[Libva] [PATCH 2/2] H.264 encoder: respect initial QP setting

[Mark Thompson]

Signed-off-by: Mark Thompson <sw at jkqxz.net>
---
This can be set by the user to ensure that the first frame of a stream is encoded at with a good QP (often it starts too high and takes a few frames to get down to the right range).  The current code continues to be used if the value is not set (is zero).


 src/gen6_mfc_common.c | 24 +++++++++++++++---------
 src/i965_encoder.c    |  2 ++
 src/i965_encoder.h    |  1 +
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/gen6_mfc_common.c b/src/gen6_mfc_common.c
index e8596ff..8907751 100644
--- a/src/gen6_mfc_common.c
+++ b/src/gen6_mfc_common.c
@@ -168,16 +168,22 @@ static void intel_mfc_brc_init(struct encode_state *encode_state,
 
         bpf = mfc_context->brc.bits_per_frame[i] = bitrate/framerate;
 
-        if ((bpf > qp51_size) && (bpf < qp1_size)) {
-            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 51 - 50*(bpf - qp51_size)/(qp1_size - qp51_size);
-        }
-        else if (bpf >= qp1_size)
-            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 1;
-        else if (bpf <= qp51_size)
-            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 51;
+        if (encoder_context->brc.initial_qp) {
+            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I] = encoder_context->brc.initial_qp;
+            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = encoder_context->brc.initial_qp;
+            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_B] = encoder_context->brc.initial_qp;
+        } else {
+            if ((bpf > qp51_size) && (bpf < qp1_size)) {
+                mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 51 - 50*(bpf - qp51_size)/(qp1_size - qp51_size);
+            }
+            else if (bpf >= qp1_size)
+                mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 1;
+            else if (bpf <= qp51_size)
+                mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P] = 51;
 
-        mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I] = mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P];
-        mfc_context->brc.qp_prime_y[i][SLICE_TYPE_B] = mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I];
+            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I] = mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P];
+            mfc_context->brc.qp_prime_y[i][SLICE_TYPE_B] = mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I];
+        }
 
         BRC_CLIP(mfc_context->brc.qp_prime_y[i][SLICE_TYPE_I], (int)encoder_context->brc.min_qp, 51);
         BRC_CLIP(mfc_context->brc.qp_prime_y[i][SLICE_TYPE_P], (int)encoder_context->brc.min_qp, 51);
diff --git a/src/i965_encoder.c b/src/i965_encoder.c
index 3056900..0a648d4 100644
--- a/src/i965_encoder.c
+++ b/src/i965_encoder.c
@@ -576,8 +576,10 @@ intel_encoder_check_rate_control_parameter(VADriverContextP ctx,
     }
 
     if (encoder_context->brc.window_size != misc->window_size ||
+        encoder_context->brc.initial_qp  != misc->initial_qp ||
         encoder_context->brc.min_qp      != misc->min_qp) {
         encoder_context->brc.window_size = misc->window_size;
+        encoder_context->brc.initial_qp  = misc->initial_qp;
         encoder_context->brc.min_qp      = misc->min_qp;
         encoder_context->brc.need_reset = 1;
     }
diff --git a/src/i965_encoder.h b/src/i965_encoder.h
index 16a6f3f..829df9d 100644
--- a/src/i965_encoder.h
+++ b/src/i965_encoder.h
@@ -92,6 +92,7 @@ struct intel_encoder_context
         unsigned int hrd_buffer_size;
         unsigned int hrd_initial_buffer_fullness;
         unsigned int window_size;
+        unsigned int initial_qp;
         unsigned int min_qp;
         unsigned int need_reset;
 
-- 
2.11.0