diff options
Diffstat (limited to 'libass/ass.h')
| -rw-r--r-- | libass/ass.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/libass/ass.h b/libass/ass.h index bd32458..1e662ba 100644 --- a/libass/ass.h +++ b/libass/ass.h @@ -167,8 +167,11 @@ void ass_renderer_done(ASS_Renderer *priv); void ass_set_frame_size(ASS_Renderer *priv, int w, int h); /** - * \brief Set the source image size in pixels. The source aspect ratio - * is automatically reset to the value corresponding to this image size. + * \brief Set the source image size in pixels. + * This is used to calculate the source aspect ratio and the blur scale. If + * a custom pixel aspect ratio is set with ass_set_aspect_ratio(), the source + * image size has no influence on the aspect ratio. + * The source image size can be reset to default by setting w and h to 0. * \param priv renderer handle * \param w width * \param h height @@ -202,6 +205,12 @@ void ass_set_use_margins(ASS_Renderer *priv, int use); /** * \brief Set aspect ratio parameters. + * You can also pass a pixel aspect ratio as dar, and set sar to 1.0. libass + * uses dar/sar as final pixel aspect ratio, and doesn't use dar or sar for + * anything else. If the pixel aspect ratio is 0 (setting dar=0 and sar=1), or + * if the aspect ratio has never been set by calling this function, libass will + * calculate a fallback value out of frame size and storage size. If the + * storage size has not been set, a pixel aspect ratio of 1 is assumed. * \param priv renderer handle * \param dar display aspect ratio (DAR), prescaled for output PAR * \param sar storage aspect ratio (SAR) |