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Re: [mediacapture-image] MediaSettingsRange "step" should be optional

From: Miguel Casas-Sanchez via GitHub <sysbot+gh@w3.org>
Date: Fri, 09 Dec 2016 02:17:37 +0000
To: public-media-capture-logs@w3.org
Message-ID: <issue_comment.created-265915214-1481249856-sysbot+gh@w3.org>
`step` as defined in `MediaSettingsRange` doesn't have any particular 
meaning except: 
> The minimum difference between consecutive values of this setting.

To my knowledge, all USB cameras comply with UVC, which uses natural 
numbers to send information, making the `step` value ` an integer 
(usually 1). 

Beyond that, in mobile platforms (see e.g. [Android 
CameraCharacteristics]( 
https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html)),
 we too have integers, including for `ISO`, that has a granularity of 
1 
([SENSOR_SENSITIVITY](https://developer.android.com/reference/android/hardware/camera2/CaptureRequest.html#SENSOR_SENSITIVITY)),
 although in some other cases, e.g. [exposure 
compensation](https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#CONTROL_AE_COMPENSATION_STEP),
 the number is nuanced and that's the reason why we must have the 
`step`.

Finally, `zoom` might be a continuous setting in digital cameras, but 
in mobile platforms it is almost always implemented by cropping a 
larger canvas and in that case the granularity is determined by the 
pixel size, and it might be supplied to the user.

My point being that every single setting has a regular step and it 
isn't straightforward to know it, hence the parameters is always need 
and non trivial.

-- 
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Received on Friday, 9 December 2016 02:17:44 UTC

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