ref: c99f9d7abf90538bc569a5683299766276b287c9
parent: a9ce3e3834fb7f790523e0f0180520034589d786
author: John Koleszar <jkoleszar@google.com>
date: Mon Apr 11 07:29:23 EDT 2011
Change rc undershoot/overshoot semantics This patch changes the rc_undershoot_pct and rc_overshoot_pct controls to set the "aggressiveness" of rate adaptation, by limiting the amount of difference between the target buffer level and the actual buffer level which is applied to the target frame rate for this frame. This patch was initially provided by arosenberg at logitech.com as an attachment to issue #270. It was modified to separate these controls from the other unrelated modifications in that patch, as well as to use the pre-existing variables rather than introducing new ones. Change-Id: Id542e3f5667dd92d857d5eabf29878f2fd730a62
--- a/vp8/common/onyx.h
+++ b/vp8/common/onyx.h
@@ -139,8 +139,9 @@
int end_usage; // vbr or cbr
- // shoot to keep buffer full at all times by undershooting a bit 95 recommended
+ // buffer targeting aggressiveness
int under_shoot_pct;
+ int over_shoot_pct;
// buffering parameters
int starting_buffer_level; // in seconds
--- a/vp8/encoder/ratectrl.c
+++ b/vp8/encoder/ratectrl.c
@@ -817,11 +817,6 @@
}
}
- // Set a reduced data rate target for our initial Q calculation.
- // This should help to save bits during earier sections.
- if ((cpi->oxcf.under_shoot_pct > 0) && (cpi->oxcf.under_shoot_pct <= 100))
- cpi->this_frame_target = (cpi->this_frame_target * cpi->oxcf.under_shoot_pct) / 100;
-
// Sanity check that the total sum of adjustments is not above the maximum allowed
// That is that having allowed for KF and GF penalties we have not pushed the
// current interframe target to low. If the adjustment we apply here is not capable of recovering
@@ -858,11 +853,6 @@
percent_low =
(cpi->oxcf.optimal_buffer_level - cpi->buffer_level) /
one_percent_bits;
-
- if (percent_low > 100)
- percent_low = 100;
- else if (percent_low < 0)
- percent_low = 0;
}
// Are we overshooting the long term clip data rate...
else if (cpi->bits_off_target < 0)
@@ -870,16 +860,16 @@
// Adjust per frame data target downwards to compensate.
percent_low = (int)(100 * -cpi->bits_off_target /
(cpi->total_byte_count * 8));
-
- if (percent_low > 100)
- percent_low = 100;
- else if (percent_low < 0)
- percent_low = 0;
}
+ if (percent_low > cpi->oxcf.under_shoot_pct)
+ percent_low = cpi->oxcf.under_shoot_pct;
+ else if (percent_low < 0)
+ percent_low = 0;
+
// lower the target bandwidth for this frame.
- cpi->this_frame_target =
- (cpi->this_frame_target * (100 - (percent_low / 2))) / 100;
+ cpi->this_frame_target -= (cpi->this_frame_target * percent_low)
+ / 200;
// Are we using allowing control of active_worst_allowed_q
// according to buffer level.
@@ -950,20 +940,29 @@
}
else
{- int percent_high;
+ int percent_high = 0;
- if (cpi->bits_off_target > cpi->oxcf.optimal_buffer_level)
+ if ((cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
+ && (cpi->buffer_level > cpi->oxcf.optimal_buffer_level))
{- percent_high = (int)(100 * (cpi->bits_off_target - cpi->oxcf.optimal_buffer_level) / (cpi->total_byte_count * 8));
+ percent_high = (cpi->buffer_level
+ - cpi->oxcf.optimal_buffer_level)
+ / one_percent_bits;
+ }
+ else if (cpi->bits_off_target > cpi->oxcf.optimal_buffer_level)
+ {+ percent_high = (int)((100 * cpi->bits_off_target)
+ / (cpi->total_byte_count * 8));
+ }
- if (percent_high > 100)
- percent_high = 100;
- else if (percent_high < 0)
- percent_high = 0;
+ if (percent_high > cpi->oxcf.over_shoot_pct)
+ percent_high = cpi->oxcf.over_shoot_pct;
+ else if (percent_high < 0)
+ percent_high = 0;
- cpi->this_frame_target = (cpi->this_frame_target * (100 + (percent_high / 2))) / 100;
+ cpi->this_frame_target += (cpi->this_frame_target *
+ percent_high) / 200;
- }
// Are we allowing control of active_worst_allowed_q according to bufferl level.
if (cpi->auto_worst_q)
--- a/vp8/vp8_cx_iface.c
+++ b/vp8/vp8_cx_iface.c
@@ -151,7 +151,8 @@
RANGE_CHECK_HI(cfg, g_lag_in_frames, 0);
#endif
RANGE_CHECK(cfg, rc_end_usage, VPX_VBR, VPX_CQ);
- RANGE_CHECK_HI(cfg, rc_undershoot_pct, 100);
+ RANGE_CHECK_HI(cfg, rc_undershoot_pct, 1000);
+ RANGE_CHECK_HI(cfg, rc_overshoot_pct, 1000);
RANGE_CHECK_HI(cfg, rc_2pass_vbr_bias_pct, 100);
RANGE_CHECK(cfg, kf_mode, VPX_KF_DISABLED, VPX_KF_AUTO);
//RANGE_CHECK_BOOL(cfg, g_delete_firstpassfile);
@@ -316,7 +317,7 @@
oxcf->fixed_q = -1;
oxcf->under_shoot_pct = cfg.rc_undershoot_pct;
- //oxcf->over_shoot_pct = cfg.rc_overshoot_pct;
+ oxcf->over_shoot_pct = cfg.rc_overshoot_pct;
oxcf->maximum_buffer_size = cfg.rc_buf_sz;
oxcf->starting_buffer_level = cfg.rc_buf_initial_sz;
@@ -362,6 +363,7 @@
printf("key_freq: %d\n", oxcf->key_freq); printf("end_usage: %d\n", oxcf->end_usage); printf("under_shoot_pct: %d\n", oxcf->under_shoot_pct);+ printf("over_shoot_pct: %d\n", oxcf->over_shoot_pct); printf("starting_buffer_level: %d\n", oxcf->starting_buffer_level); printf("optimal_buffer_level: %d\n", oxcf->optimal_buffer_level); printf("maximum_buffer_size: %d\n", oxcf->maximum_buffer_size);@@ -1091,8 +1093,8 @@
4, /* rc_min_quantizer */
63, /* rc_max_quantizer */
- 95, /* rc_undershoot_pct */
- 200, /* rc_overshoot_pct */
+ 100, /* rc_undershoot_pct */
+ 100, /* rc_overshoot_pct */
6000, /* rc_max_buffer_size */
4000, /* rc_buffer_initial_size; */
--- a/vpx/vpx_encoder.h
+++ b/vpx/vpx_encoder.h
@@ -430,20 +430,28 @@
*/
- /*!\brief Rate control undershoot tolerance
+ /*!\brief Rate control adaptation undershoot control
*
- * This value, expressed as a percentage of the target bitrate, describes
- * the target bitrate for easier frames, allowing bits to be saved for
- * harder frames. Set to zero to use the codec default.
+ * This value, expressed as a percentage of the target bitrate,
+ * controls the maximum allowed adaptation speed of the codec.
+ * This factor controls the maximum amount of bits that can
+ * be subtracted from the target bitrate in order to compensate
+ * for prior overshoot.
+ *
+ * Valid values in the range 0-1000.
*/
unsigned int rc_undershoot_pct;
- /*!\brief Rate control overshoot tolerance
+ /*!\brief Rate control adaptation overshoot control
*
- * This value, expressed as a percentage of the target bitrate, describes
- * the maximum allowed bitrate for a given frame. Set to zero to use the
- * codec default.
+ * This value, expressed as a percentage of the target bitrate,
+ * controls the maximum allowed adaptation speed of the codec.
+ * This factor controls the maximum amount of bits that can
+ * be added to the target bitrate in order to compensate for
+ * prior undershoot.
+ *
+ * Valid values in the range 0-1000.
*/
unsigned int rc_overshoot_pct;