I am confused that if chroma_format_idc in sps field is 0 (Zero), Do I process Chroma format like 4:2:0 ?
ISO_IEC 14996-10. Table 6-1 – SubWidthC, and SubHeightC values derived from chroma_format_idc and separate_colour_plane_flag
| chroma_format_idc | seperate_colour_plane_flag | Chroma Foramt | SubWidthC | SubHeightC |
|---|---|---|---|---|
| 0 | 0 | monochrome | - | - |
| 1 | 0 | 4:2:0 | 2 | 2 |
| 2 | 0 | 4:2:2 | 2 | 1 |
| 3 | 0 | 4:4:4 | 1 | 1 |
| 3 | 1 | 4:4:4 | - | - |
According to ISO_IEC 14996-10
7.4.2.1.1 Sequence parameter set data semantics
chroma_format_idc specifies the chroma sampling relative to the luma sampling as specified in subclause 6.2. The value of chroma_format_idc shall be in the range of 0 to 3, inclusive. When chroma_format_idc is not present, it shall be inferred to be equal to 1 (4:2:0 chroma format).
I intend to state that 4:2:0 should be used when chroma_format_idc is unknown; does the case where chroma_format_idc is 0 also fall under the category of "unknown"?
our internal code that forces processing to 4:2:0 when `chroma_format_idc` is 0.
I am curious about it.