Unmodified Cover Versions

Tantaly · 04-17-2011, 12:32 PM

after reading
https://www.mobileread.com/forums/sho...d.php?t=100922
https://www.mobileread.com/forums/showthread.php?t=68188

I wondered if there are any addons that allow covers to be saved "untainted" because:

every import (ex: from an exported folder) seems to recompress covers
import via metadata editing recompresses too

Is there an addon / plugin that prevents that ?
(i think Quality Check isnt that useful for covers because of that recompression mentioned above)

the source code apparently always recompresses and thereby reduces image quality via src/calibre/ebooks/metadata/sources/covers.py

Code:

def save_cover_data_to(data, path, bgcolor='#ffffff', resize_to=None,
        return_data=False, compression_quality=90, minify_to=None)

Shouldn't covers that are mentioned in metadata files be left untouched (copied instead of reprocessed)? Especially if I reimport from a folder with a .opf file ?
(Maybe implement lossless image covers via png or lossless jpeg?)

PS: i can only think of 2 "insurances" against that tainting so far
- have "good" (untouched) cover scans in a separate folder at hand/as backup
- integrated high quality covers in epub etc. format

kovidgoyal · 04-17-2011, 12:56 PM

No, the source code does not recompress, unless the image was actually changed. Read it more carefully.

04-17-2011, 12:32 PM	#1
Tantaly Junior Member Posts: 1 Karma: 10 Join Date: Apr 2011 Device: iPad	Unmodified Cover Versions after reading https://www.mobileread.com/forums/sho...d.php?t=100922 https://www.mobileread.com/forums/showthread.php?t=68188 I wondered if there are any addons that allow covers to be saved "untainted" because: every import (ex: from an exported folder) seems to recompress covers import via metadata editing recompresses too Is there an addon / plugin that prevents that ? (i think Quality Check isnt that useful for covers because of that recompression mentioned above) the source code apparently always recompresses and thereby reduces image quality via src/calibre/ebooks/metadata/sources/covers.py Code: def save_cover_data_to(data, path, bgcolor='#ffffff', resize_to=None, return_data=False, compression_quality=90, minify_to=None) Shouldn't covers that are mentioned in metadata files be left untouched (copied instead of reprocessed)? Especially if I reimport from a folder with a .opf file ? (Maybe implement lossless image covers via png or lossless jpeg?) PS: i can only think of 2 "insurances" against that tainting so far - have "good" (untouched) cover scans in a separate folder at hand/as backup - integrated high quality covers in epub etc. format

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04-17-2011, 12:56 PM	#2
kovidgoyal creator of calibre Posts: 43,843 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	No, the source code does not recompress, unless the image was actually changed. Read it more carefully.