[Digikam-users] Slow download

Jean-Fran├žois Rabasse jf at e-artefact.eu
Tue Jun 10 11:35:31 BST 2014

On Mon, 9 Jun 2014, Alan Barnett wrote:

> I'm running digikam 3.5 on a Ubuntu 14.04 system.  I have a Nikon D3100. 
> When I download images from the camera, the transfer rate is too slow to be 
> useful; it only transfers about 1 image/minute!
> Any suggestions?

Hello Alan,

I have a Nikon D3100 too, in my cameras, and I can confirm that 
downloading images via PTP is unuseable. (I may be lucky but, instead
of a loading rate of 1 image/min. I get the amazing speed (!!!) of almost
2 images/min. :-)

Doesn't seem to be a Digikam related problem. Digikam uses the libgphoto2
stuff, and gphoto2 supports many cameras, some of them are only partialy
supported (or badly supported). And the Nikon D3100 is one !

If you wish to investigate a bit more, you should try the command line
gphoto2 program. Connect your camera with the proper cable, and check
first that your camera is properly recognized :
  gphoto2 --auto-detect
This should show you something like : Nikon DSC D3100 (PTP mode)

Check that images on your camera SD card are available :
  gphoto2 --list-files

Then, do a transfert test :
  gphoto2 --get-all-files

Works but it's awful (from downloading time point of view).
And Digikam is innocent wrt that.

> Any suggestions?

My personal opinion is that you should consider abandonning that kind
of connection. PTP transfert is an interesting feature in two cases :

1. User wants to monitor a camera from a computer, e.g. take a serie
of pictures at regular intervals, e.g.
  gphoto2 --capture-image --interval 5
But this requires a properly supported camera. With a D3100 you get an
error, Error (-1: 'Unspecified error'), (really interesting !!!)
So, forget remote monitoring with not fully supported devices.

2. The photos device doesn't have a removeable memory card, and PTP
is the only way to download images (concerns probably only some old,
low cost, pocket cameras).

With a standard camera using standard SD or SDHC cards, there's
very few to expect from PTP downloading that will always be far more
inefficient than an images copy via a USB SD card reader.
Ok, you will waste 5 seconds of your time to remove the SD card out
of the camera and plug it into a USB reader, but you will then copy
hundreds of images in 20 to 30 seconds, depending on your computer
and hard drives speed.


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