Secure ripping - Revision history

82.132.186.154: /* Ripping Modes */

2017-08-20T22:46:33Z

Ripping Modes

← Older revision		Revision as of 22:46, 20 August 2017
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	* Overlap		* Overlap
	* No Verify		* No Verify
	* No ~~Sratch~~ Detection		* No Scratch Detection

	It is best to use '''Full, Paranoia''' mode unless otherwise specified (this is the default mode). '''Overlap''' and '''No Verify''' will just check read boundaries of a buffer and are therefore not recommended. '''No Scratch''' detection skips any error correcting and interpolation (compensation for missing gaps in the audio data) and should therefore be used on CD's that are brand new or have minimal scratches.		It is best to use '''Full, Paranoia''' mode unless otherwise specified (this is the default mode). '''Overlap''' and '''No Verify''' will just check read boundaries of a buffer and are therefore not recommended. '''No Scratch''' detection skips any error correcting and interpolation (compensation for missing gaps in the audio data) and should therefore be used on CD's that are brand new or have minimal scratches.

82.95.236.142: /* Rubyripper */

2013-03-21T00:25:27Z

Rubyripper

← Older revision		Revision as of 00:25, 21 March 2013
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	==Rubyripper==		==Rubyripper==
	Rubyripper externally uses the [[cdparanoia]] libraries in conjunction with ~~it's~~ own secure ripping algorithm. Rubyripper correction mechanism goes beyond that of cdparanoia. Every track gets ripped at least twice and is byte compared with the Ruby cmp feature. If any differences are found, each of the 1,000 bytes of the two files is compared. The next trial run looks to see if differing positions or a match can be found. (1,000 bytes is about 0.006 seconds).		Rubyripper externally uses the [[cdparanoia]] libraries in conjunction with its own secure ripping algorithm. Rubyripper correction mechanism goes beyond that of cdparanoia. Every track gets ripped at least twice and is byte compared with the Ruby cmp feature. If any differences are found, each of the 1,000 bytes of the two files is compared. The next trial run looks to see if differing positions or a match can be found. (1,000 bytes is about 0.006 seconds).

	Rubyripper won't guarantee a constant ''MD5-sum'' on tracks that needed correction. However it will repair any files so that it's impossible to successfully blind-test with the original. The log file will report any position that needed more than 3 trials, so you can check the position yourself.		Rubyripper won't guarantee a constant ''MD5-sum'' on tracks that needed correction. However it will repair any files so that it's impossible to successfully blind-test with the original. The log file will report any position that needed more than 3 trials, so you can check the position yourself.
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	Question: Does the current existing secure ripper print out a log file? <br>		Question: Does the current existing secure ripper print out a log file? <br>
	Yes: Rubyripper current existing libraries do print out a log file if specified		Yes: Rubyripper current existing libraries do print out a log file if specified


	==External links==		==External links==

Mjb: /* What is Secure Ripping? */ added an overview paragraph

2010-11-25T05:59:47Z

What is Secure Ripping?: added an overview paragraph

← Older revision		Revision as of 05:59, 25 November 2010
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	=Secure Ripping=		=Secure Ripping=
	===What is Secure Ripping?===		===What is Secure Ripping?===
			Secure ripping is the process of making sure there were no errors during the extraction of audio from a CD. It normally involves attempting to get consistent results from successive re-reads of the same sectors, and is sometimes combined with other strategies, such as
			* using the drive's own error reporting (after its own error correction fails) to know which sectors to re-read
			* defeating caches (some drives cache audio data during DAE)
			* and comparing checksums of extracted audio with those obtained by others.

	~~Secure ripping is the process of making sure there were no errors during the extraction of audio from a CD.~~		The basic function of ripping software is to get the CD's table of contents (an index of track start positions), and then for each track to be ripped, it tells the CD drive to go to the beginning of each of the track's data blocks (sectors) and read them in, one at a time. On an ordinary audio CD, each block is 2352 bytes and corresponds to 1/75th of a second of sound. The software saves that incoming data into an audio file (WAV or AIFF format, usually, as those formats are almost identical to the data coming in from the drive), or the software streams the data into another audio encoder "on the fly", so the user doesn't have to convert it to another format like MP3 in a separate step.

	The basic function of ripping software is to get the CD's table of contents (an index of track start positions), and then for each track to be ripped, it tells the CD drive to go to the beginning of each of the track's data blocks and read them in, one at a time. On an ordinary audio CD, each block is 2352 bytes and corresponds to 1/75th of a second of sound. The software saves that incoming data into an audio file (WAV or AIFF format, usually, as those formats are almost identical to the data coming in from the drive), or the software streams the data into another audio encoder "on the fly", so the user doesn't have to convert it to another format like MP3 in a separate step.

	This sounds simple, but it becomes complicated when parts of the CD can't be read accurately, for example due to scratches. And there's actually a lot of variation in whether each drive can reliably and accurately go to the spot it's told to read, and in the way it detects, reports, and handles errors, such as those caused by scratches. That is, every CD drive will give the ripping software 2352 bytes of data for each block the drive is told to read, but that data might be different each time, due to physical problems with the disc or limitations of the drive's hardware. Or the data might be the same each time, but is different when obtained from a different drive.		This sounds simple, but it becomes complicated when parts of the CD can't be read accurately, for example due to scratches. And there's actually a lot of variation in whether each drive can reliably and accurately go to the spot it's told to read, and in the way it detects, reports, and handles errors, such as those caused by scratches. That is, every CD drive will give the ripping software 2352 bytes of data for each block the drive is told to read, but that data might be different each time, due to physical problems with the disc or limitations of the drive's hardware. Or the data might be the same each time, but is different when obtained from a different drive.

Greynol: Removed recommendations.

2010-07-30T01:25:00Z

Removed recommendations.

← Older revision		Revision as of 01:25, 30 July 2010
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	Rubyripper won't guarantee a constant ''MD5-sum'' on tracks that needed correction. However it will repair any files so that it's impossible to successfully blind-test with the original. The log file will report any position that needed more than 3 trials, so you can check the position yourself.		Rubyripper won't guarantee a constant ''MD5-sum'' on tracks that needed correction. However it will repair any files so that it's impossible to successfully blind-test with the original. The log file will report any position that needed more than 3 trials, so you can check the position yourself.


	===Accurate Stream===		===Accurate Stream===
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	Yes: Rubyripper current existing libraries do print out a log file if specified		Yes: Rubyripper current existing libraries do print out a log file if specified

	~~=Secure Ripping Recommendations=~~

	~~===Hydrogenaudio User Recommendations===~~
	The general consensus at Hydrogenaudio is that everyone taste's are different. One Secure ripper that works for one person might not be the right match for another, depending upon the users expectations and what features their CD-ROM drives have. It best to first determine what features your CD-ROM drives have before you proceed to decide, which ripper you may be considering using (see external links below). Linux users desiring EAC or dbPowerAMP might be hard pressed to find out that that the application cannot be ported to Linux, but can be run under [http://www.winhq.com/ Wine] an abstraction layer that allows you to run Win32 applications on Linux. Linux users seeking an alternative who cannot run EAC or dbPowerAMP under Wine may want to consider [[Rubyripper]]. One of the more popular rippers at Hydrogenaudio is [[EAC]] in which there are countless guides for. The only drawback is that it nightmare to configure for a new user inexperienced with secure CD ripping. Users desiring something simpler on Windows may want to try [[dbPowerAMP]], which less painlful to configure and can provide the same secure rip's with extra features like better use of C2 error pointers and improved PefectMeta. Some who desire a secure alternative on Mac OS/X to the ITunes Ripper may want to go with [[Max]] or [[XLD]]. Ultimately what the decision comes down to is what one's drive features and expectations are.


	<b>Note: Any rippers not listed on this page are not considered "secure" and are therefore not recommended by the Hydrogenaudio community (i.e example such the Itunes Ripper). It is best to proceed with caution if one decides to use these, unless they are "frontends" for instance Grip is a cdparanoia frontend for Linux or they are considered "secure", but are not as popular and aren't listed on this wiki page. </b>

	==External links==		==External links==

Greynol: /* Accurate Stream */

2010-07-30T01:19:45Z

Accurate Stream

← Older revision		Revision as of 01:19, 30 July 2010
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	===Accurate Stream===		===Accurate Stream===
	Accurate Stream is a CD drive's ability to avoid "jitter". A CD drive, when told to go to a particular point on an audio disc, will usually go to a certain number of samples ahead or behind that point, and all the data blocks it reads will be relative to that starting point. If your CD drive supports 'Accurate Stream', this offset will be a constant value, and should be the same for each particular make and model of drive. Usually the offset is not very large (around 1/250th of a second or less). Secure ripping software can take into account whether the drive has Accurate Stream, in order to know whether extra analysis needs to be done to compensate for jitter. It's still possible to do secure ripping ~~without~~ Accurate Stream; it's just easier and faster when ~~it's supported~~.		Accurate Stream is a CD drive's ability to avoid "jitter". A CD drive, when told to go to a particular point on an audio disc, will usually go to a certain number of samples ahead or behind that point, and all the data blocks it reads will be relative to that starting point. If your CD drive supports 'Accurate Stream', this offset will be a constant value, and should be the same for each particular make and model of drive. Usually the offset is not very large (around 1/250th of a second or less). Secure ripping software can take into account whether the drive has Accurate Stream, in order to know whether extra analysis needs to be done to compensate for jitter. It's still possible to do secure ripping with drives that don't have the Accurate Stream feature; it's just easier and faster when they do.

	===Caching===		===Caching===

Greynol: /* AccurateRip */

2010-07-30T01:17:17Z

AccurateRip

← Older revision		Revision as of 01:17, 30 July 2010
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	===AccurateRip===		===AccurateRip===
	[[AccurateRip]] is a database that allows you to find out if your CD rips are the same as other people's; if they were, then it's likely the rips are truly error-free. The database stores ~~disc IDs and~~ checksums for ripped tracks~~, and it contains info for thousands of drives~~. ~~This drive info makes it possible to reliably compare the track~~ checksums, and ~~includes each drive's make & model, read offset, AccurateStream capability, audio data cache ability, and use of C2 error pointers. All data about drives and ripped tracks is user-~~submitted~~, but is managed~~ through the ripping software.		[[AccurateRip]] is a database that allows you to find out if your CD rips are the same as those ripped by other people; if they were, then it's likely the rips are truly error-free. The database stores checksums for ripped tracks in order to accomplish this. The checksums are generated when ripping and can be submitted to the database through the ripping software if the user so chooses.

	=Windows=		=Windows=

Greynol: /* Caching */

2010-07-30T01:04:51Z

Caching

← Older revision		Revision as of 01:04, 30 July 2010
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	===Caching===		===Caching===
	Caching is the ability of the CD-ROM drive to hold a certain amount of ~~samples~~ in a buffer~~. Every CD-ROM cache~~ can be ~~"flushed"~~. ~~Caching affects secure~~ ripping ~~because~~ when the drive is told to re-read something, it might just send the cached data instead of actually re-reading the disc. ~~A secure ripper~~ will ~~make sure~~ the cache ~~is flushed so~~ the ~~disc is~~ re-read.		Caching is the ability of the CD-ROM drive to hold a certain amount of data in its buffer so that it can be readily available in the event that it is requested more than once. This can cause problems for ripping programs when they request the same data be extracted more than once in order to detect errors. When the drive is told to re-read something, it might just send the cached data instead of actually re-reading the disc.

			In order to get around this problem, the ripping software will typically request additional data in order to flush the cache of the information it wants to re-read. FUA (force unit access) can be a more efficient method of defeating the caching of audio data, but doesn't have wide hardware support. Of the ripping software listed in the article, the only ones that use of this method are EAC and dBpoweramp.

	===C2 error pointers (software)===		===C2 error pointers (software)===

Greynol: /* C2 error pointers (software) */

2010-07-30T00:29:46Z

C2 error pointers (software)

← Older revision		Revision as of 00:29, 30 July 2010
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	===C2 error pointers (software)===		===C2 error pointers (software)===
	~~CD-ROMs~~ have differing levels of error recognition and correction built-in. C2 is a standard error detection & reporting scheme for certain types of audio CD read errors. When a drive with C2 support detects a read error, it does its own re-reading of the affected portion of the ~~disc and attempts~~ to ~~fix~~ the data ~~itself as best it can. When the drive is feeding this data~~ to the ripping ~~software, it sends C2 error pointers so the software knows that an error occurred and whether it was successfully fixed by the drive. Some copy-protected CDs fool the drive's firmware into thinking~~ there ~~were C2~~ errors.		Some drives have the ability to provide additional information about the audio data that has been extracted in order to alert the ripping program when there are uncorrectable errors. This category lists whether the secure ripping software is able to request and utilizes C2 pointers from drives that provide them.

	~~The process of C2 error pointer support is complicated, but can be reduced to the drive/firmware/ripping software combination.~~ This category ~~only discusses~~ whether the secure ripping software ~~can detect~~ and ~~utilize~~ C2 ~~error~~ pointers ~~if the drive sends them. Which~~ drives ~~support C2 is a separate topic; see [[AccurateRip]] or another drive capability database for~~ that.

	===AccurateRip===		===AccurateRip===

Jan at 22:28, 29 July 2010

2010-07-29T22:28:57Z

← Older revision		Revision as of 22:28, 29 July 2010
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	[[Category:Guides]]		[[Category:Guides]]
	[[Category:CD ripping]]		[[Category:Comparison of CD ripping techniques]]

Jan at 18:31, 29 July 2010

2010-07-29T18:31:13Z

← Older revision		Revision as of 18:31, 29 July 2010
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	[[Category:Guides]]		[[Category:Guides]]
			[[Category:CD ripping]]