Corrupt SNG

HardSync · Post by **HardSync** » Thu Jun 06, 2013 9:37 am

I've just had the first SNG data corruption issue on my M3 after 2.5 years. It's totally bizarre. The Master Track has "lost" nearly 40 measures in the middle of the song. And when it picks up 40 measures later, the time sig is at " -1/4". Not 1/4 but minus 1/4. See images.

Bizarrely, the song will play up until measure 94, even though the Master Track has no data from measure 52 or so. But then it all goes horribly wrong once it gets to measure 94.

So, I've tried to repair this with everything I can think of.

I've tried live re-recording with a 4/4 time signature selected in the meter field, both in Overwrite and Overdub modes. As soon as the sequencer gets to measure 94, it plays only one-half of each measure.

I've tried copying or moving the tracks (one by one or all at the same time) or the measures (some or all) to a new song and within the song. No joy. The M3 locks up every time and I need to reboot.

I've tried making RPPR patterns from the tracks before the errors occur, to try to salvage some of it. No joy. The M3 locks up. And sometimes I get a strange error (see images).

I've tried inserting measures at various points in the song. No joy. The M3 locks up.

I've tried editing the tracks in Track Edit / Event Edit and Piano Roll. No joy. The M3 locks up.

I've tried deleting tracks or recording new tracks. The M3 locks up.

I've tried resetting the song length in the hopes that it would self-repair the Master Track. No joy.

The only thing I haven't done is try to record the MIDI out into an external sequencer (because I don't have one -- I don't even connect my PC to the M3).

Well, I'm going to contact Korg Support. In an ideal world, they would be able to repair the SNG, which was 98% completed. But I'm not holding my breath on that. I would think that possibly it could be edited in a hex editor of some kind -- to manually insert the Master Track data and repair the corrupt bits? Maybe? Anybody have experience with that?

But this makes me sad. All I needed to do was tighten it up in places, quantize my rubbish timing on some tambourine stuff, create a fade-out ending and do a few mix-down passes. I really don't want to have to re-record the entire song again, because some of the things were happy accidents that I'd struggle to reproduce precisely the same way again.

Anyway, if anybody knows whether it's possible to edit the SNG in a hex editor or whatever it is, please let me know.

<iframe class="imgur-album" width="45%" height="550" frameborder="0" src="http://imgur.com/a/aEGtJ/embed"></iframe>

Bald Eagle · Post by **Bald Eagle** » Thu Jun 06, 2013 11:52 am

There isn't a hex editor built into the M3 that would allow you to edit at the level required to fix a corrupt file. Have you tried creating a new song and using the Copy Measure menu command to copy 1 track at a time up to measure 93. If it works on one track save the song and keep repeating until all tracks are copied or until it fails. You could also try only copying up to measure 50 or so which is where you said problems start occurring.

If none of that works then you may have to connect to a pc and record to a daw. You can download REAPER for free and use it once for that purpose.

HardSync · Post by **HardSync** » Thu Jun 06, 2013 11:55 am

Yes, I have tried all of that, and more. I cannot even copy 1 measure to anywhere. The M3 simply crashes. Believe me, I spent five hours trying every possible thing. Absolutely heartbreaking when everything you try fails.

The hex editing would have to be performed outside of the M3 obviously.

I'm aware that I could use an external sequencer to salvage it. This will be a last resort if Korg is unable or unwilling to help me repair the SNG file.

Bald Eagle · Post by **Bald Eagle** » Thu Jun 06, 2013 12:11 pm

Have you tried this ...

1. Reboot M3.
2. Create a new empty song in sequencer mode.
3. Go to Media Mode and select the Load tab.
4. Navigate to your song file.
5. Use the Load Tracks menu command.

I know this is a long shot but maybe it will work. It might skip loading whatever is corrupt.

HardSync · Post by **HardSync** » Thu Jun 06, 2013 12:28 pm

Yeah, mate. I tried that too. It brings in the Master Track as well, which is the problem track...

I know I didn't list everything I tried, but I do appreciate the suggestions.

r12 · Post by **r12** » Thu Jun 06, 2013 2:29 pm

have you tried to export the song to std midifile and load it on a PC ?

HardSync · Post by **HardSync** » Thu Jun 06, 2013 2:49 pm

r12 wrote:have you tried to export the song to std midifile and load it on a PC ?

I have not. I will give it a go and report back.

HardSync · Post by **HardSync** » Thu Jun 06, 2013 3:16 pm

Thanks for the suggestion, r12. You may be on to something...

OK, when I try to save/export as a STD MIDI file, Format 1, the M3 locks up. This is the export mode with 16 individual MIDI tracks saved. Which would have been ideal. Sadly, no go there.

But I could save it as a Format 0 STD MIDI file (with Exclusive checked), which combines all of the tracks into just one MIDI track. And this plays on a PC (sounds like complete crap -- and also hilarious -- because the instruments/timbres don't match due to the PC MIDI player expecting a GM bank) all the way through to the end.

However, if I try to reload this file back into the M3, the M3 gives a "Measures over limit" error.

So I wonder ... perhaps I could use Reaper or something similar to load up the STD MIDI File. Then separate the MIDI data into individual tracks and such and see if that fixes the Master Track issue. It's worth a shot. Better than nothing at all.

By the way, I've given a copy of the SNG and a snapshot of my entire M3 to Bald Eagle, and he's going to have a go at fixing this corrupted SNG as well, when he gets a chance.

Thanks again!

michelkeijzers · Post by **michelkeijzers** » Thu Jun 06, 2013 3:39 pm

In theory you can fix it with a hex editor, however:
- the file might miss important parts where you need exactly to know what is missing
- the structure of a SNG file is proprietary and undocumented, therefore it would be very hard to reverse engineer all data (which might be missing too)

Result: using a hex editor to remove some parts to make the file valid again would be possible, but not without knowing what to do ... and I don't have a clue ... Korg might help but it can take hours, days, months to fix it ... and even then possibly without not the wanted result.

What you could check (as said above) is convert it to another MIDI file ... or record what you have with a (PC) DAW and export it back to a SNG file (if this is possible).

HardSync · Post by **HardSync** » Fri Jun 07, 2013 2:07 pm

Just a short update on this issue.

Bald Eagle managed to record the first 90 measures of the corrupted song and export it as a Format 1 Standard MIDI File, and most helpfully, also saved the Exclusive data embedded in the tracks. So, while I've lost about 40 measures at the end, at least I have the bulk of the song and can redo the ending. I'm really grateful for Bald Eagle's help, which goes above and beyond the usual call of duty in Korg Forums, as well as thankful for r12's and Michel's comments and suggestions. Thanks a million, gents.

I've also sent a short missive to Korg Support yesterday asking for help in repairing the SNG. If they can repair it -- and I'm not certain that they can or will - then that would be ideal as I won't need to reproduce the lost bits. I'm still waiting to hear back from Korg Support. If they can't fix it, then at least I've got the portion that Bald Eagle restored for me. Which is loads better than having nothing at all and redoing the entire song from scratch.

michelkeijzers · Post by **michelkeijzers** » Mon Jun 10, 2013 9:47 am

I'm glad you have at least most of the song back.

Don Audio Labs · Post by **Don Audio Labs** » Fri Jun 14, 2013 8:23 pm

Pretty awesome that you guys worked so well together to kinda fix this.

Kudos to anyone involved!