iStock - Stock Audio Training Manual

6.0 Digital Audio Requirements

6.1 Audio File Standards

Accepted Formats
We will accept .wav files for 2-track stereo (or mono) sources.

Bit Depth & Sample Rates
We will only accept audio files that are uploaded at a bit depth of 16-bit and a sample rate of 48kHz or 44.1kHz. Do not encode your audio at any other sample rate or bit depth.

Audio File Length
The minimum length for an audio file is 5 seconds. Short samples may be categorized differently than an audio file with several versions of that sample, and may be valued differently. There is a 4-minute maximum length for the audio. In general the more value you can add by including additional samples, or phrases to a sample the more downloads you should experience.

6.2 Quality

All audio is exciting when its integrity is intentional and realized. That buzz from your mother’s old fridge in the back of your recording is probably only nostalgic to you. Having said this, in context or as an isolated element, that same buzz is gold.

In this example there is far too much noise. In some cases this can be removed to an acceptable standard, However in most cases something like this will need to be re-recorded.

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Too Much Noise


Keep it clean. Let the source of your audio be what it is, just don’t clip the source (by recording it at or above zero decibels, which is not only too loud, but your digital device stops recording above this level). Any material received exceeding 0db will be rejected. It is best to be conservative (-6db to -3db) and leave the end user a few db to play with. The following example is an extreme example of a clip that has digital clipping where the audio exceeded 0db.

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0dB Exceeded


6.3 Audio Content

Audio that contains lyrics needs to be free from comments, suggestions, or opinions about identifiable individuals, groups, or corporations.

We are looking for interesting and usable content of the highest quality. Poor quality recordings, uninteresting content, or music created with poor musicianship, intonation and errors may be rejected.

6.4 Effects

In choosing effects for your creations remember to leave some flexibility for the end user. The use of effects reflects more of the creator's taste than it does to the needs of the end user. Having said that, if your triple compressed, quadruple distortion, filtered delay, re-compressed flanged mayhem is just what the world needs to steer humanity back on course, then send it, because we want to hear it too.

In this case there is an excess of reverb put over a vocal track. Vocal reverb can be a very acceptable effect, but in this case it becomes a distraction rather than adding to the quality of the track. While the use of effects can be very subjective, generally heavy effects added to a mix tend to reduce a track's usability.

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Excess Reverb


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