[FFmpeg-devel] [PATCH V3] lavc/vaapi_encode_h264: Enable MB rate control.

[Jun Zhao]

V3: - Fix build error with old VAAPI version.
V2: - Refine the name/value type to mb_rate_control/bool.
    - Only supported GEN9+ (SKL/APL/KBL/...)
    - i965 driver default use frame-level rate control algorithm (generate the QP for each frame), 
      when enable mb_rate_control, it's will enable the MB-level RC algorithm (generate the QP for each MB). 
    - enables MB-level bitrate control that generally improves subjective visual quality, 
      but have negative impact on performance and objective visual quality metric. 
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From 219b06cec04a6c3f719ce80084a98b19456498e0 Mon Sep 17 00:00:00 2001
From: Jun Zhao <jun.zhao at intel.com>
Date: Tue, 9 May 2017 08:19:16 +0800
Subject: [PATCH V3] lavc/vaapi_encode_h264: Enable MB rate control.

Enables macroblock-level bitrate control that generally improves
subjective visual quality. It may have a negative impact on
performance and objective visual quality metrics. Default is off
and can't compatible with Constant QP.

Signed-off-by: Jun Zhao <jun.zhao at intel.com>
---
 libavcodec/vaapi_encode_h264.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vaapi_encode_h264.c b/libavcodec/vaapi_encode_h264.c
index 92e29554ed..44223ada55 100644
--- a/libavcodec/vaapi_encode_h264.c
+++ b/libavcodec/vaapi_encode_h264.c
@@ -168,6 +168,7 @@ typedef struct VAAPIEncodeH264Options {
     int qp;
     int quality;
     int low_power;
+    int mb_rate_control;
 } VAAPIEncodeH264Options;
 
 
@@ -1133,8 +1134,22 @@ static av_cold int vaapi_encode_h264_configure(AVCodecContext *avctx)
         priv->fixed_qp_p   = 26;
         priv->fixed_qp_b   = 26;
 
-        av_log(avctx, AV_LOG_DEBUG, "Using %s-bitrate = %"PRId64" bps.\n",
+        if (opt->mb_rate_control) {
+#if VA_CHECK_VERSION(0, 39, 2)
+            ctx->rc_params.rc.rc_flags.bits.mb_rate_control = opt->mb_rate_control;
+#else
+            av_log(avctx, AV_LOG_WARNING, "The MB rate control option is not "
+                   "supported with this VAAPI version.\n");
+#endif
+        }
+
+        av_log(avctx, AV_LOG_DEBUG, "Using %s-bitrate %s MB rate control = %"PRId64" bps.\n",
                ctx->va_rc_mode == VA_RC_CBR ? "constant" : "variable",
+#if VA_CHECK_VERSION(0, 39, 2)
+               opt->mb_rate_control ? "with" : "without",
+#else
+               "without",
+#endif
                avctx->bit_rate);
 
     } else {
@@ -1283,6 +1298,8 @@ static const AVOption vaapi_encode_h264_options[] = {
     { "low_power", "Use low-power encoding mode (experimental: only supported "
       "on some platforms, does not support all features)",
       OFFSET(low_power), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
+    { "mb_rate_control", "MB level bitrate control (only supported on GEN9+)",
+      OFFSET(mb_rate_control), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS, "mb_rate_control" },
     { NULL },
 };
 
-- 
2.11.0