1 #include "x264_speed_control.h"
11 #include <type_traits>
14 #include "shared/metrics.h"
17 using namespace std::chrono;
21 X264SpeedControl::X264SpeedControl(x264_t *x264, float f_speed, int i_buffer_size, float f_buffer_init)
22 : dyn(load_x264_for_bit_depth(global_flags.bit_depth)),
23 x264(x264), f_speed(f_speed)
26 dyn.x264_encoder_parameters(x264, ¶m);
28 float fps = (float)param.i_fps_num / param.i_fps_den;
30 set_buffer_size(i_buffer_size);
31 buffer_fill = buffer_size * f_buffer_init;
32 buffer_fill = max<int64_t>(buffer_fill, uspf);
33 buffer_fill = min(buffer_fill, buffer_size);
34 timestamp = steady_clock::now();
36 cplx_num = 3e3; //FIXME estimate initial complexity
38 stat.min_buffer = buffer_size;
40 stat.avg_preset = 0.0;
43 metric_x264_speedcontrol_buffer_available_seconds = buffer_fill * 1e-6;
44 metric_x264_speedcontrol_buffer_size_seconds = buffer_size * 1e-6;
45 metric_x264_speedcontrol_preset_used_frames.init_uniform(SC_PRESETS);
46 global_metrics.add("x264_speedcontrol_preset_used_frames", &metric_x264_speedcontrol_preset_used_frames);
47 global_metrics.add("x264_speedcontrol_buffer_available_seconds", &metric_x264_speedcontrol_buffer_available_seconds, Metrics::TYPE_GAUGE);
48 global_metrics.add("x264_speedcontrol_buffer_size_seconds", &metric_x264_speedcontrol_buffer_size_seconds, Metrics::TYPE_GAUGE);
49 global_metrics.add("x264_speedcontrol_idle_frames", &metric_x264_speedcontrol_idle_frames);
50 global_metrics.add("x264_speedcontrol_late_frames", &metric_x264_speedcontrol_late_frames);
53 X264SpeedControl::~X264SpeedControl()
55 fprintf(stderr, "speedcontrol: avg preset=%.3f buffer min=%.3f max=%.3f\n",
56 stat.avg_preset / stat.den,
57 (float)stat.min_buffer / buffer_size,
58 (float)stat.max_buffer / buffer_size );
59 // x264_log( x264, X264_LOG_INFO, "speedcontrol: avg cplx=%.5f\n", cplx_num / cplx_den );
67 float time; // relative encoding time, compared to the other presets
78 // The actual presets, including the equivalent commandline options. Note that
79 // all presets are benchmarked with --weightp 1 --mbtree --rc-lookahead 20
80 // --b-adapt 1 --bframes 3 on top of the given settings (equivalent settings to
81 // the "faster" preset). Timings and SSIM measurements were done on a four cores
82 // of a 6-core Coffee Lake i5 2.8 GHz on the first 1000 frames of “Elephants
83 // Dream” in 1080p. See experiments/measure-x264.pl for a way to reproduce.
85 // Note that the two first and the two last are also used for extrapolation
86 // should the desired time be outside the range. Thus, it is disadvantageous if
87 // they are chosen so that the timings are too close to each other.
88 static const sc_preset_t presets[SC_PRESETS] = {
89 #define I4 X264_ANALYSE_I4x4
90 #define I8 X264_ANALYSE_I8x8
91 #define P4 X264_ANALYSE_PSUB8x8
92 #define P8 X264_ANALYSE_PSUB16x16
93 #define B8 X264_ANALYSE_BSUB16x16
95 // Preset 0: 17.386db, --preset superfast
96 { .time= 1.000, .subme=1, .me=X264_ME_DIA, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4, .direct=1, .merange=16 },
98 // Preset 1: 17.919db, --preset superfast --subme 2
99 { .time= 1.707, .subme=2, .me=X264_ME_DIA, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4, .direct=1, .merange=16 },
101 // Preset 2: 18.051db, --preset veryfast
102 { .time= 1.832, .subme=2, .me=X264_ME_HEX, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
104 // Preset 3: 18.422db, --preset veryfast --subme 3
105 { .time= 1.853, .subme=3, .me=X264_ME_HEX, .refs=1, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
107 // Preset 4: 18.514db, --preset veryfast --subme 3 --ref 2
108 { .time= 1.925, .subme=3, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
110 // Preset 5: 18.564db, --preset veryfast --subme 4 --ref 2
111 { .time= 2.111, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=0, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
113 // Preset 6: 18.411db, --preset faster
114 { .time= 2.240, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=0, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
116 // Preset 7: 18.429db, --preset faster --mixed-refs
117 { .time= 2.414, .subme=4, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
119 // Preset 8: 18.454db, --preset faster --mixed-refs --subme 5
120 { .time= 2.888, .subme=5, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
122 // Preset 9: 18.528db, --preset fast
123 { .time= 3.570, .subme=6, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
125 // Preset 10: 18.762db, --preset fast --subme 7
126 { .time= 3.698, .subme=7, .me=X264_ME_HEX, .refs=2, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
128 // Preset 11: 18.819db, --preset medium
129 { .time= 4.174, .subme=7, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
131 // Preset 12: 18.889db, --preset medium --subme 8
132 { .time= 5.155, .subme=8, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=1, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
134 // Preset 13: 19.127db, --preset medium --subme 8 --trellis 2
135 { .time= 7.237, .subme=8, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=1, .merange=16 },
137 // Preset 14: 19.118db, --preset medium --subme 8 --trellis 2 --direct auto
138 { .time= 7.240, .subme=8, .me=X264_ME_HEX, .refs=3, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
140 // Preset 15: 19.172db, --preset slow
141 { .time= 7.910, .subme=8, .me=X264_ME_HEX, .refs=5, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
143 // Preset 16: 19.208db, --preset slow --subme 9
144 { .time= 8.091, .subme=9, .me=X264_ME_HEX, .refs=5, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
146 // Preset 17: 19.216db, --preset slow --subme 9 --me umh
147 { .time= 9.539, .subme=9, .me=X264_ME_UMH, .refs=5, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
149 // Preset 18: 19.253db, --preset slow --subme 9 --me umh --ref 6
150 { .time=10.521, .subme=9, .me=X264_ME_UMH, .refs=6, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
152 // Preset 19: 19.275db, --preset slow --subme 9 --me umh --ref 7
153 { .time=11.461, .subme=9, .me=X264_ME_UMH, .refs=7, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8, .direct=3, .merange=16 },
155 // Preset 20: 19.314db, --preset slower
156 { .time=13.145, .subme=9, .me=X264_ME_UMH, .refs=8, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .direct=3, .merange=16 },
158 // Preset 21: 19.407db, --preset slower --subme 10
159 { .time=16.386, .subme=10, .me=X264_ME_UMH, .refs=8, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .direct=3, .merange=16 },
161 // Preset 22: 19.483db, --preset veryslow
162 { .time=26.861, .subme=10, .me=X264_ME_UMH, .refs=16, .mix=1, .trellis=2, .partitions=I8|I4|P8|B8|P4, .direct=3, .merange=24 },
171 void X264SpeedControl::before_frame(float new_buffer_fill, int new_buffer_size, float new_uspf)
173 if (new_uspf > 0.0) {
176 if (new_buffer_size) {
177 set_buffer_size(new_buffer_size);
179 buffer_fill = buffer_size * new_buffer_fill;
180 metric_x264_speedcontrol_buffer_available_seconds = buffer_fill * 1e-6;
182 steady_clock::time_point t;
184 // update buffer state after encoding and outputting the previous frame(s)
186 t = timestamp = steady_clock::now();
189 t = steady_clock::now();
192 auto delta_t = t - timestamp;
195 // update the time predictor
197 int cpu_time = duration_cast<microseconds>(cpu_time_last_frame).count();
198 cplx_num *= cplx_decay;
199 cplx_den *= cplx_decay;
200 cplx_num += cpu_time / presets[preset].time;
203 stat.avg_preset += preset;
207 stat.min_buffer = min(buffer_fill, stat.min_buffer);
208 stat.max_buffer = max(buffer_fill, stat.max_buffer);
210 if (buffer_fill >= buffer_size) { // oops, cpu was idle
211 // not really an error, but we'll warn for debugging purposes
212 static int64_t idle_t = 0;
213 static steady_clock::time_point print_interval;
214 static bool first = false;
215 idle_t += buffer_fill - buffer_size;
216 if (first || duration<double>(t - print_interval).count() > 0.1) {
217 //fprintf(stderr, "speedcontrol idle (%.6f sec)\n", idle_t/1e6);
222 buffer_fill = buffer_size;
223 metric_x264_speedcontrol_buffer_available_seconds = buffer_fill * 1e-6;
224 ++metric_x264_speedcontrol_idle_frames;
225 } else if (buffer_fill <= 0) { // oops, we're late
226 // fprintf(stderr, "speedcontrol underflow (%.6f sec)\n", buffer_fill/1e6);
227 ++metric_x264_speedcontrol_late_frames;
231 // Pick the preset that should return the buffer to 3/4-full within a time
232 // specified by compensation_period.
234 // NOTE: This doesn't actually do that, at least assuming the same target is
235 // chosen for every frame; exactly what it does is unclear to me. It seems
236 // to consistently undershoot a bit, so it needs to be saved by the second
237 // predictor below. However, fixing the formula seems to yield somewhat less
238 // stable results in practice; in particular, once the buffer is half-full
239 // or so, it would give us a negative target. Perhaps increasing
240 // compensation_period would be a good idea, but initial (very brief) tests
241 // did not yield good results.
242 float target = uspf / f_speed
243 * (buffer_fill + compensation_period)
244 / (buffer_size*3/4 + compensation_period);
245 float cplx = cplx_num / cplx_den;
247 float filled = (float) buffer_fill / buffer_size;
249 t0 = presets[0].time * cplx;
251 t1 = presets[i].time * cplx;
252 if (t1 >= target || i == SC_PRESETS - 1)
256 // exponential interpolation between states
257 set = i-1 + (log(target) - log(t0)) / (log(t1) - log(t0));
258 set = max<float>(set, -5);
259 set = min<float>(set, (SC_PRESETS-1) + 5);
260 // Even if our time estimations in the SC_PRESETS array are off
261 // this will push us towards our target fullness
263 set += (40 * (filled-0.75));
264 float s2 = (40 * (filled-0.75));
265 set = min<float>(max<float>(set, 0), SC_PRESETS - 1);
266 apply_preset(dither_preset(set));
268 if (global_flags.x264_speedcontrol_verbose) {
269 static float cpu, wall, tgt, den;
270 const float decay = 1-1/100.;
271 cpu = cpu*decay + duration_cast<microseconds>(cpu_time_last_frame).count();
272 wall = wall*decay + duration_cast<microseconds>(delta_t).count();
273 tgt = tgt*decay + target;
275 fprintf(stderr, "speed: %.2f+%.2f %d[%.5f] (t/c/w: %6.0f/%6.0f/%6.0f = %.4f) fps=%.2f\r",
276 s1, s2, preset, (float)buffer_fill / buffer_size,
277 tgt/den, cpu/den, wall/den, cpu/wall, 1e6*den/wall );
283 void X264SpeedControl::after_frame()
285 cpu_time_last_frame = steady_clock::now() - timestamp;
288 void X264SpeedControl::set_buffer_size(int new_buffer_size)
290 new_buffer_size = max(3, new_buffer_size);
291 buffer_size = new_buffer_size * uspf;
292 cplx_decay = 1 - 1./new_buffer_size;
293 compensation_period = buffer_size/4;
294 metric_x264_speedcontrol_buffer_size_seconds = buffer_size * 1e-6;
297 int X264SpeedControl::dither_preset(float f)
311 void X264SpeedControl::apply_preset(int new_preset)
313 new_preset = max(new_preset, 0);
314 new_preset = min(new_preset, SC_PRESETS - 1);
316 const sc_preset_t *s = &presets[new_preset];
318 dyn.x264_encoder_parameters(x264, &p);
320 p.i_frame_reference = s->refs;
321 p.analyse.inter = s->partitions;
322 p.analyse.i_subpel_refine = s->subme;
323 p.analyse.i_me_method = s->me;
324 p.analyse.i_trellis = s->trellis;
325 p.analyse.b_mixed_references = s->mix;
326 p.analyse.i_direct_mv_pred = s->direct;
327 p.analyse.i_me_range = s->merange;
331 dyn.x264_encoder_reconfig(x264, &p);
334 metric_x264_speedcontrol_preset_used_frames.count_event(new_preset);