Fix global-motion + error-resilient-mode
Patch https://aomedia-review.googlesource.com/c/21783
changed things so that error-resilient frames use the default
global motion parameters as a reference, rather than taking
the reference from the previous frame.
This was implemented by clearing out cm->prev_frame->global_motion
when we have an error-resilient frame. Unfortunately, this causes
an issue: if we have an error resilient frame which isn't stored
into any reference slots, followed by a non-error-resilient frame,
then both frames refer to the same prev_frame. The second frame
then delta-codes against cm->prev_frame->global_motion, but
this was reset to the default values by the intervening
error-resilient frame!
In order to allow the above case to work as intended, expand the
default warp parameter set to a full WarpedMotionParams struct,
and use that as the reference for error-resilient frames.
This also allows us to remove set_default_warp_params, as we
can now just copy directly from default_warp_params.
Change-Id: I9645615db2700c1d3810e6e42f4f1da626fcd5e3
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 6384f5b..cdf8b69 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -4396,8 +4396,8 @@
}
#if CONFIG_GLOBAL_MOTION
-static void write_global_motion_params(WarpedMotionParams *params,
- WarpedMotionParams *ref_params,
+static void write_global_motion_params(const WarpedMotionParams *params,
+ const WarpedMotionParams *ref_params,
struct aom_write_bit_buffer *wb,
int allow_hp) {
TransformationType type = params->wmtype;
@@ -4480,10 +4480,10 @@
AV1_COMMON *const cm = &cpi->common;
int frame;
for (frame = LAST_FRAME; frame <= ALTREF_FRAME; ++frame) {
- if (cm->error_resilient_mode)
- set_default_warp_params(&cm->prev_frame->global_motion[frame]);
- write_global_motion_params(&cm->global_motion[frame],
- &cm->prev_frame->global_motion[frame], wb,
+ const WarpedMotionParams *ref_params =
+ cm->error_resilient_mode ? &default_warp_params
+ : &cm->prev_frame->global_motion[frame];
+ write_global_motion_params(&cm->global_motion[frame], ref_params, wb,
cm->allow_high_precision_mv);
// TODO(sarahparker, debargha): The logic in the commented out code below
// does not work currently and causes mismatches when resize is on.
