Commit 18490ceca0 for ffmpeg

commit 18490ceca0d0b8a1aff0bb05abe82c59ccdbe7ff
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Wed Nov 11 19:18:06 2026 +0100

    avfilter/vf_lcevc: allocate the output frame for the picture LCEVCdec outputs

    Fixes: out of array write
    Fixes: MO1ctCOYehkw
    Fixes: vf-lcevc-4x.ts
    Out of array write Replicated through UnModified FFmpeg with ASAN

    Found-by: betah4k

diff --git a/libavfilter/vf_lcevc.c b/libavfilter/vf_lcevc.c
index 01e5ded900..6fe6edb61f 100644
--- a/libavfilter/vf_lcevc.c
+++ b/libavfilter/vf_lcevc.c
@@ -354,6 +354,18 @@ static int activate(AVFilterContext *ctx)
             av_frame_free(&in);
             return ret;
         }
+
+        LCEVC_PictureDesc desc;
+        if (LCEVC_PeekDecoderPictureDesc(lcevc->decoder, in->pts, &desc) != LCEVC_Success ||
+            desc.colorFormat != map_format(outlink->format)) {
+            av_log(ctx, AV_LOG_ERROR, "Unsupported enhanced picture\n");
+            LCEVC_SkipDecoder(lcevc->decoder, in->pts);
+            LCEVC_SynchronizeDecoder(lcevc->decoder, 0);
+            flush_bases(ctx);
+            return AVERROR_EXTERNAL;
+        }
+        lcevc->w = desc.width;
+        lcevc->h = desc.height;
     }

     out = ff_get_video_buffer(outlink, lcevc->w, lcevc->h);