[vlc] how to dump subtitles produced by dvbsub.c to an image file

[Selçuk Cihan]

On Mon, Jul 5, 2010 at 10:13 AM, Selçuk Cihan <selcukcihan at gmail.com> wrote:
> Hi, i need to save dvb subtitles as images (say png). I added a method
> (call it png_save) to dvbsub.c and invoked it inside the method:
> static subpicture_t *render( decoder_t *p_dec )
>
> I could not figure out how vlc stores the subtitle image (is it YUV?
> is it an index into a table?). It is not plain RGBA. What i need is to
> get rgba value for each pixel of the subtitle image. Currently, i read
> values from p_src = p_region->p_pixbuf for each region. But i do not
> know how to interpret them and convert to rgba. Any help truely
> appreciated.
>

Hi, i managed to figure it out. Info for each pixel is a single byte.
It is used as an index into the color palette which has YUV colors.
After getting YUV values, it is straightforward to convert to RGB.