Talk:List of HDCD-encoded Compact Discs

False Positives

Not really sure how to find them. My first though was that discs detected as HDCD but with nothing to decode (no PE nor Gain adjustment enabled) would be labeled that way. However releases like "Neil Young - Are You Passiontate" or "The Cranberries - No Need to Argue" where both features are detected in, are marked as false positives. Aren't they really used in those discs? And if so, how can they be detected? --Unfinished (talk | contribs) 16:30, 31 July 2016 (CET)

Some albums just happen to have patterns that match the HDCD packet format. Below is the dump from the ffmpeg -af hdcd log. A normal HDCD-CD has ~30K valid HDCD packets (counter A+B) in each channel. This has 2 valid packets in channel 0, and none in channel 1, along with six sequences that appear to be packets but fail the check. This is not an HDCD, it is just coincidence that among the ~5.2M samples appeared a sequence (or two) that was a valid HDCD packet.

[274] Neil_Young/Neil_Young-Are_You_Passionate.flac ...
[Parsed_hdcd_0 @ 0x14c9bc0] Process mode: process stereo channels together
[Parsed_hdcd_0 @ 0x14c9bc0] Force PE: off
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control B check failed: 0x30d0 (0x30 vs 0x2f) near 24576
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control A almost: 0x0f near 247668736
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control B check failed: 0x18a5 (0x18 vs 0x5a) near 266510336
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control B check failed: 0x18ec (0x18 vs 0x13) near 266543104
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control B check failed: 0x18ee (0x18 vs 0x11) near 266543104
[Parsed_hdcd_0 @ 0x14c9bc0] hdcd error: Control B check failed: 0x16fb (0x16 vs 0x04) near 347824128
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: counter A: 0, B: 2, C: 5
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: pe: 2, tf: 1, almost_A: 0, checkfail_B: 3, unmatched_C: 0, cdt_expired: 1
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: tg 0.0: 1
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: tg -0.5: 0
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: tg -1.0: 0
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 0: tg -1.5: 1
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 1: counter A: 0, B: 0, C: 3
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 1: pe: 0, tf: 0, almost_A: 1, checkfail_B: 2, unmatched_C: 0, cdt_expired: -1
[Parsed_hdcd_0 @ 0x14c9bc0] Channel 1: tg 0.0: 0
[Parsed_hdcd_0 @ 0x14c9bc0] HDCD detected: no

Btw, what software or device are you using to detect HDCD? --Bp (talk) 15:56, 31 July 2016 (BST)