Why is there a &quot;X-second buffer&quot; on bodycams?
<p>I've seen numerous bodycam videos.</p>
<p>They frequently mention that &quot;there is no audio for the first 30 seconds&quot; (sometimes different number of seconds), so the video is muted initially.</p>
<p>What is the purpose of this &quot;feature&quot;? Why record &quot;half-assedly&quot; like that? Why is it not either on or off, where on means &quot;audio + video&quot; and off means &quot;all off&quot;? Why is such a &quot;buffer&quot; needed? It certainly cannot be for any technical reason.</p>

<p>Retaining video from the buffer period advances law-enforcement and accountability purposes by making it more likely that the camera will retain footage of whatever caused the officer to turn the camera on in the first place.</p>
<p>If a police officer says you ran a red light, the dash camera will show what actually happened if the officer turned it on within 30 seconds of you passing through the intersection. If a corrections officer says he had to use force because an inmate jumped him, the buffer period allows the camera to capture not just the officer hitting the inmate, but also whatever happened immediately prior.</p>
<p><a href="https://chicago.suntimes.com/2018/7/17/18405204/cpd-supt-johnson-explains-why-no-audio-recovered-from-fatal-police-shooting#:%7E:text=Steve%20Tuttle%2C%20spokesman%20for%20Axon,an%20audio%2Dfree%20video%20buffer." rel="noreferrer">According to Axon</a>, which seems to have largest market share in the BWC space, the lack of audio is meant to protect the officers' privacy:</p>
<blockquote>
<p>Cops feared they might tell a joke or discuss a personal situation like a divorce before they double-pressed the large button on the device to activate it. They didn’t want their private conversations to become public along with the buffer that preserves 30 seconds of video before the device is activated</p>
</blockquote>

<p><a href="/questions/tagged/england-and-wales" class="post-tag" title="show questions tagged &#39;england-and-wales&#39;" rel="tag">england-and-wales</a></p>
<p>It depends on the particular policies and operating procedures of the various police forces (or government agencies) that use body worn video devices whether the &quot;pre-event recording buffer<sup>1</sup>&quot; is soley video or captures audio as well.</p>
<p>For example, the <a href="https://www.policeprofessional.com/news/mps-doubles-pre-event-buffering-on-body-worn-video-units/" rel="nofollow noreferrer">Metropolitan Police</a> say:</p>
<blockquote>
<p>All BWV cameras operate in standby mode in which they capture video but not audio. This video is not saved but overwrites itself until an officer presses the record button. At this point, the buffered material is saved and attached to the recording. Audio is captured only when the record button is pressed.</p>
</blockquote>
<p>Whereas <a href="https://www.dorset.police.uk/news-information/body-worn-video/frequently-asked-questions/" rel="nofollow noreferrer">Dorset Police</a>'s policy is:</p>
<blockquote>
<p>The camera records a rolling 30 second loop of film in standby mode so when a recording starts the previous 30 seconds of audio and video are always captured. </p>
</blockquote>
<hr />
<p><sup>1</sup>Defined by the <a href="https://www.gov.uk/government/publications/technical-guidance-for-body-worn-video-bwv-devices-cast-2018" rel="nofollow noreferrer">Technical Guidance</a> as:</p>
<blockquote>
<p>A continuous recording loop designed to ensure that relevant information is still captured if the User is unable to immediately activate the recording</p>
</blockquote>

united-states police recording