1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
Index: encoder/ratecontrol.c
===================================================================
--- encoder/ratecontrol.c (revision 736)
+++ encoder/ratecontrol.c (working copy)
@@ -43,6 +43,7 @@
int p_tex_bits;
int misc_bits;
uint64_t expected_bits;
+ double expected_vbv;
float new_qscale;
int new_qp;
int i_count;
@@ -1149,7 +1150,7 @@
return;
rct->buffer_fill_final += rct->buffer_rate - bits;
- if( rct->buffer_fill_final < 0 && !rct->b_2pass )
+ if( rct->buffer_fill_final < 0 )
x264_log( h, X264_LOG_WARNING, "VBV underflow (%.0f bits)\n", rct->buffer_fill_final );
rct->buffer_fill_final = x264_clip3f( rct->buffer_fill_final, 0, rct->buffer_size );
}
@@ -1325,6 +1326,22 @@
double w = x264_clip3f( time*100, 0.0, 1.0 );
q *= pow( (double)total_bits / rcc->expected_bits_sum, w );
}
+ if( rcc->b_vbv )
+ {
+ double expected_size = qscale2bits(&rce, q);
+ double expected_vbv = rcc->buffer_fill + rcc->buffer_rate - expected_size;
+ if( (expected_vbv < rcc->buffer_size*.4) && (expected_vbv < rce.expected_vbv) )
+ {
+ double qmax = (expected_vbv < rcc->buffer_size*.15) ? lmax : q*1.5;
+ double size_constraint = 1 + rce.expected_vbv/rcc->buffer_size;
+ while( (expected_vbv < rce.expected_vbv/size_constraint) && (q < qmax) )
+ {
+ q *= 1.05;
+ expected_size = qscale2bits(&rce, q);
+ expected_vbv = rcc->buffer_fill + rcc->buffer_rate - expected_size;
+ }
+ }
+ }
q = x264_clip3f( q, lmin, lmax );
}
else /* 1pass ABR */
@@ -1455,6 +1472,137 @@
/* the rest of the variables are either constant or thread-local */
}
+FILE *fh_vbv;
+
+static int find_underflow( x264_t *h, double *fills, int *t0, int *t1, int over )
+{
+ /* find an interval ending on an overflow or underflow (depending on whether
+ * we're adding or removing bits), and starting on the earliest frame that
+ * can influence the buffer fill of that end frame. */
+ x264_ratecontrol_t *rcc = h->rc;
+ const double buffer_min = (over ? .1 : .1) * rcc->buffer_size;
+ const double buffer_max = .9 * rcc->buffer_size;
+ double fill = fills[*t0-1];
+ double parity = over ? 1. : -1.;
+ int i, start=-1, end=-1;
+ for(i=*t0; i<rcc->num_entries; i++)
+ {
+ fill += (rcc->buffer_rate - qscale2bits(&rcc->entry[i], rcc->entry[i].new_qscale)) * parity;
+ fill = x264_clip3f(fill, 0, rcc->buffer_size);
+ fills[i] = fill;
+ if(fill <= buffer_min || i == 0)
+ {
+ if(end >= 0)
+ break;
+ start = i;
+ }
+ else if(fill >= buffer_max && start >= 0)
+ end = i;
+ }
+ *t0 = start;
+ *t1 = end;
+ return start>=0 && end>=0;
+}
+
+static void fix_underflow( x264_t *h, int t0, int t1, double adjustment, double qscale_min, double qscale_max)
+{
+ x264_ratecontrol_t *rcc = h->rc;
+ double qscale_new;
+ int i;
+ if(t0 > 0)
+ t0++;
+ for(i=t0; i<=t1; i++) {
+ qscale_new = rcc->entry[i].new_qscale *= adjustment;
+ rcc->entry[i].new_qscale = x264_clip3f(qscale_new, qscale_min, qscale_max);
+ }
+}
+
+static double count_expected_bits( x264_t *h )
+{
+ x264_ratecontrol_t *rcc = h->rc;
+ double expected_bits = 0;
+ int i;
+ for(i=0; i<rcc->num_entries; i++)
+ {
+ ratecontrol_entry_t *rce = &rcc->entry[i];
+ rce->expected_bits = expected_bits;
+ expected_bits += qscale2bits(rce, rce->new_qscale);
+ }
+ return expected_bits;
+}
+
+static void debug_dump_vbv( x264_t *h )
+{
+ x264_ratecontrol_t *rcc = h->rc;
+ double fill = rcc->buffer_size * h->param.rc.f_vbv_buffer_init;
+ int i;
+ for(i=0; i<rcc->num_entries; i++)
+ {
+ fill += rcc->buffer_rate - qscale2bits(&rcc->entry[i], rcc->entry[i].new_qscale);
+ fill = x264_clip3f(fill, rcc->buffer_size*-.5, rcc->buffer_size);
+ fprintf(fh_vbv, "%d %.0f\n", i, fill);
+ }
+}
+
+static void vbv_pass2( x264_t *h )
+{
+ /* foreach interval of buffer_full .. underflow
+ * uniformly increase the qp of all frames in the interval until either
+ * buffer is full at some intermediate frame
+ * or the last frame in the interval no longer underflows
+ * recompute intervals and repeat
+ * then do the converse to put bits back into overflow areas until target size is met */
+
+ x264_ratecontrol_t *rcc = h->rc;
+ double *fills = x264_malloc((rcc->num_entries+1)*sizeof(double));
+ double all_available_bits = h->param.rc.i_bitrate * 1000. * rcc->num_entries / rcc->fps;
+ double expected_bits = 0;
+ double adjustment;
+ double prev_bits = 0;
+ int i, t0, t1;
+ double qscale_min = qp2qscale(h->param.rc.i_qp_min);
+ double qscale_max = qp2qscale(h->param.rc.i_qp_max);
+ int iterations = 0;
+
+ fills++;
+
+ //adjust overall stream size
+ do {
+ iterations++;
+ prev_bits = expected_bits;
+
+ if (expected_bits != 0) { //not first iteration
+ adjustment = X264_MAX(X264_MIN(expected_bits / all_available_bits, 0.999), 0.9);
+ fills[-1] = rcc->buffer_size * h->param.rc.f_vbv_buffer_init;
+ t0 = 0;
+ //fix overflows
+ while(find_underflow(h, fills, &t0, &t1, 1))
+ {
+ fix_underflow(h, t0, t1, adjustment, qscale_min, qscale_max);
+ t0 = t1;
+ }
+ }
+
+ fills[-1] = rcc->buffer_size * (1. - h->param.rc.f_vbv_buffer_init);
+ t0 = 0;
+ //fix underflows - should be done after overflow, as we'd better undersize target than underflowing VBV
+ while(find_underflow(h, fills, &t0, &t1, 0))
+ {
+ fix_underflow(h, t0, t1, 1.001, qscale_min, qscale_max);
+ }
+
+ expected_bits = count_expected_bits(h);
+ } while(expected_bits < .995*all_available_bits && expected_bits > prev_bits);
+
+ //store expected vbv filling values for tracking when encoding
+ for(i=0; i<rcc->num_entries; i++)
+ rcc->entry[i].expected_vbv = rcc->buffer_size - fills[i];
+
+// x264_log( h, X264_LOG_INFO, "VBV RC initial iterations: %d \n", iterations);
+
+ x264_free(fills-1);
+}
+
static int init_pass2( x264_t *h )
{
x264_ratecontrol_t *rcc = h->rc;
@@ -1543,7 +1691,6 @@
rcc->last_non_b_pict_type = -1;
rcc->last_accum_p_norm = 1;
rcc->accum_p_norm = 0;
- rcc->buffer_fill = rcc->buffer_size * h->param.rc.f_vbv_buffer_init;
/* find qscale */
for(i=0; i<rcc->num_entries; i++){
@@ -1580,18 +1727,11 @@
/* find expected bits */
for(i=0; i<rcc->num_entries; i++){
ratecontrol_entry_t *rce = &rcc->entry[i];
- double bits;
rce->new_qscale = clip_qscale(h, rce->pict_type, blurred_qscale[i]);
assert(rce->new_qscale >= 0);
- bits = qscale2bits(rce, rce->new_qscale);
-
- rce->expected_bits = expected_bits;
- expected_bits += bits;
- update_vbv(h, bits);
- rcc->buffer_fill = rcc->buffer_fill_final;
+ expected_bits += qscale2bits(rce, rce->new_qscale);
}
-//printf("expected:%llu available:%llu factor:%lf avgQ:%lf\n", (uint64_t)expected_bits, all_available_bits, rate_factor);
if(expected_bits > all_available_bits) rate_factor -= step;
}
@@ -1599,6 +1739,10 @@
if(filter_size > 1)
x264_free(blurred_qscale);
+ if(rcc->b_vbv)
+ vbv_pass2(h);
+ expected_bits = count_expected_bits(h);
+
if(fabs(expected_bits/all_available_bits - 1.0) > 0.01)
{
double avgq = 0;
@@ -1606,7 +1750,8 @@
avgq += rcc->entry[i].new_qscale;
avgq = qscale2qp(avgq / rcc->num_entries);
- x264_log(h, X264_LOG_WARNING, "Error: 2pass curve failed to converge\n");
+ if ((expected_bits > all_available_bits) || (!rcc->b_vbv))
+ x264_log(h, X264_LOG_WARNING, "Error: 2pass curve failed to converge\n");
x264_log(h, X264_LOG_WARNING, "target: %.2f kbit/s, expected: %.2f kbit/s, avg QP: %.4f\n",
(float)h->param.rc.i_bitrate,
expected_bits * rcc->fps / (rcc->num_entries * 1000.),
@@ -1625,7 +1770,7 @@
else
x264_log(h, X264_LOG_WARNING, "try increasing target bitrate\n");
}
- else
+ else if(!(rcc->b_2pass && rcc->b_vbv))
x264_log(h, X264_LOG_WARNING, "internal error\n");
}
|
