[digiKam-users] why is batch convert to bw so extremely slow?

[Gilles Caulier]

Hi Daniel,

Did you activate Multicore support in BQM ?

Gilles

Le mer. 1 juil. 2020 à 16:07, Daniel Bauer <linux at daniel-bauer.com> a écrit :
>
>
>
> Am 01.07.20 um 07:42 schrieb Maik Qualmann:
> > Saving large PNG files takes so long, Gimp is not faster either. Are you sure
> > you saved it as a PNG in the editor and not as a JPG? If versioning is active,
> > "Save changes" creates a JPG depending on the setting, which is very fast. If
> > you want to have a JPG in BQM, you have to attach the tool for saving in JPG
> > at the end of the tools.
> >
> > Maik
>
> I use to work with png. The difference I see is between the batch tool
> and the edit tool. Of course, saving "save as png" takes a bit, but
> compared to the batch tool it is extremely much faster.
>
> There is no versioning active. It reads the original png, converts to
> bw, then saves in a subfolder as png. This takes 2 to 3 minutes per
> image, which is really long.
>
> Doing the same manually, also in digikam: in album click on image to
> open editor, color: convert to bw, save as png... is at least ten times
> faster, but needs a lot of clicks and is very boring - and ideal job for
> a batch process. But I had to do it manually because I didn't want to
> wait almost 3 hours...
>
> I know that highly compressed png take more time, but in settings I have
> set png compression to 5, and I think, the batch process uses that
> compression, too. Or not?
>
> >
> > Am Dienstag, 30. Juni 2020, 20:11:56 CEST schrieb Daniel Bauer:
> >> Hi,
> >>
> >> Sometimes I'd like to convert a complete album to bw. I added 69 color
> >> png of 30-40MB to a batch, selected convert to bw, save in new folder, run.
> >>
> >> Each image takes more tan 2 minutes to convert. When I open it in
> >> editor, and click color->bw it works immediately, also saving the file
> >> is fast. But batch processing is so slow that it cannot be used.
> >>
> >> Now I must go through the album in editor, click color->bw->save->next
> >> 68 times, which is not comfortable but at least 10 times faster :-(
> >>
> >> Why?
> >
> >
> >
> >
>
> --
> Daniel Bauer photographer Basel Málaga
> https://www.patreon.com/danielbauer
> https://www.daniel-bauer.com