[Gen-art] Gen-ART IETF LC review of draft-ietf-xrblock-rtcp-xr-psi-decodability-04

[Tom Taylor <[e-mail]>]

I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at

<http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Please resolve these comments along with any other Last Call comments
you may receive.

Document: draft-ietf-xrblock-rtcp-xr-psi-decodability-04
Reviewer: Tom Taylor
Review Date: 6 July 2014
IETF LC End Date: 7 July 2014
IESG Telechat date: (not known)

Summary: basically ready with very minor issues and a number of 
editorial suggestions.

Major issues: none.

Minor issues:

(1) It might be helpful to add text in Section 3 explaining that 
PAT_error_2_count and PMT_error_2_count are actually replacements for 
and improvements on PAT_error_count and PMT_error_count respectively and 
are therefore preferred in future implementations.

(2) Condition (2) of PAT_error_2_count: "one table with table_id other 
than 0x00" is more precise than intended by [ETSI]. s/one/a/. This 
comment also applies to PMT_error_2_count (third from last line of first 
paragraph) and CAT_error_count (both conditions).

Nits/editorial comments:

General: blanks are missing in a number of places, typically following a 
comma or preceding a parenthesis.

Abstract
--------

   "statistics metrics" seems a bit redundant, but I wonder if "metric" 
has a special meaning to people working in this area. To me, "metric" is 
another word for "measurement result". So its use to describe the 
contents of the XR block makes sense. However, when we get to Section 3, 
"metric" is used in place of "indicator". Is that really correct usage?

   s/Program specific information/Program Specific Information/

Section 1.1
-----------
Some redundancy with the opening paragraph of 1.1, some cramming 
together of different ideas. Suggested alternative:

OLD

    This memo is based on information consistency tests and resulting
    indicators defined by ETSI [ETSI] and defines a new block type to
    augment those defined in [RFC3611] for use with MPEG2 Transport
    Stream (TS) [ISO-IEC.13818-1.2007].  The new block type supports
    reporting of the number of occurrences of each Program Specific
    Information (PSI) indicator in the first and second priorities that
    supplements information from PSI independent Decodability Statistics
    Metrics Block [RFC6990]; third priority indicators are not supported.

NEW

    This memo defines a new block type for use with MPEG2 Transport
    Stream (TS) [ISO-IEC.13818-1.2007], to
    augment those defined in [RFC3611].  The new block type supports
    reporting of the number of occurrences of each Program Specific
    Information (PSI) indicator in the first and second priorities listed
    by [ETSI] sections 5.2.1 and 5.2.2 respectively.  Third priority
    indicators are not supported. The metrics defined here
    supplement information from the PSI-independent Decodability
    Statistics Metrics Block [RFC6990].

Section 1.2
-----------
s/defined/defines/ on second line for consistency with the other sentences.

Section 1.3
-----------
s/Architectures [RFC6792]/Architecture [RFC6792]/
s/guideline/guidelines/
s/for reporting block format using RTCP XR/for RTCP XR reporting block 
formats/

Section 1.4
-----------
s/;/,/ on second line.
s/;/./ on third-last line.

Section 3
---------
See remark on use of "metric" above (Section 1.1). Could the first 
sentence be rewritten:

OLD

    ETSI TR 101290 [ETSI] generally defines metrics related to error
    events while this document contains counts of those metrics defined
    in [ETSI].

NEW

    ETSI TR 101290 [ETSI] generally defines indicators related to error
    events, while the XR block defined in this document contains counts
    of occurrences of the [ETSI] indicators.

Fifth line: s/PSI independent/PSI-independent/ (add hyphen)

Paragraph below the CRC and CAT bullets:
  (1) What do you mean by: "scrambling may be considered"? Do you mean 
that the presence or absence of scrambling is part of the error 
checking, or something else?
  (2) I'd suggest expanding "The other parameters ..." to "The other 
parameters defined in [ETSI] Section 5 [or whatever scope you intended] 
but not listed above ...".

Section 3, PID_Error_Count
--------------------------
Second sentence is not quite accurate. It should read:

OLD

       A PID_error occurs when MPEG TS streams
       are remultiplexed and any PID doesn't refer to an actual data
       stream, as defined in the section 5.2.1 of [ETSI]

NEW
       A PID error occurs [is indicated?] when no data stream is present
       corresponding to a given PID. This may be caused by multiplexing
       or demultiplexing, then remultiplexing.  See
       section 5.2.1 of [ETSI].