Mac USB output to Optoma projector problem


(PaulBrians) #1

Our local photo club is using a new Optoma ZW300UST projector to display images at our meetings. The projector was bought by the senior center where we meet. We have traditionally copied our images onto USB thumb drives and inserted them into the USB port of a digital projector, but this one has problems reading the files properly when they have been copied from a Mac.

It always displays a number of blank images at the beginning which seem to be “hidden” files created on the Apple device with filenames that duplicate the actual image filenames. We can scroll past the blanks, but sometimes the projector won’t recognize most of the images on the drive at all. We’ve found that it makes no difference how the drive was initialized, or on whether it was initialized on a Windows or Mac computer. The problem arises only when we copy images from a Mac to the drive.

All of the people who are involved in this process are Mac users without easy access to a Windows computer to do this job.

The dealer has talked about this problem with Optoma at length, and they are disinclined to fix the incompatibility in the firmware, arguing that most people use Windows (and most users of their projector are not using still images on thumb drives as sources).

I know this is a long shot, but is there any way out there that could suggest a work-around that would allow us to continue using our Macs?


(Adam Engst) #2

What happens if you use the command line to delete the hidden files?


(Richard Rettke) #3

I’m not sure I really understand this issue, but if Adam’s solution works then I would recommend Blue Harvest at www.zeroonetwenty.com/blueharvest. It has a 30 day free trial and works well for me. Sells for $14.95.


(PaulBrians) #4

Thanks, but I’m afraid I don’t know how to do this. Since I wrote it looks like another member of the club who uses Windows will probably take over the job of copying images on the USB drives.

Paul Brians


(Tommy Weir) #5

I am familiar with this issue. The small Optoma projectors have a particularly unforgiving OS.

The invisible files all commence with a period, Cmd+Shift+. will toggle displaying them on and off in the Finder. You can click on them and drag them to the Trash.

Alternatively, depending on the model of projector, you may be able to present a .PPT file. Should be easy enough to make a quick slideshow in Keynote or Powerpoint and export out a file to display. This may require placement in a particular folder either on the projector’s storage or the USB Drive, again depending on the model of projector.

If you’re looking at Pico projectors, I’ve found the feature set on the Philips models to be smaller but more robust and flexible, and the quality of output to be just as good if not better.


(PaulBrians) #6

Thanks, this is helpful. But because the projector flat out refuses to read some jpgs at all the club is nervous about me continuing to prepare the USB drives on my iMac. It looks like a Windows-using member will take over the job.

One thing we discovered is that if some uses the suffix .jpeg instead of .jpg the Optoma won’t read the file. According to the dealer Optoma is really uninterested in revising their firmware to accommodate Mac input.

Paul Brians


(Alan Forkosh) #7

Most so-called smart A/V devices have pretty brain-dead software. I find it best to treat them as dumb devices and actually connect a computer via HDMI, treating the projector as a 2nd computer display. You then do all the control from the computer. For a simple photo program, you simply mirror the base computer; for a presentation program (Powerpoint, Keynote, etc.), the program will recognize the dual display and let the computer’s screen work as a controller with the projector simply displaying the slides.


(PaulBrians) #8

That’s exactly what we’ve been doing, using my old Mac laptop, but because its remote doesn’t work reliably I have to stand in front of it and change slides manually while the presenter speaks and says “next slide.” Annoying. Our old remote-controlled Canon projector worked fine with our USB drives, but the Optoma is really fussy. It’s too old to have hdmi output, so the resolution isn’t ideal, either.

Paul Brians


(Curtis Wilcox) #9

Every drive used on a Mac will have a few hidden files and folders that the projector’s primitive operating system will list along with the regular files. The bigger problem in this case are the all the ones beginning with dot underscore for each of the image files, e.g. ._IMG_1234.JPG. These files contain the thumbnail image data displayed in the Finder. On a Mac filesystem (HFS+, APFS), this data is stored in the resource fork but the USB drive is formatted with a Windows-compatible filesystem (FAT16, FAT32, or ExFAT) which does understand the concept of files having more than one “fork,” or stream. To prevent the data from being lost, the Finder puts the resource fork data in the dot underscore file.

I’ve never used it but BlueHarvest looks like it can delete various hidden files from the drive. To get rid of just the resource fork files associated with the images, you could use ImageOptim. It’s primarily for reducing image files sizes, mostly for the web, but its Strip metadata options for PNG and JPEG will result in the dot underscore files being deleted. You probably want to set it to 100% quality, with lossy minification disabled. Because ImageOptim replaces the original file with the optimized version, you should drag the images from the flash drive rather than from the Mac’s drive.

A possibly faster, but uglier, solution is to use a program other than the Finder to copy the files to the flash drive, a program that doesn’t understand resource forks, like Double Commander. In one pane, you have your source folder and in the other you have the USB drive, drag images (or folders of images) from the source to the destination and the copied files won’t have the accompanying dot underscore files.


(Peter Drake) #10

I had similar problems trying to show photos from a USB thumbdrive on the TV, through a DVD player with USB input. My solution is a very simple app called DotCleaner, available from the App Store for a couple of dollars. It’s labelled as DotCleaner - .ds_Store remover. Launch it, choose the folder you want cleaned, do it. I guess you could clean directly on the USB drive but I usually do it first on the iMac then copy the folder over.


(PaulBrians) #11

Thanks. I may try this.

Paul Brians


(Peter Drake) #12

Ah, and I should have added, I format the USB drive for MS-DOS (FAT32), not MacOS. (Using Disk Utility.) The Mac can still save to the drive without problems.