I would like to request a linear scene-referred preview stream for Bayer RAW workflows via AVCaptureVideoDataOutput or AVCaptureVideoPreviewLayer, without tone mapping, computational processing, or a baked-in rendered look.
This is particularly important for third-party camera apps built around Bayer RAW workflows, including my app, Lampa Camera.
In other words, it would be great to have a preview mode that closely matches the CIRAWFilter output for a Bayer DNG with the following configuration:
rawFilter.baselineExposure = 0.0 rawFilter.shadowBias = 0.0 rawFilter.boostAmount = 0.0 rawFilter.localToneMapAmount = 0.0
Currently, the live preview comes from the processed camera feed. As a result, the viewfinder can differ noticeably from the final RAW-converted image in exposure, dynamic range, contrast, and sharpness.
A Bayer RAW-compatible linear preview mode would make it possible to provide a reliable what-you-see-is-what-you-get shooting experience for RAW-based camera apps.
Would Apple consider exposing such a preview mode in AVFoundation?
Related Feedback Assistant report: FB22660803
Hi, what you're asking is currently not possible. To get a linear preview stream, one can use an AVCaptureVideoDataOutput with Apple Log or Apple Log2, see AVCaptureColorSpace in AVCaptureDevice.h and -[AVCaptureDeviceFormat supportedColorSpaces]. However, currently, no format supports both Apple Log and Bayer RAW capture. Thank you for filing the feature request.