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#1
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read error indicator
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. |
#2
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read error indicator
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! |
#3
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read error indicator
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! |
#4
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read error indicator
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! |
#5
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read error indicator
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! |
#6
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read error indicator
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#7
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read error indicator
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#8
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read error indicator
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#9
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read error indicator
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#10
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read error indicator
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 |
#11
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read error indicator
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 |
#12
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read error indicator
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 |
#13
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read error indicator
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 |
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