[FFmpeg-trac] #9419(undetermined:new): support current standard font mimeypes in matroska metadata
FFmpeg
trac at avcodec.org
Sun Sep 12 17:16:45 EEST 2021
#9419: support current standard font mimeypes in matroska metadata
-------------------------------------+-------------------------------------
Reporter: bfhpx4hjah | Type:
| enhancement
Status: new | Priority: normal
Component: | Version: git-
undetermined | master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
Only legacy font mimetypes are recognized in matroska mimetype metadata
tags. E.g. a truetype font is only recognized if the mimetype metadata tag
is "application/x-truetype-font", the current standard "font/ttf" isn't
recognized.
One problem resulting from this is that when using the subtitles filter,
fonts tagged with current standard mimetypes won't be used and subtitles
thus might be rendered incorrectly.
The current standard mimetypes for fonts can be found here:
https://www.iana.org/assignments/media-types/media-types.xhtml#font
Mkvtoolnix-gui uses these mimetypes for fonts by default, any matroska
file created by it containing attached fonts will exhibit this issue
(unless the option to use legacy mimetypes for fonts is enabled or an old
version of mkvtoolnix-gui is used).
How to reproduce:
Create a matroska file with an attached font using a recent version
(58.0.0 or later, based on my testing) of mkvtoolnix-gui and try to open
the file with ffmpeg:
{{{
% ffmpeg -i mime_current.mkv
ffmpeg version N-103603-gc4973e2148
built on arch linux
...
[matroska,webm @ 0x562ab0532b40] Could not find codec parameters for
stream 1 (Attachment: none): unknown codec
...
Stream #0:1, 0, 1/90000: Attachment: none
Metadata:
filename : NotoSans-Regular.ttf
mimetype : font/ttf
...
}}}
Simply changing the mimetype metadata tag to the legacy value (e.g. using
mkvpropedit or the edit headers tool in mkvtoolnix-gui) will solve the
issue:
{{{
% ffmpeg -i mime_legacy.mkv
ffmpeg version N-103603-gc4973e2148
built on arch linux
...
[matroska,webm @ 0x55649aa2eb40] All info found
...
Stream #0:1, 0, 1/90000: Attachment: ttf
Metadata:
filename : NotoSans-Regular.ttf
mimetype : application/x-truetype-font
...
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/9419>
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