What Order Does My Car MP3 Play Files In???

Black Hole

Black Hole

May contain traces of nut
I replaced the standard audio in my car, mainly because I wanted DAB, with a JVC KW DB60AT (FM/AM/DAB/CD/MP3/Bluetooth/Aux/USB). I'm not overly enamoured of it, but it's OK (every now and again it has a hiccup and reboots, going silent while it does, and very very occasionally fails to initialise the DAB tuner properly so I can't have DAB until it reboots again - which doesn't just mean turning it off and on).

Possibly the most annoying thing is that if I have any work done on the car which involved disconnecting the battery, I have to set up all my preferences again (screen and button colours and brightnesses day and night, audio source relative volumes, DSP characteristics... I've taken to writing them down). Why doesn't every electronics system of this day and age have non-volatile settings storage?!

But all that is by-the-by. What I can't fathom is the order it plays MP3 files from a UPD. It doesn't matter so much for random music files, but if you have a talking book it's nice to have the chapters play in the right order!

Take my set of "A Delicate Truth" ripped from Radio 4's A Book at Bedtime as an example. It's ten programmes. The raw set plays in a scrambled order, but I used an audio editor to top&tail the recordings (which re-encoded them on save, resulting in larger files not smaller) and renamed the files with a strategy that I know results in the correct play order. The problem is to understand how the player decides what order to play files, and I can't explain the scrambled order of the first set:

Here's the set that plays in the right order (and my observation is that as long as I put a numeric track number at the beginning of the file name, it works):

Exhibit1.png

Here's the set that doesn't play in the right order (the actual play order is 6, 4, 7, 8, 9, 3, 2, 1, 5, 10):

Exhibit2.png

The play order doesn't match the creation order (9, 6, 10, 4, 7, 8, 5, 3, 2, 1) or the modified order (the same). I thought I might have cracked it with the short name sort order:

Exhibit3.png

...close, but no cigar (1, 2, and 3 are in the wrong order). It's not like the player can't read the long name either, or only the first n characters - the whole thing is displayed when the track starts playing.

The only other idea I have is that the tracks are being played in the order they are listed in the FAT - but I have difficulty believing that all the tracks I have played in order (with the track number at the beginning of the file name) also happen to be listed in order in the FAT by coincidence.
 
I've had a snoop around with a disk structure viewing tool / hex editor, and I can't make anything of it. Yes, the index records for the "good" set do appear to be in sequence, but the records for the "bad" set are not in the sequence that comes up (and I can't find the record for the 09 file at all).
 
I think this is a common problem with many players.
I believe it's because the files contain metadata (which can include the track name) and the players read this to decide what it thinks is right. Changing the filename doesn't change this metadata and you're stuffed basically.
On my Android phone I use an app called Folder Player which actually plays stuff in the order you'd think it should be - ie. filename order.
 
There are many items that can effect the play order :-
winamp.jpg
I have players that determine track order by following the 'Track#1' number order, I also have players that will only play in the correct order if the ID3v2 Tag is removed completely (leaving the ID3v1 in place), you can change meta data on a one off basis using WinAmp (as in picture above), if you need to change lots of files you will need something like the windows program ID3-TagIT

You can also generate an MP3 playlist file called an *.M3U file, that some players will use
 
As an aside, if tag order is being used, you need to ensure your audio editor is preserving tags.
 
I suppose the next step is to see if the JVC manual is any help :rolleyes:

It might explain things if Wavepad* doesn't preserve tags - maybe without tags the player falls back to file name order.

* Quicker to use for simple stuff than Audacity, but it nags a bit - anybody know of an MP3 editor that doesn't re-encode... is that even possible?
 
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prpr said:
mp3DirectCut
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Great, thanks. That didn't pop up in my search when I was looking before, and I ended up with Wavepad thinking it didn't re-encode (but it does).

prpr said:
Of course it is.
Click to expand...
That's not obvious. If the encoding was heavily dependent on frequency domain information, the data contributing to any particular temporal instant could be too spread out to make edits practical without decoding first and re-encoding after. As it is, I suspect some patching up may be required at the edit points.
 
Your choice of exact edit point is of course slightly limited with the audio format being 'frame' based, but it's probably good enough for most uses.
 
Black Hole said:
You might be on to something. I'll have a look at the MP3 tags for track number.
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Nothing. It's a mystery I shall have to shelve as "too hard to be worth the bother" and be satisfied with knowing that I have to prefix the file name with the track number to play them in a sensible order.
 
There are no track number tags at all - just constant fields in the title, album, and year tags (and I have no idea where they came from).
 
I have come across some mp3 players that choose to play things in the order they are stored in the directory irrespective of the file name or tag. The obvious (and very tedious) way to get the player to play in your preferred order is to transfer files one at a time in the order you want them to a fresh directory on the player.:sleep:

Oops! Need to be more alert! I didn't notice the thread was more than a month old until after I posted.
 
Black Hole said:
Been there, tried that, doesn't seem to work.
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Have you tried the CopyInOrder program? Works for me otherwisr, if it uses track numbers, mp3tag is your route.

There are also programs to sort the folders and files on fat32 volumes, but I have not found one that works consistently yet.

As for mp3 tags, the old ones were fixed length fields and prepended to the start of the file. Tags and file are like locomotive and carriages, you can change either without changing the other. The newer ones are at the end, and in the guard van. They are variable length and again independent of the rest. You can have both. For obvious reasons, a player might choose the former, since there is then no need to seek to the end of the file to read them. You would see which are used by what gets displayed on playback, the full field or an abbreviated version or a file name.

MP3Tag handles all the tag editing and even has some automation built in. For safety, I would insert track tags and also prefix the track to both the title tag and filename, with leading zeros if necessary to force alpha order.

http://www.mp3tag.de/en/
 

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To review the state of play, I have had some success controlling play order by ensuring files are copied to the UPD in the order I want to play them. WebIF helps by creating a list of files to be copied before actually committing, and then performing the copies in the list order.

However, I have now come across the fatsort utility – see https://hummy.tv/forum/threads/pull-request-–-fatsort.11083/

The thesis is that the player order is the order the files are in the FAT. I thought I had discounted that (over 7 years ago), but we'll see...
 
fatsort should work.
I used it a while ago for mp3 files on devices that couldn't recognise sorted output. Like others, I tried copying files over one at a time but that only worked to a certain degree. I also tried various GUI utilities in Windows but they didn't deliver. This Linux utility, however, worked well.
 
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