Opened 12 years ago

Closed 12 years ago

#391 closed technical change (fixed)

Slice header not parsable (slice_address)

Reported by: ksuehring Owned by: bbross
Priority: major Milestone: D7
Component: Text Version: D6 (H1003) dI/dJ/dK
Keywords: Cc: bbross, wjhan, jct-vc@…

Description

From the semantics:

The length of the slice_address syntax element is ( Ceil( Log2( PicWidthInCtbs * PicHeightInCtbs ) ) + SliceGranularity ) bits.

using

PicWidthInCtbs = Ceil( pic_width_in_luma_samples ÷ ( 1 << Log2CtbSize ) ) (7 14)
PicHeightInCtbs = Ceil( pic_height_in_luma_samples ÷ ( 1 << Log2CtbSize ) ) (7 15)

The syntax elements pic_width_in_luma_samples and pic_height_in_luma_samples are coded in the SPS. When parsing a slice header the decoder can determine the proper SPS only by activating the PPS using the syntax element pic_parameter_set_id.

According to the syntax table pic_parameter_set_id is parsed AFTER slice_address.

Attachments (1)

PossibleFix.docx​ (15.2 KB) - added by rickard 12 years ago.

Download all attachments as: .zip

Change History (7)

comment:1 Changed 12 years ago by DefaultCC Plugin

  • Cc bbross wjhan jct-vc@… added

Changed 12 years ago by rickard

comment:2 Changed 12 years ago by rickard

The attachment PossibleFix.docx contins a fix that does not change any bit costs. I think that changes that do affect bit-costs should be studied before we change anything.

BR
Rickard Sjöberg

comment:3 Changed 12 years ago by ksuehring

I have uploaded contribution JCTVC-H0113 which contains a discussion of possible solutions. I especially had a look at changing the coding of slice_address to ue(v). The contribution contains an excel sheet which allows you to calculate the number of bits used for different image sizes, numbers of slices and slice granularity parameters in both encodings. Please have a look at this so that we can make a good choice in Geneva.

comment:4 Changed 12 years ago by ksuehring

  • Type changed from defect to technical change

comment:5 Changed 12 years ago by bbross

  • Milestone set to D7

comment:6 Changed 12 years ago by bbross

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

Fixed in JCTVC-I1003 d4.

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