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Troubleshooting:
Recording Glitches
Other than USB connectivity issues,
users are most often concerned with glitches in their recorded files.
Most often it has been found that the glitches in a particular recording
are due to reception errors. There are various levels to error
correction and concealment that occur before a signal actually drops out
on the screen. A great number of errors are actually corrected inside
the STB using complex mathematical relationships that can restore
missing or corrupted data to its exact original bit pattern. The next
level is called "error concealment" and it happens inside the
receiver's decoder chip. Some errors can not be corrected, so rather
than having blank data and a possible drop-out, the decoder can conceal
it, visually making it look like nothing ever went wrong. The most common
way this is done is by repeating or interpolating data. The decoders
inside the receiver are amongst the best around at error concealment,
and with good reason -they are dealing with a highly error-prone
transmission medium.
So,
where does this leave us? The R5000-HD captures data before it enters
the decoder and encapsulates it into a transport stream to be played on
a different decoder at another time. This decoder may or may not be
(chances are it is not) as good at error concealment as the one inside
your STB. This explains why it maybe possible to see glitches in the
recording that weren't present when you watched it originally.
A useful way to check for glitches and drop-outs in the source material
is to simultaneously make an analog VHS tape recording along with the
R5000-HD. Make sure to have the SD output activated on your receiver.
Now, watch the HD recording and note the times where there is any kind
of glitch or problem. Also, if the R5000-HD reports a remuxer re-start, note that point as well. Go to those areas on the
VHS and look for any signs of a glitch or reception drop-out. A
reception drop-out results in a temporary halt of any data
transfer and will almost always force the remuxer re-start if long
enough.
Often you can trace what looks like a pretty bad glitch in the digital
recording to only a very minor and subtle disruption on the VHS tape.
You may have to go frame by frame to even see it. This is the superior
error concealment of the receiver's decoder at work. Other times the two
glitches appear identical indicating a transmission error.
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