Opened 5 years ago

Closed 11 months ago

#1456 closed defect (worksforme)

Clarification on note related to repetition of SPS

Reported by: adarsh Owned by:
Priority: minor Milestone:
Component: SCC text Version:
Keywords: Cc: Miska, Hannuksela, <miska.hannuksela@…>, rajan_joshi, jct-vc@…

Description

The following note in sub-clause F.7.4.2.4.2 in W1005-v4 seems to be contradictory due to a missing "not" in the sentence. The first sentence of the note says that the SPS ID space is shared, but the second sentence says that SPS with a particular SPS_ID and a different layer ID would update the SPS of the same SPS_ID. This needs to be corrected.

Any SPS NAL unit with any nuh_layer_id value containing the value of sps_seq_parameter_set_id for the active SPS RBSP for a particular layer shall have the same content as that of the active SPS RBSP for the particular layer unless it follows the access unit auA containing the last coded picture for which the active SPS RBSP for the particular layer is required to be active for the particular layer and precedes the first NAL unit succeeding auA in decoding order that activates an SPS RBSP with the same value of seq_parameter_set_id.

NOTE 2 – All SPSs, regardless of their values of nuh_layer_id, share the same value space for sps_seq_parameter_set_id. In other words, an SPS with nuh_layer_id equal to X and sps_seq_parameter_set_id equal to A would update the previously received SPS with nuh_layer_id not equal to X and sps_seq_parameter_set_id equal to A.

Also, in order that the note be complete w.r.t to the text in the paragraph above it, the scope should also be added to the latter sentence in the note. Suggested text for the Note is below (additions highlighted with bold font).

NOTE 2 – All SPSs, regardless of their values of nuh_layer_id, share the same value space for sps_seq_parameter_set_id. In other words, an SPS with nuh_layer_id equal to X and sps_seq_parameter_set_id equal to A would not update the previously received SPS with nuh_layer_id not equal to X and sps_seq_parameter_set_id equal to A unless the SPS with nuh_layer_id equal to X and sps_seq_parameter_set_id equal to A succeeds the last access unit containing a picture belonging to a CLVS for which the SPS with nuh_layer_id not equal to X and sps_seq_parameter_set_id equal to A is active.

Change History (2)

comment:1 Changed 15 months ago by karlsharman

This text remains present in v5.

comment:2 Changed 11 months ago by yk

  • Resolution set to worksforme
  • Status changed from new to closed

Adarsh and I had a discussion on this. We agreed that the text is correct, thus no change is needed, because the paragraph above the NOTE would disallow cases where update or overriding becomes problematic, and the second sentence in the NOTE is just describing what does the first sentence about SPS ID value space mean exactly.

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  • Adarsh Krishnan Ramasubramonian(Reporter)
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  • Ye-Kui Wang(Participant)