[ogg-dev] Ogg/Spots and Ogg/MNG

ogg.k.ogg.k at googlemail.com ogg.k.ogg.k at googlemail.com
Fri Apr 11 07:38:32 PDT 2008

> The thing about the mng libraries is they seem designed in such a way
> the using  them to do simple timed display of mng is fairly easy, but
> extracting static images becomes painful. I had been thinking about
> doing something to read only the jpeg/png subset, but thesis writing
> has taken me off ogg stuff for the past few months. I'm still of the
> opinion this might be a useful thing to do (to provide the album art
> and things that crazy people want to put into sound files).

Ah, you're the author then ? I only arrived there in january, so I'm blind
to what's happened before then around here.

FWIW, the album art stuff can be done with the existing kate spec.
The encoder reads png images (though paletted ones only are supported,
as I originally intended to let more complex images, if some were needed,
to a separate Ogg/MNG or Ogg/Spots stream).
Category set to "album-art" or something.
Then add each still image.
There still is a question of what to do with the timing. Set the granpos to
zero, and rely on the client code to interpret a category of "album-art"
to be "timeless" is the obvious idea that comes to mind. Hmm, a bit too
hardcoded though. Maybe setting granulerate to zero. Hmm, no, that'd
cause a lot of divides by zero would it.

MNG does look complex though. I also had a look at SVG, but it does
scripting, etc, which isn't something I want. APNG looks simpler and
closer to what I'd want, but I've seen comments saying it doesn't play
so nice with being a PNG extension. Still looking on and off.

Anyway, I'm thinking aloud again. Aloud not being the right word in this
particular case though.

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