#5 Android ACV comic files (CBZ based)

Alan Horkan

This is in part to inform about another comic book format and in part to consider if there are any easy parts of it that can be added to MComix.

The Android platform promoted by Google for mobile phones includes a few comic viewer programs. Droid Comic Viewer (occasionally referred to as Android Comic Viewer and shortened to "ACV") seems to be one of the more popular viewers. http://droidcomicviewer.com

They have created their own variation on the ZIP based CBZ comic archives and the format is in it's second iteration.
In the simplest terms it is a CBZ with an additional comic.xml file to provide some descriptions. The format also includes transition effects (even vibrate) minor visual settings such as the option to set the background colour.

[It does not seem to include any accessibility features such as text based transcripts or other annotations.]

I've found a discussion which includes an example of their earlier simple iteration of the format which just includes pregenerated thumbnails
thumbnails are stored in a subfolder z_tn/

It is a bit of a kludge but in the short term we might consider adding XML to the list of extensions that are considered "Comment files", until some future point where the Preferences dialog does something with that information. (Probably more relevant is that ComicRack includes ComicInfo.xml files and seems to be popular.)
Something I need to test out is how MComix works with ZIP files that have been renamed to ACV or renamed to any other extension besides CBZ or ZIP. (Tangent: From what I've seen of OpenDocument ODP slideshow files the filenames of Pictures/ are arbitrary and no useful ordering is preserved. I didn't get around to checking the file format specification to see if it was possible to force the file names to preserve ordering.)

Just thought it was interesting to see another CBZ variant, maybe it could become popular in time. Who knows.


  • Oddegamra

    Oddegamra - 2011-06-29

    The code path for opening archives in MComix is slighly differentl depending on how files are passed - for example, when opening a file from the command line (such as mcomix ~/abc.def), the magic bits will be read to determine if the file is a valid archive, regardless of actual extension. So, if ACV still has a valid ZIP header, it should open normally.

    On the other hand, the "Open" dialog uses mime type/extension filters, so files that aren't explicitly listed in code won't show up (unless "All files" is selected in the filter, of course...).

    I can see how pre-generated thumbnails could be useful on a low-power machine, though they will probably be displayed along with regular files in MComix, which might not be entirely desirable. Depending on the file/folder names of the actual files, they might even show up before these files, which would likely be quite frustrating. Maybe hard-code a filter for this filetype/folder name, as I have previously done for MacOSX meta files.

    Apart from that, it appears that the remaining information stored in the XML file is mostly for eye candy. Even without specific support, the archive format should be mostly supported (or so I hope).

  • Alan Horkan

    Alan Horkan - 2011-07-15

    A user of Droid Comic Viewer created a python script/program to convert comics to ACV format. It includes resizing and converting files from CBZ/CBR/PDF. Might provide some ideas.
    ACV optimiser

    I was thinking an easier win might be to add ACV export to the Edit dialog, with just the first basic feature would be to include pregenerated thumbnails (in a folder z_tn/ as mentioned previously).

  • Alan Horkan

    Alan Horkan - 2012-01-31

    Droid comic viewer open sourced

    I dont know when or if I'll work on this so I may as well put the ideas out there in case others are interested to try.
    Part of my interest in this ACV file format is that basically DroidComics are one of the few people who are selling Comics in what is essentially CBZ format. If a developer was interested in adding support for this format it might be possible to buy DroidComics and view them on the desktop using MComix rather than being required to use ACV on an Android phone. Not sure yet how the DRM restrictions work or if this would even be possible but I figure if you could sell ACV comics you might get a small commission on the sales.


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