Add hierarchical structure in GF group

Change-Id: I06fc4b0ad5a45c49e10a9601a2356fbc6e93d6da

diff --git a/vp9/encoder/vp9_encoder.h b/vp9/encoder/vp9_encoder.h
index d6d32abf99a9adb202b72c2720ac3ba8d38f220a..cfb77994c042bf97f0c6ecf0eac710b0adda4a9b 100644 (file)
--- a/vp9/encoder/vp9_encoder.h
+++ b/vp9/encoder/vp9_encoder.h
@@ -746,6 +746,14 @@ typedef struct VP9_COMP {
   uint8_t *count_arf_frame_usage;
   uint8_t *count_lastgolden_frame_usage;
 
+  // Parameters on multi-layer ALTREFs
+  int num_extra_arfs;
+  int arf_pos_in_gf[MAX_EXT_ARFS + 1];
+  int arf_pos_for_ovrly[MAX_EXT_ARFS + 1];
+
+  int extra_arf_allowed;
+  int bwd_ref_allowed;
+
   vpx_roi_map_t roi;
 } VP9_COMP;
 

diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index 2ec7dc51f3ec15c44eefbd418a6aa0304733c2b9..c1357634300061306cd5856989d8efe7790dd243 100644 (file)
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -2120,6 +2120,220 @@ static double calculate_group_score(VP9_COMP *cpi, double av_score,
   return score_total;
 }
 
+static void define_gf_multi_arf_structure(VP9_COMP *cpi) {
+  RATE_CONTROL *const rc = &cpi->rc;
+  TWO_PASS *const twopass = &cpi->twopass;
+  GF_GROUP *const gf_group = &twopass->gf_group;
+  int i;
+  int frame_index = 0;
+  const int key_frame = cpi->common.frame_type == KEY_FRAME;
+
+  // The use of bi-predictive frames are only enabled when following 3
+  // conditions are met:
+  // (1) ALTREF is enabled;
+  // (2) The bi-predictive group interval is at least 2; and
+  // (3) The bi-predictive group interval is strictly smaller than the
+  //     golden group interval.
+  const int is_bipred_enabled =
+      cpi->bwd_ref_allowed && rc->source_alt_ref_pending &&
+      rc->bipred_group_interval &&
+      rc->bipred_group_interval <=
+          (rc->baseline_gf_interval - rc->source_alt_ref_pending);
+  int bipred_group_end = 0;
+  int bipred_frame_index = 0;
+
+  const unsigned char ext_arf_interval =
+      (unsigned char)(rc->baseline_gf_interval / (cpi->num_extra_arfs + 1) - 1);
+  int which_arf = cpi->num_extra_arfs;
+  int subgroup_interval[MAX_EXT_ARFS + 1];
+  int is_sg_bipred_enabled = is_bipred_enabled;
+  int accumulative_subgroup_interval = 0;
+
+  // For key frames the frame target rate is already set and it
+  // is also the golden frame.
+  // === [frame_index == 0] ===
+  if (!key_frame) {
+    if (rc->source_alt_ref_active) {
+      gf_group->update_type[frame_index] = OVERLAY_UPDATE;
+      gf_group->rf_level[frame_index] = INTER_NORMAL;
+    } else {
+      gf_group->update_type[frame_index] = GF_UPDATE;
+      gf_group->rf_level[frame_index] = GF_ARF_STD;
+    }
+    gf_group->arf_update_idx[frame_index] = 0;
+    gf_group->arf_ref_idx[frame_index] = 0;
+  }
+
+  gf_group->bidir_pred_enabled[frame_index] = 0;
+  gf_group->brf_src_offset[frame_index] = 0;
+
+  frame_index++;
+
+  bipred_frame_index++;
+
+  // === [frame_index == 1] ===
+  if (rc->source_alt_ref_pending) {
+    gf_group->update_type[frame_index] = ARF_UPDATE;
+    gf_group->rf_level[frame_index] = GF_ARF_STD;
+    gf_group->arf_src_offset[frame_index] =
+        (unsigned char)(rc->baseline_gf_interval - 1);
+
+    gf_group->arf_update_idx[frame_index] = 0;
+    gf_group->arf_ref_idx[frame_index] = 0;
+
+    gf_group->bidir_pred_enabled[frame_index] = 0;
+    gf_group->brf_src_offset[frame_index] = 0;
+    // NOTE: "bidir_pred_frame_index" stays unchanged for ARF_UPDATE frames.
+
+    // Work out the ARFs' positions in this gf group
+    // NOTE: ALT_REFs' are indexed inversely, but coded in display order
+    // (except for the original ARF). In the example of three ALT_REF's,
+    // We index ALTREF's as: KEY ----- ALT2 ----- ALT1 ----- ALT0
+    // but code them in the following order:
+    // KEY-ALT0-ALT2 ----- OVERLAY2-ALT1 ----- OVERLAY1 ----- OVERLAY0
+    //
+    // arf_pos_for_ovrly[]: Position for OVERLAY
+    // arf_pos_in_gf[]:     Position for ALTREF
+    cpi->arf_pos_for_ovrly[0] = frame_index + cpi->num_extra_arfs +
+                                gf_group->arf_src_offset[frame_index] + 1;
+    for (i = 0; i < cpi->num_extra_arfs; ++i) {
+      cpi->arf_pos_for_ovrly[i + 1] =
+          frame_index + (cpi->num_extra_arfs - i) * (ext_arf_interval + 2);
+      subgroup_interval[i] = cpi->arf_pos_for_ovrly[i] -
+                             cpi->arf_pos_for_ovrly[i + 1] - (i == 0 ? 1 : 2);
+    }
+    subgroup_interval[cpi->num_extra_arfs] =
+        cpi->arf_pos_for_ovrly[cpi->num_extra_arfs] - frame_index -
+        (cpi->num_extra_arfs == 0 ? 1 : 2);
+
+    ++frame_index;
+
+    // Insert an extra ARF
+    // === [frame_index == 2] ===
+    if (cpi->num_extra_arfs) {
+      gf_group->update_type[frame_index] = INTNL_ARF_UPDATE;
+      gf_group->rf_level[frame_index] = GF_ARF_LOW;
+      gf_group->arf_src_offset[frame_index] = ext_arf_interval;
+
+      gf_group->arf_update_idx[frame_index] = which_arf;
+      gf_group->arf_ref_idx[frame_index] = 0;
+      ++frame_index;
+    }
+    accumulative_subgroup_interval += subgroup_interval[cpi->num_extra_arfs];
+  }
+
+  for (i = 0; i < rc->baseline_gf_interval - rc->source_alt_ref_pending; ++i) {
+    gf_group->arf_update_idx[frame_index] = which_arf;
+    gf_group->arf_ref_idx[frame_index] = which_arf;
+
+    // If we are going to have ARFs, check whether we can have BWDREF in this
+    // subgroup, and further, whether we can have ARF subgroup which contains
+    // the BWDREF subgroup but contained within the GF group:
+    //
+    // GF group --> ARF subgroup --> BWDREF subgroup
+    if (rc->source_alt_ref_pending) {
+      is_sg_bipred_enabled =
+          is_bipred_enabled &&
+          (subgroup_interval[which_arf] > rc->bipred_group_interval);
+    }
+
+    // NOTE: 1. BIDIR_PRED is only enabled when the length of the bi-predictive
+    //       frame group interval is strictly smaller than that of the GOLDEN
+    //       FRAME group interval.
+    //       2. Currently BIDIR_PRED is only enabled when alt-ref is on.
+    if (is_sg_bipred_enabled && !bipred_group_end) {
+      const int cur_brf_src_offset = rc->bipred_group_interval - 1;
+
+      if (bipred_frame_index == 1) {
+        // --- BRF_UPDATE ---
+        gf_group->update_type[frame_index] = BRF_UPDATE;
+        gf_group->rf_level[frame_index] = GF_ARF_LOW;
+        gf_group->brf_src_offset[frame_index] = cur_brf_src_offset;
+      } else if (bipred_frame_index == rc->bipred_group_interval) {
+        // --- LAST_BIPRED_UPDATE ---
+        gf_group->update_type[frame_index] = LAST_BIPRED_UPDATE;
+        gf_group->rf_level[frame_index] = INTER_NORMAL;
+        gf_group->brf_src_offset[frame_index] = 0;
+
+        // Reset the bi-predictive frame index.
+        bipred_frame_index = 0;
+      } else {
+        // --- BIPRED_UPDATE ---
+        gf_group->update_type[frame_index] = BIPRED_UPDATE;
+        gf_group->rf_level[frame_index] = INTER_NORMAL;
+        gf_group->brf_src_offset[frame_index] = 0;
+      }
+      gf_group->bidir_pred_enabled[frame_index] = 1;
+
+      bipred_frame_index++;
+      // Check whether the next bi-predictive frame group would entirely be
+      // included within the current golden frame group.
+      // In addition, we need to avoid coding a BRF right before an ARF.
+      if (bipred_frame_index == 1 &&
+          (i + 2 + cur_brf_src_offset) >= accumulative_subgroup_interval) {
+        bipred_group_end = 1;
+      }
+    } else {
+      gf_group->update_type[frame_index] = LF_UPDATE;
+      gf_group->rf_level[frame_index] = INTER_NORMAL;
+      gf_group->bidir_pred_enabled[frame_index] = 0;
+      gf_group->brf_src_offset[frame_index] = 0;
+    }
+
+    ++frame_index;
+
+    // Check if we need to update the ARF.
+    if (is_sg_bipred_enabled && cpi->num_extra_arfs && which_arf > 0 &&
+        frame_index > cpi->arf_pos_for_ovrly[which_arf]) {
+      --which_arf;
+      accumulative_subgroup_interval += subgroup_interval[which_arf] + 1;
+
+      // Meet the new subgroup; Reset the bipred_group_end flag.
+      bipred_group_end = 0;
+      // Insert another extra ARF after the overlay frame
+      if (which_arf) {
+        gf_group->update_type[frame_index] = INTNL_ARF_UPDATE;
+        gf_group->rf_level[frame_index] = GF_ARF_LOW;
+        gf_group->arf_src_offset[frame_index] = ext_arf_interval;
+
+        gf_group->arf_update_idx[frame_index] = which_arf;
+        gf_group->arf_ref_idx[frame_index] = 0;
+        ++frame_index;
+      }
+    }
+  }
+
+  // NOTE: We need to configure the frame at the end of the sequence + 1 that
+  //       is the start frame for the next group. Otherwise prior to the call to
+  //       av1_rc_get_second_pass_params() the data will be undefined.
+  gf_group->arf_update_idx[frame_index] = 0;
+  gf_group->arf_ref_idx[frame_index] = 0;
+
+  if (rc->source_alt_ref_pending) {
+    gf_group->update_type[frame_index] = OVERLAY_UPDATE;
+    gf_group->rf_level[frame_index] = INTER_NORMAL;
+
+    cpi->arf_pos_in_gf[0] = 1;
+    if (cpi->num_extra_arfs) {
+      // Overwrite the update_type for extra-ARF's corresponding internal
+      // OVERLAY's: Change from LF_UPDATE to INTNL_OVERLAY_UPDATE.
+      for (i = cpi->num_extra_arfs; i > 0; --i) {
+        cpi->arf_pos_in_gf[i] =
+            (i == cpi->num_extra_arfs ? 2 : cpi->arf_pos_for_ovrly[i + 1] + 1);
+
+        gf_group->update_type[cpi->arf_pos_for_ovrly[i]] = INTNL_OVERLAY_UPDATE;
+        gf_group->rf_level[cpi->arf_pos_for_ovrly[i]] = INTER_NORMAL;
+      }
+    }
+  } else {
+    gf_group->update_type[frame_index] = GF_UPDATE;
+    gf_group->rf_level[frame_index] = GF_ARF_STD;
+  }
+
+  gf_group->bidir_pred_enabled[frame_index] = 0;
+  gf_group->brf_src_offset[frame_index] = 0;
+}
+
 static void define_gf_group_structure(VP9_COMP *cpi) {
   RATE_CONTROL *const rc = &cpi->rc;
   TWO_PASS *const twopass = &cpi->twopass;
@@ -2248,7 +2462,17 @@ static void allocate_gf_group_bits(VP9_COMP *cpi, int64_t gf_group_bits,
   double this_frame_score = 1.0;
 
   // Define the GF structure and specify
-  define_gf_group_structure(cpi);
+  cpi->bwd_ref_allowed = 0;
+  cpi->extra_arf_allowed = 0;
+
+  cpi->num_extra_arfs = 0;
+  cpi->num_extra_arfs = cpi->extra_arf_allowed ? cpi->num_extra_arfs : 0;
+
+  if (cpi->bwd_ref_allowed) {
+    define_gf_multi_arf_structure(cpi);
+  } else {
+    define_gf_group_structure(cpi);
+  }
 
   key_frame = cpi->common.frame_type == KEY_FRAME;
 

diff --git a/vp9/encoder/vp9_firstpass.h b/vp9/encoder/vp9_firstpass.h
index c4bccfc8549448c093f446a3e97149675783742d..958dc128de18ed426d2cf952efb6899dbc06bec9 100644 (file)
--- a/vp9/encoder/vp9_firstpass.h
+++ b/vp9/encoder/vp9_firstpass.h
@@ -41,6 +41,8 @@ typedef struct {
 
 #define INVALID_ROW -1
 
+#define MAX_EXT_ARFS 2
+
 typedef struct {
   double frame_mb_intra_factor;
   double frame_mb_brightness_factor;
@@ -130,6 +132,8 @@ typedef struct {
   unsigned char arf_src_offset[(MAX_LAG_BUFFERS * 2) + 1];
   unsigned char arf_update_idx[(MAX_LAG_BUFFERS * 2) + 1];
   unsigned char arf_ref_idx[(MAX_LAG_BUFFERS * 2) + 1];
+  unsigned char brf_src_offset[(MAX_LAG_BUFFERS * 2) + 1];
+  unsigned char bidir_pred_enabled[(MAX_LAG_BUFFERS * 2) + 1];
   int bit_allocation[(MAX_LAG_BUFFERS * 2) + 1];
 } GF_GROUP;
 

diff --git a/vp9/encoder/vp9_ratectrl.h b/vp9/encoder/vp9_ratectrl.h
index c1b210677e2019779cfb2c7d13b66c038c5378e8..5f4e66fe3d18fb71b61e819c97fd4e0635e6c291 100644 (file)
--- a/vp9/encoder/vp9_ratectrl.h
+++ b/vp9/encoder/vp9_ratectrl.h
@@ -106,6 +106,9 @@ typedef struct {
   int source_alt_ref_active;
   int is_src_frame_alt_ref;
 
+  // Length of the bi-predictive frame group interval
+  int bipred_group_interval;
+
   int avg_frame_bandwidth;  // Average frame size target for clip
   int min_frame_bandwidth;  // Minimum allocation used for any frame
   int max_frame_bandwidth;  // Maximum burst rate allowed for a frame.