diff --git a/mpp/legacy/vpu_api_legacy.cpp b/mpp/legacy/vpu_api_legacy.cpp
index 2d07a5e8..86748a99 100644
--- a/mpp/legacy/vpu_api_legacy.cpp
+++ b/mpp/legacy/vpu_api_legacy.cpp
@@ -128,7 +128,7 @@ static MPP_RET vpu_api_set_enc_cfg(MppCtx mpp_ctx, MppApi *mpi, MppEncCfg enc_cf
     mpp_enc_cfg_set_s32(enc_cfg, "rc:mode", rc_mode ? MPP_ENC_RC_MODE_CBR : MPP_ENC_RC_MODE_FIXQP);
     mpp_enc_cfg_set_s32(enc_cfg, "rc:bps_target", bps);
     mpp_enc_cfg_set_s32(enc_cfg, "rc:bps_max", bps * 17 / 16);
-    mpp_enc_cfg_set_s32(enc_cfg, "rc:bps_min", bps * 17 / 16);
+    mpp_enc_cfg_set_s32(enc_cfg, "rc:bps_min", bps * 15 / 16);
     mpp_enc_cfg_set_s32(enc_cfg, "rc:fps_in_flex", 0);
     mpp_enc_cfg_set_s32(enc_cfg, "rc:fps_in_num", fps_in);
     mpp_enc_cfg_set_s32(enc_cfg, "rc:fps_in_denorm", 1);