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AT3 files... what are they what have you tried?

By BigFloppy · Jun 09, 2006in Hacks/Mods💬 38 posts👁️ 9,903 views
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Posted Jun 22, 2006 · 19:03 UTC#26
Pulp_Fiction:

Can you replace your TRACK01.AT3 file on your Z1 with this file and let me know if it works?

It should sound strange, like it plays through and then part of it repeats because I padded the end of it with data from the Z1 to make the files the same length. I just want to make sure it actually plays.
Attached Files (1)
Posted Jun 22, 2006 · 20:18 UTC#27
Cirbirus said:
Pulp_Fiction:

Can you replace your TRACK01.AT3 file on your Z1 with this file and let me know if it works?

It should sound strange, like it plays through and then part of it repeats because I padded the end of it with data from the Z1 to make the files the same length. I just want to make sure it actually plays.


Ok, I replaced the same size Track01 with your track01 and also replaced a much larger track01 on another album to see if the size mattered.

Both track01 played on both albums. They both ran for 28 seconds. They both sounded the same.

However they did not sound like anything you likely would have wanted it to (assuming you sent music or at least voice). The sound was a high pitched mess of mixed noises. Kind of what it sounds like when you put a data CD in a regular CD player.

My guess is you have the header correct enough for the unit to try and play it but it is interpreting something wrong.

If I can find a digital recorder around here I'll post what plays. I think my mp3 player records....
Posted Jun 22, 2006 · 20:40 UTC#28
Sweet! I was probably just sloppy in my editing of the file. I'll do a cleaner one now.

Looking at the files I think the Z1 is padding the ends of the files when it rips them which would account for the difference of size. Also since I don't really know anything about the ATRAC codec I don't know if the previous packet affects the preceding packet that could be the problem as well. I'm going to try just padding the file with silence.

I'll upload the modified file right away.
Posted Jun 22, 2006 · 20:46 UTC#29
Cirbirus said:
Sweet! I was probably just sloppy in my editing of the file. I'll do a cleaner one now.


Oh No, not sloppy coding... 8)

I'll just supply the ftp storage for everyone, I don't have time to go the coding route any more

Andy
Posted Jun 22, 2006 · 20:49 UTC#30
Cirbirus said:
Sweet! I was probably just sloppy in my editing of the file. I'll do a cleaner one now.

Looking at the files I think the Z1 is padding the ends of the files when it rips them which would account for the difference of size. Also since I don't really know anything about the ATRAC codec I don't know if the previous packet affects the preceding packet that could be the problem as well. I'm going to try just padding the file with silence.

I'll upload the modified file right away.


Since flat out replacing one file with a MP3 or other file affects the next or previous (damn, I can't remember which put I posted it somewhere) song then there may be something to the previous affecting the preceding thing you said.
Posted Jun 22, 2006 · 21:08 UTC#31
Pulp_Fiction said:

Since flat out replacing one file with a MP3 or other file affects the next or previous (damn, I can't remember which put I posted it somewhere) song then there may be something to the previous affecting the preceding thing you said.


Yeah I remember reading that post. And it scares me. Oddly the second track01 file you replaced, the one from a different album, shouldn't have worked. But it might be really good news, the header info might not matter, which I can't believe, but I still have to figure out the database structure so I can write something that will convert and add our MP3's to the Z1's hard drive automagically.

Can you send me a Dir of the entire drive, for each partition. I didn't realize that each album had some kind of directory structure. In fact I don't know the first thing about the dir structure so that would be a huge help. Man I can't wait to get my unit....

Oh, does anyone know where I can get my hands on the ATRAC SDK? I know Sony has released it in a limited maner but it doesn't seem to be easily found. It would be really helpful if I knew more about ATRAC and the SDK would allow me to write the conversion ability directly into my transfer application.
Posted Jun 22, 2006 · 21:23 UTC#32
Cirbirus said:
Pulp_Fiction said:

Since flat out replacing one file with a MP3 or other file affects the next or previous (damn, I can't remember which put I posted it somewhere) song then there may be something to the previous affecting the preceding thing you said.


Yeah I remember reading that post. And it scares me. Oddly the second track01 file you replaced, the one from a different album, shouldn't have worked. But it might be really good news, the header info might not matter, which I can't believe, but I still have to figure out the database structure so I can write something that will convert and add our MP3's to the Z1's hard drive automagically.

Can you send me a Dir of the entire drive, for each partition. I didn't realize that each album had some kind of directory structure. In fact I don't know the first thing about the dir structure so that would be a huge help. Man I can't wait to get my unit....

Oh, does anyone know where I can get my hands on the ATRAC SDK? I know Sony has released it in a limited maner but it doesn't seem to be easily found. It would be really helpful if I knew more about ATRAC and the SDK would allow me to write the conversion ability directly into my transfer application.


I posted the full file list earlier here: http://avic411.com/forum/download.php?id=194
Each file name in the zip is a partition.
Posted Jun 22, 2006 · 21:34 UTC#33
When you said the file played even when you replaced a much larger file with my file it got me thinking. The codec seems to be a packet based protocol so it might be able to work without knowing what is next (wav files can work this way so it makes sense).

So, I need you to try this file. It is a file that has the Z1 header and only data generated from the PC. It should be the first track from that Offspring album when played on the Z1. If it works this is fantastic news since I can't find what looks like header information in any of the files from the Z1.

You'll notice the file is smaller than the original Z1 file, that's because of the extra 4 seconds of silence in the Z1.

Interesting note. Silence to the Z1 looks slightly dirty, like it's got some noise in the circuit or something. That doesn't make a whole lot of sense in a digital signal but I'm just guessing at this point.



Oh, I remember reading something in the Z1's user docs about the 2-second delay when recording, can you turn that off? That way the files will be the same size in the future when you rip a file on the Z1.
Attached Files (1)
Posted Jun 22, 2006 · 21:58 UTC#34
I'm going to try your latest file shortly (next trip to the car) but in the meantime here is something for you to look at.
The attached file is a wave of 1 min. of complete silence created by goldwave and the resulting AT3 of the same file after being burned to a CDR and ripped by the Z1.
Perhaps knowing it is silence you will have better luck pulling off the headers????

Don't know about the 2 second thing. I'll look in the menus when it's back together.
Attached Files (1)
Posted Jun 22, 2006 · 22:13 UTC#35
Cirbirus said:
When you said the file played even when you replaced a much larger file with my file it got me thinking. The codec seems to be a packet based protocol so it might be able to work without knowing what is next (wav files can work this way so it makes sense).

So, I need you to try this file. It is a file that has the Z1 header and only data generated from the PC. It should be the first track from that Offspring album when played on the Z1. If it works this is fantastic news since I can't find what looks like header information in any of the files from the Z1.

You'll notice the file is smaller than the original Z1 file, that's because of the extra 4 seconds of silence in the Z1.

Interesting note. Silence to the Z1 looks slightly dirty, like it's got some noise in the circuit or something. That doesn't make a whole lot of sense in a digital signal but I'm just guessing at this point.



Oh, I remember reading something in the Z1's user docs about the 2-second delay when recording, can you turn that off? That way the files will be the same size in the future when you rip a file on the Z1.



Same result as before. File plays but sounds like it is a data CD.
Posted Jun 22, 2006 · 22:27 UTC#36
Excellent info!

The silence from the GoldWave app is true silence and what I found most interesting is that there are no A2h markers every C0h bytes. The A2h byte value repeating every C0h bytes is what made me think that the ATRAC codec was a packet based system. It still may be but this means it doesn't have a header byte. Since it doesn't have an end marker or any kind of checksum data and every block of data is the exact same size (192 bytes) it makes sense that you don't need a header marker.

The info in the header of the standard AT3 file must tell the consumer app what the bit-depth and sample rate are (plus the length of the data segment) but the Z1 always uses the same settings so maybe that info isn't needed so the header isn't needed and it knows when the file ends because, well, the file has ended.



Damn, I didn't see your post about the latest file still sounding like garbage. Double damn.

Oh, are you using a drive that doesn't support locking or did you set the the drive to unlockable?
Posted Jun 22, 2006 · 23:14 UTC#37
Cirbirus said:
Excellent info!

The silence from the GoldWave app is true silence and what I found most interesting is that there are no A2h markers every C0h bytes. The A2h byte value repeating every C0h bytes is what made me think that the ATRAC codec was a packet based system. It still may be but this means it doesn't have a header byte. Since it doesn't have an end marker or any kind of checksum data and every block of data is the exact same size (192 bytes) it makes sense that you don't need a header marker.

The info in the header of the standard AT3 file must tell the consumer app what the bit-depth and sample rate are (plus the length of the data segment) but the Z1 always uses the same settings so maybe that info isn't needed so the header isn't needed and it knows when the file ends because, well, the file has ended.


Cool, silence is golden when used correctly!

Sounds like Pioneer created the music interface from scratch (thus less header info) and just used the AT3 codec. WHY AT3??? Sony must have been the lowest bidder on the block that day.
Posted Mar 08, 2011 · 06:28 UTC#38
'Pulp_Fiction' timestamp='1149875916' post='3550' said:

Are you able to play them in anything? I'm concerned they are encrypted in some way.

yes you can download sonicstage and play them, but i need to figure out how to conver mp3/wma to at3 so i can copy my library over.
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