vp10: merge frame_parallel_decoding_mode and refresh_frame_context.

See issue 1030. The value of frame_parallel_decoding_mode was ignored
in vp9 if refresh_frame_context was 0, so instead make it a 3-member
enum where the dependency is obviously stated.

Change-Id: I37f0177e5759f54e2e6cc6217023d5681de92438

5 files changed, 68 insertions, 29 deletions

diff --git a/vp10/common/blockd.h b/vp10/common/blockd.h
index 52c77cd4f..3e455cbef 100644
--- a/vp10/common/blockd.h
+++ b/vp10/common/blockd.h
@@ -176,7 +176,6 @@ typedef struct macroblockd {
   int mb_to_bottom_edge;
 
   FRAME_CONTEXT *fc;
-  int frame_parallel_decoding_mode;
 
   /* pointers to reference frames */
   RefBuffer *block_refs[2];
diff --git a/vp10/common/onyxc_int.h b/vp10/common/onyxc_int.h
index 303a154b4..b88aa7d0e 100644
--- a/vp10/common/onyxc_int.h
+++ b/vp10/common/onyxc_int.h
@@ -63,6 +63,23 @@ typedef enum {
   RESET_FRAME_CONTEXT_ALL = 2,
 } RESET_FRAME_CONTEXT_MODE;
 
+typedef enum {
+  /**
+   * Don't update frame context
+   */
+  REFRESH_FRAME_CONTEXT_OFF,
+  /**
+   * Update frame context to values resulting from forward probability
+   * updates signaled in the frame header
+   */
+  REFRESH_FRAME_CONTEXT_FORWARD,
+  /**
+   * Update frame context to values resulting from backward probability
+   * updates based on entropy/counts in the decoded frame
+   */
+  REFRESH_FRAME_CONTEXT_BACKWARD,
+} REFRESH_FRAME_CONTEXT_MODE;
+
 typedef struct {
   int_mv mv[2];
   MV_REFERENCE_FRAME ref_frame[2];
@@ -226,7 +243,9 @@ typedef struct VP10Common {
 
   loop_filter_info_n lf_info;
 
-  int refresh_frame_context;    /* Two state 0 = NO, 1 = YES */
+  // Flag signaling how frame contexts should be updated at the end of
+  // a frame decode
+  REFRESH_FRAME_CONTEXT_MODE refresh_frame_context;
 
   int ref_frame_sign_bias[MAX_REF_FRAMES];    /* Two state 0, 1 */
 
@@ -257,7 +276,6 @@ typedef struct VP10Common {
 #endif
 
   int error_resilient_mode;
-  int frame_parallel_decoding_mode;
 
   int log2_tile_cols, log2_tile_rows;
   int byte_alignment;
@@ -372,7 +390,6 @@ static INLINE void vp10_init_macroblockd(VP10_COMMON *cm, MACROBLOCKD *xd,
       memcpy(xd->plane[i].seg_dequant, cm->uv_dequant, sizeof(cm->uv_dequant));
     }
     xd->fc = cm->fc;
-    xd->frame_parallel_decoding_mode = cm->frame_parallel_decoding_mode;
   }
 
   xd->above_seg_context = cm->above_seg_context;
diff --git a/vp10/decoder/decodeframe.c b/vp10/decoder/decodeframe.c
index 16706eeec..f1a7aa1b3 100644
--- a/vp10/decoder/decodeframe.c
+++ b/vp10/decoder/decodeframe.c
@@ -1454,8 +1454,9 @@ static const uint8_t *decode_tiles(VP10Decoder *pbi,
       tile_data->cm = cm;
       tile_data->xd = pbi->mb;
       tile_data->xd.corrupted = 0;
-      tile_data->xd.counts = cm->frame_parallel_decoding_mode ?
-                             NULL : &cm->counts;
+      tile_data->xd.counts =
+          cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD ?
+              &cm->counts : NULL;
       vp10_zero(tile_data->dqcoeff);
       vp10_tile_init(&tile_data->xd.tile, tile_data->cm, tile_row, tile_col);
       setup_token_decoder(buf->data, data_end, buf->size, &cm->error,
@@ -1652,7 +1653,7 @@ static const uint8_t *decode_tiles_mt(VP10Decoder *pbi,
   }
 
   // Initialize thread frame counts.
-  if (!cm->frame_parallel_decoding_mode) {
+  if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
     int i;
 
     for (i = 0; i < num_workers; ++i) {
@@ -1674,8 +1675,9 @@ static const uint8_t *decode_tiles_mt(VP10Decoder *pbi,
       tile_data->pbi = pbi;
       tile_data->xd = pbi->mb;
       tile_data->xd.corrupted = 0;
-      tile_data->xd.counts = cm->frame_parallel_decoding_mode ?
-                             0 : &tile_data->counts;
+      tile_data->xd.counts =
+          cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD ?
+              &tile_data->counts : NULL;
       vp10_zero(tile_data->dqcoeff);
       vp10_tile_init(tile, cm, 0, buf->col);
       vp10_tile_init(&tile_data->xd.tile, cm, 0, buf->col);
@@ -1714,7 +1716,8 @@ static const uint8_t *decode_tiles_mt(VP10Decoder *pbi,
     }
 
     // Accumulate thread frame counts.
-    if (n >= tile_cols && !cm->frame_parallel_decoding_mode) {
+    if (n >= tile_cols &&
+        cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
       for (i = 0; i < num_workers; ++i) {
         TileWorkerData *const tile_data =
             (TileWorkerData*)pbi->tile_workers[i].data1;
@@ -1948,11 +1951,20 @@ static size_t read_uncompressed_header(VP10Decoder *pbi,
   }
 
   if (!cm->error_resilient_mode) {
-    cm->refresh_frame_context = vpx_rb_read_bit(rb);
-    cm->frame_parallel_decoding_mode = vpx_rb_read_bit(rb);
+    cm->refresh_frame_context =
+        vpx_rb_read_bit(rb) ? REFRESH_FRAME_CONTEXT_FORWARD
+                            : REFRESH_FRAME_CONTEXT_OFF;
+    if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_FORWARD) {
+        cm->refresh_frame_context =
+            vpx_rb_read_bit(rb) ? REFRESH_FRAME_CONTEXT_FORWARD
+                                : REFRESH_FRAME_CONTEXT_BACKWARD;
+#if !CONFIG_MISC_FIXES
+    } else {
+      vpx_rb_read_bit(rb);  // parallel decoding mode flag
+#endif
+    }
   } else {
-    cm->refresh_frame_context = 0;
-    cm->frame_parallel_decoding_mode = 1;
+    cm->refresh_frame_context = REFRESH_FRAME_CONTEXT_OFF;
   }
 
   // This flag will be overridden by the call to vp10_setup_past_independence
@@ -2187,10 +2199,11 @@ void vp10_decode_frame(VP10Decoder *pbi,
 
   // If encoded in frame parallel mode, frame context is ready after decoding
   // the frame header.
-  if (cm->frame_parallel_decode && cm->frame_parallel_decoding_mode) {
+  if (cm->frame_parallel_decode &&
+      cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_BACKWARD) {
     VPxWorker *const worker = pbi->frame_worker_owner;
     FrameWorkerData *const frame_worker_data = worker->data1;
-    if (cm->refresh_frame_context) {
+    if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_FORWARD) {
       context_updated = 1;
       cm->frame_contexts[cm->frame_context_idx] = *cm->fc;
     }
@@ -2224,7 +2237,7 @@ void vp10_decode_frame(VP10Decoder *pbi,
   }
 
   if (!xd->corrupted) {
-    if (!cm->error_resilient_mode && !cm->frame_parallel_decoding_mode) {
+    if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
       vp10_adapt_coef_probs(cm);
 
       if (!frame_is_intra_only(cm)) {
@@ -2240,6 +2253,7 @@ void vp10_decode_frame(VP10Decoder *pbi,
   }
 
   // Non frame parallel update frame context here.
-  if (cm->refresh_frame_context && !context_updated)
+  if (cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_OFF &&
+      !context_updated)
     cm->frame_contexts[cm->frame_context_idx] = *cm->fc;
 }
diff --git a/vp10/encoder/bitstream.c b/vp10/encoder/bitstream.c
index c41f0ef79..eb5a86714 100644
--- a/vp10/encoder/bitstream.c
+++ b/vp10/encoder/bitstream.c
@@ -1142,8 +1142,13 @@ static void write_uncompressed_header(VP10_COMP *cpi,
   }
 
   if (!cm->error_resilient_mode) {
-    vpx_wb_write_bit(wb, cm->refresh_frame_context);
-    vpx_wb_write_bit(wb, cm->frame_parallel_decoding_mode);
+    vpx_wb_write_bit(wb,
+                     cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_OFF);
+#if CONFIG_MISC_FIXES
+    if (cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_OFF)
+#endif
+      vpx_wb_write_bit(wb, cm->refresh_frame_context !=
+                               REFRESH_FRAME_CONTEXT_BACKWARD);
   }
 
   vpx_wb_write_literal(wb, cm->frame_context_idx, FRAME_CONTEXTS_LOG2);
diff --git a/vp10/encoder/encoder.c b/vp10/encoder/encoder.c
index 85659a244..06cce93c0 100644
--- a/vp10/encoder/encoder.c
+++ b/vp10/encoder/encoder.c
@@ -1421,7 +1421,10 @@ void vp10_change_config(struct VP10_COMP *cpi, const VP10EncoderConfig *oxcf) {
 
   cpi->refresh_golden_frame = 0;
   cpi->refresh_last_frame = 1;
-  cm->refresh_frame_context = 1;
+  cm->refresh_frame_context =
+      oxcf->error_resilient_mode ? REFRESH_FRAME_CONTEXT_OFF :
+          oxcf->frame_parallel_decoding_mode ? REFRESH_FRAME_CONTEXT_FORWARD
+                                             : REFRESH_FRAME_CONTEXT_BACKWARD;
   cm->reset_frame_context = RESET_FRAME_CONTEXT_NONE;
 
   vp10_reset_segment_features(&cm->seg);
@@ -3549,13 +3552,11 @@ static void encode_frame_to_data_rate(VP10_COMP *cpi,
     cpi->rc.source_alt_ref_active = 0;
 
     cm->error_resilient_mode = oxcf->error_resilient_mode;
-    cm->frame_parallel_decoding_mode = oxcf->frame_parallel_decoding_mode;
 
     // By default, encoder assumes decoder can use prev_mi.
     if (cm->error_resilient_mode) {
-      cm->frame_parallel_decoding_mode = 1;
       cm->reset_frame_context = RESET_FRAME_CONTEXT_NONE;
-      cm->refresh_frame_context = 0;
+      cm->refresh_frame_context = REFRESH_FRAME_CONTEXT_OFF;
     } else if (cm->intra_only) {
       // Only reset the current context.
       cm->reset_frame_context = RESET_FRAME_CONTEXT_CURRENT;
@@ -3641,11 +3642,11 @@ static void encode_frame_to_data_rate(VP10_COMP *cpi,
     full_to_model_counts(cpi->td.counts->coef[t],
                          cpi->td.rd_counts.coef_counts[t]);
 
-  if (!cm->error_resilient_mode && !cm->frame_parallel_decoding_mode)
+  if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD)
     vp10_adapt_coef_probs(cm);
 
   if (!frame_is_intra_only(cm)) {
-    if (!cm->error_resilient_mode && !cm->frame_parallel_decoding_mode) {
+    if (cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
       vp10_adapt_mode_probs(cm);
       vp10_adapt_mv_probs(cm, cm->allow_high_precision_mv);
     }
@@ -3828,7 +3829,7 @@ static int frame_is_reference(const VP10_COMP *cpi) {
          cpi->refresh_last_frame ||
          cpi->refresh_golden_frame ||
          cpi->refresh_alt_ref_frame ||
-         cm->refresh_frame_context ||
+         cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_OFF ||
          cm->lf.mode_ref_delta_update ||
          cm->seg.update_map ||
          cm->seg.update_data;
@@ -3956,7 +3957,10 @@ int vp10_get_compressed_data(VP10_COMP *cpi, unsigned int *frame_flags,
 
   // Normal defaults
   cm->reset_frame_context = RESET_FRAME_CONTEXT_NONE;
-  cm->refresh_frame_context = 1;
+  cm->refresh_frame_context =
+      oxcf->error_resilient_mode ? REFRESH_FRAME_CONTEXT_OFF :
+          oxcf->frame_parallel_decoding_mode ? REFRESH_FRAME_CONTEXT_FORWARD
+                                             : REFRESH_FRAME_CONTEXT_BACKWARD;
 
   cpi->refresh_last_frame = 1;
   cpi->refresh_golden_frame = 0;
@@ -4100,7 +4104,7 @@ int vp10_get_compressed_data(VP10_COMP *cpi, unsigned int *frame_flags,
     Pass0Encode(cpi, size, dest, frame_flags);
   }
 
-  if (cm->refresh_frame_context)
+  if (cm->refresh_frame_context != REFRESH_FRAME_CONTEXT_OFF)
     cm->frame_contexts[cm->frame_context_idx] = *cm->fc;
 
   // No frame encoded, or frame was dropped, release scaled references.