Performance
Performance of VisionCamera
VisionCamera is highly optimized to be as fast as a native Camera app, and is sometimes even faster than that. I am using highly efficient native GPU buffer formats (such as YUV 4:2:0, or lossy compressed YUV 4:2:0), running the video pipelines in parallel, using C++ for the Frame Processors implementation, and other tricks to make sure VisionCamera is as efficient as possible.
Making it faster
There are a few things you can do to make your Camera faster which requires a core understanding of how Cameras work under the hood:
Simpler Camera Device
Selecting a "simpler" Camera Device (i.e. a Camera Device with less physical cameras) allows the Camera to initialize faster as it does not have to start multiple devices at once.
You can prefer a simple wide-angle Camera (['wide-angle-camera']
) over a triple camera (['ultra-wide-angle-camera', 'wide-angle-camera', 'telephoto-camera']
) to significantly speed up initialization time.
- Hooks API
- Imperative API
const fasterDevice = useCameraDevice('back', {
physicalDevices: ['wide-angle-camera']
})
const slowerDevice = useCameraDevice('back', {
physicalDevices: ['ultra-wide-angle-camera', 'wide-angle-camera', 'telephoto-camera']
})
const devices = Camera.getAvailableCameraDevices()
const fasterDevice = getCameraDevice(devices, 'back', {
physicalDevices: ['wide-angle-camera']
})
const slowerDevice = getCameraDevice(devices, 'back', {
physicalDevices: ['ultra-wide-angle-camera', 'wide-angle-camera', 'telephoto-camera']
})
See "Camera Devices" for more information.
Note: By default (when not passing the options object), a simpler device is already chosen.
No Video HDR
Video HDR uses 10-bit formats and/or additional processing steps that come with additional computation overhead. Disable Video HDR (don't pass videoHdr
to the <Camera>
) for higher efficiency.
Buffer Compression
Enable Buffer Compression (enableBufferCompression
) to use lossy-compressed buffers for the Camera's video pipeline. These buffers can use less memory and are more efficient.
Note: When not using a frameProcessor
, buffer compression is automatically enabled.
Video Stabilization
Video Stabilization requires additional overhead to start the algorithm, so disabling videoStabilizationMode
can significantly speed up the Camera initialization time.
Pixel Format
By default, the native
PixelFormat
is used, which is much more efficient than rgb
.
- On iOS,
native
isyuv
- On Android
native
is some kind of vendor specific format, which might beyuv
Disable unneeded pipelines
Only enable photo
and video
if needed.
Fast Photos
If you need to take photos as fast as possible, use a qualityPrioritization
of 'speed'
to speed up the photo pipeline:
camera.current.takePhoto({
qualityPrioritization: 'speed'
})
Appropriate Format resolution
Choose formats efficiently. If your backend can only handle 1080p videos, don't select a 4k format if you have to downsize it later anyways - instead use 1080p already for the Camera:
- Hooks API
- Imperative API
const format = useCameraFormat(device, [
{ videoResolution: { width: 1920, height: 1080 } }
])
const format = getCameraFormat(device, [
{ videoResolution: { width: 1920, height: 1080 } }
])
Appropriate Format FPS
Same as with format resolutions, also record at the frame rate you expect. Setting your frame rate higher can use more memory and heat up the battery.
If your backend can only handle 30 FPS, there is no need to record at 60 FPS, instead set the Camera' fps
to 30:
return <Camera {...props} fps={30} />