Re: [Fwd: Extended INFO tags (textual info in AVI files) in VirtualDubMod]

> Subject: 	Extended INFO tags (textual info in AVI
> files) in VirtualDubMod
> Date: 	Fri, 13 Jun 2003 00:07:51 +0400
> From: 	Alexander Sorkin aka Kibi <[email protected]>
> Reply-To: 	Alexander Sorkin aka Kibi
> <[email protected]>
> To: 	Christian Wiesner
> <[email protected]>
> 
> 
> 
> Hello, Christian Wiesner, author of VirtualDubMod!
> 
> I want to ask you to include support of extended
> INFO tags into your
> application.
> 
> I'm author of abcAVI Tag Editor - the utility for
> adding, browsing and
> changing textual info inside AVI files. In short
> abcAVI allows user to
> download information on movie from Internet Movie
> Database or type it
> by himself/herself and save that info inside AVI.
> 
> abcAVI Tag Editor has 1.5 years history and it's
> possible to estimate
> approximately several tens of thousands users who
> downloaded abcAVI.
> They are users who may or already use your software
> too. That's why I
> decide to send you this mail.
> 
> Tags is pretty comfortable way to hold information
> on digital movie.
> It's comfortable for users - no need to provide
> additional files with
> AVI. It's comfortable for programmers - Extended
> INFO tags introduce
> effective means to sign AVI files and keep
> information in
> computer-friendly (database oriented) form. It means
> that instead of
> one piece of information you can use a lot of
> different fields (it
> allows you to perform sorting, filtering etc data
> with eases).
> 
> Extended INFO tags are backward compatible with
> Microsoft's definition
> of RIFF INFO tags. RIFF INFO is standard way to hold
> additional
> information inside RIFF files, including AVI (DivX).
> 
> There are many tags in Microsoft definitions of RIFF
> format, you know
> "Title", "Copyright", "Author", "Comments" and
> other. The difference
> between Extended INFO Tags and RIFF INFO tags is new
> fields for
> description video/movie specific information like
> actors/actresses,
> editors, writers, producers, designers,
> certificates/rating and so on
> (you can see in the attachments at Comparison table
> of INFO tags). In
> short INFO tags for AVI are like ID3 tags for MP3
> files.
> 
> You may include ability both to read tags and to
> write tags - it
> depends on your software. You may code all the
> needed functions from
> the beginning by yourself or use following sources
> or binaries:
> 
> AVITags DLL - COM DLL for reading/writing INFO tags
> written in Delphi 5.
> It was published under GPL with open source.
> MMAviInf - little INFO tags editor written in
> Microsoft Visual C++.
> Also open source project.
> 
> P.S. The list of useful links:
> 
> DV Data in the AVI File Format (HTM)
>                   -
> http://abcavi.da.ru/dv_data_avi.zip
> Video For Windows Programmer's Guide (HLP)
>                   - http://abcavi.da.ru/dk_doc.zip
> Multimedia Registration Kit revision 3.0
>                   - http://abcavi.da.ru/mdrk.zip
> Microsoft Multimedia Standards Update, rev 2.0 (DOC)
>                   - http://abcavi.da.ru/riff1.zip
> Microsoft Multimedia Standards Update, rev 3.0 (PDF)
>                   - http://abcavi.da.ru/riff2.zip
> OpenDML AVI File Format Extensions (PDF)
>                   - http://abcavi.da.ru/odml1.zip
> The Microsoft Audio/Video Interleaved (AVI) file
> format (DOC)
>                   - http://abcavi.da.ru/avi.zip
> 
> **************
> AVITags DLL - http://abcavi.da.ru/avitagsdll.exe
> AVITags DLL Source (Delphi 5) -
> http://abcavi.da.ru/atagssrc.zip
> MMAviInf - http://abcavi.da.ru/mmaviinf.exe
> MMAviInf Source (C++) -
> http://abcavi.da.ru/mmaviinf-src.zip
> 
> P.P.S. Files in the attachments are:
>    abcavi.gif - screen shot of abcAVI Tag Editor
>    info.htm - comparison table of different tag's
> formats
>    test_avi.zip - AVI file with filled INFO tags
>    
> Best regards,
>              Alexander Sorkin aka Kibi.
> mailto:[email protected]
> http://abcavi.tk
> 

Hi Alexander

First, thanks for the information and links :)
VirtualDubMod already has basic capabilities for
reading and writing INFO tags in AVI files.
I already had a look at the table of 'official' and
'extended' tags when we implemented tags
reading/writing (which isn't part of the 'official'
VirtualDub program).

Since VirtualDubMod doesn't only work with AVI files,
but also OGM and Matroska files, we had to make some
choices concerning comments handling. To maintain an
easy to use system, for both the users and us (the
programmers) we chose a set of most-used kind of
comments (title, description, copyright, license, etc
...) independently from the containers. Thus when
processing a file the program holds in memory a list
of comments associated to the file (actually even on
each stream since for OGM - and Matroska - comments
can be specific to a track), and has a parameter (an
integer) describing the type of comment it is.
This way when someone opens an AVI file containing
some known tags (title etc) those comments will be
kept when saving to OGM (the program knows how to
write a comment describing a title, etc)
transparently.

For this reason, and again for keeping an easy to use
system, the set of known comments inside the program
is limited (listing every possible kind of comment for
each supported format - AVI, OGM, Matroska - isn't the
aim of VirtualDubMod which purpose is to process
multimedia streams).

For each container we used only the 'official' tags.
It's the case of AVI (anyway our set of known comments
doesn't really need tags that are defined in the
extended set of AVI tags) because those ones should be
supported (the others are only recognised by specific
filters or specific programs that defined those new
tags).

Still there are 2 important things in our system :
- when using the same container on input & output
(e.g. you open an AVI file and intend to save to
another AVI file) then the tags that wasn't recognised
(because they aren't part of our set of known
comments) will be saved again in the output file
(unless the user didn't want)
- to overcome the limitation of our limited set of
comments the users can still use 'user-defined'
comments : in this case they choose what is the tag
that will be used, and of course it's up to them to be
sure the tag they use exist


In my mind our program only needs to handle the
most-used tags (for AVI, OGM, Matroska ; as it does
already currently - not completly for Matroska though
;)) since its purpose isn't to 'tag' the files. I
believe that external (and specialized) programs like
yours still are the best for a more powerful tagging
:), like I believe that external programs like BeSweet
are a best choice for processing audio separatly
before muxing it with video :)


Best regards
Cyrius

__________________________________
Do you Yahoo!?
SBC Yahoo! DSL - Now only $29.95 per month!
http://sbc.yahoo.com


-------------------------------------------------------
This SF.NET email is sponsored by: eBay
Great deals on office technology -- on eBay now! Click here:
http://adfarm.mediaplex.com/ad/ck/711-11697-6916-5