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|
CTA-861 version:
CTA-861-H Standard from January 2021
+---------------+
| KNOWN ISSUES: |
+---------------+
1. CEA/CTA-861: Data Block Collection (DBC):
The data structures in DBC are variable, and their layout depends on complex
combinations of various fields values. Changing a single value (even a single bit)
can change the whole layout of the block.
In many cases, more than one value has to be changed to obtain a valid structure of
different type, f.e.:
changing ADB.SAD.AFC value to 15 (ACE: Audio Coding Extension Type Code) will cause
error, because AFC=15 in byte 1 requires also a valid ACE value in byte 3.
In such cases the editor will switch to a fallback mode, and the data structures
will be displayed as "unknown/damaged".
wxEDID Solution: (not yet implemented):
A set of constructors which will immediately initialize the required block data
fields, depending on selected type.
The constructors could be invoked from contextual menus, by right-clicking on
particular block in the block tree structure.
2. SVD: Short Video Descriptor:
The data layout for this block depends on:
a) CEA-861 header revision
b) Video ID Code (VIC)
wxEDID will always show the "native_mode" bit7 and the VIC as 8-bit value at
the same time.
This means, that changing "native_mode" bit can also change the VIC value.
3. VDDDB: VESA Display Device Data Block:
VESA DDDB Standard, Version 1; September 25, 2006, section 2.7: Device Native
Pixel Format.
A bug in the specification: The STD defines stored 16-bit H/V pixel count as
(pix_count-1), (what gives the effective range of 1-65536 for 0x0-0xFFFF),
but the Std says that thanks to (pix_count-1) formula the maximum is 65535x65535,
which is not true.
wxEDID will use range of 1-65536.
4. CEA::VDB:
The pseudo-code for VIC values decoding treats VIC range 193..253 as valid,
while the max Video ID value in Table 3 (Video Formats) is 219.
wxEDID will report VIC values in range 220..255 as reserved.
5. T10VTDB: unit for V-Refresh rate is not explicitly defined: assuming [Hz]
V-refresh range depnds on layout type:
T10_M=0: 0..255Hz, T10_M=1: 0..1023Hz
6. Discrepancy in block length handling:
a) CEA-DBC: Extended Tag Code=32: section 7.5.9 IFDB: InfoFrame Data Block:
InfoFrame Type Code != 0x01 || 0x00: Short InfoFrame Descriptor Header:
The payload length is counted from the first byte after the header
b) CEA-DBC: Extended Tag Code=32: 7.5.9 IFDB: InfoFrame Data Block:
InfoFrame Type Code = 0x01: Short Vendor-Specific InfoFrame Descriptor Header:
The payload length excludes the first 3 bytes of IEEE OUI.
This means that the length of header depends on InfoFrame Type Code.
7. For any block type, the payload data which is not strictly defined by the CTA-861-H
is displayed as "unknown".
8. SLDB, SAB: Some speakers used in CTA-861-G are removed in CTA-861-H
9. VSD: The payload is interpreted as for 00-0C-03 "HDMI Licensing, LLC", what means that
for other IEEE-OUI codes the interpretation is incorrect.
10. RMCD::SPKD: CTA-861-H essentially agrees with G-spec, but (apparentl erroneously)
defines default values for X/Y/Zmax, saying that f.e. 0x10 (16 dec) corresponds
to 32 decimeters.
If You'll find any bugs, please don't hesitate to contact me:
tomasz.pawlak@wp.eu
|
