RE: WOFF2 and 'meta' table

Yes, 4 bytes even.
However, the list of “known” tables currently includes everything we could find under the sun (I don’t even remember what some of them are), and I agree that some of those tables are not likely to be ever encountered in the wild – thus it may make sense to revisit the list and see what can be eliminated without any adverse consequences.

Thank you,
Vlad


From: Roderick Sheeter [mailto:rsheeter@google.com]
Sent: Friday, May 29, 2015 1:47 PM
To: Behdad Esfahbod
Cc: David Kuettel; Levantovsky, Vladimir; Sergey Malkin; WebFonts WG
Subject: Re: WOFF2 and 'meta' table

Isn't it just +4 bytes for the UInt32 with the tag value? (http://dev.w3.org/webfonts/WOFF2/spec/#table_dir_format)

On Fri, May 29, 2015 at 10:18 AM, Behdad Esfahbod <behdad@google.com<mailto:behdad@google.com>> wrote:
On Fri, May 29, 2015 at 10:14 AM, David Kuettel <kuettel@google.com<mailto:kuettel@google.com>> wrote:
On Thu, May 28, 2015 at 7:24 PM, Levantovsky, Vladimir <Vladimir.Levantovsky@monotype.com<mailto:Vladimir.Levantovsky@monotype.com>> wrote:
We can definitely revisit the list of known tables and see if anything there could be eliminated / swapped for 'meta' tag, but for all intent and purposes the list has nothing to do with how compression is applied, it only helps to save some bytes by reducing the size of the table directory.

Any arbitrary table that is not "known" would be represented in the table directory by the 'arbitrary' flag followed by the table tag, the table data itself will be a part of the compressed data stream regardless of whether it's known or not.

It would be great to actually measure this for a font with a 'meta' table, just to have the hard data.  Any volunteers?

I believe we know the difference to be < 4 bytes, no?


Thank you,
Vlad


On May 28, 2015, at 7:29 PM, "Sergey Malkin" <sergeym@microsoft.com<mailto:sergeym@microsoft.com>> wrote:
Apple defines ‘meta’ table that is still outside of OpenType spec. It contains information about languages font supports and designed for. We in Windows 10 decided to add this table to our system fonts and are in process of doing so.

I noticed that this table is not in the list of known table tags (http://www.w3.org/TR/WOFF2/#table_dir_format) and this may be the only real world table that is not compressed by this mechanism. Can we consider adding this table to the list? I know that list is currently full, but maybe we can replace some rarely used table with it?

Thanks,
Sergey