diff --git a/libavcodec/proresdec.c b/libavcodec/proresdec.c
index 40c15a0c85..5c6b505527 100644
--- a/libavcodec/proresdec.c
+++ b/libavcodec/proresdec.c
@@ -185,7 +185,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
 static int decode_frame_header(ProresContext *ctx, const uint8_t *buf,
                                const int data_size, AVCodecContext *avctx)
 {
-    int hdr_size, width, height, flags;
+    int hdr_size, width, height, flags, dimensions_changed = 0;
     int version;
     const uint8_t *ptr;
     enum AVPixelFormat pix_fmt;
@@ -214,6 +214,7 @@ static int decode_frame_header(ProresContext *ctx, const uint8_t *buf,
                avctx->width, avctx->height, width, height);
         if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
             return ret;
+        dimensions_changed = 1;
     }
 
     ctx->frame_type = (buf[12] >> 2) & 3;
@@ -250,7 +251,7 @@ static int decode_frame_header(ProresContext *ctx, const uint8_t *buf,
         }
     }
 
-    if (pix_fmt != ctx->pix_fmt) {
+    if (pix_fmt != ctx->pix_fmt || dimensions_changed) {
 #define HWACCEL_MAX (CONFIG_PRORES_VIDEOTOOLBOX_HWACCEL + CONFIG_PRORES_VULKAN_HWACCEL)
 #if HWACCEL_MAX
         enum AVPixelFormat pix_fmts[HWACCEL_MAX + 2], *fmtp = pix_fmts;