Re: [Bino-list] Cant make subtitles work

[Martin Lambers]

On Thu, 16 Jan 2014 19:00:04 +0100, Federico Cuello wrote:
> On 16.01.2014 18:09, Martin Lambers wrote:
> > Hi!
> > 
> > On Thu, 16 Jan 2014 13:07:27 +0100, Federico Cuello wrote:
> >> There is an open bug reported here:
> >>
> >>  http://savannah.nongnu.org/bugs/?func=detailitem&item_id=38150
> >>
> >> I have the same problem and also would like to have subtitles
> >> working.
> > 
> > Chances to fix this are not too good. The AMD Catalyst OpenGL
> > driver is known to be of very bad quality, and working around its
> > problems may be impossible. Also, no developer seems to have access
> > to a test system with this hardware (as far as I know).
> 
> Yeah, I know. The "strange" thing is that other programs like mplayer
> and vlc are working with subtitles, and as far as I know all of them
> are using the same libraries. I'll try to fix it myself if I have
> time. I already started to look at the code.

I suspect that the problem is not with ffmpeg/libass etc. Decoding
subtitles with ffmpeg and rendering them on the CPU into a memory
buffer with libass probably work fine.

The problem is probably triggered either at the end of
video_output::prepare_next_frame(), when that memory buffer is copied
to a texture, or in video_output::display_current_frame(), when this
texture is used in the fragment shader video_output_render.fs.glsl.

I'd start with checking if the subtitle texture has correct contents.
Maybe you can add debug code that copies the texture back to memory and
saves it to a file?

Regards,
Martin