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How-to Identify Clipping Events

The Analyze API can be used to identify how many and where in your media there are any clipping instances. This can be a common smoke test in a QC workflow as a high number of clipping events may indicate a poor recording.

In some cases, the use of a clap or clapboard may show up as a clipping event to indicate the beginning of a take.

Example Output

If you run the Media Analyze API as described in the Analyzing Media getting started guide you can inspect the output for the clipping section. This is an example that has a single clipping event.

"clipping": {
    "num_sections": 1,
    "sections": [
          {
            "section_id": "cl_1",
            "start": 31.54,
            "duration": 0.12000000000000455,
            "channels": [
              "ch_0"
            ]
          }
    ]
}

Explanation

Given the num_sections value, you can make a judgment of how poor the quality might be of an individual media file overall. The duration of the media is also worth consideration as five clipping events in a sixty minute podcast is not as significant as five clipping events in a sixty second video. If there are a large number of events, it may be worth checking the recording equipment and re-recording the media whenever possible.

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Event Count Only

If you are only interested in the total number of clipping events and not where they are in the media, the Media Diagnose API can also return that value.

The sections then provides a list for all of the areas where a clipping event was identified. The section_id is a unique identifier with a cl short code and incrementing numerical identifier (e.g. cl_1).

The start and duration of the clipping event can be useful in trying to minimize the sonic effect of each instance. In combination with audio editing software you can seek to the timed start location and take corrective steps. The channels listed can be an indicator if there is an imbalance or faulty equipment in the capture process.


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