Commit cdc954fd authored by Pengchong Jin's avatar Pengchong Jin
Browse files

skip the un-necessary motion search in the first pass

This patch allows the VP9 encoder to skip the un-necessary
motion search in the first pass. It computes the motion error
of 0,0 motion using the last source frame as the reference,
and skips the further motion search if this error is small.

Borg test shows overall the patch gives PSNR gain (derf -0.001%,
yt 0.341%, hd 0.282%). Individual clips may have PSNR gain or
loss. The best PSNR performance is 7.347% and the worst is -0.662%.
The first pass encoding speedup for slideshow clips is over 30%.

Change-Id: I4cac4dbd911f277ee858e161f3ca652c771344fe
parent 95fb9008
......@@ -594,8 +594,9 @@ void vp9_first_pass(VP9_COMP *cpi) {
// Other than for the first frame do a motion search.
if (cm->current_video_frame > 0) {
int tmp_err, motion_error;
int tmp_err, motion_error, raw_motion_error;
int_mv mv, tmp_mv;
struct buf_2d unscaled_last_source_buf_2d;
xd->plane[0].pre[0].buf = first_ref_buf->y_buffer + recon_yoffset;
motion_error = get_prediction_error(bsize, &x->plane[0].src,
......@@ -603,67 +604,82 @@ void vp9_first_pass(VP9_COMP *cpi) {
// Assume 0,0 motion with no mv overhead.
mv.as_int = tmp_mv.as_int = 0;
// Test last reference frame using the previous best mv as the
// starting point (best reference) for the search.
first_pass_motion_search(cpi, x, &best_ref_mv.as_mv, &mv.as_mv,
&motion_error);
if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
vp9_clear_system_state();
motion_error = (int)(motion_error * error_weight);
}
// If the current best reference mv is not centered on 0,0 then do a 0,0
// based search as well.
if (best_ref_mv.as_int) {
tmp_err = INT_MAX;
first_pass_motion_search(cpi, x, &zero_mv, &tmp_mv.as_mv,
&tmp_err);
// Compute the motion error of the 0,0 motion using the last source
// frame as the reference. Skip the further motion search on
// reconstructed frame if this error is small.
unscaled_last_source_buf_2d.buf =
cpi->unscaled_last_source->y_buffer + recon_yoffset;
unscaled_last_source_buf_2d.stride =
cpi->unscaled_last_source->y_stride;
raw_motion_error = get_prediction_error(bsize, &x->plane[0].src,
&unscaled_last_source_buf_2d);
// TODO(pengchong): Replace the hard-coded threshold
if (raw_motion_error > 25) {
// Test last reference frame using the previous best mv as the
// starting point (best reference) for the search.
first_pass_motion_search(cpi, x, &best_ref_mv.as_mv, &mv.as_mv,
&motion_error);
if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
vp9_clear_system_state();
tmp_err = (int)(tmp_err * error_weight);
motion_error = (int)(motion_error * error_weight);
}
if (tmp_err < motion_error) {
motion_error = tmp_err;
mv.as_int = tmp_mv.as_int;
// If the current best reference mv is not centered on 0,0 then do a
// 0,0 based search as well.
if (best_ref_mv.as_int) {
tmp_err = INT_MAX;
first_pass_motion_search(cpi, x, &zero_mv, &tmp_mv.as_mv, &tmp_err);
if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
vp9_clear_system_state();
tmp_err = (int)(tmp_err * error_weight);
}
if (tmp_err < motion_error) {
motion_error = tmp_err;
mv.as_int = tmp_mv.as_int;
}
}
}
// Search in an older reference frame.
if (cm->current_video_frame > 1 && gld_yv12 != NULL) {
// Assume 0,0 motion with no mv overhead.
int gf_motion_error;
// Search in an older reference frame.
if (cm->current_video_frame > 1 && gld_yv12 != NULL) {
// Assume 0,0 motion with no mv overhead.
int gf_motion_error;
xd->plane[0].pre[0].buf = gld_yv12->y_buffer + recon_yoffset;
gf_motion_error = get_prediction_error(bsize, &x->plane[0].src,
&xd->plane[0].pre[0]);
xd->plane[0].pre[0].buf = gld_yv12->y_buffer + recon_yoffset;
gf_motion_error = get_prediction_error(bsize, &x->plane[0].src,
&xd->plane[0].pre[0]);
first_pass_motion_search(cpi, x, &zero_mv, &tmp_mv.as_mv,
&gf_motion_error);
if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
vp9_clear_system_state();
gf_motion_error = (int)(gf_motion_error * error_weight);
}
first_pass_motion_search(cpi, x, &zero_mv, &tmp_mv.as_mv,
&gf_motion_error);
if (cpi->oxcf.aq_mode == VARIANCE_AQ) {
vp9_clear_system_state();
gf_motion_error = (int)(gf_motion_error * error_weight);
}
if (gf_motion_error < motion_error && gf_motion_error < this_error)
++second_ref_count;
// Reset to last frame as reference buffer.
xd->plane[0].pre[0].buf = first_ref_buf->y_buffer + recon_yoffset;
xd->plane[1].pre[0].buf = first_ref_buf->u_buffer + recon_uvoffset;
xd->plane[2].pre[0].buf = first_ref_buf->v_buffer + recon_uvoffset;
// In accumulating a score for the older reference frame take the
// best of the motion predicted score and the intra coded error
// (just as will be done for) accumulation of "coded_error" for
// the last frame.
if (gf_motion_error < this_error)
sr_coded_error += gf_motion_error;
else
sr_coded_error += this_error;
if (gf_motion_error < motion_error && gf_motion_error < this_error)
++second_ref_count;
// Reset to last frame as reference buffer.
xd->plane[0].pre[0].buf = first_ref_buf->y_buffer + recon_yoffset;
xd->plane[1].pre[0].buf = first_ref_buf->u_buffer + recon_uvoffset;
xd->plane[2].pre[0].buf = first_ref_buf->v_buffer + recon_uvoffset;
// In accumulating a score for the older reference frame take the
// best of the motion predicted score and the intra coded error
// (just as will be done for) accumulation of "coded_error" for
// the last frame.
if (gf_motion_error < this_error)
sr_coded_error += gf_motion_error;
else
sr_coded_error += this_error;
} else {
sr_coded_error += motion_error;
}
} else {
sr_coded_error += motion_error;
}
// Start by assuming that intra mode is best.
best_ref_mv.as_int = 0;
......
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