ref: 30d8ba541ede1d79b3d1d72f66ff05fcab6b5f92
parent: 0e213fb999665b382b3937cb7ab1ff2385cd5265
author: John Koleszar <jkoleszar@google.com>
date: Mon Oct 8 04:39:47 EDT 2012
multi-res: work around reference mismatch In some situations, believed to be an interaction between temporal scalability and dropped frames, the references available to an encoder may not be the same references available to its parent. Previously, the code tried to force the reference frame chosen by the parent to be used on this frame, even if it was disabled. This was preventing the pick mode loop from running even once, which led to a crash. Attempts to reproduce this bug locally were unsuccessful, so it is still undetermined what the underlying cause of this issue is. In the specific case that was failing, the application did not set any flags which influenced the reference selection on that frame. ref_frame_flags indicated that the golden frame was disabled, believed to be because the last frame updated the last and golden frames, so golden was shut off by default. It's not clear why this wouldn't have also been true in the lower res encoder, ie, why the lower res encoder decided to use and/or was allowed to use the golden frame. We weren't able to debug into the non-crashing lower res encoder as the crash couldn't be reproduced locally. Change-Id: Ifb265253d26963ac2afde0e20cf6792788be6af7
--- a/vp8/encoder/pickinter.c
+++ b/vp8/encoder/pickinter.c
@@ -610,8 +610,34 @@
MB_PREDICTION_MODE parent_mode = 0;
if (cpi->oxcf.mr_encoder_id && cpi->mr_low_res_mv_avail)
+ {+ int parent_ref_flag;
+
get_lower_res_motion_info(cpi, xd, &dissim, &parent_ref_frame,
&parent_mode, &parent_ref_mv, mb_row, mb_col);
+
+ /* TODO(jkoleszar): The references available (ref_frame_flags) to the
+ * lower res encoder should match those available to this encoder, but
+ * there seems to be a situation where this mismatch can happen in the
+ * case of frame dropping and temporal layers. For example,
+ * GOLD being disallowed in ref_frame_flags, but being returned as
+ * parent_ref_frame.
+ *
+ * In this event, take the conservative approach of disabling the
+ * lower res info for this MB.
+ */
+ parent_ref_flag = 0;
+ if (parent_ref_frame == LAST_FRAME)
+ parent_ref_flag = (cpi->ref_frame_flags & VP8_LAST_FRAME);
+ else if (parent_ref_frame == GOLDEN_FRAME)
+ parent_ref_flag = (cpi->ref_frame_flags & VP8_GOLD_FRAME);
+ else if (parent_ref_frame == ALTREF_FRAME)
+ parent_ref_flag = (cpi->ref_frame_flags & VP8_ALTR_FRAME);
+
+ //assert(!parent_ref_frame || parent_ref_flag);
+ if (!parent_ref_flag)
+ parent_ref_frame = 0;
+ }
#endif
mode_mv = mode_mv_sb[sign_bias];
@@ -620,6 +646,16 @@
vpx_memset(&best_mbmode, 0, sizeof(best_mbmode));
/* Setup search priorities */
+#if CONFIG_MULTI_RES_ENCODING
+ if (cpi->oxcf.mr_encoder_id && cpi->mr_low_res_mv_avail
+ && parent_ref_frame && dissim < 8)
+ {+ ref_frame_map[0] = INTRA_FRAME;
+ ref_frame_map[1] = parent_ref_frame;
+ ref_frame_map[2] = -1;
+ ref_frame_map[3] = -1;
+ } else
+#endif
get_reference_search_order(cpi, ref_frame_map);
/* Check to see if there is at least 1 valid reference frame that we need
@@ -670,25 +706,6 @@
continue;
x->e_mbd.mode_info_context->mbmi.ref_frame = this_ref_frame;
-
-#if CONFIG_MULTI_RES_ENCODING
- if (cpi->oxcf.mr_encoder_id && cpi->mr_low_res_mv_avail)
- {- /* TODO: If parent MB is intra, child MB is intra. This is removed
- * now since it cause noticeable quality loss for some test clip.
- * Will come back to evaluate more.
- * if (!parent_ref_frame && this_ref_frame)
- * continue;
- */
-
- /* If parent MB is inter, and it is unlikely there are multiple
- * objects in parent MB, we use parent ref frame as child MB's
- * ref frame. */
- if (parent_ref_frame && dissim < 8
- && parent_ref_frame != this_ref_frame)
- continue;
- }
-#endif
/* everything but intra */
if (x->e_mbd.mode_info_context->mbmi.ref_frame)
--
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