[FFmpeg-cvslog] avcodec/magicyuvenc: Fix setting nb_slices

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Fri Apr 11 22:46:57 2025 +0200| [685f658524314a7e70a1fe3ad11e2cd59a010be4] | committer: Andreas Rheinhardt

avcodec/magicyuvenc: Fix setting nb_slices

Do not derive it via av_cpu_count() in case AVCodecContext.slices
is unset. Instead default to AVCodecContext.thread_num instead
(which is one in case frame-threading is used and gives the actual
number of slice threads for slice threading).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=685f658524314a7e70a1fe3ad11e2cd59a010be4
---

 libavcodec/magicyuvenc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/magicyuvenc.c b/libavcodec/magicyuvenc.c
index bf0e7d99bb..a10da9684f 100644
--- a/libavcodec/magicyuvenc.c
+++ b/libavcodec/magicyuvenc.c
@@ -201,7 +201,7 @@ static av_cold int magy_encode_init(AVCodecContext *avctx)
 
     s->planes = av_pix_fmt_count_planes(avctx->pix_fmt);
 
-    s->nb_slices = (avctx->slices <= 0) ? av_cpu_count() : avctx->slices;
+    s->nb_slices = avctx->slices > 0 ? avctx->slices : avctx->thread_count;
     s->nb_slices = FFMIN(s->nb_slices, avctx->height >> s->vshift[1]);
     s->nb_slices = FFMAX(1, s->nb_slices);
     s->slice_height = FFALIGN((avctx->height + s->nb_slices - 1) / s->nb_slices, 1 << s->vshift[1]);