Magic Lantern Forum

Using Magic Lantern => Raw Video => Topic started by: kaco on July 19, 2014, 09:07:16 PM

Title: Empty 82 Gb MLV file?
Post by: kaco on July 19, 2014, 09:07:16 PM
Hi,

I've got one 82,2 GB (88 354 624 096 bytes) MLV file and I cannot read it. Could someone please help me to investigate if the file is totally empty, or just partially corrupted?

We shoot whole day on many cards. Card containing this file had previous and next MLV without a problem. We even do not remember any on location problem. Maybe the battery run out during recording? We really can't remember. We shoot with the some build from feb to may, but don't know exactly which (we updated the cards in the meantime.

Here's some details:
Code: [Select]
K:\>mlv_dump -v M07-1702.MLV

 MLV Dumper v1.0
-----------------

Mode of operation:
   - Input MLV file: 'M07-1702.MLV'
   - Verbose messages
   - Verify file structure
   - Dump all block information
File M07-1702.MLV opened
File M07-1702.M00 not existing.
Processing...
[ERROR] Invalid block size at position 0x00000000
Processed 0 video frames
Done

Here's the screenshot from HxD:
https://drive.google.com/file/d/0B-7-kTVW5sAqSjNaaHM2eHQ3bUU/edit?usp=sharing

How could the camera create 82 gigs of zeros?
Title: Re: Empty 82 Gb MLV file?
Post by: dmilligan on July 19, 2014, 09:41:00 PM
If the whole file is 0s like that then I'm afraid there's nothing that can be done. You should plan for and expect this kind of thing to happen on untested software.
Title: Re: Empty 82 Gb MLV file?
Post by: g3gg0 on July 20, 2014, 03:36:14 PM
How could the camera create 82 gigs of zeros?

likely: no
possible: yes

never have seen anything like that before.
the *whole* file? e.g. search for 0xff or 0x01
Title: Re: Empty 82 Gb MLV file?
Post by: jimmyD30 on July 20, 2014, 07:27:17 PM
Even though my camera can handle files larger than 4GB, just from a practical/safety point of view I still limit my raw video files to 4GB. The thought is if something should go wrong at some point of the recording, hopefully with many smaller files, less footage will be lost.
Title: Re: Empty 82 Gb MLV file?
Post by: Midphase on July 20, 2014, 11:14:52 PM
Even though my camera can handle files larger than 4GB, just from a practical/safety point of view I still limit my raw video files to 4GB. The thought is if something should go wrong at some point of the recording, hopefully with many smaller files, less footage will be lost.

You mean you don't use ExFAT, or do you mean you limit your takes to about 1 minute or less?
Title: Re: Empty 82 Gb MLV file?
Post by: jimmyD30 on July 21, 2014, 02:42:04 AM
I don't use exFAT and with the 5DM3 build I think there's a ML menu setting for it too?
Title: Re: Empty 82 Gb MLV file?
Post by: kaco on July 21, 2014, 03:10:39 AM
To all: If that shot could have been done with smaller file we would have done that. I am okay with the risks. Just wanted to know, if it's completely or partly corrupted. (Btw, we shoot more that 2-3tb/day and have filmed many many days)

G3gg0: i will search for it in a week, currently away from office
Title: Re: Empty 82 Gb MLV file?
Post by: jimmyD30 on July 21, 2014, 12:21:56 PM
Did you try rebuilding the file header? Maybe copy from a different working .mlv file? If you are going to mess with the file content, I would suggest making a copy first ;)
Title: Re: Empty 82 Gb MLV file?
Post by: kaco on July 23, 2014, 06:14:36 PM
JimmyD30-- how can i change thr headers?
Title: Re: Empty 82 Gb MLV file?
Post by: g3gg0 on July 23, 2014, 07:28:24 PM
JimmyD30-- how can i change thr headers?

not that simple. first check if there is any data ;)
Title: Re: Empty 82 Gb MLV file?
Post by: kaco on July 29, 2014, 11:03:55 PM
OKay, not any  0xff or 0x01 phrazes found, so I'd say we'll done here :(