[Vorbis-dev] Cover art

[Ralph Giles]

On Tue, Mar 31, 2009 at 4:02 PM, Ian Malone <ibmalone at gmail.com> wrote:

> I'm not really familiar with base64, can 0x00 occur?

No. Base64 was designed for binary transmission over 7-bit ascii. The
binary string is recast as a base-64 number and each digit is
expressed as a printable ascii character, with a padding convention
for strings that don't convert exactly. The expansion is always 33%
(plus a small overhead for padding and line breaks) because every 3
octets is represented by 4 characters.
http://en.wikipedia.org/wiki/Base64

It's widely used as a binary encoding in text contexts, starting with
email attachments, but also in XML, PDF, and many other complex
formats. We originally recommended it for binary data in vorbis
comments because it is utf-8 clean and because, if it does get
printed, at least it's less scary garbage and won't screw up your
terminal.

> 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.)

Were people upset about that? I thought the main objection to
embedding PNG or JNG cover art directly was that some vorbis players
reject muliplexed streams. That objection applies to copying the FLAC
meta headers too.

 -r