types of files you're working, you can tell by looking at the file extension. This is the set of three letters that follow the point, as, for example, 'interview.wav'

The different types of files have all the advantages and disadvantages for transcription services, the most obvious of which is a trade-off between quality and file size. Audio files can be very, very big, if not compressed, but the compression is 'lossy', in other words a complete or a sound file 'lossless' has been taken and compressed, which removes redundant data that is considered, with a consequent reduction in audio quality, which can cause problems for the transcriber.

You may at first seem obvious that you and your transcriptionist wants the best quality, but in reality, many lossy formats have a negligible loss of quality, but are much smaller files. If you are sending files to the transcriptionist for transcription, the advantage of a 2MB file, as opposed to a size of 40MB, it should be obvious! Any audio files of any length is small, but at least you can send a 2MB file for transcription. Most service providers do not allow a file to 50MB, and even if they did could take hours to download, blocking both your email and the transcriptionist. Transcriptionists are increasingly using a system that bypasses email, you can upload files directly on their website or send your files using a simple file transfer program. However, these options have limitations on file size, as a rule.

It 's also interesting to note that depending on the playback software used for transcription, the transcriber may only be able to play certain file types. Some cover practically all types of digital files, while others are more limited, so it's worth checking first.

The type of 'law' and attributes of files for you and your transcriptionist will also depend on what the purpose of registration. If it is a dictation, a sound quality will continue to provide a recording is clear enough for a digital transcription.

If you are recording a focus group, for example, where several people are sitting at different distances from the recorder and talk to different levels and pitches, you probably need a higher sound quality to accommodate this.

Your equipment can enable you to set different attributes for the type of file. This can make a big difference for the sound quality and size of the file, and consequently the quality transcription. In some cases, for example dictation (a person speaking in the car, in a quiet environment), you can probably afford to lose the sound quality and recording for transcription is still unclear. In other cases (focus groups, noisy environments) you may find it necessary to choose a file size slightly larger in order to maintain audio quality decent.

The attributes are often shown as 8000 Hz mono kHz is suitable for dictation and the range is up to 44,100 kHz stereo, which is the higher quality, which is used for music CDs.

Examples of different file formats and some details about their use in the transcript follows:

Waveform audio (. Wav)

Waveform audio (. Wav) is a common file format and has been one of the first audio file types developed for use with the PC. E 'lossless, but in general very large. This means that you will probably need to send files to a CD, but then via email, although some transcriptionists, including myself, http://www.penguin-transcription.co.uk on my site, have a system whereby can send large files via the Internet without the use of electronic mail. You certainly need a broadband connection, or the like, to use them effectively, however.
Warning! Not all wav files are the same! Even if you end up. Wav, depending on the recorder, you and your transcriber may need a special 'codec' to play it. Sanyo is one example, a registration system to a popular and affordable, but one in particular Sanyo that records WAV files. You should check that the transcriber has the ability to transcribe wavs Sanyo. Otherwise, Sanyo may oblige by sending the relevant codec on CD, if you ask them right!

The following types are all lossy, but generally the change in sound quality is negligible and will save you time and money with reduced transfer times. This is not an exhaustive list of all types of audio files, there are a huge number. It aims to cover most types recorded by the transcription software available.

MPEG-1 Audio Layer 3 (. MP3)

This is a compressed WAV files often used in music. Many digital voice recorders will also record MP3 or WAV files allowing you to record and then compress to MP3 to send up the transcript. Compressed files are about one-twelfth the size of WAV files.

Windows Media Audio (. Wma)

Windows Media Audio (. Wma) has been developed for Windows Media Player that is bundled with all Windows-based PCs these days. It is even more of a compressed MP3, about thirty sixth the size of a file. Wav, but apparently retaining the original quality of sound. I must say that in my experience to transcribe I do not know if this was not always so.

Digital Speech Standard (. DSS)

In my experience, copies of software used for transcription play. DSS. Otherwise, there is a free download available at Olympus. I think. DSS was developed by Olympus and almost everyone, but not all, records Olympus recorders. DSS. Recorders Lanier and Grundig also generally used. DSS. The file size is reduced from twelve to twenty-fold, compared to a WAV file, and is ideal for transcription because it is small and easy to e-mail.

DVF

This is Sony's answer. Dss file. This is a very highly compressed files, but it works for voice and its small size makes it very easy to send e-mail.

Dictation encrypted (. DCT)

Often used for medical transcription, which requires confidentiality very high, these recordings are encrypted in order of registration and must be decrypted on receipt by the transcriber. A wide range of playback software will handle these files.

TrueSpeech from DSP Group

TrueSpeech, from the group DSP, is designed for personal computers and personal communication devices. Has very high compression ratios ranging from 15:1 to 27:1. If you are able to record in this format is probably best limited to use with dictation or one-on-one interview in a quiet environment. It 's probably too much for the loss of focus groups, etc.

There are a whole host of other types of files available, so do not worry if the type that the machine produces is not listed above. Contact your VA and s / he will probably be able to help, or at least point you in the right direction.

CD audio files (. CDA)

These files are standard recordings on CD, and are generally the type of music files purchased without CD. I understand that (not too well!) The CDA is really just a sort of cover that says that file is a file on a CD, and the underlying file is probably a wave file or one of the other types of files listed above. Most recorders transcription CDA does not store, but if you have a professional recording at a conference or series of lessons, for example, you may find yourself with the CDA. Most transcription software does not work with the CDA. There are a number of ways to convert CDA file but these can be costly and / or time. Transcriptionists specializing in digital transcription will probably be able to write these files, but you may be charged a premium for the time taken to convert into a usable format. There are a variety of converters available, but the one I used with success, and that provides a trial version, Easy CD Ripper is, a shareware with a fully functional trial version can be downloaded from various places including http:// / www. tucows.com/preview/209478

You will probably have only a limited number of file types available for transcription, depending on your recording device, but any unit should provide a wide range of options to suit your needs. If you have the possibility is always a good idea to do a test recording with the settings that you think may be right. Then reproduce, or sent to your transcriber to reproduce, in order to verify that the sound quality is acceptable.

Finally, let me just say that this information is based on my understanding and experience of digital transcription. I can not absolutely guarantee its accuracy, but it would be very interested in hearing about any errors and will be happy to correct them. Similarly if you feel that there is an important area I have not covered, please let me know and I will do my best to incorporate it.

This article is protected by copyright, Anne Hickley, 2007 .......