Tom Moertel's Blog

How to download photos and movies from the Palm Centro to a Linux desktop

Posted by Tom Moertel Fri, 02 Nov 2007 19:32:00 GMT

I recently got a Palm Centro smartphone, and so far I love it. Like most modern cell phones, it has a built-in camera and takes decent snapshots and even records short movies. It’s great for spur-of-the-moment shots when I don’t have my real camera. The trick – and there’s always a trick when it comes to cell phones – is getting the photos off the camera and onto my computer.

To get at my pictures, Sprint would prefer that I sign up for their ludicrously expensive “PictureMail” service. Leave it to weasely telecom execs to come up with another way to squeeze money from teenagers: charge them $5 each month for the “privilege” of sharing their pictures with friends. This fee, of course, is in addition to the fee for “unlimited” mobile Internet use. I guess picture bits are somehow more expensive to move over the air than other kinds of bits.

In any case, my next goal after getting my Centro to hotsync with my Linux workstation was to figure out how to download my photos and movies.

After a bit of hacking, I figured out that the Centro stores images in a typical digital-camera-image (DCIM) hierarchy. For example, I have a 4-GB microSD card installed in my Centro, and I store my photos in the “Palm” album on it. This album ends up stored in the /DCIM/Palm directory on the card.

Using the pilot-xfer program from the pilot-link project, I was able to find the directory and its contents. The trick was to use the sparsely documented –D flag to work with the Centro’s virtual filesystem. Here, for example, is how I list the contents of the Palm album:

$ pilot-xfer -p usb: -D /DCIM/Palm -l

   Listening for incoming connection on usb:... connected!

   Directory of /DCIM/Palm...
        652 Fri Nov  2 08:17:06 2007  Album.db
     292053 Fri Nov  2 09:04:20 2007  Photo_110207_001.jpg
      78493 Fri Nov  2 08:17:06 2007  Video_110207_001.3g2
         20 Wed Oct 31 12:09:20 2007  Thumbnail.db

   Thank you for using pilot-link.

Here, you can see that I have one photo and one movie in the album. (Movies are stored in .3g2 files that contain MPEG4 video.)

To download the files, I again turned to pilot-xfer, this time using the –f (fetch) flag to fetch a list of files. Here, for example, I’ll fetch the image from the listing above:

$ pilot-xfer -p usb: -D /DCIM/Palm -f Photo_110207_001.jpg

   Listening for incoming connection on usb:... connected!

   Fetching '/DCIM/Palm' ... (292053 bytes)   285 KiB total.

   Thank you for using pilot-link.

So that’s the process. It’s kind of clunky, so I wrote a small Python program to automate it. (I’m learning Python. If you’re a Pythonista, please consider critiquing my code. I would be especially thankful if you could point out any helpful idioms that I may have overlooked.)

Here’s how to use the program:

$ get-pilot-photos.py --help
Usage: get-pilot-photos.py [options]

Options:
  -h, --help            show this help message and exit
  -s SRCDIR, --srcdir=SRCDIR
                        VFS dir on Palm device from which to fetch images
  -d DESTDIR, --destdir=DESTDIR
                        Where to save the images on your computer

Both the —srcdir and —dstdir options are optional. If you omit the first, the program will download photos and movies from the /DCIM/Palm album. If you omit the second, the program will save the downloads to a new, timestamped directory within your home directory.

That’s it. The code is below.

#!/usr/bin/env python

# get-pilot-photos.py -
# Download photos and movies from my Palm Centro via pilot-link
#
# Tom Moertel <tom@moertel.com>
# 2007-11-01
#
# Copyright 2007 Thomas G. Moertel
#
# This program is free software: you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# See <http://www.gnu.org/licenses/> for more.

import os
import optparse
import re
import subprocess
import time

PILOT_XFER = 'pilot-xfer'
DEFAULT_PALM_IMAGE_DIR = '/DCIM/Palm'

class PhotoImporter(object):

    def __init__(self, src_dir, dest_dir=None):
        self.src_dir = src_dir
        self.dest_dir = dest_dir or self.get_image_dir()

    def run(self):
        print 'Finding images in %s on your Palm device.' % self.src_dir
        print 'Begin hotsync now...'
        images = self.get_image_list()
        if len(images) == 0:
            print 'No images were found.  Done.'
            return
        print 'Found %s images' % len(images)
        print 'Waiting for hotsync to complete...'
        time.sleep(10) # give 1st hotsync time to complete
        print 'Begin another hotsync now...'
        self.fetch_images(images)
        print 'Done.  The images were fetched to the following directory:'
        print self.dest_dir

    def get_image_list(self):
        cmdline = [PILOT_XFER, '-p',  'usb:', '-D', self.src_dir, '-l']
        proc = subprocess.Popen(cmdline, stdout=subprocess.PIPE)
        listing = proc.stdout.read()
        proc.wait()
        return re.findall(r'\b\S+\.(?:jpg|3g2)\b', listing)

    def fetch_images(self, images):
        cmdline = [PILOT_XFER, '-p',  'usb:', '-D', self.src_dir, '-f'] + images
        subprocess.Popen(cmdline, cwd=self.dest_dir).wait()

    def get_image_dir(self):
        root = os.getenv('HOME') or tempfile.mkdtemp()
        now = time.strftime("%Y-%m-%d--%H.%M.%S", time.localtime())
        dir = os.path.join(root, 'images', 'unsorted-pix', now)
        os.makedirs(dir, mode=0771)
        return dir

def main():
    p = optparse.OptionParser()
    p.add_option('--srcdir', '-s', default=DEFAULT_PALM_IMAGE_DIR,
                 help='VFS dir on Palm device from which to fetch images')
    p.add_option('--destdir', '-d',
                 help='Where to save the images on your computer')
    opts, args = p.parse_args()
    PhotoImporter(opts.srcdir, opts.destdir).run()

if __name__ == '__main__':
    main()