1JEILIN JL2005A STILLCAM DRIVER 2Copyright Theodore Kilgore <kilgota@auburn.edu> September 16, 2007. 3 4(Everything in libgphoto2/camlibs/jl2005a is LGPL-licensed, including this 5README. See any of the source files for a more complete statement of the 6license.) 7 8INTRODUCTION 9 10This driver is intended to support cameras containing the JL2005A chip from 11Jeilin Technologies. The interface is proprietary, and these cameras are 12supported commercially only in Windows. Jeilin Technologies also manufactures 13chips which go into mass storage cameras. Those cameras can be accessed 14directly using mass storage support. The company also manufactures some other 15chips with proprietary interface, but with very different protocols. Some of 16the cameras may be supported in the future in libgphoto2. The USB Vendor and 17Product number for the JL2005A cameras is 0x0979:0x0224. At least, I do not 18know at this time about any other USB id for these cameras, and I also am not 19aware of any other JL2005A cameras which have different functionality from 20what is done here. 21 22RECOMMENDATIONS FOR REPORTING CAMERAS 23 24Right now, I only own one of these for testing. It is the so-called American 25Idol keychain camera, which I found at a local KB Toys. I am aware that several 26others exist. If people will be so kind as to send me the needed details I 27would be happy to add them explicitly to the list in library.c. Please 28understand that I need to have whatever information you can find, so please do 29not throw away the manual, the driver CD, or the plastic package the camera 30was sold in until we get this information! It happens quite often that the 31camera itself has no name at all, or just some embossed letters on the plastic 32which say "DIGITAL CAMERA" -- hardly a unique identifier. 33 34Quite often, the only way to identify uniquely an entry-level consumer digital 35camera is by something appearing in fine print on the packing materials, which, 36alas, the purchaser can easily overlook and may have simply thrown in the 37trash. The computer, of course, uses the Vendor:Product ID, but that is of 38course never printed on the outside of packages. The point is, others should 39be able to find the camera in the store by the name and description which is 40given to it in libgphoto2, and moreover it is quite inappropriate if we add 41support for some dozens of distinct devices, each of which has the name string 42calling it "DIGITAL CAMERA". 43 44 45WHAT DOES THIS CAMERA LIBRARY CURRENTLY DO? 46 47There is support for all of the basic gphoto2 still camera operations which 48my JL2005A camera is known to support through hardware. This includes support 49for downloading photos in each of the two available resolution sizes 352*288 50and 176*144. The data in neither case is compressed, though the raw data for 51176*144 size is obfuscated and thus not in a completely standard format. Both 52of these formats are supported in the driver. 53 54Support for the option gphoto2 -p (for downloading selected photos or frames) 55seems to work "out of the box" unlike what happens with some other low-priced 56cameras. Thus, it ought not to be a problem to use one of these cameras with 57any of the GUI frontends which are based upon libgphoto2. 58 59The camera will not shoot snapshots, neither for immediate download (gphoto2 60--capture-preview option nor to be stored on the camera for later downloading 61(--capture-image option). These operations can be done but are implemented 62through the pccam or webcam interface, which uses isochronous data transmission 63and is therefore outside the boundaries of the stillcam operations which 64libgphoto2 supports. 65 66The camera also does not support the deletion of individual photos, even with 67a button press, but only the deletion of all. It does seem that to put the 68camera into pccam mode will delete all photos, but it is not clear at which 69stage in that process the photos get deleted. Pccam mode involves a different 70altsetting, which would involve a reset, and then the isochronous inep must 71be accessed. As my impression by watching the camera being put into pccam mode 72while photos are already in it is that said photos do not get deleted until 73the camera actually starts sending data, I have made no attempt at this time 74to try to use the pccam function to delete all photos. 75 76The camera will shoot clips in "continuous" mode, meaning it will shoot frames 77until the camera is full. The resolution setting for these frames is whatever 78was the resolution setting before one started to shoot frames. Moreover, this 79function will not delete any previous photos already in the camera. The 80resulting frames are downloaded and treated as ordinary photos. If you want to 81use this function, then, and get an animation, that can easily be done using 82the "animate" function from the ImageMagick toolkit, or with a similar tool 83from a similar image processing suite. 84 85ANOTHER JL2005A CAMERA, WHICH IN ADDITION TO THE ABOVE, USES COMPRESSION 86 87has been discovered by Jeronimo Barraco <jerobarraco@yahoo.com.ar>. That 88camera is the TDC-15, sold by NogaNet in Argentina. The compressed mode is 89optional on this camera; one is not forced to use it. On closer investigation, 90the compression is not actual compression at all, but data truncation. What has 91been done is that every four lines of data have been "compressed" to two lines. 92by the simple expedient of suppressing two of them. The same photo still comes 93out if nothing at all is done to it, but the vertical dimension is divided by 94two. As an inevitable result, the "decompression" is necessarily some kind of 95interpolation of the missing lines of data. I have used simple linear 96interpolation. If someone comes up with a better way which gives nicer-looking 97images from these cameras, then please let me know. Actually, from the samples 98which I have on hand the results do not look too bad most of the time. However, 99the user is advised that occasional raggedness is inevitable from data which 100has been thus truncated. 101 102Another camera which seems to be functionally similar to the TDC-15 is the 103Cobra DC-125, reported by Tim Johnson <tim@johnsons-web.com>. 104 105 106WARRANTY? 107 108Absolutely none. Remember, I did not sell you this software. I have written 109this driver for my own edification and in the sincere hope that it might help 110you to use of your camera. Please see also the warranty clauses 111in the LGPL license. 112 113Updated 12/02/2007, 02/21/2009