[FFmpeg-devel] [PATCH] Ogg Theora granules confused by spec

Baptiste Coudurier baptiste.coudurier
Tue Apr 22 12:58:49 CEST 2008


Henrik Gulbrandsen wrote:
> On Sun, 2008-04-20 at 08:58 +0200, Henrik Gulbrandsen wrote:
>> On Fri, 2008-04-18 at 09:55 +0200, Diego Biurrun wrote:
>>> On Fri, Apr 18, 2008 at 12:37:45AM -0700, Baptiste Coudurier wrote:
>>>> Henrik Gulbrandsen wrote:
> [...]
>>>>> I doubt the intention of its author was to turn the third part of the version
>>>>> field (the version revision) into a generic flag field for the future.
>>>> IMHO specs writers must really take care and think before writing such 
>>>> statements.
>>> There is a better solution IMO: Get in contact with the spec writers and
>>> ask them to clarify the spec.
>>> Diego
>> Good idea!
>> I've sent an email, so we'll see what the next spec version says.
> A statement from the guy responsible for this particular section of the
> Theora specification follows:
> On Sun, 2008-04-20 at 15:41 -0700, Ralph Giles wrote:
>> No, the tiny revision number isn't a flag. We changed the granulepos  
>> definition and bumped the revision number to indicate the change, but  
>> that's all. The intent was just that old streams could be handled  
>> correctly based on their version number; we expect later revisions to  
>> have the same granulepos scheme as 3.2.1 streams.
>> VREV signals optional features that are generally compatible with the  
>> major and minor revision numbers. Since the granulepos is only a off- 
>> by-one, usually in the more forgiving direction, we thought it was  
>> reasonable to treat it as backward-compatible.

IMHO this was not a reasonable backward-compatible change for ogg
container, considering how it clutters the code and force every muxer to
handle it when stream copy.

> I guess this means that the original patch is reasonable. It doesn't
> influence regression tests (or anything else, actually), so I simply
> attach it again, without any real updates.

Im sorry but I won't accept this patch until theora official specs are
updated. This patch is strictly not needed atm.

Besides what was the original email ?
Did you ask him to update specs and/or what will happen when they will
use vrev 0 again, considering old software did strictly what was written
in specs ?

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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