RE: TS clarification (was: [rohc] The discussion on slope(s) (red ux))

[zhigang.c.liu at nokia.com]

I'm amazed. I haven't seen a "clarification" that has so many 
logic holes in it. I may be alone on this (it seems so at this moment),
but it in worst case will break RFC 3095, and at the best will make 
text of RFC 3095 inconsistent. 

Just a few examples below.

> > TS_SCALED is incorrectly written 
> > as TS / TS_STRIDE. This formula is incorrect both because it 
> > excludes TS_OFFSET, 

No, it does NOT. Did anyone read the following text from section 
4.5.3 in RFC 3095? Or it simply doesn't matter, as people can now 
freely change RFC 3095 in whichever way they like?

   1. Initialization: The compressor sends to the decompressor the value
      of TS_STRIDE and the absolute value of one or several TS fields.
      The latter are used by the decompressor to initialize TS_OFFSET to
      (absolute value) modulo TS_STRIDE.

> > and because it would prevent a TS_STRIDE value of 0. 

That's how it is intended to be. TS_STRIDE is a scale factor, not slope.
Therefore, it is supposed to be non-zero.

Isn't that obvious from section 4.5.3???

> If "/" were a generally unambiguously defined operation meaning "the
> integral part of the result from dividing X by Y", 

That *is* the meaning of "/". Otherwise, what else could it mean here?
Or in the following appearances throughout RFC 3095? Are all of them
going be to be called "ambiguous" as well?

Section 4.5.3:
- the TS will increase by n * 3000 (= n * 90000 / 30) between video frames.
- 0xFFFFFFFF / TS_STRIDE

Section 4.5.4:
- (a_n - a_j) / TIME_STRIDE
- T_approx = T_ref + (a_n - a_ref) / TIME_STRIDE

(Section 4.5.4 even goes extra mile to note: "Integer arithmetic is used in all 
equations above." Now it seems this should also be put in section 4.5.3. Well,
I don't believe even that can prevent the twisting of words ...)

Section 5.7.6.8:
- (a_i - a_j) / TIME_STRIDE

> the absence of TS_OFFSET could be explained, 

What absence??? Isn't the TS_OFFSET clearly specified (see above)?

BR, Zhigang

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