[ios/ipad OS]Multi-file ZIP archiving converts HEIF to JPEG and HEVC to H.264 despite "Current" export setting⁠

[7chirrupy1emblazing]

When selecting multiple photo and video assets from the iOS/iPadOS system image picker to send as a batch payload, the app automatically compresses the assets into a ZIP archive before initiating the transfer.
During this batch archiving step, iOS automatically transcodes master 10-bit HEIF (⁠.heic⁠) images into JPEGs and re-wraps 10-bit Dolby Vision HEVC (⁠.mov⁠) video streams into standard H.264 containers. This occurs even when the user's system-level export setting on the Share Sheet / Photos settings is explicitly set to "Current" / "Keep Originals".
Steps to Reproduce

1. Ensure the iOS system photo transfer/export setting is configured to "Current" (or "Keep Originals").
2. Open Wormhole File Transfer on iOS/iPadOS.
3. Select 2 or more HEIF (⁠.heic⁠) images and/or 10-bit Dolby Vision HEVC (⁠.mov⁠) videos via the Photo Library picker to trigger a batch upload (ZIP archive creation).
4. Complete the transfer and inspect the received ZIP archive payload on the receiving device.
   Expected Behavior
   The assets inside the generated ⁠.zip⁠ archive should remain in their raw bitstream formats—preserving ⁠.heic⁠ file extensions, original file sizes, and 10-bit HEVC / Dolby Vision metadata untouched.
   Actual Behavior
   All HEIF images inside the ⁠.zip⁠ archive are converted to ⁠.jpg⁠ format, and HEVC ⁠.mov⁠ videos undergo generation loss / container transcoding to standard H.264, stripping master HDR metadata and reducing file fidelity.
   Root Cause & Suggested Fix
   When requesting asset URLs or reading bitstream data from ⁠PHPickerViewController⁠ or ⁠PHImageManager⁠ for archiving, the iOS pickerdefaults to returning "compatible" media representations unless explicitly instructed otherwise.
   Suggested Remediation:

Configure the underlying ⁠PHPickerConfiguration⁠ asset representation mode to ⁠.current⁠:

// Swift / Native iOS Picker configuration
configuration.preferredAssetRepresentationMode = .current

Ensure the Flutter image/file picker plugin or native iOS bridge requests raw file paths (⁠PHAssetResource⁠) or standard bitstream URLs rather than requesting generic ⁠UIImage⁠ or compatible data streams prior to invoking the ZIP compression routine.

[7chirrupy1emblazing]

Update: I re-tested this with single-file selections as well. The app converts HEIF to JPEG and HEVC to H.264 even when selecting a single image and video through the media picker. This confirms that the system photo picker defaults to compatibility mode across all selection types unless ⁠preferredAssetRepresentationMode = .current⁠ is explicitly set on the ⁠PHPickerConfiguration⁠.

[emmiebyte]

Hi!
Did you click on "Select File" or "Send Media" in the app?
I'm using the file_picker and image_picker libraries, which don't directly let me control this parameter.

[7chirrupy1emblazing]

Hi

First off, I want to congratulate you on building such an incredible app! The privacy focus, zero-knowledge architecture, and seamless cross-platform speed make Wormhole File Transfer a standout tool—especially for zero-trust, one-off media transfers.
Thank you for clarifying the underlying mechanics! That makes complete sense regarding the Flutter library limitations. I re-tested both selection paths in the app to confirm:
"Select File" (via ⁠file_picker⁠): Works flawlessly. It routes through the native iOS Document Picker (⁠UIDocumentPickerViewController⁠), which treats files as generic binary streams. This completely preserves raw HEIF photos and 10-bit Dolby Vision HEVC ⁠.mov⁠ videos without any system transcoding.
"Send Media" (via ⁠image_picker⁠): Triggers Apple’s ⁠PHPickerViewController⁠. Because the standard Flutter ⁠image_picker⁠ package doesn't expose or allow setting Apple's ⁠preferredAssetRepresentationMode = .current⁠ parameter in its underlying native wrapper, iOS defaults to compatibility mode. To prevent potential crashes in unconfigured apps, iOS automatically transcodes both single and multiple HEIF/HEVC selections into JPEGs and H.264 before passing the file URI back to Flutter.
Having "Send Media" work without auto-transcoding would definitely cut sending friction in half for media creators.
Always defaulting the Apple picker setting to ⁠.current⁠ is really the ultimate solution here—it guarantees there is never any chance of silent conversion, ensuring original master images and videos are preserved bit-for-bit every time.
It would be fantastic if the core Flutter team added a configuration parameter for ⁠.current⁠ upstream in ⁠flutter/packages⁠. If you decide to open or upvote a feature request on Flutter's GitHub repo for this, please let me know—I’d be more than happy to add my support and detailed test results there as well!
In the meantime, knowing that "Select File" serves as a direct workaround for sending uncompressed originals is incredibly helpful. Thank you again for your great work on Wormhole!