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Missing 588 samples always in same place


DickN
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I'm making a practice CD from a mix of WAV's & WMP's (WMP version 2, FFmpeg) exported from Audacity. The CD has 41 tracks, and track #4 gets a defect on the CD which is not in the WMP file. I first noticed the glitch on playback, so burned another copy with Verify checked. It verified OK but has the same glitch. I tried making another cue file and burning another CD with just that track and two others, one on each side of it. No glitch! I exited and restarted ImgBurn using the original cue file to make yet another CD, Verify ON, and drat! Same glitch in the same place, still passes Verify. All in all, I burned a half dozen CD's trying to get a good one.

 

I captured the CD playback (too much frustration with CD rippers) from Stereo Mix back into Audacity so I could see exactly what happened. 588 samples are missing at a point 49+ seconds into the track. The resulting time offset persists for the rest of the track. The fact that all the CD's pass Verify suggests to me that ImgBurn is getting the error when reading the WMP, but it didn't happen when I made the test CD with just 3 tracks.

 

Is ImgBurn caching the files somewhere so I keep getting the defective copy? Under the hood, is it making an Image file for the burn and reusing it whenever it gets the same cue file? If either is the case, how can I force ImgBurn to empty the cache and start afresh?

 

I'd post this on the bugs forum but I'm not sure it's repeatable to anyone else, and besides it looks like I'd have to upload the works over my dialup to put the track where it is when I have the problem.

 

I did upload the log file, having observed that's what you usually ask people for. I note that for the test CD with 3 tracks, that doesn't show the glitch, the sector count is 8773-4218 = 4555, same as for that track (#4) on the longer one. I should think they'd differ by 1.

 

- DickN

ImgBurn.log

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I don't even know what a 'WMP' file is. To me, WMP means Windows Media Player.... so do you actually mean WMA files?

 

If DirectShow isn't decoding 'Track 4' properly then I guess there's something wrong with it. Why it worked for the 3 track disc is anyone's guess.

 

There's no cache involved and there are no intermediate files.

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Oops - I meant WMA. That's what I get for working till 4 AM. I've been experimenting with this and it happens regardless of what precedes the track, except that the time offset from the start of the disk to track 4 seems to matter. I found a CD that I burned about a month ago with about the same time offset to start of track 4, for which I still have the Audacity project. That one has a sector missing at about 13 seconds into track 4. But I have another CD I burned a few months ago with just 1 long track, for which I also still have the Audacity project, and that one has no glitches at all. What I'm doing for test is importing back to Audacity, lining up the tracks, inverting the one from the CD and summing. If a sector was missed, the sum is nonzero from there on.

 

The other odd thing is that the disk verifies OK if I have Verify checked. Does Verify for CD's compare the CD with the input files, or just verify that all sectors are readable? I also had a couple of program hangs at "analyzing sector xx" for verify. When this happens, the hard drive light stays on pretty steadily but nothing happens until I abort the verify.

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You mean 'analysing track xx' rather than 'sector' I should think... that's a known issue although it should be less of a problem with 2.5.2.0 than it was in 2.5.1.0. (You need to update your version!)

 

There are 2 reasons why Verify doesn't work how you think it does in your situation.

 

1. The files have to be decoded so it's impossible to actually compare anything to the original file.

 

2. Due to drives offsetting audio when they burn / read (what you write to a sector doesn't end up on it exactly as you intended), it's impossible to verify CD-DA data. There's an option you can enable to have the program compare the CD-DA data but you'll always get miscompare errors unless you have a drive that has a combined read/write offset of 0 (I think LiteOn drives do). Without that option enabled, all the program does is check the sectors are readable.

 

If you can find a single track that won't ever burn correctly on its own (i.e. 1 track on a disc) but sounds fine if you play it normally, I can help. Messing with hit and miss stuff is just a waste of time I'm afraid and I won't get involved in that.

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