diff --git a/libavcodec/h264_mp4toannexb_bsf.c b/libavcodec/h264_mp4toannexb_bsf.c
index a927bab3f8..2d447f7550 100644
--- a/libavcodec/h264_mp4toannexb_bsf.c
+++ b/libavcodec/h264_mp4toannexb_bsf.c
@@ -122,7 +122,7 @@ pps:
         if (!unit_nb && !sps_done++) {
             unit_nb = *extradata++; /* number of pps unit(s) */
             if (unit_nb) {
-                ctx->pps_offset = (extradata - 1) - (avctx->extradata + 4);
+                ctx->pps_offset = total_size;
                 pps_seen = 1;
             }
         }