Simple tags with spaces can get parsed incorrectly, first word of name removed from output

[jupester]

Hi,

First off, thank you so much for such a great and useful application. I am using the most recent beta "MediaInfo_CLI_25.10.20260103_Windows_x64" and the issue I have noticed that has occurred in I think all versions since 25.07 is that I have mkv files with simple global tags such as this:

<!-- <!DOCTYPE Tags SYSTEM "matroskatags.dtd"> -->
<Tags>
  <Tag>
    <Simple>
      <Name>Encoded by</Name>
      <String>String1 String2</String>
    </Simple>
  </Tag>
</Tags>

for some reason the first word is removed (in this case "Encoded") from output text, see here example ffprobe output:

compared to the latest version of MediainfoCLI:

Here is a sample mkv for repro purposes:

medinfo_bug.zip

I have actually seen this issue in the past a few years ago, but it was resolved but has since come back again recently.

[cjee21]

Not sure what happened in MediaInfo but MKV specifications say:

https://www.matroska.org/technical/tagging.html#:~:text=The%20TagName%20SHOULD%20NOT%20contain%20any%20space

---

In MediaInfo, XML is okay:

            <Encoded_Application>mkvmerge v97.0 ('You Don't Have A Clue') 64-bit</Encoded_Application>
            <Encoded_Library>libebml v1.4.5 + libmatroska v1.7.1</Encoded_Library>
            <extra>
                <Encoded_by>String1 String2</Encoded_by>
            </extra>

So I guess it is because it became sub of Encoded_Library in text view so it only has 2nd part (by) and is indented.

[cjee21]

Anyway, this issue should be edited. It is not because of the space although there isn't supposed to be spaces in MKV tag names. FFmpeg automatically convert tag names to all caps and spaces to underscores if using it to write MKV tags.

Here is a sample file that demonstrates tags with space can be parsed correctly by MediaInfo.

output.zip

[jupester]

I was trying to be concise in my original post, I thought the screenshots and repro mkv were sufficient, but maybe I should have mentioned that I didn't create any of the mkv that display the issue, they seem to all have been made with mkvtoolnix, some are over a decade old, (but my repro was made in the latest v97 as you can see from the screenshot), and I guess I should of mentioned that if I remux my original repro mkv with ffmpeg that mediainfo displays it normally again.

I don't know what you want me to edit this issue to say?, even it matroska tags shouldn't have spaces, I'd assume they need to be tolerated like they were in the past up to v25.07? If not then I can just close the issue, and even if mediainfo can sometimes display ok with spaces I named the topic "...CAN get parsed incorrectly" not "...DO get parsed incorrectly" although I guess maybe they are parsed correctly, but not output as expected.

Anyway if required here is another repro that doesn't use the word "Encoded" but still shows the issue:

repro2.zip

[cjee21]

Did some more tests, here's what I think is going on.

Whatever tag or element that is immediately displayed after certain tags like "Writing library" will become a sub element if it contains spaces. This causes first word to be removed and the rest to be indented.

This appears to be introduced by MediaArea/MediaInfoLib@21074e3 which is in version 25.09 onwards.

Test files to demonstrate that is is due to position of element and not the actual content of element.

tests.zip

Only @JeromeMartinez knows what to do.

PS. This issue should be in MediaInfoLib repo?