Recovered m2ts fragments: Resurrection

[Alex_B]

After eight years of recording and deleting video on a Panasonic HDC-HS80, running assorted data recovery software has yielded a couple thousand m2ts fragments, most of which are unplayable. Obviously, the smallest of these contain little or no actual visual data but I'm interested in viewing the ones that do. I hope to salvage even individual frames if that's all that's possible. I've been looking into comparative hex editing and searching for time code info but (being new to this) I feel a bit out of my depth.

Any suggestions on how to proceed would be greatly appreciated!

Thanks!
A.B.

[themaster1]

Have you tried to recover these videos with Photorec? I know for a fact none of the "paywares" worked better than this beast. Food 4 thought

[Alex_B]

Wow! Had never used photorec before. Did an amazing job on larger video fragments but actually recovered fewer of them than other programs I'd used. Possibly just need to dial in the scanning options. Really interesting program. Thanks!

[abolibibelot]

Wow! Had never used photorec before. Did an amazing job on larger video fragments but actually recovered fewer of them than other programs I'd used. Possibly just need to dial in the scanning options. Really interesting program. Thanks!

Fewer in number I suppose, but is the total size of recovered fragments similar, or the total size of actually readable recovered fragments similar ? Most recovery softwares will analyse the FAT32 metadata and then blindly extract whatever is detected as a file there, even if it's been overwritten since and is therefore “garbage” (no valid header). Photorec only does a “raw file carving” type of recovery, based on the detection of known “file signatures”, so when it extracts a file of a certain type, it should be readable – unless it's a false positive, which is more likely to happen for file types which have a short signature sequence (for instance a random JPG signature can be found quite often inside other media files, in which case Photorec can erroneously interrupt the extraction of a valid MP4 video file and extract a dummy JPG, then consider the valid MP4 file as “broken”) ; therefore, for best results, if you only need to recover AVCHD files, you should first go to "File Opt", then uncheck all file types, except m2ts).
R-Studio is generally excellent for both metadata based recovery and raw / signature based recovery, but for a few file types which have a sort of “modular” structure (a new header for each chunk of data), like MPG, VOB, and MTS/M2TS, it gets confused and can extract thousands of small fragments (considering that one header = one file) instead of recovering the original files as a single chunk, even if those were not fragmented. Of course, the problem is compounded if there's fragmentation involved, which is highly likely “after eight years of recording and deleting videos”...

But I'm not exactly sure of what you intend to do... Do you need to recover a particular clip, or is it just out of curiosity, for the sake of science ?

[Alex_B]

Yes, definitely more for the sake of science/a more avant garde style video project, exploring the aesthetics of corruptions, distortions and data moshing which can be sort of accidentally beautiful. As far as "intact" video is concerned, I've had really similar results from Disk Drill, Recoverit, Ontrack Easyrec, EaseUS, and now photorec. What I find really interesting (and what I need to educate myself about) are the differences between the programs' algorithms. Each has a very different idea of what is "useable" and since I'm looking for video that most programs would consider garbage (overwritten and truncated) it's proving challenging but fun all the same. Of all the recovery programs I've tried, EaseUS Data Recovery Wizard yielded the most viewable fragments. What I dream of (and which probably does not exist) would be a recovery system which, beyond recognizing individual frames of visual data, ignores file structure almost entirely and shows you 100% of your drive contents. Don't know if such a thing exists without getting into forensic software. In lieu of this, I may keep trying to learn how to fix m2ts streams in a hex editor though I'm not having much luck.

[abolibibelot]

Yes, definitely more for the sake of science/a more avant garde style video project, exploring the aesthetics of corruptions, distortions and data moshing which can be sort of accidentally beautiful.

Well, at least it gives hope to ugly people that perhaps someone, some day, will find 'em "accidentally beautiful"...

I'm not quite sure of what you're trying to achieve, though. Those "accidentally beautiful" distortions are a matter of interpretation of the invalid/corrupt data by a particular hardware or software player, and most likely another player will display something different – or nothing at all – since this is no standard video data (in my experience, SMPlayer is good at displaying "whatever there is" in a corrupt video file, better than VLC Media Player, which is itself usually better than MPC). But then if you want to use the result for a video project, you have to import the wanted bits in such a way that the editor displays them just the same as you watched them initially, so how do you proceed, by doing screen captures or something to that effect ?

As for getting "100% of the drive's contents", you can easily do that with a hexadecimal editor, for instance with WinHex, open the whole drive (Tools => Open Disk), search the first instance of a valid M2TS header (normally it should be found at the sector number corresponding to the name of the first file extracted by Photorec, as it names files after their 1st sector number, e.g. f12345.m2ts starts at sector 12345, or offset 12345 x 512 = 6320640), so that video players will be forced to at least attempt to play something out of it, set this as the beginning of a "block" (right-click => Beginning of block), then go all the way to the end (either by scrolling down, or with Navigation => Go to => End of file, or with CTRL+END), set the last byte as the end of block (right-click => End of block), then extract this block as a file (Edit => Copy block => Into new file) – and select a location large enough to store that gigantic bunch of potentially accidentally beautiful garbage... then try to have various players find some hidden avant garde garbled weirdness in that !

[Alex_B]

Haha! Yeah, all artsy stuff aside, it's also just really interesting to look back at the life of an eight year old camera. If something can be made of the fragments, great! If not, no big deal. This info will still be useful in the future I'm sure. I'm enjoying getting acquainted with hex editing. Thanks for indulging a noob!