[FFmpeg-devel] [PATCH] aacenc: optimize cost cache.

[Reimar Döffinger]

Avoids trashing the CPU cache each time the
cost cache is cleared.
---
 libavcodec/aaccoder_twoloop.h         | 20 ++++----------------
 libavcodec/aacenc.c                   |  7 +------
 libavcodec/aacenc.h                   |  4 +---
 libavcodec/aacenc_quantization_misc.h | 17 +++++++----------
 4 files changed, 13 insertions(+), 35 deletions(-)

diff --git a/libavcodec/aaccoder_twoloop.h b/libavcodec/aaccoder_twoloop.h
index 397a4db..73bd082 100644
--- a/libavcodec/aaccoder_twoloop.h
+++ b/libavcodec/aaccoder_twoloop.h
@@ -391,10 +391,7 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
                                                    sce->ics.swb_sizes[g],
                                                    sce->sf_idx[w*16+g],
                                                    cb,
-                                                   1.0f,
-                                                   INFINITY,
-                                                   &b, &sqenergy,
-                                                   0);
+                                                   &b, &sqenergy);
                         bits += b;
                         qenergy += sqenergy;
                     }
@@ -472,10 +469,7 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
                                                     sce->ics.swb_sizes[g],
                                                     sce->sf_idx[w*16+g],
                                                     cb,
-                                                    1.0f,
-                                                    INFINITY,
-                                                    &b, &sqenergy,
-                                                    0);
+                                                    &b, &sqenergy);
                             bits += b;
                             qenergy += sqenergy;
                         }
@@ -628,10 +622,7 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
                                                         sce->ics.swb_sizes[g],
                                                         sce->sf_idx[w*16+g]-1,
                                                         cb,
-                                                        1.0f,
-                                                        INFINITY,
-                                                        &b, &sqenergy,
-                                                        0);
+                                                        &b, &sqenergy);
                                 bits += b;
                                 qenergy += sqenergy;
                             }
@@ -665,10 +656,7 @@ static void search_for_quantizers_twoloop(AVCodecContext *avctx,
                                                             sce->ics.swb_sizes[g],
                                                             sce->sf_idx[w*16+g]+1,
                                                             cb,
-                                                            1.0f,
-                                                            INFINITY,
-                                                            &b, &sqenergy,
-                                                            0);
+                                                            &b, &sqenergy);
                                     bits += b;
                                     qenergy += sqenergy;
                                 }
diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c
index 5a70da1..e60bbfe 100644
--- a/libavcodec/aacenc.c
+++ b/libavcodec/aacenc.c
@@ -78,12 +78,7 @@ static void put_audio_specific_config(AVCodecContext *avctx)
 
 void ff_quantize_band_cost_cache_init(struct AACEncContext *s)
 {
-    int sf, g;
-    for (sf = 0; sf < 256; sf++) {
-        for (g = 0; g < 128; g++) {
-            s->quantize_band_cost_cache[sf][g].bits = -1;
-        }
-    }
+    memset(s->quantize_band_cost_cache_state, 0xff, sizeof(s->quantize_band_cost_cache_state));
 }
 
 #define WINDOW_FUNC(type) \
diff --git a/libavcodec/aacenc.h b/libavcodec/aacenc.h
index 2252e29..d937d17 100644
--- a/libavcodec/aacenc.h
+++ b/libavcodec/aacenc.h
@@ -85,9 +85,6 @@ typedef struct AACQuantizeBandCostCacheEntry {
     float rd;
     float energy;
     int bits; ///< -1 means uninitialized entry
-    char cb;
-    char rtz;
-    char padding[2]; ///< Keeps the entry size a multiple of 32 bits
 } AACQuantizeBandCostCacheEntry;
 
 /**
@@ -126,6 +123,7 @@ typedef struct AACEncContext {
     DECLARE_ALIGNED(16, int,   qcoefs)[96];      ///< quantized coefficients
     DECLARE_ALIGNED(32, float, scoefs)[1024];    ///< scaled coefficients
 
+    uint8_t quantize_band_cost_cache_state[256][128];
     AACQuantizeBandCostCacheEntry quantize_band_cost_cache[256][128]; ///< memoization area for quantize_band_cost
 
     struct {
diff --git a/libavcodec/aacenc_quantization_misc.h b/libavcodec/aacenc_quantization_misc.h
index eaa71c9..29bb986 100644
--- a/libavcodec/aacenc_quantization_misc.h
+++ b/libavcodec/aacenc_quantization_misc.h
@@ -30,22 +30,19 @@
 
 static inline float quantize_band_cost_cached(struct AACEncContext *s, int w, int g, const float *in,
                                 const float *scaled, int size, int scale_idx,
-                                int cb, const float lambda, const float uplim,
-                                int *bits, float *energy, int rtz)
+                                int cb, int *bits, float *energy)
 {
+    uint8_t *cache_state = &s->quantize_band_cost_cache_state[scale_idx][w*16+g];
     AACQuantizeBandCostCacheEntry *entry;
     av_assert1(scale_idx >= 0 && scale_idx < 256);
     entry = &s->quantize_band_cost_cache[scale_idx][w*16+g];
-    if (entry->bits < 0 || entry->cb != cb || entry->rtz != rtz) {
+    if (*cache_state != cb) {
         entry->rd = quantize_band_cost(s, in, scaled, size, scale_idx,
-                                       cb, lambda, uplim, &entry->bits, &entry->energy, rtz);
-        entry->cb = cb;
-        entry->rtz = rtz;
+                                       cb, 1.0f, INFINITY, &entry->bits, &entry->energy, 0);
+        *cache_state = cb;
     }
-    if (bits)
-        *bits = entry->bits;
-    if (energy)
-        *energy = entry->energy;
+    *bits = entry->bits & 0xffffff;
+    *energy = entry->energy;
     return entry->rd;
 }
 
-- 
2.7.0