[FFmpeg-devel,2/2] avcodec/cbs_vp9: keep track of reference frames

diff --git a/libavcodec/cbs_vp9.h b/libavcodec/cbs_vp9.h
index 5b99c90c2e..47c3052c7d 100644
--- a/libavcodec/cbs_vp9.h
+++ b/libavcodec/cbs_vp9.h
@@ -117,7 +117,7 @@  typedef struct VP9RawFrameHeader {
     uint8_t frame_context_idx;
 
     // Frame/render size.
-    uint8_t found_ref[VP9_REFS_PER_FRAME];
+    uint8_t found_ref;
     uint16_t frame_width_minus_1;
     uint16_t frame_height_minus_1;
     uint8_t render_and_frame_size_different;
@@ -183,6 +183,13 @@  typedef struct VP9RawSuperframe {
     VP9RawSuperframeIndex index;
 } VP9RawSuperframe;
 
+typedef struct VP9ReferenceFrameState {
+    int frame_width;    // RefFrameWidth
+    int frame_height;   // RefFrameHeight
+    int subsampling_x;  // RefSubsamplingX
+    int subsampling_y;  // RefSubsamplingY
+    int bit_depth;      // RefBitDepth
+} VP9ReferenceFrameState;
 
 typedef struct CodedBitstreamVP9Context {
     // Frame dimensions in 8x8 mode info blocks.
@@ -192,6 +199,12 @@  typedef struct CodedBitstreamVP9Context {
     uint16_t sb64_cols;
     uint16_t sb64_rows;
 
+    int bit_depth;
+    int frame_width;
+    int frame_height;
+
+    VP9ReferenceFrameState ref[VP9_NUM_REF_FRAMES];
+
     // Write buffer.
     uint8_t *write_buffer;
     size_t write_buffer_size;
diff --git a/libavcodec/cbs_vp9_syntax_template.c b/libavcodec/cbs_vp9_syntax_template.c
index b4a7f65e85..b6209d979b 100644
--- a/libavcodec/cbs_vp9_syntax_template.c
+++ b/libavcodec/cbs_vp9_syntax_template.c
@@ -43,10 +43,14 @@  static int FUNC(frame_sync_code)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(color_config)(CodedBitstreamContext *ctx, RWContext *rw,
                               VP9RawFrameHeader *current, int profile)
 {
+    CodedBitstreamVP9Context *vp9 = ctx->priv_data;
     int err;
 
-    if (profile >= 2)
+    if (profile >= 2) {
         f(1, ten_or_twelve_bit);
+        vp9->bit_depth = current->ten_or_twelve_bit ? 12 : 10;
+    } else
+        vp9->bit_depth = 8;
 
     f(3, color_space);
 
@@ -81,8 +85,11 @@  static int FUNC(frame_size)(CodedBitstreamContext *ctx, RWContext *rw,
     f(16, frame_width_minus_1);
     f(16, frame_height_minus_1);
 
-    vp9->mi_cols = (current->frame_width_minus_1  + 8) >> 3;
-    vp9->mi_rows = (current->frame_height_minus_1 + 8) >> 3;
+    vp9->frame_width  = current->frame_width_minus_1  + 1;
+    vp9->frame_height = current->frame_height_minus_1 + 1;
+
+    vp9->mi_cols = (vp9->frame_width  + 7) >> 3;
+    vp9->mi_rows = (vp9->frame_height + 7) >> 3;
     vp9->sb64_cols = (vp9->mi_cols + 7) >> 3;
     vp9->sb64_rows = (vp9->mi_rows + 7) >> 3;
 
@@ -107,12 +114,24 @@  static int FUNC(render_size)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(frame_size_with_refs)(CodedBitstreamContext *ctx, RWContext *rw,
                                       VP9RawFrameHeader *current)
 {
+    CodedBitstreamVP9Context *vp9 = ctx->priv_data;
     int err, i;
 
     for (i = 0; i < VP9_REFS_PER_FRAME; i++) {
-        fs(1, found_ref[i], 1, i);
-        if (current->found_ref[i])
+        f(1, found_ref);
+        if (current->found_ref) {
+            VP9ReferenceFrameState *ref =
+                &vp9->ref[current->ref_frame_idx[i]];
+
+            vp9->frame_width  = ref->frame_width;
+            vp9->frame_height = ref->frame_height;
+
+            vp9->mi_cols = (vp9->frame_width  + 7) >> 3;
+            vp9->mi_rows = (vp9->frame_height + 7) >> 3;
+            vp9->sb64_cols = (vp9->mi_cols + 7) >> 3;
+            vp9->sb64_rows = (vp9->mi_rows + 7) >> 3;
             break;
+        }
     }
     if (i >= VP9_REFS_PER_FRAME)
         CHECK(FUNC(frame_size)(ctx, rw, current));
@@ -249,6 +268,7 @@  static int FUNC(tile_info)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(uncompressed_header)(CodedBitstreamContext *ctx, RWContext *rw,
                                      VP9RawFrameHeader *current)
 {
+    CodedBitstreamVP9Context *vp9 = ctx->priv_data;
     int profile, i;
     int err;
 
@@ -339,6 +359,18 @@  static int FUNC(uncompressed_header)(CodedBitstreamContext *ctx, RWContext *rw,
 
     f(16, header_size_in_bytes);
 
+    for (i = 0; i < VP9_NUM_REF_FRAMES; i++) {
+        if (current->refresh_frame_flags & (1 << i)) {
+            vp9->ref[i] = (VP9ReferenceFrameState) {
+                .frame_width    = vp9->frame_width,
+                .frame_height   = vp9->frame_height,
+                .subsampling_x  = current->subsampling_x,
+                .subsampling_y  = current->subsampling_y,
+                .bit_depth      = vp9->bit_depth,
+            };
+        }
+    }
+
     return 0;
 }