MP3 weirdness confirmed

[altivo]

You know that thing I mentioned a couple of days ago? About how my car sound system won't play MP3 CD-Rs written by either of Gary's Windows computers? It is now confirmed to exist. Hell if I can explain it, but sure enough, load the unreadable CD into either of my Linux machines and it seems readable. So I copy the files off, put in a new blank CD-R, and write them back. The new CD created by Linux is perfectly readable in the car. The former one written by Windows is still not readable.

First week of Summer Reading Club ends in a noisy flurry as 50 or so kids descend on the library for a "craft" session. I was definitely glad to get out of there and take Gary to dinner for his birthday tomorrow.

Dog has a vet appointment at 8:30 am tomorrow, so I'm about to try to get some actual sleep. Lightning bugs are flickering occasionally outside the window.

Comments

[marzolan.livejournal.com]

Do the two computers burn disks at different speeds by chance? I had this issue in the past where an mp3 cd I'd burn would play in my mother's Toyota's stereo system, but not in my portable mp3 cd player. I made multiple attempts, tried with friend's devices, but it seemed hit or miss as to what devices would play it. Until I read a line in the manual regarding burn speed, and, for whatever reason, slowing the burn speed to 1x or 2x solved the issue. I don't know why, it shouldn't make a difference, but it did.

[frith]

I should try that when I burn my next disk of MLPFIM fan music. The tracks by Jeffthestrider that I had burned on disk 1 were silent, all the other tracks played normally.

[altivo]

That is indeed one of the possible symptoms of my experience. Sometimes the entire disc is unreadable and the car player just flashes "reading disc" over and over forever. Other times it can read a few tracks but not others, and plays back the readable ones over and over with long pauses between as it scans the unreadable segments.

[altivo]

I'm not sure of the speed, but it's a possible factor. Also the power or intensity of the writing signal, the type of physical medium, and several other things. There's also the question of the writing drive, which is a DVD-R in his machine and a CD-R in my machine at home. My desktop at work has a DVD-R so I tried that yesterday. (I was thinking of incompatibilities that used to arise between 80 track and 40 track floppy drives, even though the 80 track drive was supposed to be downward compatible with 40 track diskettes.)

As it happens, I do normally try to slow down the writing software when I create a CD-R myself. Gary is using a Windows utility that most likely defaults to the fastest possible speed, as limited by either the hardware or the physical media type.

On the other paw, the latest version of cdrecord/wodim that I've been using seems now to ignore the forcespeed parameter that I specify. The test CDs I wrote yesterday were 52x media manufactured by Ridata. I told wodim to use the slowest possible speed (which I think should have been something like 12x) and it reported that it was using 48x, which I think is the fastest speed the DVD-R drive in that machine supports. The actual average speed achieved was reported as 42x at the end.

But... the two discs I wrote on the DVD-R at work are both readable in the car. The unreadable discs are a different brand of media, and I don't yet know what writing parameters are set by Gary's software. It does seem odd to me that his discs are readable in all my computers that I've tried, and in my portable CD player, but not in the Ford player. Particularly so since they play in his own Ford, which is a couple of years older than mine.

I also need to try one of his music discs. These were audiobooks, which are often recorded at a reduced sampling rate, though the new copies I made dealt with them as raw data and wouldn't have converted the file structures in any way.