Changing the datestamp

[Matt Zedit]

Hi,

I was looking for a good place where people know what they are talking about, and i think i found it ! This forum has real impressive threads !

My question is : i want to change the datestamp of my DV AVI files.

The reason : i captured old Hi8 tapes with my Digital8 Sony and i made the individual clips myself using Virtualdub, because there is no timecode so a tool like Scenalyzer can't make scenes from changes in the timecodes (optical detection ? too bad...).

I'd like now re-export them into a Digital8 tape, being able to recapture it later, automatically creating AVI files for each scenes. Scenalyzer will do that for me if i can put a date/time stamp on each frame of the AVI file as DV would do.

I found a tool that can change the timecode, but the guy did it wrong i think : he puts only the time code at each second, so each frame is not datestamped ! (the site of this utility : http://icqphone.ru/video2tv/ where you can find a tool to extract DV timecode in SUB format for subttles...this one works great).

I have two solutions :
- looking for a software that will do it for me. I could'nt find one, till several days. Any ideas ?
- making myself this kind of tool. I can do it, but i could not find any info concerning where they are putting the timecodes in AVI files (the OpenDML specification tells where, but my AVI files are not like they should be regarding this specification).

Anyone can help me ?

Thanks

Matt

(oups, i hope it was'nt too long, and sorry for my bad english...)

[Jeff Donald]

Hi Matt, welcome to DV Info. There is a tremendous amount of knowledge among our members. A large amount of that accumulates on a daily basis and is stored in the archives. You can search the archives for your answers by using the search button in the upper right.

Your topic was covered recently and a search will turn up several threads that discuss what you want to do. If you have additional questions on the topic you might want to post in an existing thread so the information will be easier to find for the next guy in your shoes. Thanks again for posting.

[Matt Zedit]

Hi Jeff,

Thanks for your reply, and sorry about having put this thread in a wrong forum...

I've searched a lot in the forum before asking this question, as i am useually doing in the other forums i'm registered. And i found nothing about changing the datestamp in an AVI DV file...

I searched again after your post, and nothing... If you know where is the post that is talking about that, you'll make me an happy man ;)

It seems that the search engines has problems when checking the "Search titles only" button.

Thnaks a lot

Matt

[Nigel Moore]

Try a search on "date avi", I found about 5 hits, one of thich was this. I'm afraid that my weblink is currently too unstable for me to cross-check all of the threads against your requirements. That is your mission, should you choose to accept it! :-)

[Jeff Donald]

Hi,

Start with this post, I think it may help with your project. If I've got it wrong, post back and the topic will get bumped back to the top.

[Matt Zedit]

Jeff, Nigel,

Thanks a lot for your time, i found these threads when doing my searches.

My problem is not to capture individual clips according to the date time (i'm doing that for long time with scnealyzer), nor to show the date time (i'm doing that with DVSubmaker if i need it, for example for doing an index of all my tapes), but to CHANGE the date/time stamps of a a clip (or of each frame in a AVI file).

Any ideas ?

Matt

[Rob Lohman]

Matt,

As far as I know there is no software other then the one you
pointed out to change date/time/timecode INSIDE a DV STREAM.
Avi can have a timecode track as well and I believe most NLE's
can work with this.

DV does have its own data information. The problem is that the
DV format is not open. You need to pay to get the specs and then
hope you bought the right one to see what bits do what. I have
reverse engineered with the help of some information on the
internet parts of the format, but it is not enough to write a good
datetime changer. Sorry.

Your best bet might be to simply e-mail the author of the program
to talk about your problem and that his code only seems insert
the stuff every second instead of every frame.

[Matt Zedit]

Rob,

Thanks for your reply. I think we have the same kind of "problem" with the DV format.

Yes, unfortunately, we need to pay to have the "Blue book" that contains the DV specs... That's too bad because, for example, part of the DVCAM PRO format is freely available...

A friend of mine has Vegas 4 and he tolds me that when he exports a film to AVI DV format, the AVI has datestamps of his computer at the time he is doing the export !!! That could be a solution : change the date/time of your PC, launch an export, and you have the AVI file at the datestamp you want !

That's not a very "nice" solution, but i'll try it like that : make a macro with Visual Basic that will automate the loading of an AVI file, change the date/time of my computer, export the timeline, and do it again for the next AVI file.

Do you know if exporting from Vegas, and then having it back to the tape will only change this timecode ? The video won't be affected at all ?

Besides, studying 2 AVI DV files exported like that being only differerent on the datestamp will allow me to study byte per byte what is diffferent.

I'll give my results here.

Thnaks a lot

Matz

PS : The email of the guy who made DVSubmaker is not working... I sent an email to the guy who made Scenalzyer, i'll see if he will reply me :)

[Rob Lohman]

I have studied what information there is regarding the specs
and I don't think the DVC Blue book spec holds the answer
to our questions. I'm not sure because everyone I have asked
about this hasn't responded. Also it looks like the DVC Blue
blook spec isn't available anymore. It seems the spec is now
known as IEC 61834, see:

http://www.iec.ch/cgi-bin/procgi.pl/...&submit=Submit

This costs 187 swiss francs (around $150). However it looks like
this spec only describes the physical tape format and how data
should be stored and video/audio encoded etc. I don't think it
talks about the format and structure of the VAUX block which we
are interested in (I'm not sure though since information is hard
to find on this).

The second spec is the SMPTE 314M spec which can be bought
from:

http://www.smpte.org/smpte_store/sta...&stdtype=smpte

This costs $56 and seems to describe the digital side of things:

" Television - Data Structure for DV-Based Audio, Data and Compressed Video - 25 and 50 Mb/s "

But I'm not really sure on this either. Now if someone could just
tell me/us in which spec the information is definitely in I could
perhaps buy it (the $56 one then. I'm not gonna pay $150 for
a spec).....

Anyway, I know where the datetime is stored exactly and can
also tell you how it should work in basic form. I have some
algorithms to extract the datetime, but the problem is that there
is more info in the bytes than just the date time. It seems there
is also a morning/afternoon flag, day of the week bits etc. These
seem to mess up my result and I doubt comparing two headers
will get you definite answers on this.

If you want to know any more technical details or if someone
has some more information regarding technical details or those
specs please contact me at visuar@iname.com

[Matt Zedit]

I think the SMPTE 314M is the right document. Look at this thread, they give infos, but not something that we could really use. Check them, it's VERY interesting :

http://groups.yahoo.com/group/LinuxMovies/message/32
http://groups.yahoo.com/group/LinuxMovies/message/27

and also go to the main thread, and look at the answers :

http://groups.yahoo.com/group/LinuxMovies/message/25

They are saying that the SMPTE document is the one we need...

Matz

[Rob Lohman]

Together with what I have and the links you provided I think
I can construct a workable reader at least. I have received
your e-mail and will be sending a reply on all of this shortly!

[Matt Zedit]

Hi Rob,

I could get a copy of the standard S314M from SMPTE. This document describes the organisation of bytes within a frame in a DV video file : how DIF are organized, headers, subcode, vaux (no date time info inside), how video are encoded, how audio is sampled...

Concerning date or time, they are not saying more than the links i gave you on the Yahoo forum. There is only info about time in the subcode/timecode of a frame. I tried to apply the calculation on several DV files : the time returned is not the recording time.

In the document, they are mentionning the SMPTE 309M, and the 12M, for more info about the recording date and time : somewhere there are 8 BINARY GROUPS ((it's not clear where they are) where it seems that we can find recording date and time.

I searched with Google, it seems that SMPTE date and time actually resides within thoses binary groups : a search for 12 M return a lot of info, though i think the info we need are in 309M, which title is : "Television — Transmission of Date and Time Zone Information in Binary Groups of Time and Control Code".

Concering the date/time in 309M, I only found that (in http://swpat.ffii.org/pikta/txt/ep/1220/152/) :

The Time-Date Format
[0113] The date-time format is 8 bytes where the first 4 bytes are a UTC (Universal Time Code) based time component. The time is defined either by an AES3 32-bit audio sample clock or SMPTE 12M depending on the essence type.
[0114] The second 4 bytes define the date based on the Modified Julian Data (MJD) as defined in SMPTE 309M. This counts up to 999,999 days after midnight on the 17th November 1858 and allows dates to the year 4597.

The 309M standard is only 22 $, i think i'll get a copy.

Hope that will help our project.

Matt.

[Rob Lohman]

Did you get a copy of 314M? I was hoping it would include
detailed instructions on how to decode date/time, timecode and
things like camera settings. I have a wealth off information
that I reverse engineered myself. I'm currently in the middle
of delivering two projects so it is really hectic. I'll try to mail
you ASAP. Thank you for getting back to me and sorry it is
taking me so long to respond back....

Anyone know how to replicate time? :)

Thanks!

[Walter Berndl]

Originally Posted by Rob Lohman

Did you get a copy of 314M? I was hoping it would include detailed instructions on how to decode date/time, timecode and things like camera settings. I have a wealth off information that I reverse engineered myself. I'm currently in the middle of delivering two projects so it is really hectic. I'll try to mail you ASAP. Thank you for getting back to me and sorry it is taking me so long to respond back....

I see no one has added to this thread for a long time.

Matt and Rob - did you ever figure out how to rewrite the date and time in the DV AVI stream?

If so, you could now use a program, Hi8DateTime, that writes a SAMI subtitle file containing recording dates and times, to provide the data to rewrite the date and time in the DV stream.

Hi8DateTime extracts the recording dates and times from Hi8 tapes, indexed by timecode. For a 2 hour Hi8 tape, the SAMI file has around 7200 entries, one for each timecode second, and the corresponding recording date and time. Hi8DateTime only works with Hi8 tapes that were recorded with a camcorder that had the RC Timecode and Data Code function, and actually uses the old Hi8 camcorder. (You can tell if your Hi8 camera had this datecode feature if you could view the date and time on the TV screeen by pushing the DATA button, or the DATE(+) or TIME(NEXT) buttons on the camcorder. )

The following link has a list of Sony Hi8 PAL or NTSC Camcorders with the RC Timecode and the DATA Code feature: http://www.octochron.com/faqSonyHi8R...deDataCode.htm . And you can get more information about Hi8DateTime here: http://www.octochron.com/faqProduct.htm

Regards

Walter

[R Geoff Baker]

Not sure why this thread went on as long as it did -- the link below leads to a little utility that offers exactly what the OP asked for. I've used it to change the embedded date stamp to reflect the actual shoot date on analog material I transferred to DV -- you can also use it to change 16.9 flags and PAL/NTSC flags.

http://video2dv.com/index.php?lang=en&page=dvdtc

GB