FIRSTPASS_STATS: Add comments for struct members.
Noting down my understanding of these fields, so that everyone doesn't
need to rediscover their meaning.
Change-Id: Icfd2a734d3f7fb66c6fca842a638757cce73eaa9
diff --git a/av1/encoder/firstpass.c b/av1/encoder/firstpass.c
index cb8ebd7..f6a0fb2 100644
--- a/av1/encoder/firstpass.c
+++ b/av1/encoder/firstpass.c
@@ -475,11 +475,6 @@
av1_encode_intra_block_plane(cpi, x, bsize, 0, 0, mb_row * 2, mb_col * 2);
this_error = aom_get_mb_ss(x->plane[0].src_diff);
- // Keep a record of blocks that have almost no intra error residual
- // (i.e. are in effect completely flat and untextured in the intra
- // domain). In natural videos this is uncommon, but it is much more
- // common in animations, graphics and screen content, so may be used
- // as a signal to detect these types of content.
if (this_error < UL_INTRA_THRESH) {
++intra_skip_count;
} else if ((mb_col > 0) && (image_data_start_row == INVALID_ROW)) {
diff --git a/av1/encoder/firstpass.h b/av1/encoder/firstpass.h
index e898314..1b8636c 100644
--- a/av1/encoder/firstpass.h
+++ b/av1/encoder/firstpass.h
@@ -31,28 +31,65 @@
#define VLOW_MOTION_THRESHOLD 950
typedef struct {
+ // Frame number in display order, if stats are for a single frame.
+ // No real meaning for a collection of frames.
double frame;
+ // Weight assigned to this frame (or total weight for the collection of
+ // frames) currently based on intra factor and brightness factor. This is used
+ // to distribute bits betweeen easier and harder frames.
double weight;
+ // Intra prediction error.
double intra_error;
+ // Average wavelet energy computed using Discrete Wavelet Transform (DWT).
double frame_avg_wavelet_energy;
+ // Best of intra pred error and inter pred error using last frame as ref.
double coded_error;
+ // Best of intra pred error and inter pred error using golden frame as ref.
double sr_coded_error;
+ // Percentage of blocks with inter pred error < intra pred error.
double pcnt_inter;
+ // Percentage of blocks using (inter prediction and) non-zero motion vectors.
double pcnt_motion;
+ // Percentage of blocks where golden frame was the best reference. That is:
+ // inter pred error using golden frame < inter pred error using last frame and
+ // inter pred error using golden frame < intra pred error
double pcnt_second_ref;
+ // Percentage of blocks where intra and inter prediction errors were very
+ // close. Note that this is a 'weighted count', that is, the so blocks may be
+ // weighted by how close the two errors were.
double pcnt_neutral;
+ // Percentage of blocks that have almost no intra error residual
+ // (i.e. are in effect completely flat and untextured in the intra
+ // domain). In natural videos this is uncommon, but it is much more
+ // common in animations, graphics and screen content, so may be used
+ // as a signal to detect these types of content.
double intra_skip_pct;
- double inactive_zone_rows; // Image mask rows top and bottom.
- double inactive_zone_cols; // Image mask columns at left and right edges.
+ // Image mask rows top and bottom.
+ double inactive_zone_rows;
+ // Image mask columns at left and right edges.
+ double inactive_zone_cols;
+ // Average of row motion vectors.
double MVr;
+ // Mean of absolute value of row motion vectors.
double mvr_abs;
+ // Mean of column motion vectors.
double MVc;
+ // Mean of absolute value of column motion vectors.
double mvc_abs;
+ // Variance of row motion vectors.
double MVrv;
+ // Variance of column motion vectors.
double MVcv;
+ // Value in range [-1,1] indicating fraction of row and column motion vectors
+ // that point inwards (negative MV value) or outwards (positive MV value).
+ // For example, value of 1 indicates, all row/column MVs are inwards.
double mv_in_out_count;
+ // Count of unique non-zero motion vectors.
double new_mv_count;
+ // Duration of the frame / collection of frames.
double duration;
+ // 1.0 if stats are for a single frame, OR
+ // Number of frames in this collection for which the stats are accumulated.
double count;
// standard deviation for (0, 0) motion prediction error
double raw_error_stdev;
