Why are autosave files so much smaller?

[philbrown]

Distantly related to Shooshie's story about hold 'em/fold 'em I had been carrying forward a file for years, re-naming and re-using it as a new starting place for each week's job. Long story short, I just started using autosave and immediately noticed how much smaller the autosave file was, in comparison with the original - in one case a TENTH of the size! I started thinking about what could cause that and theorized it might be undo history. Then I looked at the Undo History preferences and realized I'd never changed the factory default and seems like the default settings would add up to a lot of cumulative bloat over time.
Anyone have any experience or thoughts about this?

I could not find any mention whatsoever of Autosave in the DP 7 manual.

[FMiguelez]

I've always assumed the undo history is part of the autosaved DP file.
I've never noticed those files being any smaller than the original. I'll check how it is with mine when I fire up DP later today.

[philbrown]

I'm seeing now where even if I start a fresh file and work on it for a few hours the autosave file is always way smaller.

It's funny, I was looking at SSD drives to improve load times and such, and by setting aside older files and using the the much smaller autosave files my load times are WAY quicker with no hardware $$ needed.

[buzzsmith]

Are you doing any audio, Phil, on your projects that the Autosave files are smaller?

Just guessing that the AS files may not actually include the audio and contain just pointers.

Dunno...I guess I'll have to go look for myself!

Buzzy

[philbrown]

Are you doing any audio, Phil, on your projects that the Autosave files are smaller?

Just guessing that the AS files may not actually include the audio and contain just pointers.

Dunno...I guess I'll have to go look for myself!

Buzzy

Yes there are usually 3 hour long stereo files in the work I do, but when I trash the original and use the autosave file, there's nothing lost at all that I can see. The only difference is the load time is so much faster, and DP seems to be a little "snappier". The original DP can't contain all the audio info as the DP file would be gigabytes instead of MB's in this case.

[buzzsmith]

Yes there are usually 3 hour long stereo files in the work I do, but when I trash the original and use the autosave file, there's nothing lost at all that I can see. The only difference is the load time is so much faster, and DP seems to be a little "snappier". The original DP can't contain all the audio info as the DP file would be gigabytes instead of MB's in this case.

When you say "trash the original", you are disposing of the DP file, but not the audio folder within the project folder?

So (maybe) the audio is still being pointed to by a DP Autosave file.

Now, I HAVE to go look for myself!

Buzzy

[philbrown]

When you say "trash the original", you are disposing of the DP file, but not the audio folder within the project folder?

So (maybe) the audio is still being pointed to by a DP Autosave file.

Buzzy

Yes to your questions, Buzzy. The DP folder is the same, I'm just taking the single original DP file itself, removing it from the folder, removing "autsosave" suffix from the autosave file (that's already in the folder) and using that in place of the original. Everything else, audio files, analysis files, etc unchanged. In my case, on different types of files, the autosave has ranged from 1/2 to 1/10 of the original file size.

I'll do some more testing and observation when I have more non-work time. I just thought 1. someone might know more of what's going on here behind the scenes (maybe some Magic person) and 2. It seems to be a really easy way to trim file size, load/save time and I swear even bounces seem to be going noticeably faster. I haven't found a down side or anything missing so far. Obviously cover your butt and don't trash anything valuable or irreplaceable on my advice though!

[MIDI Life Crisis]

I'd like to know what's causing the original file to be bloated in the first place.

[Killahurts]

My theory is, that the Autosave files have some kind of compression applied when they are made, to make them smaller on purpose.. It makes sense really, because one might build up hundreds of Autosaves, and that would eventually become wasteful of HD space. When you open an Autosave, it would expand back out (the compression would be lossless).

[buzzsmith]

Well, curiosity got the best of me so I checked a few...
(All are 22 Autosaves per song.)

Song 1: 5.5 MB - - - 1.75 GB in the Audio Folder
Autosaves: Most Recent: 496 KB...oldest (2 days ago) 1.7 MB

Song 2: 3.6 MB - - - 742 MB in the Audio Folder
Autosaves: Most recent: 2.7 MB...oldest (6 days ago) 2.7 MB

Song 3: 3.7 MB - - - 1.25 GB in the Audio Folder
Autosaves: Most recent: 393 KB...oldest (30 days ago) 664 KB

So, I'm not sure what this means other than to verify what Phil is seeing.

Buzzy

[philbrown]

Answer: UNDO HISTORY. That's the only difference I see.

A simple DP file: 16.1 MB
Same file.autosave: 254KB
Same autosave file re-saved with no changes except name change: 254KB
(eliminates some kind of autosave-specific compression, which I thought was extremely unlikely anyway).

The only difference I can find is Undo History - it's been emptied out in the autosave files.
If you save versions as you go like I do, you might consider changing Undo History prefs to save some unneeded file bloat.

[bayswater]

Answer: UNDO HISTORY. That's the only difference I see.
---
If you save versions as you go like I do, you might consider changing Undo History prefs to save some unneeded file bloat.

I would have hoped autosave would relieve us of the need to constantly save versions of a project by including the undo history. If we still need to do that, autosave is pretty pointless.

[philbrown]

Answer: UNDO HISTORY. That's the only difference I see.
---
If you save versions as you go like I do, you might consider changing Undo History prefs to save some unneeded file bloat.

I would have hoped autosave would relieve us of the need to constantly save versions of a project by including the undo history. If we still need to do that, autosave is pretty pointless.

It just depends on how you like to work and save things I think. I feel like I'm better informed about choices though and how to set my preferences accordingly. I personally am looking at autosave more as a failsafe if I have forgotten to save the last hour and DP folds up its tent (and that NEVER happens after I have just saved) so I haven't lost an hour of PITA editing or whatever. At least we know now that autosaves have no undo history, in case you were depending on the fact that it did.

[FMiguelez]

I just checked some DP files, and the regular file equals the corresponding autosaved file in size.

For instance, my empty template (no audio) currently is 24 MBs, just like the autosaved versions. If I dump the undo history, the file size still matches both version (regular and autosaved).

[philbrown]

I just checked some DP files, and the regular file equals the corresponding autosaved file in size.

For instance, my empty template (no audio) currently is 24 MBs, just like the autosaved versions. If I dump the undo history, the file size still matches both version (regular and autosaved).

Weird! Not at all what Buzzy and I are seeing. I haven't got a clue...