Downloading JPEG is amazingly slow

[Gabriel Kerneis-5]

Hi,

I run Digikam 1.1.0 from Debian testing and I really enjoy using it,
except for the "downloading from a camera" part.

I shoot in RAW+JPEG and observe that downloading my RAW files (which are
bigger) is very fast, whereas Digikam seems to stall on every JPEG file,
performing whatever operation which makes it much slower. The resulting
speed (several seconds for every JPEG) makes it really unusable, and I
resort to using mv in command-line instead.

I first thought it was related to this bug [1] but disabling
autorotation leads no noticeable speedup.  The behavior is consistent
when I download directly from my D90 or when I use an SD-card reader.

As I understand it, Digikam must perform some operations on JPEG files
(inserting exif data into some database, maybe) which takes a lot of
time. It would be much better (IMHO) if there were a "quick download"
mode where those operations could be backgrounded AFTER the download has
completed (Digikam performing a mere "mv" and then running the usual
"new shot detection" stuff).  I am about to recommend Digikam to a close
relative, and already know I will have trouble explaining him why it
takes so much time to download his shots.

But maybe does this option exist already, and I missed it.  Do you have
any hint?

[1] https://bugs.kde.org/show_bug.cgi?id=161783

Regards,
--
Gabriel Kerneis
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[Gabriel Kerneis-5]

On Sat, Mar 13, 2010 at 10:13:44AM +0100, Gabriel Kerneis wrote:
> I shoot in RAW+JPEG and observe that downloading my RAW files (which are
> bigger) is very fast, whereas Digikam seems to stall on every JPEG file,
> performing whatever operation which makes it much slower. The resulting
> speed (several seconds for every JPEG) makes it really unusable, and I
> resort to using mv in command-line instead.
> [...]
> But maybe does this option exist already, and I missed it.  Do you have
> any hint?

Is there at least someone here facing the same behaviour, or is this
something specific to my config?  Could this be related with the fact
that I asked digikam to record its metadata in JPEG files, but not in
RAW files (because of the "experimental" status)?

Regards,
--
Gabriel Kerneis
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[Remco Viëtor]

On Thursday 18 March 2010 08:12:33 Gabriel Kerneis wrote:

> On Sat, Mar 13, 2010 at 10:13:44AM +0100, Gabriel Kerneis wrote:
> > I shoot in RAW+JPEG and observe that downloading my RAW files (which are
> > bigger) is very fast, whereas Digikam seems to stall on every JPEG file,
> > performing whatever operation which makes it much slower.
> > [...]
> Is there at least someone here facing the same behaviour, or is this
> something specific to my config?  Could this be related with the fact
> that I asked digikam to record its metadata in JPEG files, but not in
> RAW files (because of the "experimental" status)?
>
> Regards,

Well, I use the same options wrt. metadata, and for me, the raw files are
slower to transfer than jpg (and 3x as big at least, from sony A330).

On the other hand, when transferring photos _into_ digikam, are the files
modified by digikam (i.e. is digikam recording any metadata during the
transfer)? I always thought that option about writing metadata to raw files
concerned tags, captions etc. added later on in digikam.

Regards,

Remco


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[Leonardo Giordani-2]

Pay attention to "on-the-fly" JPEG conversion to PNG, you find it in
the download window (where all the thumbnails of your camera images
are shown), in the last tab on the right (if I remember correctly).

PNG is not lossy, so converting a JPEG to PNG enables you to edit it
without losing quality every time you save it. Obviously, conversion
is not cheap. If you do not plan to edit your images or are simply
happy with plain JPEG, turn off this option and download will speed
up.

Bye

Leo

2010/3/18 Remco Viëtor <[hidden email]>:

> On Thursday 18 March 2010 08:12:33 Gabriel Kerneis wrote:
>> On Sat, Mar 13, 2010 at 10:13:44AM +0100, Gabriel Kerneis wrote:
>> > I shoot in RAW+JPEG and observe that downloading my RAW files (which are
>> > bigger) is very fast, whereas Digikam seems to stall on every JPEG file,
>> > performing whatever operation which makes it much slower.
>> > [...]
>> Is there at least someone here facing the same behaviour, or is this
>> something specific to my config?  Could this be related with the fact
>> that I asked digikam to record its metadata in JPEG files, but not in
>> RAW files (because of the "experimental" status)?
>>
>> Regards,
>
> Well, I use the same options wrt. metadata, and for me, the raw files are
> slower to transfer than jpg (and 3x as big at least, from sony A330).
>
> On the other hand, when transferring photos _into_ digikam, are the files
> modified by digikam (i.e. is digikam recording any metadata during the
> transfer)? I always thought that option about writing metadata to raw files
> concerned tags, captions etc. added later on in digikam.
>
> Regards,
>
> Remco
>
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>

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[Gabriel Kerneis-5]

Leonardo,

On Thu, Mar 18, 2010 at 12:44:07PM +0100, Leonardo Giordani wrote:
> Pay attention to "on-the-fly" JPEG conversion to PNG, you find it in
> the download window (where all the thumbnails of your camera images
> are shown), in the last tab on the right (if I remember correctly).

This was not selected, but I found the bottle-neck: in the same tab, the
template was set to "To remove" instead of "Do not change".  Using "Do
not change" makes things fast, so thanks for pointing me to this part of
the configuration :-)

> PNG is not lossy, so converting a JPEG to PNG enables you to edit it
> without losing quality every time you save it. Obviously, conversion
> is not cheap. If you do not plan to edit your images or are simply
> happy with plain JPEG, turn off this option and download will speed
> up.

I rather use my RAW files when I wish lossless operation (and save the
result as PNG).  But having JPEG is handy to share files quickly with
friends.

Regards,
--
Gabriel Kerneis
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