I recently discovered an intriguing issue I'd like to share.
While attempting to back up one of my UHD discs, I encountered read errors using AnyDVD HD, prompting me to switch to ISO-Buster, my preferred tool for rescuing such discs.
I observed peculiar behaviour during my tests with various drives and firmware, specifically with LG drives.
This led to a conversation with @coopervid, who mentioned a discussion on another forum about LG drives, sparking my interest in investigating further.
I discovered that the odd behaviour is linked to the LG Jamless Play feature.
What exactly is LG Jamless Play?
LG describes it as follows:
"Jamless Play: A damaged disc can cause interruptions during movie playback. Jamless play technology automatically skips past damaged parts of a disc to maintain smooth playback while reducing interruptions."
Source:
At first glance, Jamless Play appears to be a beneficial feature. However, the reality is quite the contrary.
Why is Jamless Play problematic?
The issue with Jamless Play is that it fails to report defective sectors. Instead, it seemingly substitutes the information for these sectors with irrelevant data.
How does this impact backups made with LG drives featuring Jamless Play?
Backups created appear to be flawless, as no errors are reported.
Nevertheless, each backup must be meticulously verified by processing them through a program.
For instance, using CloneBD to process a complete copy from the ISO backup can reveal errors, indicating defective data.
How was it determined that Jamless Play, not the drive itself, was the culprit?
To confirm this, the following drives were utilized:
Rigorous Testing:
Performing these tests was a cumbersome process as it required precise identification of defective sectors.
However, it was crucial to eliminate any doubts and confirm that Jamless Play was the underlying cause of the observed anomalies.
The involvement of multiple drives added complexity to the testing process, but it also ensured the accuracy and reliability of the findings.
The tests revealed a consistent pattern:
It has been discovered that LG drives equipped with Jamless Play failed to report errors as expected. This raises serious concerns about the reliability of data backups when using these drives. Users may assume that their backups are secure and error-free due to the absence of error reports, which is not the case.
The Complexities Beyond Standard Testing:
It was a challenging task to comprehend the exact mechanism of Jamless Play and its error bypassing method without reporting them. After conducting extensive ISO analysis and comparison, it became evident that the technical details of how Jamless Play works at a granular level may exceed the standard testing methods' capabilities without in-depth technical documentation or insider knowledge from LG.
Ensuring Backup Integrity:
If you're worried about the reliability of your ISO backups, there is a practical solution that has emerged from the testing process. Although Jamless Play may not detect all errors, using software like CloneBD to process ISO backups or mounting the ISO with virtual CloneDrive and re-ripping it with AnyDVD HD can reveal hidden errors consistently. While this method requires additional steps, it can provide a reliable way for users to verify the integrity of their backups.
Firmware Fix:
During the test, it was observed that the behaviour of LG drives improves when cross-flashed with ASUS firmware. This suggests that any problematic behaviour related to Jamless Play is due to firmware rather than hardware. This distinction is important because it implies that firmware updates or modifications may be sufficient to resolve the issue, without requiring physical alterations to the drives.
Choosing Reliability:
Users who want to ensure high data integrity in backups may prefer drives from manufacturers like Pioneer or ASUS that don't feature Jamless Play or similar issues.
Verifying Jamless Play:
In order to find out if your LG drive has a Jamless Play feature, you can refer to the specifications section on the LG website, which is specific to your drive model. For instance, if you own an LG WH16NS60, you can visit the provided LG webpage link to access the specifications, which clearly state whether or not the drive has Jamless Play.
This information is essential for users to make informed decisions about their hardware choices and avoid any potential data integrity issues.
Example:
While attempting to back up one of my UHD discs, I encountered read errors using AnyDVD HD, prompting me to switch to ISO-Buster, my preferred tool for rescuing such discs.
I observed peculiar behaviour during my tests with various drives and firmware, specifically with LG drives.
This led to a conversation with @coopervid, who mentioned a discussion on another forum about LG drives, sparking my interest in investigating further.
I discovered that the odd behaviour is linked to the LG Jamless Play feature.
What exactly is LG Jamless Play?
LG describes it as follows:
"Jamless Play: A damaged disc can cause interruptions during movie playback. Jamless play technology automatically skips past damaged parts of a disc to maintain smooth playback while reducing interruptions."
Source:
Code:
https://www.lg.com/us/support/products/documents/SPEC_GP65NW60_101426_PR.pdfAt first glance, Jamless Play appears to be a beneficial feature. However, the reality is quite the contrary.
Why is Jamless Play problematic?
The issue with Jamless Play is that it fails to report defective sectors. Instead, it seemingly substitutes the information for these sectors with irrelevant data.
How does this impact backups made with LG drives featuring Jamless Play?
Backups created appear to be flawless, as no errors are reported.
Nevertheless, each backup must be meticulously verified by processing them through a program.
For instance, using CloneBD to process a complete copy from the ISO backup can reveal errors, indicating defective data.
How was it determined that Jamless Play, not the drive itself, was the culprit?
To confirm this, the following drives were utilized:
- Pioneer BDR-S12UHD
- Pioneer BDR-XS07UHD
- LG WH16NS58
- LG WH16NS60 <-> ASUS BW-16D1HT (notably important later)
- LG BU40
- Buffalo BRUHD-PU3-BK (is essentially an LG BU40 in a Buffalo external USB case.)
Rigorous Testing:
Performing these tests was a cumbersome process as it required precise identification of defective sectors.
However, it was crucial to eliminate any doubts and confirm that Jamless Play was the underlying cause of the observed anomalies.
The involvement of multiple drives added complexity to the testing process, but it also ensured the accuracy and reliability of the findings.
The tests revealed a consistent pattern:
It has been discovered that LG drives equipped with Jamless Play failed to report errors as expected. This raises serious concerns about the reliability of data backups when using these drives. Users may assume that their backups are secure and error-free due to the absence of error reports, which is not the case.
The Complexities Beyond Standard Testing:
It was a challenging task to comprehend the exact mechanism of Jamless Play and its error bypassing method without reporting them. After conducting extensive ISO analysis and comparison, it became evident that the technical details of how Jamless Play works at a granular level may exceed the standard testing methods' capabilities without in-depth technical documentation or insider knowledge from LG.
Ensuring Backup Integrity:
If you're worried about the reliability of your ISO backups, there is a practical solution that has emerged from the testing process. Although Jamless Play may not detect all errors, using software like CloneBD to process ISO backups or mounting the ISO with virtual CloneDrive and re-ripping it with AnyDVD HD can reveal hidden errors consistently. While this method requires additional steps, it can provide a reliable way for users to verify the integrity of their backups.
Firmware Fix:
During the test, it was observed that the behaviour of LG drives improves when cross-flashed with ASUS firmware. This suggests that any problematic behaviour related to Jamless Play is due to firmware rather than hardware. This distinction is important because it implies that firmware updates or modifications may be sufficient to resolve the issue, without requiring physical alterations to the drives.
Choosing Reliability:
Users who want to ensure high data integrity in backups may prefer drives from manufacturers like Pioneer or ASUS that don't feature Jamless Play or similar issues.
Verifying Jamless Play:
In order to find out if your LG drive has a Jamless Play feature, you can refer to the specifications section on the LG website, which is specific to your drive model. For instance, if you own an LG WH16NS60, you can visit the provided LG webpage link to access the specifications, which clearly state whether or not the drive has Jamless Play.
This information is essential for users to make informed decisions about their hardware choices and avoid any potential data integrity issues.
Example:
Code:
https://www.lg.com/us/burners-drives/lg-wh16ns60-internal-blu-ray-dvd-drive#pdp_specs