Digital audio and video Formats for transcription

You can choose the format in which you want your final transcription to be laid out in. If you do not know for certain then we can discuss and offer several suggestions. This will depend on the number of speakers and the final use of the transcription. Most of the formats will not change the cost though extra can be charged if the format requested is special.

You also have several options in the way you want your transcriptions. You can get your transcription in print outs, on disks, in emails or can be posted to our website where you can download them.

With electronic files, there are several formats they can come in. We use the Microsoft office suite but can still use other formats like word perfect, open office, text files, Macintosh files to name but a few. A good thing with modern word processors is that they can read different formats so format may not really matter.

Digital audio Files

Most materials these days are found in digital computer formats. This is due to the establishment of multi- media computers. There are now hand held digital recorders that record on memory cards. They generate audio that you can store on a disk or use the internet to send it. Transcription wave can convert these files and transcribe them even though they come in different formats.

From your audio or video tapes we are able to create files to use on your website. Through consulting with you we will get to know what you need. We understand these formats well and we know which ones can work the best on the internet and web. We use several methods to make your audio files for your purpose to ensure that it is downloaded or transmitted effectively.

Some of the formats for digital audio files include;

Windows WMV, windows PCM (WAV), Microsoft ADPCM (WAV), MPEG3,FHG (MP3)*, MP4, M4A, IMA/DVI ADPCN (WAV),CD and DVD audio disk. Video formats (AVI, MOV, WMV), CCITT mu-law and A-law (WAV).

It is important to note that you should use Constant Bit Rate (CBR) when creating MP3 files for transcription. If you use the Variable Bit Rate (VBR) it will lower quality of the transcription because compression may cause the files to jump while transcribing. Transcription wave will convert the VBR files for you into CBR files.

Hand held digital recorders use some of these file formats that are proprietary,

Sony memory Stick Voice (MSV), Sony Digital Voice File (DVF), Sony IC Recorder sound (ICS), Olympus (DSS, DS2).

The following are multi track propriety file formats. They are mostly used for court room sessions and law enforcement. They also have other multi-channel recording applications. They include: FTR Gold for The record (ftrgold.com), Libert Court Recorder/Player High Criteria Inc. (highcriteria.com) DCR.

The following are single track or stereo files.

  • 8-bit signed raw format (SAM)
  • ACM waveform (WAV)
  • CCITT mu-Law and A-Law (WAV)
  • Dialogic ADPCM (VOX)
  • IMA/DVI ADPCM (WAV)
  • Real Audio (RA, RAM, RMM, RM, etc.)
  • MPEG audio (layers I and II)
  • Next/Sun CCITT mu-Law, A-Law and PCM (AU)
  • Apple Quicktime
  • Raw PCM Data
  • SampleVision format (SMP)
  • Sound Blaster voice file (VOC)
  • TrueSpeech (WAV)
  • DiamondWare Digitized (DWD)
  • Apple AIFF (PCM encoded data only) (AIF)

Transcription wave are able to transcribe your audio from internet and web sources if we are able to access it from a browser or program. Different audio files have several options that are important for the transcriptions and dictations. The options include:

Tracks: Mono, stereo, multi- track

The tracks you have determine the file size required, the more they are the bigger the file services. For the stereo or multi track unless each track represents a separate microphone at a different location then it is not very useful when it come to transcribing. If this is the case then all the tracks need to be combined for ease of transcription or can be transcribed separately.

Sample Rate

  • Sample rates show the number of times each second of audio is recorded. Quality is much better in the faster rates but it takes a bigger size while slow rate’s quality is low but files are smaller.
  • The typical sample rates are deducted in sample per second and they are normally 6000, 8000, 11025, 22050, 32000, 44100, 48000, 64000, 88200, 9600 and 176400. 44100 samples per second is the sample rate for CD quality audio.
  • The audio frequency that can be reproduced in digital format is at most half the size of the sample rate. So, at 44100 samples per second, a CD audio can be reproduced at most 22 kilohertz frequencies.
  • For voice transcription it is best to use a sample rate of about 22050 samples per second. Transcriptions can be done at lower rates but this compromises the quality by lowering it.

Compression

  • Compression can be done to some degree in some audio formats. This makes the files smaller but compromise the audio quality. The compromise may not really affect the quality but if the compression is extreme then it is likely to be seriously affected. These file formats, since they can lose some of their audio quality, are known as lossy files. A good example of this is the MP3 format.
  • Compressing files is a trade off of file size to audio quality. One needs to select a compression file that will not lower the quality of the audio files. To compress the MP3 files one can use the Variable Bit Rate (VBR) which will significantly reduce the size of the file. It is not advisable to use it though as it cannot be used in that format by the transcriptionist. The recommended format is the Constant Bit Rate (CBR) format.

Sample size (bits)

  • Bits are used to measure each of the samples as they have a standard size. The larger the size then it the audio reproduction is accurate and the file created is also large in size. For the smaller size, then the audio will be less accurate but the file size created size will be small.
  • The most common sample sizes are 8- bit, 16 bit and 32 bit. The most commonly used is 16 bit.

Be on the lookout for more formats as there are new ones all the time. More on audio and video formats.

Jessica Miller, Marketing Head in Transcriptionwave, General Transcription Services Company in the US.

Leave a Reply

Your email address will not be published. Required fields are marked *