DVB subtitles, version 0.8.1

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irkuck

DVB subtitles, version 0.8.1

Postby irkuck » 07 Dec 2004 21:05

Is it so that DVB subtitles are WHITE for purpose or it is only in my system because of some reason??? Or it is possible to change them somewhere?

Subtitles in white color are not readable.

By the way, is it possible to make subtitles activated permanently by default? Where?

timok

DVB subtitles, version 0.8.1

Postby timok » 08 Dec 2004 22:13

I may have the same problem - subtitles are not completely white though, but nearly unreadable. I found a solution which worked for me. I changed lines at about 560 in file modules/codec/dvbsub.c from:

if( i_type & 0x04 )
-
if( i_type & 0x02 )
-
if( i_type & 0x01 )

to:

if( i_type & 0x04 && i_id<4)
-
if( i_type & 0x02 && i_id<16)
-
if( i_type & 0x01 && i_id<256)

These changes prevents the index overflowing into wrong tables. The last check is probably unnecessary

I have no idea if this is a correct solution or if it works for you. Maybe someone with deeper understanding would take a look.

--

Timo

Guest

Re: DVB subtitles, version 0.8.1

Postby Guest » 09 Dec 2004 09:32

if( i_type & 0x04 && i_id<4)
-
if( i_type & 0x02 && i_id<16)
-
if( i_type & 0x01 && i_id<256)

These changes prevents the index overflowing into wrong tables. The last check is probably unnecessary
I have no idea if this is a correct solution or if it works for you. Maybe someone with deeper understanding would take a look.
Timo
Thanks Timo for confirming I am not alone in this problem :D .This requires compilation of VLC which I have to try yet.

But VLC developers could take a note.
The problem is that there is NO black
border around subtitles, the border
is JUST white as the rest of the font is.

Otherwise, subtitles are displayed
correctly and work fine. I am testing
them on Finnish public TV channels
where sometimes they broadcast
subtitles on two tracks in Finnish and Swedish and switching between them works well too.

By the way, is there any method to make subtitles displaying be default?
That is whenever vlc starts, subtitles
would display without the need for enabling them?

Another nice feature would be to have
full control over DVB subtitles: font type, size, color, position.

Even the possibility to display several tracks of subtitles at the same time would not be stupid but useful for language learning 8)

Sigmund
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Postby Sigmund » 09 Dec 2004 10:45

I've just tested a couple of file with vlcs dvb subtitle decoder, and here is what I found:
subtitles are displayed on a black background.
subtitles are displayed quite a bit to high up on the video
subtitle appear word by word, as on a karaoke, sing along, system
subtitles some times change color between white and cyan.

So I have quite a few problems myself, but not the problems you have. If any of you could provide a sample that has these problems, it would wastly ease the task of fixing it. (Sorry if you allready have, I couldn't find it in that case)

Gibalou
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Postby Gibalou » 09 Dec 2004 14:18

I've just tested a couple of file with vlcs dvb subtitle decoder, and here is what I found:
subtitles are displayed on a black background.
This is entirely up to the broadcaster.
For instance most BBC channels do that (likely because it helps readability).
subtitles are displayed quite a bit to high up on the video
Again this is entirely up to the broadcaster.
We just respect the subtitles placement indicated in the stream. This is necessary because for instance in a scene where you see 2 people on the screen discussing with each other, the subtitles can be placed just below their respective characters. DVB subtitles can also be used to carry logos, etc...
subtitle appear word by word, as on a karaoke, sing along, system
Again this is completely up to the broadcaster. This technic (stenographic subtitling) is mainly used for live content because subtitles are typed live.
subtitles some times change color between white and cyan.
Broadcaster also usually use color switching to indicate a different character started speaking.
So I have quite a few problems myself, but not the problems you have. If any of you could provide a sample that has these problems, it would wastly ease the task of fixing it. (Sorry if you allready have, I couldn't find it in that case)
Looks like you rather have everthing working fine :p

Gibalou
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Re: DVB subtitles, version 0.8.1

Postby Gibalou » 09 Dec 2004 14:39

These changes prevents the index overflowing into wrong tables. The last check is probably unnecessary

I have no idea if this is a correct solution or if it works for you. Maybe someone with deeper understanding would take a look.
These extra sanity checks do make sense. I just applied them to the development version.
Thanks for the patch.

Gibalou
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Re: DVB subtitles, version 0.8.1

Postby Gibalou » 09 Dec 2004 14:45

But VLC developers could take a note.
The problem is that there is NO black
border around subtitles, the border
is JUST white as the rest of the font is.
Could you check how the subtitles are displayed on a commercial set-top-box ? That would help to see if VLC's decoding is at fault.
It could just be that this is the way they are broadcasted.
Otherwise, subtitles are displayed
correctly and work fine. I am testing
them on Finnish public TV channels
where sometimes they broadcast
subtitles on two tracks in Finnish and Swedish and switching between them works well too.

By the way, is there any method to make subtitles displaying be default?
That is whenever vlc starts, subtitles
would display without the need for enabling them?
There's an option named --spu-channel in the preferences. Set it to 0 and it will always select the first subtitles channel by default.
Another nice feature would be to have
full control over DVB subtitles: font type, size, color, position.
Not possible. DVB subtitles are graphic subtitles (not text) so we don't have any control over how they are displayed.


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