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View Full Version : Another AccurateRip/PefectTUNES question.



mathmat
12-18-2014, 11:30 AM
Hi. I have a few questions I was hoping could be clarified for me.

1) If I check a previously ripped CD with PerfectTUNES, does it go into the AccurateRip database? Also, if I check that same CD rip with CUETools does that go into the AccurateRip database?


2) I ripped 2 versions of The Wall that were released in different years with different packaging, different barcodes, etc. I'll stick to CD2 in each of the 2 versions I ripped (The CD with Comfortably Numb on it.)

Now when I checked them with PefectTUNES I got the same AccurateRip DiscID for both discs, the ARv2 CRCs were identical for all 13 tracks, and I got the same confidence level for corresponding tracks. The only difference was the offsets for the 2 rips were different. My question is does that mean the original CDs were identical, even though they had different barcodes, packaging, etc?


3) Furthermore, let's say I have 2 unknown rips and I check them with PerfectTUNES and I get the same results I mentioned (AccurateRip DiscIDs match, ARv2 CRCs all match for all tracks, confidence matches, but pressing offset is different. Does that mean I have 2 copies of an identical disc, even though (yypothetically speaking) I don't know what those CDs are? And if so, is this a way of checking if 2 unknown CD rips are from the same disc? This is just a theoretical question to help understand how AccurateRip works.


4) Here's where my real problem comes in. Getting back to my original 2 The Wall rips (CD2). First I will post the logs from the rips of Comfortably Numb from each CD:

From the first CD rip: Track 6: AccurateRip Verified Confidence 153, Pressing Offset -202 [ARv2 CRC EB624BEE] C:\Users\A\Desktop\Lossless CD Rips\The Wall CD2\2-06 Comfortably Numb.m4a

From the second: Track 6: AccurateRip Verified Confidence 153, Pressing Offset +102 [ARv2 CRC EB624BEE] C:\Users\A\Desktop\Lossless CD Rips\The Wall CD2\2-06 Comfortably Numb.wav

So both have the same ARv2 CRC values and have a confidence of 153, but different offsets. Also one is ripped as ALAC and the other as WAV, but I don't think that matters. Anyway this leads me to believe they are the same track (see my question 2 above.)

Anyway, when I play each one by itself I hear a "popping type" sound at the end of the tracks. These sounds come at the VERY end and make me think they are the fraction of a second beginnings of the next track. Because when I play Comfortably Numb from both rips followed by the next track there is a smooth transition and I don't hear anything. But the problem is the "popping" sounds (I really don't know how to describe them) are different from each other. So my question is, if the tracks are identical shouldn't all the musical information be identical? Shouldn't the tracks sound EXACTLY the same? Because here they don't. So I'm wondering what is happening...

Any help would be tremendously appreciated!

Thank you!

garym
12-18-2014, 01:31 PM
1. No, checking tracks with PerfectTunes or Cuetools does not add to the AR database. Only RIPPING the CD itself adds to the AR database.
2. offsets and CRCs are two different things.
3. see *2 above. But I'm really not sure what you're trying to get at here. Tracks are either correct match back to AR or AR2 database or they are not. After that, you're now in the "how many angels can dance on the head of a pin" territory.
4. popping sounds. If the tracks are accurately ripped (and they are reported as being Accurately ripped, so I'm sure they are), I suspect your popping sound is something that is being caused by the PLAYER and it is not in the track itself. This is actually very common with some players (VLC and others), particularly with ALAC files. And some players don't handle WAV and tags very well and you year a pop when the player messes up slightly because of the tag in the WAV file.

What player are you using. Try the files on, say, Foobar2000 instead. Do you hear the pop? Also, listen to the tracks as they move from one to another without fast forwarding or clicking ahead to move faster. Do you still have the pop when a track transitions to the next track.

Spoon
12-18-2014, 02:28 PM
2) Yes, the only difference is the pressing offset.

4) There have also been CDs which are incorrectly mastered, so everyone gets this pop.

mathmat
12-18-2014, 02:32 PM
Hi garym. Thanks for replying.

I'll get back to my original questions 2 and 3 later as I'm more concerned with the popping sounds.

Again, the pops come from the tracks in my first post that come from 2 different CDs with the same ARv2 CRCs as well as identical AccurateRip DiscIDs and confidence values. And of course are listed as being ripped accurately. And I do not hear anything when I play either straight through to the next song for each CD Rip. Sounds normal.

One was originally ripped as WAV and the other as ALAC. When I play the WAV with Windows Media Player I don't hear the pop. But when I play it with iTunes I DO hear it. Also I hear it with VLC.

For the ALAC, I hear it with VLC and iTunes. But then I converted it to a WAV and played it with WMP and no pop. But when I play the converted WAV with iTunes or VLC I still hear it.

So my question is why do the "pops" sound different? The fact that I got the CRCs, and confidence, and IDs all the same makes me think it's the same Remaster. (That's what I was getting at in questions 2 and 3.) But the CDs were different releases with different packaging, barcodes, etc. I'm pretty sure they are the same remastered version based on the AccurateRip data as well as checking the Pink Floyd Archives. 1992 Remaster. But I'm not 100% sure since I'm new to all this technical stuff and not educated enough about this.

I could snip the last 2 seconds of each and upload them but I don't want to get into any copyright violation. (Although I doubt putting 2 seconds of silence followed by a "pop" would be a problem.)

Anyway, just not sure why the "pops" are different sounding given the accurate rip data. One is clearly louder than the other.

Any help appreciated greatly!

Thanks again!

mathmat
12-18-2014, 02:39 PM
4) There have also been CDs which are incorrectly mastered, so everyone gets this pop.

Thanks Spoon. That makes sense. But what would cause the "pops" to sound different on the different CDs? Because the CRCs, confidence, Disc IDs are all identical and I believe they are the same remaster as I mentioned in my reply to garym. But as I also mentioned, the CDs were different releases with different packaging.

Thanks!

garym
12-18-2014, 02:58 PM
first, the pops have nothing to do with the accruateripping (or matches to AR). You're going down the wrong path. These are Accurately ripped tracks and the pops are not in the digital track itself (that's why you do NOT hear the pops when you play the songs straight through; if the pops were inherent in the tracks, you'd hear them there too!).

Some players pop when switching quickly from one track to another. Also, if you have "use track replaygain" turned on in your player (or soundcheck in itunes), the pops might be related to the slight volume changes when moving from one track to another. By the way VLC is a terrible player for audio. I use it for videos, but it is very lacking on many dimensions for Audio playback.

mathmat
12-18-2014, 03:39 PM
first, the pops have nothing to do with the accruateripping (or matches to AR). You're going down the wrong path. These are Accurately ripped tracks and the pops are not in the digital track itself (that's why you do NOT hear the pops when you play the songs straight through; if the pops were inherent in the tracks, you'd hear them there too!).

Thanks again garym. I figured that since the tracks played straight through without hearing anything there wasn't a problem in the rip, especially since 2 different rips came back as identical, even though they had different sounding pops.

I thought it could be the first few microseconds of the next track (since Pink Floyd albums don't have clean breaks between tracks most of the time), but since the pop sounds were different that would mean the that the track that followed Comfortably Numb would have a different length on the 2 CDs, correct? But the following tracks (The Show Must Go On) came back with the same CRCs and confidence level and Disc ID. My understanding of how AccurateRip works is through some use of checksums. (I know if you have a word document, for example, and change a period to a question mark you'll get different checksums.) So if these "pops" were the beginnings of the next track, the next tracks would have different lengths and hence I'd get different AccurateRip results.

As far as Spoon's suggestion that the CDs were incorrectly mastered, I wonder. It makes sense, but Pink Floyd has always had a reputation for putting out the highest quality product. So I have some doubt at least that they'd let any errors in mastering come out. But Spoon knows better than me.

But again, if the CD Rips give the same AccurateRip results and are working off the same 1992 Remaster, why are the pop sounds for the 2 different rips of Comfortably Numb different?

garym
12-18-2014, 04:24 PM
But again, if the CD Rips give the same AccurateRip results and are working off the same 1992 Remaster, why are the pop sounds for the 2 different rips of Comfortably Numb different?

I don't think it is the mastering of CD (an error in CD). You've already proven that. And its not in the digital file itself, you've proven that. None of this has anything to do with the tracks. It is something in the PLAYER. Try playing with foobar2000 instead, for example. Bottom line, the pops are a function of your PLAYER.

mathmat
12-18-2014, 04:59 PM
I don't think it is the mastering of CD (an error in CD). You've already proven that. And its not in the digital file itself, you've proven that. None of this has anything to do with the tracks. It is something in the PLAYER. Try playing with foobar2000 instead, for example. Bottom line, the pops are a function of your PLAYER.

Thanks again garym. I appreciate your responses and your patience with me. :smile:

I think you're right. The AccurateRip checks came back fine so whatever I have the other 150 or so must have the same thing. The encouraging thing is when I play the WAV files with Windows Media Player I don't hear the pops. I wonder if the reason for the different sounds of the pops has something to do with the fact that they're different pressings of the same CD.

Anyway, thanks for all your advice!

P.S. The reason I have always used iTunes and ALAC is because I listen to my music almost exclusively in my car using my iPod. But I find Windows Media Player to be better at playing both video and audio than VLC or iTunes. Only problem is that it's limited in the kinds of files it can play.

garym
12-18-2014, 05:03 PM
I wonder if the reason for the different sounds of the pops has something to do with the fact that they're different pressings of the same CD.


Do you mean that you play, for example, track 1 ripped from one CD, then track 2 ripped from a different physical CD, and you hear the pop between the two tracks?

mathmat
12-18-2014, 07:35 PM
Do you mean that you play, for example, track 1 ripped from one CD, then track 2 ripped from a different physical CD, and you hear the pop between the two tracks?

No. I hear the pop when I play the track (Comfortably Numb) in isolation. For example, by itself in a playlist in iTunes or just opening the file with a program.

I have 2 rips of CD2 of The Wall from 2 different physical discs, and 2 pops at the very, very end of each rip of Comfortably Numb, but the pops sound VERY different (even though the AccurateRip data for each track was identical-see my original post). But when I play Comfortably Numb from CDRip1 followed by the following track (The Show Must Go On) from CDRip1 (in iTunes or my iPod) I don't hear the pop. The same for CDRip2. I actually just tried Comfortably Numb from CDRip1 followed by the following track (The Show Must Go On) from CDRip2 and there was no pop. That would make sense since both CDs are the same remaster (as far as I know) even though they were different releases (diff packaging, barcode, etc.)

But like I said earlier, either rip when played as a WAV file using Windows Media Player, there is no pop. Pops only come from ALAC, iTunes, and VLC. The only combination where it doesn't pop is WAV+WMP.

I can upload the last 2 seconds of each rip (silence followed by the pop) as long as it doesn't break any copyright laws. But I'm not sure if that's necessary or not.

It's just strange that the "pops" sound different, since they are from the same remaster, albeit different pressings. (Not to mention identical AccurateRip data)

Thanks for all your help.

garym
12-18-2014, 07:55 PM
You're barking up the wrong tree. None of this relates to the digital files, the ripping, the cd versions, the offsets, or any of the things you are hypothesizing. I'll say it once again: it's all related to your players. And again, VLC is really crap as an audio player.

mville
12-18-2014, 07:56 PM
2) I ripped 2 versions of The Wall that were released in different years with different packaging, different barcodes, etc. I'll stick to CD2 in each of the 2 versions I ripped (The CD with Comfortably Numb on it.

Can you be more specific about the 2 versions of Pink Floyd - The Wall, that you are ripping i.e. Year, Label, Country of release, Barcode etc.

mathmat
12-18-2014, 08:18 PM
You're barking up the wrong tree. None of this relates to the digital files, the ripping, the cd versions, the offsets, or any of the things you are hypothesizing. I'll say it once again: it's all related to your players. And again, VLC is really crap as an audio player.

I don't think it's a problem with the digital files. My question is simply why the "pops" sound different. I just think that since the tracks are from the same remasters the pops should sound the same, since they're supposedly identical files. I say they are identical because of the AccurateRip dtata. That's all.

I don't use VLC really. I think it sucks as a music player as well. I'm just saying that when I play on that program I get the "pop.' Same with iTunes and my iPod.

mathmat
12-18-2014, 08:19 PM
Can you be more specific about the 2 versions of Pink Floyd - The Wall, that you are ripping i.e. Year, Label, Country of release, Barcode etc.

I don't have the discs handy, but I will check the Pink Floyd archives and do best from memory. Hang on...

mathmat
12-18-2014, 09:16 PM
OK. I just found something that throws a wrench into all of this. Back in the day before I was introduced to "lossless ripping" I would rip all my CDs as 192 AAC files with iTunes. I remember the first Wall CD I had. And I just found the 192 AAC rip of it. This was a direct 192 AAC rip from the CD. I just played it in isolation with iTunes and there was NO pop at the end of Comfortably Numb.

Now my ALAC rip comes from this same exact CD. My other Wall copy I ripped as WAV (for whatever reason.) But as I have mentioned, the "pop" exists on this ALAC rip. (Keep in mind that the whole CD was verified as accurate. See original post for just Comfortably Numb stats.) Anyway, I just converted the ALAC file with the 'Pop" to 192 AAC and I am hearing the same pop! I don't understand. If my ALAC rip of this CD is supposed to be lossless, and is verified with a confidence of over 150, how is it that the 192 AAC rip directly from the CD has NO pop, yet the 192 AAC conversion from the ALAC has the pop?

Please help! Thank you.

garym
12-18-2014, 09:18 PM
I don't think it's a problem with the digital files. My question is simply why the "pops" sound different. I just think that since the tracks are from the same remasters the pops should sound the same, since they're supposedly identical files. I say they are identical because of the AccurateRip dtata. That's all.

I don't use VLC really. I think it sucks as a music player as well. I'm just saying that when I play on that program I get the "pop.' Same with iTunes and my iPod.

You seem to be missing my point. The identical nature of files proved by accuraterip is irrelevant. The files are irrelevant. The *player* is creating the pops--not the files. With better players, THERE ARE NO POPS. You even have no pops when played under certain circumstances.

mathmat
12-18-2014, 09:26 PM
You seem to be missing my point. The identical nature of files proved by accuraterip is irrelevant. The files are irrelevant. The *player* is creating the pops--not the files. With better players, THERE ARE NO POPS. You even have no pops when played under certain circumstances.

I do understand what you are saying and I greatly appreciate all your input. Please keep it coming! :smile:

My point is simply if you have 2 identical files played under identical conditions, shouldn't they sound identical? I believe the answer to that should be "yes." But when I do play the identical files under identical conditions I get 2 different sounding pops. I think that if there is a "pop" that a specific player is causing, it should sound the same for identical files. But it's not. That's confusing me. Maybe I'm missing something here, as I am new to all this, but commom sense seems to suggest what I just said should be the case.

Also my post *16 above seems to confuse things more.

garym
12-18-2014, 09:30 PM
I do understand what you are saying and I greatly appreciate all your input. Please keep it coming! :smile:

My point is simply if you have 2 identical files played under identical conditions, shouldn't they sound identical? I believe the answer to that should be "yes." But when I do play the identical files under identical conditions I get 2 different sounding pops. I think that if there is a "pop" that a specific player is causing, it should sound the same for identical files. But it's not. That's confusing me. Maybe I'm missing something here, as I am new to all this, but commom sense seems to suggest what I just said should be the case.

Also my post *16 above seems to confuse things more.

pops can be random with the player. To confirm, if you just let the album play through you have no pops between songs. Correct?

mathmat
12-18-2014, 09:35 PM
pops can be random with the player. To confirm, if you just let the album play through you have no pops between songs. Correct?

The pops for Rip1 sound identical for both iTunes and VLC every time I've played them. And I've played them too many times now. lol. Same for Rip2. But yes, if the album plays through I hear nothing out of the ordinary, and I like to think I'm pretty good at picking up anomalies. lol.

Is it possible that the reason that WAV+Windows Media Player produces no pops be that WMP is somehow stopping the track a few fractions of a second earlier?

Also I just did another experiment. I burned one of the Comfortably Numb tracks to a CD by itself, then played it in my car CD player. I did hear something as the song ended that sounded similar to the pop I was hearing. I don't know if that's normal, as I don't ever use the CD player. I will burn another song to another CD and see if I hear the same sound when the song ends.

Anyway garym, I was hoping you could give some feedback for my post *16. Thanks!

garym
12-18-2014, 09:39 PM
No clue about post 16. At this point I would rerip cd with dbpa and try playing the new rips.

mathmat
12-18-2014, 09:44 PM
No clue about post 16. At this point I would rerip cd with dbpa and try playing the new rips.

Unfortunately I don't have access to the CDs so I can't do a re-rip. I can see if I can somehow track down some Wall CDs. But the fact that they all came back as Accurately ripped should be reason enough that no further rips are necessary, correct?

Also regarding post 16, I did rip the original 192 AAC with a much earlier version of iTunes than my ALAC rip so maybe it somehow chopped off the end? I'm guessing it could be the ripping software. I don't know...

garym
12-18-2014, 10:30 PM
Unfortunately I don't have access to the CDs so I can't do a re-rip. I can see if I can somehow track down some Wall CDs. But the fact that they all came back as Accurately ripped should be reason enough that no further rips are necessary, correct?

Also regarding post 16, I did rip the original 192 AAC with a much earlier version of iTunes than my ALAC rip so maybe it somehow chopped off the end? I'm guessing it could be the ripping software. I don't know...

Itunes doesn't necesarily do secure rips. But I can't really think of anything else to add to this inquiry.

mathmat
12-18-2014, 10:43 PM
Itunes doesn't necesarily do secure rips. But I can't really think of anything else to add to this inquiry.

But if an iTunes rip comes back as Accurate when tested against AccurateRip, that means the rip is identical to the CD, right? So at that point it doesn't matter what ripper was used. (Of course that doesn't explain the original 192 AAC rip.)

I have a theory as to what is happening here, but I'm in the process of doing some more experiments first. Also it depends on my understanding of exactly how AccurateRip compares a rip to its database, which I'm hoping is correct, at least on a basic level. I will report back as soon as I get my thoughts together and my experiments done. I hope to have it by tomorrow. If not it will be after the weekend most likely.

Anyway, thank you again, garym, for responding to me and giving me stuff to ponder. I really appreciate your time and effort a lot. :smile:

Spoon
12-19-2014, 03:46 AM
If you use PerfectTUNES to check the files and one is verified as Accurate then yes it is identical to the CD.

mathmat
12-19-2014, 02:59 PM
Ok. I think I have figured out what was happening with my "pop" problem. Mind you, this is all speculation so if Spoon, garym, or anyone else can point out any errors in my analysis that would be tremendously welcome! I apologize in advance for the long post.

So to reiterate, the problem I'm having is I have 2 lossless rips of The Wall from 2 different physical discs. Now at the VERY end of the Comfortably Numb track (track 6 on CD2) I was hearing some sort of "pop" sound from both rips of the track when I played them in isolation. But these "pops" sounded different for each rip, even though they occurred at the exact spot on the track, that is at the very end as the track stopped playing. But everytime I played Rip1 the "pop" sounded the same and everytime I played Rip2 the "pop" sounded the same. But the 2 "pops" sounded different from each other. (This was with both VLC and iTunes.) Just to note these "pops" occur within the last few hundreths of a second at the end of the track

When I checked the 2 CD Rips (Rip1 and Rip2) against AccurateRip using PerfectTUNES I got identical results. Accurately Ripped with identical CRCs, confidence level, and Disc Ids. I know both CDs are the same 1992 remaster so the Accurate Rip results were not surprising.

But what confused me was why, if the 2 Comfortably Numb rips were different due to the different sounding "pops," did the AccurateRip results come back as verified accurate with identical data. It seemd to me that if the files were different (and they are because the pops are different &*8211; they are clearly NOT bit-for-bit copies of each other) then at least one of the Comfortably Numb tracks should come back as InAccurate. That just seems to be common sense. (As an aside, if you have a 1000 page word document and you change just 1 period to a comma the 2 word documents are no longer bit for bit identical. They will have different checksums.)

Now I thought that maybe it was the players I was using that were causing these pops. But I don't believe it's the players anymore. I believe the "pops" to be inherent to the Cds.

I decided to go on a "treasure hunt" and scoured the local library system to see if I could track down any copies of The Wall, since mine are inaccessible. And I luckily found 2 identical CD copies!

So I played the Cds (not rips and specifically Comfortably Numb) with iTunes and VLC and Comfortably Numb on BOTH Cds on BOTH players gave me the Identical sounding "pop" in the identical place. Itunes and VLC may not be the favorite music players of some, but my results here make me confident that the "pops' are inherent in the Cds. I mentioned that when I played my original 2 rips of Comfortably Numb as WAV files using Windows Media Player, I heard no "pops." I now believe that is because WMP cuts a track slightly short when it plays it. The VLC and iTunes results just seemed too coincidental to be the player.

Now the question is what is the cause of the "pops?" Spoon suggested it could be a bad master, and BOTH my original Cds that I ripped are the same 1992 remaster (although different releases.) That's definitely a possibility. The other possibility is that the "pops" are the beginning of the next song (Track 7, The Show Must Go On.) I tend to think it's the beginning of the next song, as Pink Floyd albums usually do not have breaks between songs, as they are intended to be listened to as a whole. If you listen to the 2011 remaster of The Wall, specifcally Comfortably Numb with the volume up and with headphones, you will hear at the first fraction of a second the end of the previous song, Bring the Boys Back Home. The fact that there is a smooth transition from Comfortably Numb to the next track (no "pop") further makes me think the "pop" is the beginning of the next song.

Now I also mentioned in a previous post that I had ripped Comfortably Numb as 192 AAC from the same CD that produced Rip1. But this compressed file did NOT have the "pop" at the end. I did a closer inspection and noticed that the file length of this track was approximately 3/100ths of a second SHORTER that the lossless rips. So it seems iTunes cut those fractions of a second off, hence resulting in NO "pop." Now the length of the lossless rips is 6:23.066. I tried converting the file to 192 AAC but the time came back as 6:23.066, and hence the "pop" was still there. So I decided to adjust the lossless file to an ending time of 6:23.033 and NO "pop." This was very encouraging and explained a lot. The reason the ALAC to 192 AAC came back with the same time (and pop) but the CD to 192 AAC I did many years ago came back as 6:23.033 I attribute to an earlier version of iTunes where the compresssion wasn't as good as today's version of iTunes.

But I was still left wondering why 2 different files (that is, the 2 rips of Comfortably Numb with DIFFERENT pops would both come back as Accurately Ripped with Identical CRCs, confidence, etc. So I tried to figure out how AccurateRip was checking rips against its database. I believe I saw a post by Spoon somewhere talking about how the MUSICAL data was compared, not metadata or anything else. So that got me thinking. How do you compare 2 digital files to see if they are identical? (Which is EXACTLY what AccurateRip is doing.) The only way I know, and again I am no expert at this stuff, would be through some sort of checksum process. It's certainly some bit for bit analysis.

Now for those who remember, Comfortably Numb was originally issued on LP as the last track on side 3. That means there would be silence after the track. And my "pops" occur after about 1-2 seconds of silence at the end of the tracks. I'm GUESSING what AccurateRip is doing (and this is a VERY simplified non-technical description) is taking a track, finding the first bit of sound, going through the rest of the track until it reaches a point of silence. And silence is, after all, by definition, the ABSENCE of muscial information. So once AccurateRip sees that silence on my 2 rips of Comfortably Numb it stops, performs some type of bit for bit comparison with its database on the data it's already analyzed, checks it against other rips, and reports Accurate or InAccurate. That would be the only way to explain why the 2 Comfortably Numb tracks (which are NOT identical due to the different sounding "pops") came back with the same exact AccurateRip results. (Please, Spoon, correct me if I'm wrong. Again, I'm sure this is not exactly how it works, but I'm guessing the basic idea is the same.)

In conclusion, I never doubted AccurateRips results but I couldn't explain why 2 different files both came back as Accurate. Luckily after checking 2 library Cds and getting the results I was hoping to with them, I am fairly confident that my analysis is correct. I may be WAY off, but I can't come up with any other explanation.

One final note. I mentioned the "pops" sounded different for each rip, but they were consistent with whichever player I used. I now think my first rip, with the louder sounding "pop" was an error in ripping. (That's the only explanation. The ripper somehow made the "pop" louder.) But as I reasoned above, since it occurred after 1-2 seconds of silence, AccurateRip ignored it and hence reported the track as Accurate. I believe there are certain CD rippers that allow you to add silence at the beginning or end of a track, or to move silence from the end to the beginning, or vice versa. I am convinced that if I ripped the same CD and added silence to the beginnning of the tracks on one rip, then added silence to the ends of the tracks on a second rip, both would be verified as Accurate, and come back with identical CRCs as well as confidence levels, disc id, etc.

Sorry for the novel, but as you can see I'm quite passionate about this stuff. Lol.

Any feedback is greatly appreciated!

Thanks again.

garym
12-20-2014, 08:53 AM
Your explanation is plausible. Particularly because I recall (but I'm not 100% sure), that the first few or last few "frames" of a CD are not counted when checking against AR database. I could be wrong about this. And the fact that you don't here the pop when you let the track play naturally from one song to the next supports your hypothesis (and confirms that this pop is not inherent in the rip itself).

mville
12-20-2014, 12:53 PM
FYI, I have ripped both the 1994 UK Remaster and the 2011 Discovery Remaster of Pink Floyd - The Wall, AccurateRip reports tracks ripped accurately.

I have listened to the Comfortably Numb/The Show Must Go On transitions on both rips in foobar2000 and there are no pops.

garym
12-20-2014, 02:42 PM
I have the discovery box set 2011 remaster. I don't here any pops before or after comfortably numb transition in foobar2000 or in LMS/Squeezeboxes. Then again, I can often hear a pop on beginning of ANY song in Squeezebox if I simply click to start an otherwise gapless album song without letting it naturally transition from the prior song. This "pop" is very "discrete" and is certainly not embedded in the file itself.

mathmat
12-20-2014, 09:37 PM
Hi garym. Thanks for replying. I was worried the length of my post would scare people off. lol.

I just got the 2011 remaster (verified accurate) and NO popping when I played the track in isolation in iTunes, VLC, or my iPod. I think this problem is strictly for the 1992 remaster. But the thing with the 2011 remaster is if you put on headphones and turn the volume up high and play the track, the first maybe 3/100ths of a second are actually the end of the previous song! (Bring the Boys Back Home.) Listen carefully and you'll hear it. If it's not a problem at the end of the track, it's a problem at the beginning. lol. (Although in this case it's really not a "problem.")

I racked my brain trying to figure out what those "pops" were and why I got the AccurateRip results I did and that's all I could come up with. I just wish I knew what the "pops" actually were. The fact that the 2 identical copies I managed to get from the library both gave identical results, which were identical with my original Rip2 that I did way back when, made me stop worrying (for the most part. lol.)

I'm fairly convinced my Rip1 is a ripping error at the very end, but I explained my reasons in my novel length post for why I think it came back as Accurately Ripped.

Basically at this point I have 2 hypotheses. The "pop" is either a "glitch" in the mastering process (as Spoon suggested it could be) or the first few hundreths of a second of the next song. To summarize what I think are the possibilities:

Rip1: a) "Glitch" in mastering with a possible ripping errror, or
b) Beginning of next song with a definite ripping error

Rip2: a) "Glitch" in mastering with NO ripping error (due to the 2 CDs that produced identical results), or
b) Beginning of next track with NO ripping error.

I think at this point I'm going to "retire" my Rip1 of The Wall and either go with my Rip2 or the new 2011 remaster. (I'm leaning towards the 2011 remaster.)

As long as my analysis of how AccurateRip checks rips is correct (or at least along my line reasoning), and the fact that the 2 library CDs gave identical results, I'm certain of the possibilities above and fairly content with accepting them and willing to move on from this.

If you have the 1992 remaster, try playing it in iTunes in a playlist by itself. I'd be curious what would happen.

Also, to reply to mville, I get the same results as you when playing Comfortably Numb immediately followed by The Show Must Go On. It's only when Comfortably Numb is played in isolation, as if it were the last track of the album, that the "pop" occurs. (These are the US 1992 remasters. As I mentioned the 2011 remaster does NOT have this issue.)

One last point. I did an "experiment" where I "snipped" the last 3/100ths of a second off the end of Comfortably Numb so I still had silence at the end of the track, but NO "pop." I then checked AccurateRip using this new version and I got an error saying the track length was too short. I thought that interesting. It implies that AccurateRip actually checks the ENTIRE length of the track to identify the CD, but I still think it VERIFIES using only musical data, and not silence.

(Actually, as I'm writing this I just had an insight. When I snipped the end of the track (about 3/100ths of a second) I got no "pop." Regardless of any player I used. This reinforces my belief that the "pop" is either a mastering "glitch" or the beginning of the next song.)

garym
12-21-2014, 06:40 AM
I only have the 2011 remasters. These are gapless tracks, as are many of pink floyd's albums. Do you ever get a pop at beginning of song on non-gapless album tracks.

mathmat
12-21-2014, 11:31 AM
I only have the 2011 remasters. These are gapless tracks, as are many of pink floyd's albums. Do you ever get a pop at beginning of song on non-gapless album tracks.

The thing with The Wall is that Comfortably Numb was the last song on side 3 of the LP, so there is a gap between that and the next song. I can hear it fade to no sound before that dreaded "pop." (About 2 seconds of silence.) But NO "pop" when I play The Show Must Go On.

Anyway, I just played my entire Pink Floyd collection as a test (as those are the only albums that readily come to mind that are gapless) using iTunes and every track started normally. No "pops." Even the 2011 Wall had no pops. I have a hard time hearing any actual silence at the end of the 2011 remaster of Comfortably Numb, whereas the 1992 remaster you can CLEARLY hear the silence.

So then I played my entire Rush collection (14 or so albums) using iTunes. Those are all non-gapless and I didn't heard any pops at the beginning of any track. All sounded fine. I do not recall hearing anything prior to when I discoverd this with Comforatbly Numb. I know that if I did, it would have been something I certainly would have noted.

I'm starting to think my analysis of how AccurateRip verifes tracks might be wrong, based on the accuraterip entry I read in the hydrogenaudio wiki. But again, I am NO expert in this stuff, and any analysis I may have is based simply on ideas of how I think things should, or might, work. So this is making me wonder even more as to why the 2 "pops" at the end of my Rip1 and Rip2 of Comfortably Numb are different sounding. I don't think it's any player, because when I "snipped" the last few hundreths of a second off there was no "pop" for any player.

I'd love to somehow upload the last 4 or 5 seconds of each version so you can actually hear it, but, again, I don't want to get in trouble.

Maybe my 2 rips of the Wall that AccuarateRip is verifying as accurate are somehow inherently different. The only reason I think they are the same CD is because the confidence, CRC ARv2 values, and DiscIDs all came back the same for EVERY track. (See my original post.) The 2011 remaster has different CRC and confidence values (as well as a different DiscID) than my original 2 rips.

I wish I had access to the CD I did the first rip from. I might try to get a copy from eBay or something. I'm just wondering how much money is finding an answer to this "pop" issue worth. lol!

garym
12-21-2014, 01:57 PM
My 2cents: Time to move forward and get back to enjoying the music. You've done everything humanly possible to confirm bit perfect rips. Any other discussion is purely theoretic. At this point you're basically talking to yourself. :)

Enjoy the music and have a great holiday season and happy new year.

mville
12-22-2014, 06:59 AM
... and to complicate things further, the 1992 US Re-Issue appears to be mastered with Pre-Emphasis. Are you sure you haven't used SoX to de-emphasize the CD at some point?

mathmat
12-22-2014, 10:57 AM
... and to complicate things further, the 1992 US Re-Issue appears to be mastered with Pre-Emphasis. Are you sure you haven't used SoX to de-emphasize the CD at some point?

I ripped all the CDs with iTunes, but different versions of iTunes. Just ripped with the Apple Lossless setting. I'm not sure what Pre-Emphasis is?

For the record the first rip came from a copy with barcode: 0 7464-68519-2 0, and the second rip came from a copy with barcode: 7 2438 31243-2 9. (All US releases.) The first rip was done with iTunes v 7.1.1.5 in May, 2007, and the second rip with iTunes v 11.0.2.26.

Also, as I mentioned, I managed to find 2 library copies of the second CD I originally ripped and I hear that same "pop" or "click" (whatever it is) when I PLAY the CD, not rip it.

Thanks!

mathmat
12-22-2014, 12:08 PM
Continuation of above post:

I just read that newer versions of iTunes apply de-emphasis when playing and ripping CDs. Could that explain why the "clicks" or pops" (or whatever they are) sound differently for the 2 rips? Interesting. Thanks for the input, mville. Wondering if this is the answer. If it is, then if I obtained a copy of the original ripped CD, I would expect the "click" to sound the same as the 2nd copy. Hmm. (This is, of course, if the 1992 remaster does have pre-emphasis.

And thank you, garym, for the Holiday wishes. I wish you a Happy Holiday season and I have some other questions that I'll post in other forums that I'm hoping you'll give feedback on. :)

mville
12-23-2014, 06:11 AM
I managed to find 2 library copies of the second CD I originally ripped and I hear that same "pop" or "click" (whatever it is) when I PLAY the CD, not rip it.

... and does it pop/click in players other than iTunes, e.g. does it pop/click in a standalone CD player?

In my opinion (as a Sound Engineer/IT Tech), iTunes is a poor piece of software. I would not use it as a media player and I certainly wouldn't rip with it. I would ditch it if I could but I have an 160GB iPod Classic. I look forward to the day that an affordable portable player supporting flac appears on the market, then I would say goodbye to Apple (and mp3) for good.

mathmat
12-23-2014, 10:18 AM
... and does it pop/click in players other than iTunes, e.g. does it pop/click in a standalone CD player?

In my opinion (as a Sound Engineer/IT Tech), iTunes is a poor piece of software. I would not use it as a media player and I certainly wouldn't rip with it. I would ditch it if I could but I have an 160GB iPod Classic. I look forward to the day that an affordable portable player supporting flac appears on the market, then I would say goodbye to Apple (and mp3) for good.

It only pops/clicks whenI play it in a playlist in iTunes (or if I uncheck all the following songs.) VLC gives the same result (when the tracks are played in isolation) Also in my iPod Classic and 5th Generation Touch (when played, again, in a playlist by itself.)

The pop/click occurs when the track ends and the screen is "refreshing" if you will. For example, on my iPod, as the screen goes back to the home screen, that's when I hear it. I burned the track to a CD (a one track CD) and played it in my car and heard it. Again, the pop/click sounds different for the 2 rips. I checked the Pink Floyd Archives and both CDs came from the sme remaster (but different pressing plants), and all have identical peak levels.

Also, when I "snip" the last 3/100ths of a second off the end of each rip so there is still some silence at the end of each track and then play it in iTunes or VLC, I don't hear it. (That suggests it's not the player.) And as I mentioned, the 2 library CDs (which are the sane CD as my 2nd rip), when I play the track in isolation (not ripped, but directly from the CD) I hear it. It's some sort of "glitch" or the first few 100ths of a second of the next track. I tend to think it's a "glitch" or mastering error as a louder and different sounding pop/click (the one from my first rip) would contain more information from the following track as would the 2nd rip with a softer and different sounding pop. Hence the following tracks would have different lengths, albeit by maybe 2/100ths of a second or less. And that would suggest that they both would NOt come back as Accurate, but, of course, they did come back as Accurate! So that's why I think mastering glitch. Again, I may be wrong.

98% (or something like that) of my ALAC rips with iTunes have come back as Accurate. I'm happy with that level, as most of the bad tracks are songs I don't listen to. And I use iTunes because I listen to my music exclusively in my car with my iPod so I need to use it. It's just the pop/click sounds different from the 2 rips from 2 different copies which is something I'm very curious about since both CD Rips came back as accurate. So that made me wonder how 2 different sounding tracks both came back as Accurate? I put an explanation in a previous post as to how Accurate Rip verifes CD Rips, but that was just an idea. I don't think AR does checksums, because if I rip a CD as ALAC or WAV, then all tracks will give different checksums, yet the 2 rips will both come back as Accurate. I'm thinking that since on my rips there is about 2 or 3 seconds of silence at the end of Comfortably Numb that AccurateRip somehow stops "reading" the track when it reaches 2 or so seconds of silence because that would indicate that the track is over. I may be completely wrong, though.

I don't think it's the players that are causing this, given its's happening consistently across multiple players. (Same pop/click sound for each rip EVERY time I use any player.) And I don't think it's pre-emphasis. I think this is inherent to the discs. If I can get a copy of the first CD I ripped for really cheap (under $10) I could determine with more certainty what's happening.

I'm not so concerned about my music being Accurate at this point (although that is still a huge part and I obviously want it as Accurate) but rather how AccurateRip verifies as Accurate 2 different sounding tracks. I'm the type who, when I come across a problem, especially a techinical issue, I like to be able to understand it and get an answer. Given you're a sound engineer I think you're my best hope now. :)

I'm just trying to understand what's happening here and how this works...

Thanks, mville, for your input. I apreciate all of it.

P.S. I uderstand Apple stopped making the Classic, and they're selling for crazy amounts on eBay. I think they will discontinue the Touch shortly as well. Most people use Pandora and all and I don't think people buy too many songs from Amazon or iTunes anymore. Not to mention CDs are really hard to find. I had to go to 5 Targets/Walmarts to get the 2011 Wall! It seems HDTracks are the future for audiophoiles, but I doubt there will be a portable player to play them. It's disappointing as everything seems to be headed in a streaming direction. 90% of people don't care about sound quality so they're happy to stream using their phones, in the process using lots of data and battery life.

mville
12-24-2014, 05:45 AM
It only pops/clicks whenI play it in a playlist in iTunes (or if I uncheck all the following songs.) VLC gives the same result (when the tracks are played in isolation)

What I am trying to determine is whether the original 1992 US Re-Issue has the pop/click. If you put CD2 into a standalone CD player (not a PC, too many variables there) and you hear the pop/click then it is probably a pressing issue or mastering problem and there is little you can do.

If there is no pop/click and you rip to flac with dBpoweramp, I expect the resulting flac to also be pop/click free.

mathmat
12-24-2014, 08:57 AM
What I am trying to determine is whether the original 1992 US Re-Issue has the pop/click. If you put CD2 into a standalone CD player (not a PC, too many variables there) and you hear the pop/click then it is probably a pressing issue or mastering problem and there is little you can do.

If there is no pop/click and you rip to flac with dBpoweramp, I expect the resulting flac to also be pop/click free.

Hi mvilee. Happy Holidays to you!

Just to reiterate, the first CD I ripped had barcode: 0 7464-68519-2 0 (1997 Columbia USA) and the second CD had barcode: 7243 8 31243 2 9 (2000 Capitol USA). Both, according to the Pink Floyd Archives are the 1992 Doug Sax Remaster, albeit different pressings from different pressing plants.

Now I don't have access to the first CD (the one with the slightly louder pop) but as I mentioned I was able to find 2 copies in the local library system of the second CD (2000 issue.)

I went ahead and tried both library CDs in my CD player (technically blu-ray player) and I was able to create a playlist so that I could play Comfortably Numb in isolation. And on BOTH CDs I heard the SAME click/pop as I did when I played Comfortably Numb from those same CDs (in isolation in a playlist) through iTunes and VLC. And this is the same sounding click/pop as my original rip of the 2000 CD which was done a few years ago. I am convinced it is part of the CD. Now whether it is a "glitch" or the first hundreths of a second of the next song (The Show Must Go On) I don't know. If I had to guess, I'd say it was the beginning of the next song.

Now because the first rip (from the 1997 issue) has the click in the same EXACT location as on the other CD issue makes me think it is inherent in that CD as well, They are, after all, the same remaster with identical peak levels (according to the Pink Floyd Archives.) Not to mention all the tracks from BOTH pressings each have IDENTICAL track lengths to the thousandth of a second.

Now since the click/pop sounds different in each rip is what is making me wonder. Keep in mind that I used PerfectTUNES to check both rips and the results came back identical. Every track from Rip1 (1997) had the same ARv2 CRC value as well as the same confidence value (and the same Disc ID) as Rip2 (2000). The only difference was the offsets. Also, just as a reminder, the click/pop occurs at the extreme end of the track. You hear it as the track ends and the screen refreshes. (Or on the CD player, as the song ends and the screen goes back to the playlist.)

I don't know why the click/pops sound different. Keep in mind it's not a very big difference, but it's clear that it's NOT the same sound. I don't know if the 1997 issue is slightly different than the 2000, but I doubt it since the AccurateRip results came back identical. My theory, which I can only confirm once I get a copy of the 1997 CD, is that the click/pop will sound the same as the 2000 issue and different than my rip of the 1997 CD. The reason for the different sounding clicks in my 2 rips? I think that when the reading/ripping head was moving from Comfortably Numb to the next track on the 1997 CD Rip some error occurred. But regardless of why this error occcurred (if it is an error or just a difference in the pressings of the same remaster) I don't underdstand the AccurateRip results. That's what's intriguing me.

How could AccurateRip give identical results for 2 CDs where one track clearly sounds different?

(This is simply a "trying to understand what's happening" question, as I am intrigued and fascinated by the concept of AccurateRip.)

Thanks, and Happy Holidays to all!

mville
12-25-2014, 07:31 PM
I went ahead and tried both library CDs in my CD player (technically blu-ray player) and I was able to create a playlist so that I could play Comfortably Numb in isolation. And on BOTH CDs I heard the SAME click/pop

It definitely looks like a problem (pressing or mastering) with those CDs and if so, any rip will also contain the pop/click.

Post no. 3 in this thread from Spoon also suggests this and explains why accuraterip treats the different CD releases as the same.

I too suspect that the digital audio contained in both releases is identical, but that the track start and end points (i.e. the edit points when ripped) are slightly different so giving different pop/clicks on playback. However, without having definitive knowledge of how these CDs were manufactured, any reasons given here is pure speculation.

mathmat
12-26-2014, 02:32 PM
It definitely looks like a problem (pressing or mastering) with those CDs and if so, any rip will also contain the pop/click.

Post no. 3 in this thread from Spoon also suggests this and explains why accuraterip treats the different CD releases as the same.

I too suspect that the digital audio contained in both releases is identical, but that the track start and end points (i.e. the edit points when ripped) are slightly different so giving different pop/clicks on playback. However, without having definitive knowledge of how these CDs were manufactured, any reasons given here is pure speculation.

I think I have a better understanding of what is hapening now. Thank you. The fact that the offsets were diffferent suggests the cause of the different sounding clicks/pops. From what I understand, different pressings of the same CD can have different offsets, which, though musically identical, can have slightly different start/stop times for the corresponding tracks. So Track 6 on a particulat pressing can start, for example, 2/100ths of a second later than the same track on a different pressing of that identical CD. But AccurateRip takes this into account when it does its comparison. Is that a correct understanding?

Also, when I do a PerfectTUNES check and I get a particular "pressing offset" value, is that the offset that is inherent in the CD, or does that take the offset of the CD drive into account? For example, let's say my CD drive has an offset of +150 and my CD has an offset of -50, what offset value would PerfectTUNES return? Again, I'm new to all this and trying to learn the basics of how it all works. Forgive me if the questions are simple.

Finally, if I rip the same physical CD with 2 different computers, will the pressing offset values be the same after running them through PerfectTunes? I ask this because I ripped the same physical CD with 2 different computers and got different offset values. (Again, I used iTunes, but different versions.)

Thanks!

Spoon
12-26-2014, 03:31 PM
dBpoweramp corrects for drive offsets, iTunes does not, so any drive offset is like a pressing offset.

AndrewFG
12-27-2014, 05:52 AM
My guess is that your pop is actually an ID3v2 metadata tag at the end of your file. And that your player is wrongly trying to play that tag as if it was music. This normally sounds like a pop or a blip of static. The exact sound of the tag depends on what is actually in the tag. So for example two instances of the same track with identical perfect accurate rip music content might have different meta data tags (e.g. different album art images) and so they might pop differently. Solution is to change your player..

mathmat
12-27-2014, 01:54 PM
dBpoweramp corrects for drive offsets, iTunes does not, so any drive offset is like a pressing offset.

Thanks, Spoon. This explains a lot conceptually and also explains a lot of the data I've been getting with AccurateRip.

mathmat
12-27-2014, 02:12 PM
My guess is that your pop is actually an ID3v2 metadata tag at the end of your file. And that your player is wrongly trying to play that tag as if it was music. This normally sounds like a pop or a blip of static. The exact sound of the tag depends on what is actually in the tag. So for example two instances of the same track with identical perfect accurate rip music content might have different meta data tags (e.g. different album art images) and so they might pop differently. Solution is to change your player..

Hi AndrewFG, thanks for your input. I appreciate it. I actually thought this could be the case and I almost posted asking if this might be the cause. The only problem is that the sounds for each track are the same regardless of which player I used (and I tried a few different ones.) Furthermore, when I played the CD (not the rip) that was the source CD of the 2nd Rip, I heard the same sound as the corresponding rip. And I played the CD both in my computer as well as a stand alone CD player.

I'm inclined to think now that the reason for the different sounding clicks/pops is due to different offsets. All experiments suggest that, but I'm still not 100% sure. Maybe 98% sure since I am still a novice at this and don't understand all the technical aspects.

As an aside, I had a rip of Goodbye yellow Brick Road, but I found that one track was corrupt. So I obtained another copy of that CD and when I played Saturday Night's Alright for Fighting, I noticed the track began with the last fraction of a second of the previous song, which my original CD Rip did not do. I remember being very confused at the time and just figured it was something in the pressing. So when I recently did a PerfectTUNES check on the 2nd rip of Goodbye, I saw an offset of -1441! That's the equivalent of about 2-3 100ths of a second, which jibes with what I hear in the rip.