expand.c

来自「linux下的MPEG1」· C语言 代码 · 共 456 行 · 第 1/2 页

  this->enable_automatic_shift = param->enable_automatic_shift;
  this->overlay_y_offset       = param->overlay_y_offset;
  this->aspect                 = param->aspect;
  this->centre_cut_out_mode    = param->centre_cut_out_mode;

  return 1;
}

static int expand_get_parameters(xine_post_t *this_gen, void *param_gen)
{
  post_expand_t *this = (post_expand_t *)this_gen;
  expand_parameters_t *param = (expand_parameters_t *)param_gen;
  
  param->enable_automatic_shift = this->enable_automatic_shift;
  param->overlay_y_offset       = this->overlay_y_offset;
  param->aspect                 = this->aspect;
  param->centre_cut_out_mode    = this->centre_cut_out_mode;
  
  return 1;
}

static char *expand_get_help(void) {
  return _("The expand plugin is meant to take frames of arbitrary aspect ratio and "
           "converts them to a different aspect (4:3 by default) by adding black bars "
           "on the top and bottom of the frame. This allows us to shift overlays "
           "down into the black area so they don't cover the image.\n"
           "\n"
           "Parameters (FIXME: better help)\n"
           "  Enable_automatic_shift: Enable automatic overlay shifting\n"
           "  Overlay_y_offset: Manually shift the overlay vertically\n"
           "  aspect: The target aspect ratio (default 4:3)\n"
           "  Centre_cut_out_mode: extracts 4:3 image contained in 16:9 frame\n"
           "\n"
         );
}


static int is_pixel_black(vo_frame_t *frame, int x, int y)
{
  int Y = 0x00, Cr = 0x00, Cb = 0x00;

  if (x < 0)              x = 0;
  if (x >= frame->width)  x = frame->width - 1;
  if (y < 0)              y = 0;
  if (y >= frame->height) y = frame->height - 1;
  
  switch (frame->format)
  {
  case XINE_IMGFMT_YV12:
    Y  = *(frame->base[ 0 ] + frame->pitches[ 0 ] * y     + x);
    Cr = *(frame->base[ 1 ] + frame->pitches[ 1 ] * y / 2 + x / 2);
    Cb = *(frame->base[ 2 ] + frame->pitches[ 2 ] * y / 2 + x / 2);
    break;
    
  case XINE_IMGFMT_YUY2:
    Y  = *(frame->base[ 0 ] + frame->pitches[ 0 ] * y + x * 2 + 0);
    x &= ~1;
    Cr = *(frame->base[ 0 ] + frame->pitches[ 0 ] * y + x * 2 + 1);
    Cb = *(frame->base[ 0 ] + frame->pitches[ 0 ] * y + x * 2 + 3);
    break;
  }

  return (Y == 0x10 && Cr == 0x80 && Cb == 0x80);
}


static int expand_draw(vo_frame_t *frame, xine_stream_t *stream)
{
  post_video_port_t *port = (post_video_port_t *)frame->port;
  post_expand_t     *this = (post_expand_t *)port->post;
  int                skip;

  if (this->centre_cut_out_mode && !frame->bad_frame)
  {
    /* expected area of inner 4:3 image */
    int centre_width = frame->width * (9 * 4) / (16 * 3);
    int centre_left  = (frame->width - centre_width ) / 2;

    /* centre point for detecting a black frame */
    int centre_x = frame->width  / 2;
    int centre_y = frame->height / 2;

    /* ignore a black frame as it could lead to wrong results */
    if (!is_pixel_black(frame, centre_x, centre_y))
    {
      /* coordinates for testing black border near the centre area */
      int test_left  = centre_left - 16;
      int test_right = centre_left + 16 + centre_width;

      /* enable cropping when these pixels are black */
      this->cropping_active = is_pixel_black(frame, test_left, centre_y)
        && is_pixel_black(frame, test_right, centre_y);
    }

    /* crop frame */
    if (this->centre_cut_out_mode && this->cropping_active) {
      frame->crop_left  += centre_left;
      frame->crop_right += centre_left;

      /* get_frame() allocated an extra high frame */
      frame->crop_top    += (frame->next->height - frame->height) / 2;
      frame->crop_bottom += (frame->next->height - frame->height) / 2;
    }
  }

  frame->ratio = this->aspect;
  _x_post_frame_copy_down(frame, frame->next);
  skip = frame->next->draw(frame->next, stream);
  _x_post_frame_copy_up(frame, frame->next);

  return skip;
}


static vo_frame_t *expand_get_frame(xine_video_port_t *port_gen, uint32_t width, 
				    uint32_t height, double ratio, 
				    int format, int flags)
{
  post_video_port_t *port = (post_video_port_t *)port_gen;
  post_expand_t     *this = (post_expand_t *)port->post;
  vo_frame_t        *frame;
  uint32_t           new_height, top_bar_height;
  int                i, end;
  
  _x_post_rewire(&this->post);
  
  if (ratio <= 0.0) ratio = (double)width / (double)height;
  
  /* Calculate height of expanded frame */
  new_height = (double)height * ratio / this->aspect;
  new_height = (new_height + 1) & ~1;
  top_bar_height = (new_height - height) / 2;
  top_bar_height = (top_bar_height + 1) & ~1;
  
  this->top_bar_height = top_bar_height;

  if (new_height > height &&
      (format == XINE_IMGFMT_YV12 || format == XINE_IMGFMT_YUY2)) {
    frame = port->original_port->get_frame(port->original_port,
      width, new_height, this->aspect, format, flags);
    
    _x_post_inc_usage(port);
    frame = _x_post_intercept_video_frame(frame, port);
    
    /* paint black bars in the top and bottom of the frame and hide these
     * from the decoders by modifying the pointers to and
     * the size of the drawing area */
    frame->height = height;
    frame->ratio  = ratio;
    switch (format) {
    case XINE_IMGFMT_YV12:
      /* paint top bar */
      memset(frame->base[0],   0, frame->pitches[0] * top_bar_height    );
      memset(frame->base[1], 128, frame->pitches[1] * top_bar_height / 2);
      memset(frame->base[2], 128, frame->pitches[2] * top_bar_height / 2);
      /* paint bottom bar */
      memset(frame->base[0] + frame->pitches[0] * (top_bar_height + height)    ,   0,
        frame->pitches[0] * (new_height - top_bar_height - height)    );
      memset(frame->base[1] + frame->pitches[1] * (top_bar_height + height) / 2, 128,
        frame->pitches[1] * (new_height - top_bar_height - height) / 2);
      memset(frame->base[2] + frame->pitches[2] * (top_bar_height + height) / 2, 128,
        frame->pitches[2] * (new_height - top_bar_height - height) / 2);
      /* modify drawing area */
      frame->base[0] += frame->pitches[0] * top_bar_height;
      frame->base[1] += frame->pitches[1] * top_bar_height / 2;
      frame->base[2] += frame->pitches[2] * top_bar_height / 2;
      break;
    case XINE_IMGFMT_YUY2:
      /* paint top bar */
      end = frame->pitches[0] * top_bar_height;
      for (i = 0; i < end; i += 2) {
	frame->base[0][i]   = 0;
	frame->base[0][i+1] = 128;
      }
      /* paint bottom bar */
      end = frame->pitches[0] * new_height;
      for (i = frame->pitches[0] * (top_bar_height + height); i < end; i += 2) {
	frame->base[0][i]   = 0;
	frame->base[0][i+1] = 128;
      }
      /* modify drawing area */
      frame->base[0] += frame->pitches[0] * top_bar_height;
    }
  } else {
    frame = port->original_port->get_frame(port->original_port,
      width, height, ratio, format, flags);
    /* no need to intercept this one, we are not going to do anything with it */
  }
  
  return frame;
}


static int expand_intercept_ovl(post_video_port_t *port)
{
  post_expand_t         *this = (post_expand_t *)port->post;

  if (this->centre_cut_out_mode && this->cropping_active) return 0;
  
  /* we always intercept overlay manager */
  return 1;
}


static int32_t expand_overlay_add_event(video_overlay_manager_t *this_gen, void *event_gen)
{
  video_overlay_event_t *event = (video_overlay_event_t *)event_gen;
  post_video_port_t     *port = _x_post_ovl_manager_to_port(this_gen);
  post_expand_t         *this = (post_expand_t *)port->post;
  
  if (event->event_type == OVERLAY_EVENT_SHOW) {
    switch (event->object.object_type) {
    case 0:
      /* regular subtitle */
      if (this->enable_automatic_shift)
	event->object.overlay->y += 2 * this->top_bar_height;
      else
	event->object.overlay->y += this->overlay_y_offset;
      break;
    case 1:
      /* menu overlay */
      event->object.overlay->y += this->top_bar_height;
    }
  }
  
  return port->original_manager->add_event(port->original_manager, event_gen);
}