WMV "Encoded date" metadata, a mystery?

[Gew]

Hi!

I was just curious on this metadata. Since running mediainfo.exe on a few of my .wmv files turned out with:

Encoded date : UTC 1970-01-01 00:00:00.000

Is there any way to modify it? Now check this out. I downloaded an metadata util called "TigoTago v2.0", where you can see the metadata for each file really detailed. I found this (UInt64) value there, "WM_EncodingTime", which I thought seemed logical that would be the right setting. So, I assumed that its value was of type "ctime" (seconds passed since the magical date stated above). So, I entered a random bounce of digits there. Re-saved. Now, Mediainfo gives me:

Encoded date : UTC 1970-01-01 00:00:00.000 / UTC 2066-11-12 21:47:43

Strange, huh? The first (70-01-01..) date is still there, but the new one is somehow "added". Wtf. I was looking for a way to edit the date, not add another. Aawergh. I thught that this metadata field could perhaps not be used at all, but just some issue with mediainfo. So, to test this theory, I ran wmenc.exe and encoded a couple of seconds of pure screen cap. Saved. Now I ran Mediainfo on this -- newly produced -- file. I get:

Encoded date : UTC 2010-03-22 23:30:40.806

Which was just about how I wanted it to look on the other ones. What's the magical trick here? Anyone who knows some answers? I popped this fresh .wmv in TigoTago and tried to look for some suspicious metadata field, but it simply isn't there.

Anyone who has any ideas? Perhaps some other metadata editor for WMV's? I found TigoTago av reading this old thread, which is a couple of years old:

https://forum.videohelp.com/threads/254797-Editing-WMV-metadata-attributes-tags

Anyways, thankful for all answers!

[Baldrick]

Tried Windows Media File Editor that is included in Windows Media encoder?

[Gew]

Yep!

Tried that aswell, first thing I did actually. There's no field for date, but I also tried importing a XML header with <WMENC_QWORD Name="WM/EncodingTime" value set, which yields the same results as directly modifying the WM_EncodingTime value in TigoTago. So, no luck so far.

[poisondeathray]

You can probably do it with a hex editor

[Gew]

You can probably do it with a hex editor

Indeed, I prolly could. Question is why it has got to be so darn complicated, with mnfo returning multiple encoded date stamps, etc.

I just made another elaboration. I capped a couple of secs with wmenc.exe (to get a .wmv with proper/recent dates present @mediainfo.exe). Then I exported its XML header sheet, just to inspect it, to see if there would be something there of interest. Nothing. So it's simply not there.

My conclusion is as follows, WMV files may contain two "encoded date" stamps. One (the first one returned by mediainfo.exe) is "hardcoded" somewhere in the container, thus -- like you say -- only possible to change through manual hex editing (a process that must be a real b-tch, first converting the file's given encoded date into ctime format, to know what and where to hex-search, etc), whereas a second encoded date stamp is returned by mnfo only if <WMENC_QWORD Name="WM/EncodingTime" value is set.

[Gew]

Correction..

WM/EncodingTime is stored as a FILETIME structure, which is an offset
from January 1, 1601.

Apparently not 'ctime', but 'filetime', a date-time structure that I haven't even heard about until now.