1 #include "x264_speed_control.h"
10 #include <type_traits>
15 using namespace std::chrono;
17 X264SpeedControl::X264SpeedControl(x264_t *x264, float f_speed, int i_buffer_size, float f_buffer_init)
18 : x264(x264), f_speed(f_speed)
21 x264_encoder_parameters(x264, ¶m);
23 float fps = (float)param.i_fps_num / param.i_fps_den;
25 set_buffer_size(i_buffer_size);
26 buffer_fill = buffer_size * f_buffer_init;
27 buffer_fill = max<int64_t>(buffer_fill, uspf);
28 buffer_fill = min(buffer_fill, buffer_size);
29 timestamp = steady_clock::now();
31 cplx_num = 3e3; //FIXME estimate initial complexity
33 stat.min_buffer = buffer_size;
35 stat.avg_preset = 0.0;
39 X264SpeedControl::~X264SpeedControl()
41 fprintf(stderr, "speedcontrol: avg preset=%.3f buffer min=%.3f max=%.3f\n",
42 stat.avg_preset / stat.den,
43 (float)stat.min_buffer / buffer_size,
44 (float)stat.max_buffer / buffer_size );
45 // x264_log( x264, X264_LOG_INFO, "speedcontrol: avg cplx=%.5f\n", cplx_num / cplx_den );
50 float time; // relative encoding time, compared to the other presets
63 // The actual presets, including the equivalent commandline options. Note that
64 // all presets are benchmarked with --weightp 1 --mbtree --rc-lookahead 20
65 // on top of the given settings (equivalent settings to the "faster" preset).
66 // Timings and SSIM measurements were done on a quadcore Haswell i5 3.2 GHz
67 // on the first 1000 frames of "Tears of Steel" in 1080p.
69 // Note that the two first and the two last are also used for extrapolation
70 // should the desired time be outside the range. Thus, it is disadvantageous if
71 // they are chosen so that the timings are too close to each other.
73 static const sc_preset_t presets[SC_PRESETS] = {
74 #define I4 X264_ANALYSE_I4x4
75 #define I8 X264_ANALYSE_I8x8
76 #define P4 X264_ANALYSE_PSUB8x8
77 #define P8 X264_ANALYSE_PSUB16x16
78 #define B8 X264_ANALYSE_BSUB16x16
79 // Preset 0: 14.179db, --preset superfast --b-adapt 0 --bframes 0
80 { .time= 1.000, .subme=1, .me=X264_ME_DIA, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4, .badapt=0, .bframes=0, .direct=0, .merange=16 },
82 // Preset 1: 14.459db, --preset superfast
83 { .time= 1.283, .subme=1, .me=X264_ME_DIA, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4, .badapt=1, .bframes=3, .direct=1, .merange=16 },
85 // Preset 2: 14.761db, --preset superfast --subme 2
86 { .time= 1.603, .subme=2, .me=X264_ME_DIA, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4, .badapt=1, .bframes=3, .direct=1, .merange=16 },
88 // Preset 3: 15.543db, --preset veryfast
89 { .time= 1.843, .subme=2, .me=X264_ME_HEX, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
91 // Preset 4: 15.716db, --preset veryfast --subme 3
92 { .time= 2.452, .subme=3, .me=X264_ME_HEX, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
94 // Preset 5: 15.786db, --preset veryfast --subme 3 --ref 2
95 { .time= 2.733, .subme=3, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
97 // Preset 6: 15.813db, --preset veryfast --subme 4 --ref 2
98 { .time= 3.085, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
100 // Preset 7: 15.849db, --preset faster
101 { .time= 3.101, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
103 // Preset 8: 15.857db, --preset faster --mixed-refs
104 { .time= 3.284, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
106 // Preset 9: 15.869db, --preset faster --mixed-refs --subme 5
107 { .time= 3.587, .subme=5, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
109 // Preset 10: 16.051db, --preset fast
110 { .time= 3.947, .subme=6, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
112 // Preset 11: 16.356db, --preset fast --subme 7
113 { .time= 4.041, .subme=7, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
115 // Preset 12: 16.418db, --preset fast --subme 7 --ref 3
116 { .time= 4.406, .subme=7, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
118 // Preset 13: 16.460db, --preset medium
119 { .time= 4.707, .subme=7, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
121 // Preset 14: 16.517db, --preset medium --subme 8
122 { .time= 5.133, .subme=8, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
124 // Preset 15: 16.523db, --preset medium --subme 8 --me umh
125 { .time= 6.050, .subme=8, .me=X264_ME_UMH, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=1, .bframes=3, .direct=1, .merange=16 },
127 // Preset 16: 16.543db, --preset medium --subme 8 --me umh --direct auto --b-adapt 2
128 { .time= 6.849, .subme=8, .me=X264_ME_UMH, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
130 // Preset 17: 16.613db, --preset slow
131 { .time= 8.042, .subme=8, .me=X264_ME_UMH, .refs=5, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
133 // Preset 18: 16.641db, --preset slow --subme 9
134 { .time= 8.972, .subme=9, .me=X264_ME_UMH, .refs=5, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
136 // Preset 19: 16.895db, --preset slow --subme 9 --trellis 2
137 { .time=10.073, .subme=9, .me=X264_ME_UMH, .refs=5, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
139 // Preset 20: 16.918db, --preset slow --subme 9 --trellis 2 --ref 6
140 { .time=11.147, .subme=9, .me=X264_ME_UMH, .refs=6, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
142 // Preset 21: 16.934db, --preset slow --subme 9 --trellis 2 --ref 7
143 { .time=12.267, .subme=9, .me=X264_ME_UMH, .refs=7, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .badapt=2, .bframes=3, .direct=3, .merange=16 },
145 // Preset 22: 16.948db, --preset slower
146 { .time=13.829, .subme=9, .me=X264_ME_UMH, .refs=8, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .badapt=2, .bframes=3, .direct=3, .merange=16 },
148 // Preset 23: 17.058db, --preset slower --subme 10
149 { .time=14.831, .subme=10, .me=X264_ME_UMH, .refs=8, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .badapt=2, .bframes=3, .direct=3, .merange=16 },
151 // Preset 24: 17.268db, --preset slower --subme 10 --bframes 8
152 { .time=18.705, .subme=10, .me=X264_ME_UMH, .refs=8, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .badapt=2, .bframes=8, .direct=3, .merange=16 },
154 // Preset 25: 17.297db, --preset veryslow
155 { .time=31.419, .subme=10, .me=X264_ME_UMH, .refs=16, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .badapt=2, .bframes=8, .direct=3, .merange=24 },
163 void X264SpeedControl::before_frame(float new_buffer_fill, int new_buffer_size, float new_uspf)
165 if (new_uspf > 0.0) {
168 if (new_buffer_size) {
169 set_buffer_size(new_buffer_size);
171 buffer_fill = buffer_size * new_buffer_fill;
173 steady_clock::time_point t;
175 // update buffer state after encoding and outputting the previous frame(s)
177 t = timestamp = steady_clock::now();
180 t = steady_clock::now();
183 auto delta_t = t - timestamp;
186 // update the time predictor
188 int cpu_time = duration_cast<microseconds>(cpu_time_last_frame).count();
189 cplx_num *= cplx_decay;
190 cplx_den *= cplx_decay;
191 cplx_num += cpu_time / presets[preset].time;
194 stat.avg_preset += preset;
198 stat.min_buffer = min(buffer_fill, stat.min_buffer);
199 stat.max_buffer = max(buffer_fill, stat.max_buffer);
201 if (buffer_fill >= buffer_size) { // oops, cpu was idle
202 // not really an error, but we'll warn for debugging purposes
203 static int64_t idle_t = 0;
204 static steady_clock::time_point print_interval;
205 static bool first = false;
206 idle_t += buffer_fill - buffer_size;
207 if (first || duration<double>(t - print_interval).count() > 0.1) {
208 //fprintf(stderr, "speedcontrol idle (%.6f sec)\n", idle_t/1e6);
213 buffer_fill = buffer_size;
214 } else if (buffer_fill <= 0) { // oops, we're late
215 // fprintf(stderr, "speedcontrol underflow (%.6f sec)\n", buffer_fill/1e6);
219 // Pick the preset that should return the buffer to 3/4-full within a time
220 // specified by compensation_period.
222 // NOTE: This doesn't actually do that, at least assuming the same target is
223 // chosen for every frame; exactly what it does is unclear to me. It seems
224 // to consistently undershoot a bit, so it needs to be saved by the second
225 // predictor below. However, fixing the formula seems to yield somewhat less
226 // stable results in practice; in particular, once the buffer is half-full
227 // or so, it would give us a negative target. Perhaps increasing
228 // compensation_period would be a good idea, but initial (very brief) tests
229 // did not yield good results.
230 float target = uspf / f_speed
231 * (buffer_fill + compensation_period)
232 / (buffer_size*3/4 + compensation_period);
233 float cplx = cplx_num / cplx_den;
235 float filled = (float) buffer_fill / buffer_size;
237 t0 = presets[0].time * cplx;
239 t1 = presets[i].time * cplx;
240 if (t1 >= target || i == SC_PRESETS - 1)
244 // exponential interpolation between states
245 set = i-1 + (log(target) - log(t0)) / (log(t1) - log(t0));
246 set = max<float>(set, -5);
247 set = min<float>(set, (SC_PRESETS-1) + 5);
248 // Even if our time estimations in the SC_PRESETS array are off
249 // this will push us towards our target fullness
251 set += (40 * (filled-0.75));
252 float s2 = (40 * (filled-0.75));
253 set = min<float>(max<float>(set, 0), SC_PRESETS - 1);
254 apply_preset(dither_preset(set));
256 if (global_flags.x264_speedcontrol_verbose) {
257 static float cpu, wall, tgt, den;
258 const float decay = 1-1/100.;
259 cpu = cpu*decay + duration_cast<microseconds>(cpu_time_last_frame).count();
260 wall = wall*decay + duration_cast<microseconds>(delta_t).count();
261 tgt = tgt*decay + target;
263 fprintf(stderr, "speed: %.2f+%.2f %d[%.5f] (t/c/w: %6.0f/%6.0f/%6.0f = %.4f) fps=%.2f\r",
264 s1, s2, preset, (float)buffer_fill / buffer_size,
265 tgt/den, cpu/den, wall/den, cpu/wall, 1e6*den/wall );
271 void X264SpeedControl::after_frame()
273 cpu_time_last_frame = steady_clock::now() - timestamp;
276 void X264SpeedControl::set_buffer_size(int new_buffer_size)
278 new_buffer_size = max(3, new_buffer_size);
279 buffer_size = new_buffer_size * uspf;
280 cplx_decay = 1 - 1./new_buffer_size;
281 compensation_period = buffer_size/4;
284 int X264SpeedControl::dither_preset(float f)
298 void X264SpeedControl::apply_preset(int new_preset)
300 new_preset = max(new_preset, 0);
301 new_preset = min(new_preset, SC_PRESETS - 1);
303 const sc_preset_t *s = &presets[new_preset];
305 x264_encoder_parameters(x264, &p);
307 p.i_frame_reference = s->refs;
308 p.i_bframe_adaptive = s->badapt;
309 p.i_bframe = s->bframes;
310 p.analyse.inter = s->partitions;
311 p.analyse.i_subpel_refine = s->subme;
312 p.analyse.i_me_method = s->me;
313 p.analyse.i_trellis = s->trellis;
314 p.analyse.b_mixed_references = s->mix;
315 p.analyse.i_direct_mv_pred = s->direct;
316 p.analyse.i_me_range = s->merange;
320 x264_encoder_reconfig(x264, &p);