unreadable AVI files

[pijo]

Good evening Videohelpers,

I bought a tiny gadget camera that creates huge (but only 5-minute-long) 1080p AVI files, but only about 4 of them can be read.

The others (about 30, saved directly by the device onto mini TF memory cards, are around 800Mb each but cannot be read by VLC.

I have already tried using DivFix++ and VirtualDub to try to repair the indexes, to no avail.

I just read on another thread about Avidemux, but I get this error when trying to open them with Avidemux: Cannot find a demuxer for (pathway to file)...avi. / Could not open the file.

The following two screenshots are the results of using Media Info and XMediaRecode, respectively.

Thank you for any suggestions on repairing these huge AVI files.

[redwudz]

If it works, you might try to open one in VDs Hex Editor. If it shows as mostly all zeros, there likely isn't any data.

And welcome to our forums.

[pijo]

Thank you for your welcome, and tip, Redwudz.

I'm not familiar with Hex Editors, and cannot find VDs one, but I just ran one of my unreadable AVIs with AviHex, and here is the screenshot of the bottom of the results... you're right, the 1st two columns are all 0's, but the file takes up 806Mb, and takes forever to move to a new location, so there must be data there, mustn't there be?

[raffriff42]

You're looking at the very end of the file, where all FF's aka junk chunks are not unusual. Try getting a screen shot from the middle to the file.
(BTW the gray column is file position, not actual file contents)

The Hex Editor mentioned by redwudz is a VirtualDub feature: Tools menu, Hex editor. (screen shot)

You say you "tried using DivFix++ and VirtualDub" but without saying exactly what you did and quoting the exact error message(s). We need this information to help you.

[pijo]

Thank you for helping RaffRiff42.

Here are screenshots from running one of my AVIs through "fix" with DivFix++ (the error message says "Input file is not an AVI file!", and I believe it told me the same thing when I tried to "strip index" as well. Here is also a screenshot from the middle of the data generated by running the same AVI through AviHex (all 0000s and FFs from top to bottom). I'll now go ahead and do a VirtualDub Hex edit and report back.

[pijo]

As feared, my unreadable AVIs / non-AVIs are still showing all FFs and .... from top to bottom using VirtualDub's hex editor.

So how is this file still occupying 806MB of disk space?

Thanks again!

[redwudz]

This is from a photo, but similar to a VD Hex Editor grab from a video. You can see it looks pretty much random, but not as many zeros or FF's.
I'm guessing that the header or footer relates the size of the file, so that may be what you see for size.

[raffriff42]

With all FF's it's obviously not recoverable. Maybe what happened is the camera allocated disk space for AVI writing (I know Fraps does this for instance) and then abandoned it for some reason - like crashing?

[JVRaines]

So how is this file still occupying 806MB of disk space?

Because 00 (zero), FF (255) and everything in between are valid byte values to put in a disk file. The disk operating system doesn't care whether the data means anything to your application.

[pijo]

Well, I do appreciate your help, gentlemen.

I admit I know next to nothing about file storage, i.e. what a device is actually doing when alloting space, indexing, and presumably recording data, but if these files truly are nothing then why does Explorer show their sizes to be anywhere from 650 to 900MB, and take forever to upload from the device to my PC?

When I connect the device to my PC via USB cable, Windows asks me if I should "correct" the device or "open it anyway", the same question it asks me each time I connect my (older) cell phone to upload the contents of its memory card, and I always choose "open it anyway". Is this a question of formatting the memory card? And could it have something to do with the underlying problem of creating these massive "empty" AVI / non-AVI files?

Thank you once again.

[gdx]

There is also the posibility that the card is fake, the symptoms also point to that direction.

http://www.phonearena.com/news/Beware-of-fake-microSD-cards-Heres-how-to-tell-a-counte...iginal_id77769
http://www.happybison.com/reviews/how-to-check-and-spot-fake-micro-sd-card-8/
http://www.bestmicrosdcard.com/verify-fake-micro-sd-card/

[JVRaines]

I admit I know next to nothing about file storage, i.e. what a device is actually doing when alloting space, indexing, and presumably recording data, but if these files truly are nothing then why does Explorer show their sizes to be anywhere from 650 to 900MB, and take forever to upload from the device to my PC?

A computer data file is a series of byte values. Whatever they are, they are not "nothing." The number of bytes in the file determines its size, regardless of whether those bytes could be interpreted as a video or your grocery list. Even if they are all the same meaningless value, they take up the same amount of space.

When I connect the device to my PC via USB cable, Windows asks me if I should "correct" the device or "open it anyway", the same question it asks me each time I connect my (older) cell phone to upload the contents of its memory card, and I always choose "open it anyway". Is this a question of formatting the memory card? And could it have something to do with the underlying problem of creating these massive "empty" AVI / non-AVI files?

There could be problems with the file system that are related to your AVI woes. Or it could just be that you didn't safely remove the drive last time (Windows gets cranky about that). Once you suspect corruption, don't try to repair the disk or write anything to it until you have a backup.

[pijo]

Thanks gdx and JVRaines.

I hadn't heard of fake SD cards circulating, and since I did indeed buy this as a pair of 32GB TF cards on eBay (I've been using the other one in a smaller capacity device and haven't noticed any lack of storage issues for that other one), so I found a small program called h2testw from the German site Heise

http://translate.google.ca/translate?hl=en&sl=de&u=http://www.heise.de/software/downlo...%3Den%26sa%3DG

that tests a card's actual capacity and performance.

Here's a screen shot of the results, showing that it's actually only got 14GB of storage as opposed to the 32GB advertised, and as it was a "no-name" cheap brand, I guess I got what I paid for... so, problem solved?

[gdx]

I think that you did the test wrong, to do the test you need the card empty and do a "write+verify" on al the availble space. But even if the test file that dosen't means a fake card as the card can also be damged or defective, if both card were purchased at the same time this seconcd option is also a posibility. You can test thecards copying to it good files and then check does files, you can use videos for this.

[pijo]

Thanks for sticking with me, gdx.

I just did a "write and verify" scan of the mini memory card using H2testw, and although it took forever, the results are indeed more complete:

Warning: Only 30569 of 31984 MByte tested.
The media is likely to be defective.
5.5 GByte OK (11704535 sectors)
24.2 GByte DATA LOST (50900777 sectors)
Details:0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
24.2 GByte corrupted (50900777 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x0000000060a58000
Expected: 0x0000000060a58000
Found: 0x0000004060a58000
H2testw version 1.3
Writing speed: 4.99 MByte/s
Reading speed: 3.57 MByte/s
H2testw v1.4

I'm not sure what any of this means, however.

[pijo]

I forgot to add that after using the H2testw utility the 1st time, it wrote two little folders to the problematic mini data card, and the icon is also a snazzy blue SD icon now instead of a generic mass storage unit icon.

The second time I used it (write and verify), it created 29gb of 1gb files, which I just had to erase afterward. So the program does think the data card has nearly 30gb of memory?

By the way, here is the generic packaging of the cards I bought (on eBay, sent from Vanuatu...)

[gdx]

I'm practically sure that the card is fake, the card is recognized as 32GB card but only 5,5GB was tested as good, the good space is odd bus as not all the space was tested is posible that originally is a 8GB with the firmware altered. That generic packaging is comon in generic fake cards and some vendors can send fake and good generic cards in the same purchase.

The fake cards can bedivided in:

generic that lies about is capacity and posibly speed rating.
generic that lies about its speed rating but have the declared capacity, the majority of generic cards that are advertised as class10 or higther fall here as the are only class4 or with luck class6.
brand falsification that lies about capacity and posibly speed rating.
brand falsification of full capacity, this cards typically also lies about is speed rating.

To buy cards online is generally a bad idea if the shop is not really reputable and most from ebay aren't, specially the cheap ones.

[pijo]

Thank you very much, gdx.

I'll buy a new card from a more reputable source in the coming days, and report back here. For 32gb, it seems the going rate is just under 15€ 'round these parts.