diff --git a/mpp/legacy/vpu_api_legacy.cpp b/mpp/legacy/vpu_api_legacy.cpp
index 8cbab4f2..f3b1612b 100644
--- a/mpp/legacy/vpu_api_legacy.cpp
+++ b/mpp/legacy/vpu_api_legacy.cpp
@@ -143,9 +143,9 @@ static MPP_RET vpu_api_set_enc_cfg(MppCtx mpp_ctx, MppApi *mpi,
         /* 0 - constant qp mode: fixed qp */
         rc_cfg->rc_mode     = MPP_ENC_RC_MODE_FIXQP;
         rc_cfg->quality     = MPP_ENC_RC_QUALITY_MEDIUM;
-        rc_cfg->bps_target  = -1;
-        rc_cfg->bps_max     = -1;
-        rc_cfg->bps_min     = -1;
+        rc_cfg->bps_target  = bps;
+        rc_cfg->bps_max     = bps * 17 / 16;
+        rc_cfg->bps_min     = bps * 15 / 16;
     } else if (rc_mode == 1) {
         /* 1 - constant bitrate: small bps range */
         rc_cfg->rc_mode     = MPP_ENC_RC_MODE_CBR;