I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

Some chipsets have a "C2 uncorrected" error flag, brought out to a
pin, which you could use to drive a one-shot (pulse stretcher) and an
LED.

Another option would be to take the CDP's S/PDIF digital output
(assuming it has one), run it into an S/PDIF receiver/decoder, and
check the subcode bits. If I recall properly, there is a "frame in
error" bit which a CDP or transport can set in a data frame, to
indicate that the data in the frame is known to be incorrect. I don't
know how reliably this bit is set, though.

In many CD players, there's probably no way at all to get to the error
correction / correction-failure information - the chipsets just don't
bother to expose it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

Some chipsets have a "C2 uncorrected" error flag, brought out to a
pin, which you could use to drive a one-shot (pulse stretcher) and an
LED.

Another option would be to take the CDP's S/PDIF digital output
(assuming it has one), run it into an S/PDIF receiver/decoder, and
check the subcode bits. If I recall properly, there is a "frame in
error" bit which a CDP or transport can set in a data frame, to
indicate that the data in the frame is known to be incorrect. I don't
know how reliably this bit is set, though.

In many CD players, there's probably no way at all to get to the error
correction / correction-failure information - the chipsets just don't
bother to expose it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

Some chipsets have a "C2 uncorrected" error flag, brought out to a
pin, which you could use to drive a one-shot (pulse stretcher) and an
LED.

Another option would be to take the CDP's S/PDIF digital output
(assuming it has one), run it into an S/PDIF receiver/decoder, and
check the subcode bits. If I recall properly, there is a "frame in
error" bit which a CDP or transport can set in a data frame, to
indicate that the data in the frame is known to be incorrect. I don't
know how reliably this bit is set, though.

In many CD players, there's probably no way at all to get to the error
correction / correction-failure information - the chipsets just don't
bother to expose it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

Some chipsets have a "C2 uncorrected" error flag, brought out to a
pin, which you could use to drive a one-shot (pulse stretcher) and an
LED.

Another option would be to take the CDP's S/PDIF digital output
(assuming it has one), run it into an S/PDIF receiver/decoder, and
check the subcode bits. If I recall properly, there is a "frame in
error" bit which a CDP or transport can set in a data frame, to
indicate that the data in the frame is known to be incorrect. I don't
know how reliably this bit is set, though.

In many CD players, there's probably no way at all to get to the error
correction / correction-failure information - the chipsets just don't
bother to expose it.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Fri, 12 Mar 2004 05:28:21 -0000, (Dave Platt)
wrote:

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

[Remainder of good explanation snipped]

Even more, C1 errors are not repeatable. You can read a CD several
times and get C1 errors at different places and in different numbers,
although the number of errors/minute do not very much.

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk
function reads the CD sequentially in CAV mode (Constant Angular
Velocity) unless there massive C1 errors. C1 errors cause the CD
drive to slow down to reduce those errors. The speed is plotted over
the play time of the CD. Another graph shows the number of uncorrected
C2 errors that usually get noticable while the speed slows down to 8x
or less (of normal audio speed). A CD with litte C1 errors is read at
24x to 52x audio speed.

Nero's Scan Disk function plots a map of a CD with C2 errors
classified as "no error" left after C2 stage, "correctable error" and
"uncorrectable error".

There are a couple of other CD scan programs available, some of them
are freeware. All of them rely on some firmware function in the CD
burner and only a few models support it.

Norbert

On Fri, 12 Mar 2004 05:28:21 -0000, (Dave Platt)
wrote:

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

[Remainder of good explanation snipped]

Even more, C1 errors are not repeatable. You can read a CD several
times and get C1 errors at different places and in different numbers,
although the number of errors/minute do not very much.

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk
function reads the CD sequentially in CAV mode (Constant Angular
Velocity) unless there massive C1 errors. C1 errors cause the CD
drive to slow down to reduce those errors. The speed is plotted over
the play time of the CD. Another graph shows the number of uncorrected
C2 errors that usually get noticable while the speed slows down to 8x
or less (of normal audio speed). A CD with litte C1 errors is read at
24x to 52x audio speed.

Nero's Scan Disk function plots a map of a CD with C2 errors
classified as "no error" left after C2 stage, "correctable error" and
"uncorrectable error".

There are a couple of other CD scan programs available, some of them
are freeware. All of them rely on some firmware function in the CD
burner and only a few models support it.

Norbert

On Fri, 12 Mar 2004 05:28:21 -0000, (Dave Platt)
wrote:

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

[Remainder of good explanation snipped]

Even more, C1 errors are not repeatable. You can read a CD several
times and get C1 errors at different places and in different numbers,
although the number of errors/minute do not very much.

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk
function reads the CD sequentially in CAV mode (Constant Angular
Velocity) unless there massive C1 errors. C1 errors cause the CD
drive to slow down to reduce those errors. The speed is plotted over
the play time of the CD. Another graph shows the number of uncorrected
C2 errors that usually get noticable while the speed slows down to 8x
or less (of normal audio speed). A CD with litte C1 errors is read at
24x to 52x audio speed.

Nero's Scan Disk function plots a map of a CD with C2 errors
classified as "no error" left after C2 stage, "correctable error" and
"uncorrectable error".

There are a couple of other CD scan programs available, some of them
are freeware. All of them rely on some firmware function in the CD
burner and only a few models support it.

Norbert

On Fri, 12 Mar 2004 05:28:21 -0000, (Dave Platt)
wrote:

I was thinking about the possibility of installing a LED on a CDP that would
light when a read error is encountered. How could this be accomplished?

It depends a lot on the chipset.

The bitstream from the laser head goes through a whole bunch of
processing in the CDP's chip[s]. Of particular importance is the
two-level (C1/C2) Reed-Solomon cross-interleaved error correction.
The first (C1) level corrects the great majority of the errors in the
incoming bitstream (of which there are often tens to hundreds per
second). The second (C2) level takes the output of the C1 correction
process, and performs the second round of interleaving and error
correction.

[Remainder of good explanation snipped]

Even more, C1 errors are not repeatable. You can read a CD several
times and get C1 errors at different places and in different numbers,
although the number of errors/minute do not very much.

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk
function reads the CD sequentially in CAV mode (Constant Angular
Velocity) unless there massive C1 errors. C1 errors cause the CD
drive to slow down to reduce those errors. The speed is plotted over
the play time of the CD. Another graph shows the number of uncorrected
C2 errors that usually get noticable while the speed slows down to 8x
or less (of normal audio speed). A CD with litte C1 errors is read at
24x to 52x audio speed.

Nero's Scan Disk function plots a map of a CD with C2 errors
classified as "no error" left after C2 stage, "correctable error" and
"uncorrectable error".

There are a couple of other CD scan programs available, some of them
are freeware. All of them rely on some firmware function in the CD
burner and only a few models support it.

Norbert

Norbert Hahn wrote:

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk


Or get a Plextor Premium, and the included PlexTools Pro, and you can get a
niuce pretty graph with C1, C2, and CU errors plotted against time. As well
as other stuff unavailable on any (?) other drives.

geoff

Norbert Hahn wrote:

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk


Or get a Plextor Premium, and the included PlexTools Pro, and you can get a
niuce pretty graph with C1, C2, and CU errors plotted against time. As well
as other stuff unavailable on any (?) other drives.

geoff

Norbert Hahn wrote:

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk


Or get a Plextor Premium, and the included PlexTools Pro, and you can get a
niuce pretty graph with C1, C2, and CU errors plotted against time. As well
as other stuff unavailable on any (?) other drives.

geoff

Norbert Hahn wrote:

In case you habe a recent computer CD burner there is some chance to
run a CD test program that shows the error by classification.
I have a LiteOn LTR 48246K burner and the utility "CD Speed" in the
Nero program package offers to views on CD errors. The Scan Disk


Or get a Plextor Premium, and the included PlexTools Pro, and you can get a
niuce pretty graph with C1, C2, and CU errors plotted against time. As well
as other stuff unavailable on any (?) other drives.

geoff