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Add more rate control stats to vpx_temporal_svc_encoder.

Average and variance of actual encoding bitrate over fixed short-time window.

Change-Id: Icc3d6d93792c81e1fb9fd3b56008bf47a503b204

--- a/examples/vpx_temporal_svc_encoder.c

+++ b/examples/vpx_temporal_svc_encoder.c

@@ -61,6 +61,15 @@

   double layer_avg_rate_mismatch[VPX_TS_MAX_LAYERS];

   // Actual encoding bitrate per layer (cumulative).

   double layer_encoding_bitrate[VPX_TS_MAX_LAYERS];

+  // Average of the short-time encoder actual bitrate.

+  // TODO(marpan): Should we add these short-time stats for each layer?

+  double avg_st_encoding_bitrate;

+  // Variance of the short-time encoder actual bitrate.

+  double variance_st_encoding_bitrate;

+  // Window (number of frames) for computing short-timee encoding bitrate.

+  int window_size;

+  // Number of window measurements.

+  int window_count;

 };

 // Note: these rate control metrics assume only 1 key frame in the

@@ -92,6 +101,10 @@

     rc->layer_avg_frame_size[i] = 0.0;

     rc->layer_avg_rate_mismatch[i] = 0.0;

   }

+  rc->window_count = 0;

+  rc->window_size = 15;

+  rc->avg_st_encoding_bitrate = 0.0;

+  rc->variance_st_encoding_bitrate = 0.0;

 }

 static void printout_rate_control_summary(struct RateControlMetrics *rc,

@@ -99,6 +112,7 @@

                                           int frame_cnt) {

   unsigned int i = 0;

   int tot_num_frames = 0;

+  double perc_fluctuation = 0.0;

   printf("Total number of processed frames: %d\n\n", frame_cnt -1);

   printf("Rate control layer stats for %d layer(s):\n\n",

       cfg->ts_number_layers);

@@ -125,6 +139,17 @@

         100.0 * num_dropped / rc->layer_input_frames[i]);

     printf("\n");

   }

+  rc->avg_st_encoding_bitrate = rc->avg_st_encoding_bitrate / rc->window_count;

+  rc->variance_st_encoding_bitrate =

+      rc->variance_st_encoding_bitrate / rc->window_count -

+      (rc->avg_st_encoding_bitrate * rc->avg_st_encoding_bitrate);

+  perc_fluctuation = 100.0 * sqrt(rc->variance_st_encoding_bitrate) /

+      rc->avg_st_encoding_bitrate;

+  printf("Short-time stats, for window of %d frames: \n",rc->window_size);

+  printf("Average, rms-variance, and percent-fluct: %f %f %f \n",

+         rc->avg_st_encoding_bitrate,

+         sqrt(rc->variance_st_encoding_bitrate),

+         perc_fluctuation);

   if ((frame_cnt - 1) != tot_num_frames)

     die("Error: Number of input frames not equal to output! \n");

 }

@@ -469,6 +494,9 @@

 #else

   const int min_args = min_args_base;

 #endif  // CONFIG_VP9_HIGHBITDEPTH

+  double sum_bitrate = 0.0;

+  double sum_bitrate2 = 0.0;

+  double framerate  = 30.0;

   exec_name = argv[0];

   // Check usage and arguments.

@@ -604,6 +632,7 @@

     die("Failed to open %s for reading", argv[1]);

   }

+  framerate = cfg.g_timebase.den / cfg.g_timebase.num;

   // Open an output file for each stream.

   for (i = 0; i < cfg.ts_number_layers; ++i) {

     char file_name[PATH_MAX];

@@ -652,7 +681,7 @@

   // For generating smaller key frames, use a smaller max_intra_size_pct

   // value, like 100 or 200.

   {

-    const int max_intra_size_pct = 200;

+    const int max_intra_size_pct = 900;

     vpx_codec_control(&codec, VP8E_SET_MAX_INTRA_BITRATE_PCT,

                       max_intra_size_pct);

   }

@@ -703,6 +732,33 @@

                   fabs(8.0 * pkt->data.frame.sz - rc.layer_pfb[i]) /

                   rc.layer_pfb[i];

               ++rc.layer_enc_frames[i];

+            }

+          }

+          // Update for short-time encoding bitrate states, for moving window

+          // of size rc->window, shifted by rc->window / 2.

+          // Ignore first window segment, due to key frame.

+          if (frame_cnt > rc.window_size) {

+            sum_bitrate += 0.001 * 8.0 * pkt->data.frame.sz * framerate;

+            if (frame_cnt % rc.window_size == 0) {

+              rc.window_count += 1;

+              rc.avg_st_encoding_bitrate += sum_bitrate / rc.window_size;

+              rc.variance_st_encoding_bitrate +=

+                  (sum_bitrate / rc.window_size) *

+                  (sum_bitrate / rc.window_size);

+              sum_bitrate = 0.0;

+            }

+          }

+          // Second shifted window.

+          if (frame_cnt > rc.window_size + rc.window_size / 2) {

+            sum_bitrate2 += 0.001 * 8.0 * pkt->data.frame.sz * framerate;

+            if (frame_cnt > 2 * rc.window_size &&

+                frame_cnt % rc.window_size == 0) {

+              rc.window_count += 1;

+              rc.avg_st_encoding_bitrate += sum_bitrate2 / rc.window_size;

+              rc.variance_st_encoding_bitrate +=

+                  (sum_bitrate2 / rc.window_size) *

+                  (sum_bitrate2 / rc.window_size);

+              sum_bitrate2 = 0.0;

             }

           }

           break;