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CameraView/docs/_posts/2019-02-24-snapshot-size.md

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---
layout: page
title: "Snapshot Size"
subtitle: "Sizing the snapshots output"
description: "Sizing the snapshots output"
category: docs
Metering APIs (#580) * Add cameraPictureMetering and cameraPictureSnapshotMetering * Adapt Meter and metering package to picture use * Simplify Full2PictureRecorder, we'll use metering package instead * Add doMetering parameter * Implement cameraPictureMetering and cameraPictureSnapshotMetering in engine * Add options in demo app * Add better logs * Add Snapshot2PictureRecorder * Capture the correct frame based on timestamp * Lock AE and AWB. Account for captureBuilder changes * Fix runtime flash changes bug * Small changes * Flash support for metered snapshots * Remove AE and AWB locks * Lock AE/AWB/AF inside the snapshot recorder * Small changes * Fix AutoExposure metering * Create Locker and locking.* parameters * Implement Locker in Camera2Engine * Implement reset delay in Camera2Engine instead of Meter * Simplify Snapshot2PictureRecorder * Fix success value * Unlock inside Camera2Engine * Do not lock for normal gestures * Simplify logic * Improve locking/AutoFocus * Fix TORCH bug * Small changes to locking and metering * Remove AF and AWB for testing * Create action package * Create OneShotAction * Create LogAction * Revisit Full2VideoRecorder using actions * Revisit Full2PictureRecorder using actions * Enable missing functionality in Snapshot2PictureRecorder * Move Snapshot2PictureRecorder using actions, rewrite lock package * Add TimeoutAction * Add comments to the action package * Add meter package * Remove old metering package * Fix various bugs * Add action.abort() * Abort old MeterAction when running new ones * Fix various bugs * Add doc empty page * Add documentation * Fix tests
5 years ago
order: 10
date: 2019-02-24 17:36:39
disqus: 1
---
Snapshots are captured from the preview stream instead of using a separate capture channel.
They are extremely fast, small in size, and give you a low-quality output that can be easily
uploaded or processed.
The snapshot size is based on the size of the preview stream, which is described in the [Preview Size](preview-size) document.
Although the preview stream size is customizable, note that this is considered an advanced feature,
as the best preview stream size selector already does a good job for the vast majority of use cases.
When taking snapshots, the preview stream size is then changed to match some constraints.
### Matching the preview ratio
Snapshots will automatically be cropped to match the preview aspect ratio. This means that if your
preview is square, you can finally take a square picture or video, regardless of the available sensor sizes.
Take a look at the [Preview Size](preview-size) document to learn about preview sizing.
### Other constraints
You can refine the size further by applying `maxWidth` and a `maxHeight` constraints:
```java
cameraView.setSnapshotMaxWidth(500);
cameraView.setSnapshotMaxHeight(500);
```
These values apply to both picture and video snapshots. If the snapshot dimensions exceed these values
(both default `Integer.MAX_VALUE`), the snapshot will be scaled down to match the constraints.
This is very useful as it decouples the snapshot size logic from the preview. By using small constraints,
you can have a pleasant, good looking preview stream, while still capturing fast, low-res snapshots
with no issues.
### Video Codec requirements
When taking video snapshots, the video codec that the device provides might require extra constraints,
like
- width / height alignment
- maximum width or height
CameraView will try to read these requirements and apply them, which can result in video snapshots
that are smaller than you would expect, or with a **very slightly** different aspect ratio.
### XML Attributes
```xml
<com.otaliastudios.cameraview.CameraView
app:cameraSnapshotMaxWidth="500"
app:cameraSnapshotMaxHeight="500"/>
```
### Related APIs
|Method|Description|
|------|-----------|
|`setSnapshotMaxWidth(int)`|Sets the max width for snapshots. If out of bounds, the output will be scaled down.|
|`setSnapshotMaxHeight(int)`|Sets the max height for snapshots. If out of bounds, the output will be scaled down.|