JEILIN JL2005A STILLCAM DRIVER Copyright Theodore Kilgore <kilgota@auburn.edu> September 16, 2007. (Everything in libgphoto2/camlibs/jl2005a is LGPL-licensed, including this README. See any of the source files for a more complete statement of the license.) INTRODUCTION This driver is intended to support cameras containing the JL2005A chip from Jeilin Technologies. The interface is proprietary, and these cameras are supported commercially only in Windows. Jeilin Technologies also manufactures chips which go into mass storage cameras. Those cameras can be accessed directly using mass storage support. The company also manufactures some other chips with proprietary interface, but with very different protocols. Some of the cameras may be supported in the future in libgphoto2. The USB Vendor and Product number for the JL2005A cameras is 0x0979:0x0224. At least, I do not know at this time about any other USB id for these cameras, and I also am not aware of any other JL2005A cameras which have different functionality from what is done here. RECOMMENDATIONS FOR REPORTING CAMERAS Right now, I only own one of these for testing. It is the so-called American Idol keychain camera, which I found at a local KB Toys. I am aware that several others exist. If people will be so kind as to send me the needed details I would be happy to add them explicitly to the list in library.c. Please understand that I need to have whatever information you can find, so please do not throw away the manual, the driver CD, or the plastic package the camera was sold in until we get this information! It happens quite often that the camera itself has no name at all, or just some embossed letters on the plastic which say "DIGITAL CAMERA" -- hardly a unique identifier. Quite often, the only way to identify uniquely an entry-level consumer digital camera is by something appearing in fine print on the packing materials, which, alas, the purchaser can easily overlook and may have simply thrown in the trash. The computer, of course, uses the Vendor:Product ID, but that is of course never printed on the outside of packages. The point is, others should be able to find the camera in the store by the name and description which is given to it in libgphoto2, and moreover it is quite inappropriate if we add support for some dozens of distinct devices, each of which has the name string calling it "DIGITAL CAMERA". WHAT DOES THIS CAMERA LIBRARY CURRENTLY DO? There is support for all of the basic gphoto2 still camera operations which my JL2005A camera is known to support through hardware. This includes support for downloading photos in each of the two available resolution sizes 352*288 and 176*144. The data in neither case is compressed, though the raw data for 176*144 size is obfuscated and thus not in a completely standard format. Both of these formats are supported in the driver. Support for the option gphoto2 -p (for downloading selected photos or frames) seems to work "out of the box" unlike what happens with some other low-priced cameras. Thus, it ought not to be a problem to use one of these cameras with any of the GUI frontends which are based upon libgphoto2. The camera will not shoot snapshots, neither for immediate download (gphoto2 --capture-preview option nor to be stored on the camera for later downloading (--capture-image option). These operations can be done but are implemented through the pccam or webcam interface, which uses isochronous data transmission and is therefore outside the boundaries of the stillcam operations which libgphoto2 supports. The camera also does not support the deletion of individual photos, even with a button press, but only the deletion of all. It does seem that to put the camera into pccam mode will delete all photos, but it is not clear at which stage in that process the photos get deleted. Pccam mode involves a different altsetting, which would involve a reset, and then the isochronous inep must be accessed. As my impression by watching the camera being put into pccam mode while photos are already in it is that said photos do not get deleted until the camera actually starts sending data, I have made no attempt at this time to try to use the pccam function to delete all photos. The camera will shoot clips in "continuous" mode, meaning it will shoot frames until the camera is full. The resolution setting for these frames is whatever was the resolution setting before one started to shoot frames. Moreover, this function will not delete any previous photos already in the camera. The resulting frames are downloaded and treated as ordinary photos. If you want to use this function, then, and get an animation, that can easily be done using the "animate" function from the ImageMagick toolkit, or with a similar tool from a similar image processing suite. ANOTHER JL2005A CAMERA, WHICH IN ADDITION TO THE ABOVE, USES COMPRESSION has been discovered by Jeronimo Barraco <jerobarraco@yahoo.com.ar>. That camera is the TDC-15, sold by NogaNet in Argentina. The compressed mode is optional on this camera; one is not forced to use it. On closer investigation, the compression is not actual compression at all, but data truncation. What has been done is that every four lines of data have been "compressed" to two lines. by the simple expedient of suppressing two of them. The same photo still comes out if nothing at all is done to it, but the vertical dimension is divided by two. As an inevitable result, the "decompression" is necessarily some kind of interpolation of the missing lines of data. I have used simple linear interpolation. If someone comes up with a better way which gives nicer-looking images from these cameras, then please let me know. Actually, from the samples which I have on hand the results do not look too bad most of the time. However, the user is advised that occasional raggedness is inevitable from data which has been thus truncated. Another camera which seems to be functionally similar to the TDC-15 is the Cobra DC-125, reported by Tim Johnson <tim@johnsons-web.com>. WARRANTY? Absolutely none. Remember, I did not sell you this software. I have written this driver for my own edification and in the sincere hope that it might help you to use of your camera. Please see also the warranty clauses in the LGPL license. Updated 12/02/2007, 02/21/2009
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