[Matroska-devel] Hi, question about the MKV tags

Santiago Jimeno sjimeno at ya.com
Mon Jan 31 13:23:21 CET 2011


Hi all

In the email I sent speaking about CodecSpecs a while ago, I said that I 
would write other about Tags.
I think the current message provides me this opportunity.

Reading Tags is relatively easy (in spite of Nested Tags) in Visual .NET 
because of the easiness that .NET provides to work with XML Documents.

Editing or re-writing Tags is complicated. But I have it done in my program 
FileList.
But it's not still completed because of the difficulties that I have found 
with Cover Art.

Cover Art are in a Attachments block (separated of Tags block) that is a bag 
for everything that also includes fonts, text and subtitles and located in 
any place of the file. The result in this case is that, in spite of its 
initial advantages, it doesn't exist a program for editing Tags and I think 
it's for the extreme difficulty that implies to almost modify the whole 
file. I think that to have two different blocks for Tags and Pictures is not 
a good design. In Flac files a similar thing happens.

I am working in two possible solutions.
1.- Declaring VOID the block part that contains Pictures and writing them at 
the file end (next to Tags) in a second Attachments block.
2.- Including them in a new SimpleTag <TagName> COVERART inside TAGS, 
maintaining its structure. The binary data could be written as <TagBinary> 
or as <TagString> in Base64 so that was compatible with UTF8 (Vorbis 
Comments do it this way).

If somebody wants to test FileList program, one can download it in 
http://personales.ya.com/sjimeno/Download/MATROSKAFileList.zip
To show edit form --> double click in List Item.
This program is designed for audio files MKA, although it also reads video 
files MKV. Apply Tags edition is disabled at the moment due to the problem 
above mentioned.

Regards. Santiago Jimeno 





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