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/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index 6107b2f..a363352 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -4480,7 +4480,7 @@
#if CONFIG_GLOBAL_MOTION
static int read_global_motion_params(WarpedMotionParams *params,
- WarpedMotionParams *ref_params,
+ const WarpedMotionParams *ref_params,
struct aom_read_bit_buffer *rb,
int allow_hp) {
TransformationType type = aom_rb_read_bit(rb);
@@ -4498,7 +4498,7 @@
int trans_bits;
int trans_dec_factor;
int trans_prec_diff;
- set_default_warp_params(params);
+ *params = default_warp_params;
params->wmtype = type;
switch (type) {
case HOMOGRAPHY:
@@ -4577,11 +4577,11 @@
static void read_global_motion(AV1_COMMON *cm, struct aom_read_bit_buffer *rb) {
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]);
+ const WarpedMotionParams *ref_params =
+ cm->error_resilient_mode ? &default_warp_params
+ : &cm->prev_frame->global_motion[frame];
int good_params = read_global_motion_params(
- &cm->global_motion[frame], &cm->prev_frame->global_motion[frame], rb,
- cm->allow_high_precision_mv);
+ &cm->global_motion[frame], ref_params, rb, cm->allow_high_precision_mv);
if (!good_params)
aom_internal_error(&cm->error, AOM_CODEC_CORRUPT_FRAME,
"Invalid shear parameters for global motion.");
@@ -4597,7 +4597,7 @@
&cm->prev_frame->global_motion[frame], rb,
cm->allow_high_precision_mv);
} else {
- set_default_warp_params(&cm->global_motion[frame]);
+ cm->global_motion[frame] = default_warp_params;
}
*/
/*
@@ -5456,8 +5456,8 @@
#if CONFIG_GLOBAL_MOTION
int i;
for (i = LAST_FRAME; i <= ALTREF_FRAME; ++i) {
- set_default_warp_params(&cm->global_motion[i]);
- set_default_warp_params(&cm->cur_frame->global_motion[i]);
+ cm->global_motion[i] = default_warp_params;
+ cm->cur_frame->global_motion[i] = default_warp_params;
}
xd->global_motion = cm->global_motion;
#endif // CONFIG_GLOBAL_MOTION
