cdrecord to ignore the L-EC error

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Goal

Any way to ignore the "L-EC error" data, save them as is, without error correction and retrying?

Symptom

$ cdrdao read-cd --read-raw --eject --device $CDR_DEVICE --speed 48 --datafile $ToBurn.bin $ToBurn.toc
Cdrdao version 1.1.9 - (C) Andreas Mueller <andreas@daneb.de>
Using libscg version 'schily-0.8'
Using driver: Generic SCSI-3/MMC (raw writing) - Version 2.0 (options 0x0000)

PQ sub-channel reading (data track) is supported, data format is BCD.
Raw P-W sub-channel reading (data track) is supported.
Cooked R-W sub-channel reading (data track) is supported.
Copying data track 1 (MODE2_RAW): start 00:00:00, length 01:14:00 to "hwdd-31.bin"...
WARNING: Found L-EC error at sector 2114 - ignored.
[...]
WARNING: Found L-EC error at sector 2128 - ignored.
[...]

Conclusion

That's pretty much all I can do.

Source Analysis

The "L-EC error" is handled in dao/CdrDriver.cc, function CdrDriver::readDataTrack.

When the L-EC error is met (readTrackData returns -2), readDataTrack will stop the burst read mode and switch to single step mode, re-reading a single track instead, by setting the burst = 1 then n=1.

Should the readTrackData fails the 2nd time, readDataTrack will create a dummy sector for the sector with L-EC errors.

The readTrackData is defined in several places, e.g., dao/SonyCDU920.cc, dao/CDD2600.cc, etc. Normally it is provided by dao/GenericMMC.cc (and trackdb/Track.cc?).

When reading, the GenericMMC.cc will only "sendCmd" then use "getSense" to retrieve the return status of the command. When there is "Medium error", it simply return -2.

That's all handling in cdrdao. No several retries from this level.

Trying History, read-subchan

from man

--read-raw
       Only used for commands read-cd and read-toc.  All  data  sectors
       will  be written as 2352 byte blocks including the sector header
       and L-EC data to the image file. The track mode will be  set  to
       MODE1_RAW or MODE2_RAW in the created toc-file.

--read-subchan mode
       Used by commands read-cd, read-toc and copy.  Specifies the type
       of sub-channel data that is extracted from  the  source  CD  and
       written  to  the  track  image  or copied to the destination CD.
       Mode may be rw for reading  packed  R-W  sub-channel  data  (de-
       interleaved  and error corrected) and rw_raw for reading raw R-W
       sub-channel data (not de-interleaved, not error corrected,  L-EC
       data included in the track image).  If this option is not speci-
       fied no sub-channel data will be extracted.

adding "read-subchan rw_raw" won't help

$ cdrdao read-cd --read-raw --read-subchan rw_raw --eject --device $CDR_DEVICE --speed 48 --datafile $ToBurn.bin $ToBurn.toc
PQ sub-channel reading (data track) is supported, data format is BCD.
Raw P-W sub-channel reading (data track) is supported.
Cooked R-W sub-channel reading (data track) is supported.
Copying data track 1 (MODE2_RAW): start 00:00:00, length 01:14:00 to "hwdd-31.bin"...
WARNING: Found L-EC error at sector 2114 - ignored.

don't know the effect adding it, and don't seem to speed up any. So, decided not to use it.

using "read-subchan rw_raw" alone nok

$ cdrdao read-cd --read-subchan rw_raw --eject --device $CDR_DEVICE --speed 48 --datafile $ToBurn.bin $ToBurn.toc
Copying data track 1 (MODE2_FORM_MIX): start 00:00:00, length 01:14:00 to "hwdd-31.bin"...
ERROR: L-EC error around sector 2106 while copying data from track.
ERROR: Use option '--read-raw' to ignore L-EC errors.

documented on: 2005.02.15