Re: [Bino-list] Subtitles

[Martin Lambers]

On 22/04/11 16:45, Joe wrote:
>> On 20/04/11 12:45, Robert Pliszko wrote:
>>> I've noticed that when I used "<i>", "</i>" or "/" tags in srt/txt/sub
>>> subtitles, bino didn't show subtitle as italic, only display these tags
>>> on screen.
>>
>> Hm, I'm unsure about this. Can you give some more information? There are
>> two cases:
>>
>> 1. Plain text subtitles (such as those in your sample). Are such tags
>> supposed to be supported in plain text subtitles? Is this documented
>> somewhere?
> 
> Plain text should be really "plain", however I also have one example of plain 
> text subs with html tags - they are in matroska container. Maybe we could 
> reuse srt_to_ass from ffmpeg to convert these tags to ASS format. Is it 
> possible to call srt_to_ass function from ffmpeg public API?
> 
>> 2. SRT subtitles. SRT is translated to ASS by FFmpeg for us, so Bino
>> never sees SRT. This conversion from SRT to ASS is done here:
>> <http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/srtdec.c;h=aa73f4
>> c7bf45a74f6dd7ec0789bfe12fea756237;hb=HEAD> line 48-184. This function
>> converts several SRT tags to ASS tags, but not <i>. If <i> is supposed to
>> be supported by SRT, then FFmpeg needs to be fixed.
> 
> I believe support for <i> and other HTML tags is there - just look at line 
> 151: 
> http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/srtdec.c;h=aa73f4c7bf45a74f6dd7ec0789bfe12fea756237;hb=HEAD#l151
> I can confirm that it is working and subtitles are displayed in italics. So 
> maybe Robert is using plaintext subtitles or has some old version of ffmpeg.

I have an update on this issue.

According to this specification
<http://matroska.org/technical/specs/codecid/index.html>, text subtitles
in Matroska a really meant to be interpreted as SRT. However, during
decoding FFmpeg treats such subtitles as plain text, which in my opinion
is not correct.

I reported this to the FFmpeg developers in this mail:
<http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/131176>. If they
change this, then the problems will go away with future versions of
FFmpeg. If they don't change this for some reason, then we may need to
implement a workaround.

Until a decision is made, I think we should keep the current behaviour
of handling plain text as plain text, without tags.

Martin