shithub: libvpx

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Add detect_flash_from_frame_stats()

Change-Id: I06a64b45045334cf9563d27e154a3b8095ad80a3

--- a/vp9/encoder/vp9_firstpass.c

+++ b/vp9/encoder/vp9_firstpass.c

@@ -1831,9 +1831,7 @@

 // This function detects a flash through the high relative pcnt_second_ref

 // score in the frame following a flash frame. The offset passed in should

 // reflect this.

-static int detect_flash(const TWO_PASS *twopass, int offset) {

-  const FIRSTPASS_STATS *const next_frame = read_frame_stats(twopass, offset);

-

+static int detect_flash_from_frame_stats(const FIRSTPASS_STATS *frame_stats) {

   // What we are looking for here is a situation where there is a

   // brief break in prediction (such as a flash) but subsequent frames

   // are reasonably well predicted by an earlier (pre flash) frame.

@@ -1840,12 +1838,19 @@

   // The recovery after a flash is indicated by a high pcnt_second_ref

   // useage or a second ref coded error notabley lower than the last

   // frame coded error.

-  return next_frame != NULL &&

-         ((next_frame->sr_coded_error < next_frame->coded_error) ||

-          ((next_frame->pcnt_second_ref > next_frame->pcnt_inter) &&

-           (next_frame->pcnt_second_ref >= 0.5)));

+  if (frame_stats == 0) {

+    return 0;

+  }

+  return (frame_stats->sr_coded_error < frame_stats->coded_error) ||

+         ((frame_stats->pcnt_second_ref > frame_stats->pcnt_inter) &&

+          (frame_stats->pcnt_second_ref >= 0.5));

 }

+static int detect_flash(const TWO_PASS *twopass, int offset) {

+  const FIRSTPASS_STATS *const next_frame = read_frame_stats(twopass, offset);

+  return detect_flash_from_frame_stats(next_frame);

+}

+

 // Update the motion related elements to the GF arf boost calculation.

 static void accumulate_frame_motion_stats(const FIRSTPASS_STATS *stats,

                                           double *mv_in_out,

@@ -2559,6 +2564,7 @@

   i = 0;

   while (i < rc->static_scene_max_gf_interval && i < rc->frames_to_key) {

+    const FIRSTPASS_STATS *next_next_frame;

     ++i;

     // Accumulate error score of frames in this gf group.

@@ -2576,7 +2582,8 @@

     // Test for the case where there is a brief flash but the prediction

     // quality back to an earlier frame is then restored.

-    flash_detected = detect_flash(twopass, 0);

+    next_next_frame = read_frame_stats(twopass, 0);

+    flash_detected = detect_flash_from_frame_stats(next_next_frame);

     // Update the motion related elements to the boost calculation.

     accumulate_frame_motion_stats(