While creating some ISO images for backup purposes earlier this week, I got the error message "Incorrectly encoded string" and "Possibly creating an invalid Joliet extension" when using genisoimage/mkisofs to create the image.
The command I used was as follows:
mkisofs -J -r -hide-rr-moved -joliet-long -o cd.iso .
The start of the output looked like this:
I: -input-charset not specified, using utf-8 (detected in locale settings) Using SERVI000.PHP;1 for...
and the command then showed me a full list of the filename used and the actual full filename and finished with this:
Incorrectly encoded string (SER?E_LIMANI.pdf) encountered. Possibly creating an invalid Joliet extension. Aborting.
I assumed that because of the "-input-charset not specified" message at the start that this was going to be due to an characterset encoding issue, because the PDF file causing the issue used some odd character that wasn’t supported by the default character set used.
A quick look at the manpage for genisoimage/mkisofs revealed this: (man genisoimage)
-input-charset charset Input charset that defines the characters used in local filenames. To get a list of valid charset names, call genisoimage -input-charset help. To get a 1:1 mapping, you may use default as charset name. The default initial values are cp437 on DOS-based systems and iso8859-1 on all other systems. See the CHARACTER SETS section below for more details.
I decided to try using iso8859-1 as the input character set and issued the command again like so:
mkisofs -input-charset iso8859-1 -J -r -hide-rr-moved -joliet-long -o cd.iso .
This then worked perfectly and there were no errors. If you continue to get errors after trying the iso8859-1 character set then you can try another one. The available character sets can be displayed by issuing the following command:
genisoimage -input-charset help
This will display the available character sets, e.g.:
Unknown charset Known charsets are: cp10081 cp10079 cp10029 cp10007 cp10006 cp10000 koi8-u koi8-r cp1251 cp1250 cp874 cp869 cp866 cp865 cp864 cp863 cp862 cp861 cp860 cp857 cp855 cp852 cp850 cp775 cp737 cp437 iso8859-15 iso8859-14 iso8859-9 iso8859-8 iso8859-7 iso8859-6 iso8859-5 iso8859-4 iso8859-3 iso8859-2 iso8859-1 Additional input charsets are available for Joliet through the iconv support. Run "iconv -l" to display them. Iconv charsets cannot be used with HFS, Apple extension, ISO9660 version 2 or Rock Ridge.
About genisoimage/mkisofs
mkisofs and genisoimage are command line tools for creating ISO images which can then be burnt to CD or DVD; genisoimage is a fork of mkisofs and is part of the cdrkit suite. Most Linux distributions will symbolically link the command "mkisofs" to the "genisoimage" command to make it easy for people who are unfamiliar with the new command and for backward compatbility purposes.