[FFmpeg-devel] [PATCH v1 1/2] avcodec/dds: simplify the calculation of slice start and end

[lance.lmwang at gmail.com]

From: Limin Wang <lance.lmwang at gmail.com>

Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
---
 libavcodec/dds.c | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/libavcodec/dds.c b/libavcodec/dds.c
index 9154f692fa..7c0ad9ee72 100644
--- a/libavcodec/dds.c
+++ b/libavcodec/dds.c
@@ -434,7 +434,7 @@ static int parse_pixel_format(AVCodecContext *avctx)
 }
 
 static int decompress_texture_thread(AVCodecContext *avctx, void *arg,
-                                     int slice, int thread_nb)
+                                     int jobnr, int thread_nb)
 {
     DDSContext *ctx = avctx->priv_data;
     AVFrame *frame = arg;
@@ -442,21 +442,8 @@ static int decompress_texture_thread(AVCodecContext *avctx, void *arg,
     int w_block = avctx->coded_width / TEXTURE_BLOCK_W;
     int h_block = avctx->coded_height / TEXTURE_BLOCK_H;
     int x, y;
-    int start_slice, end_slice;
-    int base_blocks_per_slice = h_block / ctx->slice_count;
-    int remainder_blocks = h_block % ctx->slice_count;
-
-    /* When the frame height (in blocks) doesn't divide evenly between the
-     * number of slices, spread the remaining blocks evenly between the first
-     * operations */
-    start_slice = slice * base_blocks_per_slice;
-    /* Add any extra blocks (one per slice) that have been added before this slice */
-    start_slice += FFMIN(slice, remainder_blocks);
-
-    end_slice = start_slice + base_blocks_per_slice;
-    /* Add an extra block if there are still remainder blocks to be accounted for */
-    if (slice < remainder_blocks)
-        end_slice++;
+    int start_slice = (h_block * jobnr) / ctx->slice_count;
+    int end_slice = (h_block * (jobnr+1)) / ctx->slice_count;
 
     for (y = start_slice; y < end_slice; y++) {
         uint8_t *p = frame->data[0] + y * frame->linesize[0] * TEXTURE_BLOCK_H;
-- 
2.21.0