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

[Daniel Bauer]

Am 01.07.20 um 18:55 schrieb Maik Qualmann:
> The cause is the set compression. The BQM has its own setting for compression,
> see the "Save Images" tab. The default is 9, here with a 20MB PNG it takes
> about 1 minute, at level 5 only 10 seconds. The compression settings are also
> saved when you save a workflow.

Hm. I have set png compression to 5 in digikam settings
(Bildbearbeitung -> Einstellungen speichern -> PNG Kompression)

Just to look what happens I put a jpg image in batch processor and there 
chose "convert to png", then a dialog is offered to set compression, and 
this dialog is already set to 5.

... Just now I see:

When converting a color png to a bw png the batch processor does not 
take the settings from digikam settings, but one has to set it again 
within the batch processor under "save images" (a tab that I have never 
looked at before, just used the "rename images", because I thought the 
standard digikam settings were used)

> The Multicore setting is in the "Behavior" tab.

Ha, after desperately searching for that "Behaviour" in the digikam 
settings, I finally found it in the batch window :-)
> 
> Maik

So, thanks. The problem is solved for me.

(Although me personally thinks that the batch processor should use the 
settings saved in the general digikam settings as default. That would be 
more logical from my point of view because usually one only opens those 
tabs of things one wants to change, and does not check again those 
settings that one believes that one has already set them...)

> 
> Am Mittwoch, 1. Juli 2020, 17:49:23 CEST schrieb Daniel Bauer:
>> Am 01.07.20 um 16:08 schrieb Gilles Caulier:
>>> Hi Daniel,
>>>
>>> Did you activate Multicore support in BQM ?
>>
>> Hi Gilles,
>>
>> where do I find that setting?
>>
>>> 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
> 
> 
> 
> 

-- 
Daniel Bauer photographer Basel Málaga
https://www.patreon.com/danielbauer
https://www.daniel-bauer.com