I recently acquired a set of VCD's
containing an old TV series. I had
skipped the "VCD thing" over the
years due to their poor quality,
and the lack of error correction
which made generational disc
copying prone to deterioration
with cumulative errors (how odd
for a digital medium).
In any case ... now I had a stack
of VCD's. I had first tried to
play them on my PC only to find
several of them would stall with
"media errors". Attempts to scan
for errors using a media scanner
(like Nero CDSpeed's scandisk
function) showed missing sectors.
The discs themselves were on good
quality blanks and freshly burned,
so it seemed odd that they would
have such serious read errors.
The person I obtained these from
stopped answering questions the
more deeply I probed into how they
were created...
Oddly enough, on several DVD
players those same discs played
without errors; in fact, without
even showing the slightest glitch
at the point of the missing
sectors.
I was determined to try "fixing"
such discs without investing money
in software that I would have no
continuing use for. VCD Gear, with
its "correct MPEG errors" option
seemed attractive, but without
masking the OS's intolerance for
media read errors, it stalled at
the point the CD drive stalled and
would not deliver useable data
past that point.
Ultimately I came upon the freebie
solution archived here:
- extract the raw track using ISO
Buster set to ignore errors.
- convert to MPEG (fix errors)
using VCD Gear
- master to CUE/BIN using VCD
Gear
- re-burn CUE/BIN to VCD using
BurnAtOnce
The "fixed" VCD plays fine on
those same standalone DVD players;
again, without even the slightest
hint of a glitch at the
damaged/missing region. Now that I
can play them on the PC, I see a
momentary breakup/pixellization
at the point of the glitch.

Which leads me to the question
that nags me after this experience
- is the error concealment
performed by a standalone disc
player that much better than that
performed by a PC? Or does PC
software even bother to conceal
errors? Further, why does a
standalone player (including one
Apex which, after all, uses a PC
DVD-ROM drive as a loader) totally
ignore "missing sectors" in the
raw MPEG track, while a PC stalls
at the first read error?