[FFmpeg-cvslog] avcodec/magicyuvenc: Fix Huffman element probabilities

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Fri Apr 11 23:23:56 2025 +0200| [a6c2c463c76be03c8fd4e1986b85734eab87b9da] | committer: Andreas Rheinhardt

avcodec/magicyuvenc: Fix Huffman element probabilities

The earlier code only used the counts from the last slice.
The two FATE tests using slices show compression improvements
due to this.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a6c2c463c76be03c8fd4e1986b85734eab87b9da
---

 libavcodec/magicyuvenc.c              | 14 +++++++-------
 tests/ref/vsynth/vsynth1-magicyuv     |  4 ++--
 tests/ref/vsynth/vsynth_lena-magicyuv |  4 ++--
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/libavcodec/magicyuvenc.c b/libavcodec/magicyuvenc.c
index ba39bbb89f..9e9c3ecd46 100644
--- a/libavcodec/magicyuvenc.c
+++ b/libavcodec/magicyuvenc.c
@@ -395,20 +395,20 @@ static int encode_table(AVCodecContext *avctx,
                         PutBitContext *pb, HuffEntry *he, int plane)
 {
     MagicYUVContext *s = avctx->priv_data;
-    PTable counts[256] = { {0} };
+    PTable counts[256];
     uint16_t codes_counts[33] = { 0 };
 
+    for (size_t i = 0; i < FF_ARRAY_ELEMS(counts); i++) {
+        counts[i].prob  = 1;
+        counts[i].value = i;
+    }
+
     for (int n = 0; n < s->nb_slices; n++) {
         Slice *sl = &s->slices[n * s->planes + plane];
         PTable *slice_counts = sl->counts;
 
         for (int i = 0; i < 256; i++)
-            counts[i].prob = slice_counts[i].prob;
-    }
-
-    for (int i = 0; i < 256; i++) {
-        counts[i].prob++;
-        counts[i].value = i;
+            counts[i].prob += slice_counts[i].prob;
     }
 
     magy_huffman_compute_bits(counts, he, codes_counts, 256, 12);
diff --git a/tests/ref/vsynth/vsynth1-magicyuv b/tests/ref/vsynth/vsynth1-magicyuv
index 2e883bf1a0..c67066088e 100644
--- a/tests/ref/vsynth/vsynth1-magicyuv
+++ b/tests/ref/vsynth/vsynth1-magicyuv
@@ -1,4 +1,4 @@
-dc919cb0b3415d31fd51dfc6d7c22a6b *tests/data/fate/vsynth1-magicyuv.avi
-3013600 tests/data/fate/vsynth1-magicyuv.avi
+c52dd1622adefa1d863ed3fea03b304e *tests/data/fate/vsynth1-magicyuv.avi
+2972044 tests/data/fate/vsynth1-magicyuv.avi
 c5ccac874dbf808e9088bc3107860042 *tests/data/fate/vsynth1-magicyuv.out.rawvideo
 stddev:    0.00 PSNR:999.99 MAXDIFF:    0 bytes:  7603200/  7603200
diff --git a/tests/ref/vsynth/vsynth_lena-magicyuv b/tests/ref/vsynth/vsynth_lena-magicyuv
index 4a9aae3989..52f515bf62 100644
--- a/tests/ref/vsynth/vsynth_lena-magicyuv
+++ b/tests/ref/vsynth/vsynth_lena-magicyuv
@@ -1,4 +1,4 @@
-3f74bf17bb8d9ba2022004f95de4b666 *tests/data/fate/vsynth_lena-magicyuv.avi
-3477676 tests/data/fate/vsynth_lena-magicyuv.avi
+b7cd87cec898d66cfce82e649376bb0d *tests/data/fate/vsynth_lena-magicyuv.avi
+3471504 tests/data/fate/vsynth_lena-magicyuv.avi
 d7bfbe259af9ae323bb94b09c33570a5 *tests/data/fate/vsynth_lena-magicyuv.out.rawvideo
 stddev:   18.65 PSNR: 22.72 MAXDIFF:   72 bytes:  7603200/  7603200