[FFmpeg-devel] [PATCH] movtextdec: fix handling of UTF-8 subtitles

Jan Ekström jeebjp at gmail.com
Sat Mar 24 18:27:33 EET 2018


On Sat, Mar 24, 2018 at 6:05 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> Could you confirm that this is also what QT does?
>
> Or is it impossible that the patch breaks something?
>

Everything can in theory break something. Anyways, it was widely
understood that 3GPP timed text was a better defined MOV timed text,
but I did have a quick look at Apple's qtff.pdf, which happily enough
actually defined the start and end characters (yes, they are marked as
"characters") as follows from the "Subtitle Style Atom" definition
("styl"):

Start character
    A 16-bit value that is the offset of the first character that is
to use the style specified in this record.
    Zero (0) is the first character in the subtitle.
End character
    A 16-bit value that is the offset of the character that follows
the last character to use this style.

Best regards,
Jan


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