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Fudge 1 year writeup

June 9 2024

Fudge is an unofficial app that can pair with Fujifilm cameras. It's an open-source reimplementation of Fuji's official apps, 'Camera Connect' and their 'Xapp'. The project is one year old today, and is worthy of a writeup.

First of all, let's take a look at Fuji's apps.
FUJIFILM Camera Remote on Google Play
FUJIFILM Camera Remote on the App Store

The operation of the 'Camera Remote' is pretty typical of IoT pairing apps. You go through the WiFi setup menu on your camera, follow the instructions on your phone, and you have access to liveview, remote shoot, and all your photos. Sounds pretty nitfy, but the ratings for this app tell a different story.

Here's a list of common compliants:

Fuji tried to solve these problems with their new app, called 'Xapp'. This new app looks more modern and is more responsive, but still receives complaints:

Side note: 'all the time' approximate location permissions in Android are required for scanning wireless access points or bluetooth devices.

Most Fuji customers still have to use the old 'Camera Remote' app. This includes me, as I own an X-A2 and X-H1.

So, one year ago, I got to work on a new app to see if I could do better than Fujifilm and fix any of these pain points.

The PTP Protocol

To transfer photos, run a liveview, and alter camera settings, Fuji cameras expose a WiFi access point with a PTP/IP server running at 192.168.0.1. I had previously written my own PTP library, so I had a great starting point already.

Fujifilm actually offers a developer SDK, which supports PTP and PTP/IP. Other than binaries only being offered on x86_64 MacOS and Windows, it only supports a small range of Fuji's latest cameras (15 to be exact). The SDK also hot a lot of heat for voiding warranties, so I felt it's probably best to avoid it altogether.

Within a few days, I was able to get a basic Android PoC working on my X-A2:

fujiapp screenshot fujiapp screenshot 2

The trickiest part here is the setup process. Once connected to the access point, you connect to a PTP/IP server on port 55740. Communication starts with a typical REQ/ACK, after that the client runs a PtpOpenSession command. Everything that follows is Fuji's proprietary setup:

For connecting to older Fuji cameras to download photos:

Fuji also has a "MULTIPLE TRANSFER" mode (at least on older cameras), where the camera will only allow the client to download a few select photos. This is the process of downloading those photos that follows the previously mentioned setup process:

Note: In PTP, 'objects' are images/files/folders, and PtpObjectInfo is a structure describing an object.

In later cameras, Fuji added what I call 'remote mode'. Entering remote mode (and setting up liveview/event sockets) seems to be necessary to continue with doing anything else (downloading thumbnails/photos). This mode has a more tricky setup process:

Overall, Fuji's PTP/IP has several notable client modes:

I recommend checking out lib/fuji.c which describes how most of these modes are setup or how they work.

To be specific Fuji uses a non-standard version of PTP/IP where they send/receive ISO-compliant PTP/IP REQ/ACK packets, but use USB-style PTP packets for everything else. They simply forked their MTP codebase and made it work over TCP.

vcam

Understanding Fuji's protocols by disassembling their app seems... pretty lame. So I needed a better way to help develop Fudge that would help speed up development.

vcam is a complete reimplementation of Fuji's PTP wireless backend (and Canon too). With a modern WiFi card, it can perfectly emulate a Fuji WiFi access point that is indistinguishable from the one that a real camera would expose. Thus, I can spoof Fuji's own software and try and match the behavior of my app with theirs.

Fujis Camera Remote connected to a vcam server running on my laptop

It also helps a ton with testing Fudge since I don't need to keep resetting a real camera (and keep it charged) when testing and debugging.

Code

Also I thought briefly going over the codebase might be interesting?

Fudge also includes a libui-compatible UI library: libuifw
This is to allow C/C++ or Lua code to create/alter UI. As a side effect, the same code can be run on Windows/Linux/MacOS (and eventually iOS)

Roadmap

Liveview

I'm slowly working on implementing a liveview with libjpeg-turbo, with the ability to change common camera settings. horizontal fudge liveview

iOS

Surprise! Fudge works on iOS!

png

Okay, it's barely working and doesn't have a UI, but it's a decent PoC. I don't know if I have the time to finish an iOS port, but at least I had the chance to try Objective-C for the first time :)

Bluetooth

SimpleBLE looks like a good option as a cross-platform BLE library, at least when their Android port is finished.

PC AUTO SAVE

'PC AUTO SAVE' is a long-standing Fuji feature (2014-2022) where a Fuji camera and Fujifilm's software connect to a WiFi network, the software discovers the camera over SSDP and can then download raws, jpegs, and mov files over PTP. This functionality can easily be implemented in Fudge.

USB

Over OTG, Fudge can replace the functionality of Fuji desktop apps:

I don't know anybody who carrys around the cables needed to connect an Android phone to a camera, but it might be a useful feature.

Conclusion

Fudge continues to be an active project. I'm interested in seeing if I can do do better than Fujifilm, without documentation, an SDK, or development team, in my free time. Just me, some tcpdumps, and a whole bunch of C.

Fudge on Github

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