video: remove slice based filtering and video output

Slices allowed filtering or drawing video in horizontal bands or
blocks. This allowed working on the video in smaller units. In theory,
this could bring a performance win by lowering cache pressure, as you
didn't have to keep the whole video frame in cache while filtering,
only the slice.

In practice, the slice code path was barely used for the following
reasons:
- Multithreaded decoding with ffmpeg didn't use slices. The ffmpeg
  slice callback was disabled, because it can be called from another
  thread, and the mplayer video chain is not thread-safe.
- There was nothing that would turn "full" images into appropriate
  slices, so slices were rarely used.
- Most filters didn't actually support slices.

On the other hand, supporting slices lead to code duplication and more
complex code in general. I made some experiments and didn't find any
actual measurable performance improvements when using slices. Even
ffmpeg removed slices based filtering from libavfilter in favor of
simpler code.

The most broken thing about the slices code path is that slices can't
be queued, like it is done for images in vo.c.

1 files changed, 0 insertions, 14 deletions

diff --git a/video/out/vo.h b/video/out/vo.h
index 9206883183..bcc751e5f2 100644
--- a/video/out/vo.h
+++ b/video/out/vo.h
@@ -52,8 +52,6 @@ enum mp_voctrl {
     VOCTRL_GET_EQUALIZER,               // struct voctrl_get_equalizer_args
     VOCTRL_DUPLICATE_FRAME,
 
-    VOCTRL_START_SLICE,
-
     /* for vdpau hardware decoding */
     VOCTRL_HWDEC_DECODER_RENDER,        // pointer to hw state
 
@@ -194,17 +192,6 @@ struct vo_driver {
     void (*get_buffered_frame)(struct vo *vo, bool eof);
 
     /*
-     * Draw a planar YUV slice to the buffer:
-     * params:
-     *   src[3] = source image planes (Y,U,V)
-     *   stride[3] = source image planes line widths (in bytes)
-     *   w,h = width*height of area to be copied (in Y pixels)
-     *   x,y = position at the destination image (in Y pixels)
-     */
-    int (*draw_slice)(struct vo *vo, uint8_t *src[], int stride[], int w,
-                      int h, int x, int y);
-
-    /*
      * Draws OSD to the screen buffer
      */
     void (*draw_osd)(struct vo *vo, struct osd_state *osd);
@@ -302,7 +289,6 @@ int vo_draw_image(struct vo *vo, struct mp_image *mpi, double pts);
 int vo_redraw_frame(struct vo *vo);
 int vo_get_buffered_frame(struct vo *vo, bool eof);
 void vo_skip_frame(struct vo *vo);
-int vo_draw_slice(struct vo *vo, uint8_t *src[], int stride[], int w, int h, int x, int y);
 void vo_new_frame_imminent(struct vo *vo);
 void vo_draw_osd(struct vo *vo, struct osd_state *osd);
 void vo_flip_page(struct vo *vo, unsigned int pts_us, int duration);