diff options
| -rw-r--r-- | libass/ass.h | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/libass/ass.h b/libass/ass.h index 8a8613a..60b8453 100644 --- a/libass/ass.h +++ b/libass/ass.h @@ -353,8 +353,10 @@ void ass_renderer_done(ASS_Renderer *priv); * \brief Set the frame size in pixels, including margins. * The renderer will never return images that are outside of the frame area. * The value set with this function can influence the pixel aspect ratio used - * for rendering. If the frame size doesn't equal to the video size, you may - * have to use ass_set_pixel_aspect(). + * for rendering. + * If after compensating for configured margins the frame size + * is not an isotropicly scaled version of the video display size, + * you may have to use ass_set_pixel_aspect(). * @see ass_set_pixel_aspect() * @see ass_set_margins() * \param priv renderer handle @@ -409,10 +411,6 @@ void ass_set_shaper(ASS_Renderer *priv, ASS_ShapingLevel level); * the bottom "black bar" between video bottom screen border when playing 16:9 * video on a 4:3 screen.) * - * When using this function, it is recommended to calculate and set your own - * aspect ratio with ass_set_pixel_aspect(), as the defaults won't make any - * sense. - * @see ass_set_pixel_aspect() * \param priv renderer handle * \param t top margin * \param b bottom margin @@ -439,9 +437,8 @@ void ass_set_use_margins(ASS_Renderer *priv, int use); * If the pixel aspect ratio is 0, or if the aspect ratio has never been set * by calling this function, libass will calculate a default pixel aspect ratio * out of values set with ass_set_frame_size() and ass_set_storage_size(). Note - * that this is useful only if the frame size corresponds to the video display - * size. Keep in mind that the margins set with ass_set_margins() are ignored - * for aspect ratio calculations as well. + * that this default assumes the frame size after compensating for margins + * corresponds to an isotropicly scaled version of the video display size. * If the storage size has not been set, a pixel aspect ratio of 1 is assumed. * \param priv renderer handle * \param par pixel aspect ratio (1.0 means square pixels, 0 means default) |