[FFmpeg-cvslog] avcodec/ffv1enc: compute the max number of slices and limit by that

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Jun 27 13:09:58 2017 +0200| [0f8d3d8a462c0152ac489dbb013f6df027edd6c4] | committer: Michael Niedermayer

avcodec/ffv1enc: compute the max number of slices and limit by that

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0f8d3d8a462c0152ac489dbb013f6df027edd6c4
---

 libavcodec/ffv1enc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavcodec/ffv1enc.c b/libavcodec/ffv1enc.c
index 39b52d5a48..c9a885ebfa 100644
--- a/libavcodec/ffv1enc.c
+++ b/libavcodec/ffv1enc.c
@@ -849,16 +849,17 @@ FF_ENABLE_DEPRECATION_WARNINGS
 
     if (s->version > 1) {
         int plane_count = 1 + 2*s->chroma_planes + s->transparency;
+        int max_h_slices = AV_CEIL_RSHIFT(avctx->width , s->chroma_h_shift);
+        int max_v_slices = AV_CEIL_RSHIFT(avctx->height, s->chroma_v_shift);
         s->num_v_slices = (avctx->width > 352 || avctx->height > 288 || !avctx->slices) ? 2 : 1;
 
-        if (avctx->height < 5)
-            s->num_v_slices = 1;
+        s->num_v_slices = FFMIN(s->num_v_slices, max_v_slices);
 
         for (; s->num_v_slices < 32; s->num_v_slices++) {
             for (s->num_h_slices = s->num_v_slices; s->num_h_slices < 2*s->num_v_slices; s->num_h_slices++) {
                 int maxw = (avctx->width  + s->num_h_slices - 1) / s->num_h_slices;
                 int maxh = (avctx->height + s->num_v_slices - 1) / s->num_v_slices;
-                if (s->num_h_slices > avctx->width || s->num_v_slices > avctx->height)
+                if (s->num_h_slices > max_h_slices || s->num_v_slices > max_v_slices)
                     continue;
                 if (maxw * maxh * (int64_t)(s->bits_per_raw_sample+1) * plane_count > 8<<24)
                     continue;