diff --git a/test/mpi_enc_multi_test.c b/test/mpi_enc_multi_test.c
index 3d5efe5b..6890a812 100644
--- a/test/mpi_enc_multi_test.c
+++ b/test/mpi_enc_multi_test.c
@@ -614,6 +614,7 @@ MPP_RET test_mpp_run(MpiEncTestData *p)
         mpp_frame_set_eos(p->frame, p->frm_eos);
 
         mpp_packet_init_with_buffer(&packet, pkt_buf_out);
+        mpp_packet_set_length(packet, 0);
 
         ret = mpi->poll(ctx, MPP_PORT_INPUT, MPP_POLL_BLOCK);
         if (ret) {
diff --git a/test/mpi_rc2_test.c b/test/mpi_rc2_test.c
index 788bbb28..4d83fb93 100644
--- a/test/mpi_rc2_test.c
+++ b/test/mpi_rc2_test.c
@@ -634,6 +634,7 @@ static MPP_RET mpi_rc_enc_encode(MpiRc2TestCtx *ctx, MppFrame frm)
     MppApi *enc_mpi = ctx->enc_mpi;
 
     mpp_packet_init_with_buffer(&ctx->enc_pkt, pkt_buf_out);
+    mpp_packet_set_length(ctx->enc_pkt, 0);
 
     ret = enc_mpi->poll(ctx->enc_ctx, MPP_PORT_INPUT, MPP_POLL_BLOCK);
     if (ret) {
diff --git a/test/mpi_rc_test.c b/test/mpi_rc_test.c
index d9706e9e..4abd5714 100644
--- a/test/mpi_rc_test.c
+++ b/test/mpi_rc_test.c
@@ -731,6 +731,7 @@ static MPP_RET mpi_rc_codec(MpiRcTestCtx *ctx)
         mpp_frame_set_eos(frame_in, frm_eos);
 
         mpp_packet_init_with_buffer(&packet, pkt_buf_out);
+        mpp_packet_set_length(packet, 0);
 
         ret = enc_mpi->poll(enc_ctx, MPP_PORT_INPUT, MPP_POLL_BLOCK);
         if (ret) {