[Vorbis-dev] Cover art

[Tor-Einar Jarnbjo]

Ian Malone schrieb:
> I'm not really familiar with base64, can 0x00 occur?
>   
No. Base64 uses lower and upper case letters a-z, digits 0-9 and the 
characters '+', '/' for data encoding and '=' for padding. 64 distinct 
"data characters" means 6 bits, so groups of 3 bytes are encoded with 4 
characters. Other characters, e.g. LF and CR, are allowed to restrict 
line length, but are simply ignored when decoding the data and are not 
necessary for the Vorbis comment. All the required characters are in the 
range 32-127, so the ASCII and UTF-8 encoding of a Base64 encoded string 
are identical.
> Completely off-message suggestion follows:
> It's things like this that really argue for the sense of doing the
> multiplexed approach...
>
> How about: FLAC picture block packets + some kind of modified FLAC bos
> to identify as a cover art stream? Compromise between quick-hack and
> technically elegant. (For those people upset by the other off-message
> suggestion that both PNG and JNG could be encapsulated following the
> MNG-Ogg format.)
>   
I am not sure how hardware players generally cope with Vorbis files 
containing additional logical streams with other content, software 
players are probably quite tolerant. Either way, having a Base64 or 
directly UTF-8 encoded binary value in a comment or adding a multiplexed 
stream, the extension is strictly speaking standard compliant, but I 
don't know if it will increase Vorbis acceptance if suddenly lots of 
hardware players are not able to handle the "new" Vorbis files.

Tor