encoder: VP9: Add CBR encoding supportvp9_enc_cbr

https://bugzilla.gnome.org/show_bug.cgi?id=749950

2 files changed, 102 insertions, 3 deletions

diff --git a/gst-libs/gst/vaapi/gstvaapiencoder_vp9.c b/gst-libs/gst/vaapi/gstvaapiencoder_vp9.c
index 6006f682..01b0d6ed 100644
--- a/gst-libs/gst/vaapi/gstvaapiencoder_vp9.c
+++ b/gst-libs/gst/vaapi/gstvaapiencoder_vp9.c
@@ -39,7 +39,8 @@
 
 /* Supported set of VA rate controls, within this implementation */
 #define SUPPORTED_RATECONTROLS                  \
-  (GST_VAAPI_RATECONTROL_MASK (CQP))
+  (GST_VAAPI_RATECONTROL_MASK (CQP) |           \
+  GST_VAAPI_RATECONTROL_MASK (CBR))
 
 /* Supported set of tuning options, within this implementation */
 #define SUPPORTED_TUNE_OPTIONS \
@@ -56,6 +57,9 @@
 #define MAX_FRAME_WIDTH 4096
 #define MAX_FRAME_HEIGHT 4096
 
+/* Default CPB length (in milliseconds) */
+#define DEFAULT_CPB_LENGTH 1500
+
 typedef enum
 {
   GST_VAAPI_ENCODER_VP9_REF_PIC_MODE_0 = 0,
@@ -101,8 +105,47 @@ struct _GstVaapiEncoderVP9
   guint frame_num;
   GstVaapiSurfaceProxy *ref_list[GST_VP9_REF_FRAMES];   /* reference list */
   guint ref_list_idx;           /* next free slot in ref_list */
+
+  /* Bitrate contral parameters, CPB = Coded Picture Buffer */
+  guint bitrate_bits;           // bitrate (bits)
+  guint cpb_length;             // length of CPB buffer (ms)
 };
 
+/* Estimates a good enough bitrate if none was supplied */
+static void
+ensure_bitrate (GstVaapiEncoderVP9 * encoder)
+{
+  GstVaapiEncoder *const base_encoder = GST_VAAPI_ENCODER_CAST (encoder);
+  guint bitrate;
+
+  switch (GST_VAAPI_ENCODER_RATE_CONTROL (encoder)) {
+    case GST_VAAPI_RATECONTROL_CBR:
+    case GST_VAAPI_RATECONTROL_VBR:
+      if (!base_encoder->bitrate) {
+        /* Fixme: Provide better estimation */
+        /* Using a 1/6 compression ratio */
+        /* 12 bits per pixel fro yuv420 */
+        base_encoder->bitrate =
+            (GST_VAAPI_ENCODER_WIDTH (encoder) *
+            GST_VAAPI_ENCODER_HEIGHT (encoder) * 12 / 6) *
+            GST_VAAPI_ENCODER_FPS_N (encoder) /
+            GST_VAAPI_ENCODER_FPS_D (encoder) / 1000;
+        GST_INFO ("target bitrate computed to %u kbps", base_encoder->bitrate);
+      }
+
+      bitrate = (base_encoder->bitrate * 1000);
+      if (bitrate != encoder->bitrate_bits) {
+        GST_DEBUG ("HRD bitrate: %u bits/sec", bitrate);
+        encoder->bitrate_bits = bitrate;
+      }
+
+      break;
+    default:
+      base_encoder->bitrate = 0;
+      break;
+  }
+}
+
 /* Derives the profile that suits best to the configuration */
 static GstVaapiEncoderStatus
 ensure_profile (GstVaapiEncoderVP9 * encoder)
@@ -110,6 +153,9 @@ ensure_profile (GstVaapiEncoderVP9 * encoder)
   /* Always start from "simple" profile for maximum compatibility */
   encoder->profile = GST_VAAPI_PROFILE_VP9_0;
 
+  /* Ensure bitrate if not set already */
+  ensure_bitrate (encoder);
+
   return GST_VAAPI_ENCODER_STATUS_SUCCESS;
 }
 
@@ -183,6 +229,7 @@ fill_sequence (GstVaapiEncoderVP9 * encoder, GstVaapiEncSequence * sequence)
   seq_param->kf_max_dist = base_encoder->keyframe_period;
   seq_param->intra_period = base_encoder->keyframe_period;
 
+  seq_param->bits_per_second = encoder->bitrate_bits;
   return TRUE;
 }
 
@@ -212,6 +259,37 @@ error:
   return FALSE;
 }
 
+static gboolean
+ensure_misc_params (GstVaapiEncoderVP9 * encoder, GstVaapiEncPicture * picture)
+{
+  GstVaapiEncMiscParam *misc = NULL;
+  VAEncMiscParameterRateControl *rate_control;
+
+  /* RateControl params */
+  if (GST_VAAPI_ENCODER_RATE_CONTROL (encoder) == GST_VAAPI_RATECONTROL_CBR ||
+      GST_VAAPI_ENCODER_RATE_CONTROL (encoder) == GST_VAAPI_RATECONTROL_VBR) {
+
+    misc = GST_VAAPI_ENC_MISC_PARAM_NEW (RateControl, encoder);
+    g_assert (misc);
+    if (!misc)
+      return FALSE;
+
+    rate_control = misc->data;
+    memset (rate_control, 0, sizeof (VAEncMiscParameterRateControl));
+    rate_control->bits_per_second = encoder->bitrate_bits;
+    rate_control->target_percentage = 70;
+    rate_control->window_size = encoder->cpb_length;
+    rate_control->initial_qp = encoder->yac_qi;
+    rate_control->min_qp = 1;   /* Fixme: provide user control */
+    rate_control->basic_unit_size = 0;
+
+    gst_vaapi_enc_picture_add_misc_param (picture, misc);
+    gst_vaapi_codec_object_replace (&misc, NULL);
+  }
+
+  return TRUE;
+}
+
 static void
 get_ref_indices (guint ref_pic_mode, guint ref_list_idx, guint * last_idx,
     guint * gf_idx, guint * arf_idx, guint8 * refresh_frame_flags)
@@ -356,6 +434,8 @@ gst_vaapi_encoder_vp9_encode (GstVaapiEncoder * base_encoder,
 
   if (!ensure_sequence (encoder, picture))
     goto error;
+  if (!ensure_misc_params (encoder, picture))
+    goto error;
   if (!ensure_picture (encoder, picture, codedbuf, reconstruct))
     goto error;
   if (!gst_vaapi_enc_picture_encode (picture))
@@ -432,10 +512,11 @@ gst_vaapi_encoder_vp9_init (GstVaapiEncoder * base_encoder)
   encoder->loop_filter_level = DEFAULT_LOOP_FILTER_LEVEL;
   encoder->sharpness_level = DEFAULT_SHARPNESS_LEVEL;
   encoder->yac_qi = DEFAULT_YAC_QINDEX;
+  encoder->bitrate_bits = 0;
+  encoder->cpb_length = DEFAULT_CPB_LENGTH;
 
   memset (encoder->ref_list, 0, G_N_ELEMENTS (encoder->ref_list));
   encoder->ref_list_idx = 0;
-
   return TRUE;
 }
 
@@ -463,6 +544,9 @@ gst_vaapi_encoder_vp9_set_property (GstVaapiEncoder * base_encoder,
     case GST_VAAPI_ENCODER_VP9_PROP_REF_PIC_MODE:
       encoder->ref_pic_mode = g_value_get_enum (value);
       break;
+    case GST_VAAPI_ENCODER_VP9_PROP_CPB_LENGTH:
+      encoder->cpb_length = g_value_get_uint (value);
+      break;
     default:
       return GST_VAAPI_ENCODER_STATUS_ERROR_INVALID_PARAMETER;
   }
@@ -548,6 +632,19 @@ gst_vaapi_encoder_vp9_get_default_properties (void)
           gst_vaapi_encoder_vp9_ref_pic_mode_type (),
           GST_VAAPI_ENCODER_VP9_REF_PIC_MODE_0,
           G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+  /**
+   * GstVaapiEncoderVP9:cpb-length:
+   *
+   * The size of the Coded Picture Buffer , which means
+   * the window size in milliseconds.
+   * 
+   */
+  GST_VAAPI_ENCODER_PROPERTIES_APPEND (props,
+      GST_VAAPI_ENCODER_VP9_PROP_CPB_LENGTH,
+      g_param_spec_uint ("cpb-length",
+          "CPB Length", "Length of the CPB_buffer/window_size in milliseconds",
+          1, 10000, DEFAULT_CPB_LENGTH,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
 
   return props;
diff --git a/gst-libs/gst/vaapi/gstvaapiencoder_vp9.h b/gst-libs/gst/vaapi/gstvaapiencoder_vp9.h
index 2ddcbd40..7967a980 100644
--- a/gst-libs/gst/vaapi/gstvaapiencoder_vp9.h
+++ b/gst-libs/gst/vaapi/gstvaapiencoder_vp9.h
@@ -38,6 +38,7 @@ typedef struct _GstVaapiEncoderVP9 GstVaapiEncoderVP9;
  * @GST_VAAPI_ENCODER_VP9_PROP_LOOP_SHARPNESS_LEVEL: Sharpness Level(uint).
  * @GST_VAAPI_ENCODER_VP9_PROP_YAC_Q_INDEX: Quantization table index for luma AC
  * @GST_VAAPI_ENCODER_VP9_PROP_REF_PIC_MODE: Reference picute selection modes
+ * @GST_VAAPI_ENCODER_VP9_PROP_CPB_LENGTH:Length of CPB buffer in milliseconds
  *
  * The set of VP9 encoder specific configurable properties.
  */
@@ -45,7 +46,8 @@ typedef enum {
   GST_VAAPI_ENCODER_VP9_PROP_LOOP_FILTER_LEVEL = -1,
   GST_VAAPI_ENCODER_VP9_PROP_SHARPNESS_LEVEL = -2,
   GST_VAAPI_ENCODER_VP9_PROP_YAC_Q_INDEX = -3,
-  GST_VAAPI_ENCODER_VP9_PROP_REF_PIC_MODE = -4
+  GST_VAAPI_ENCODER_VP9_PROP_REF_PIC_MODE = -4,
+  GST_VAAPI_ENCODER_VP9_PROP_CPB_LENGTH = -5
 } GstVaapiEncoderVP9Prop;
 
 GstVaapiEncoder *