[x264-devel] Fix 8x8dct in lossless encoding

[Anton Mitrofanov]

x264 | branch: master | Anton Mitrofanov <BugMaster at narod.ru> | Tue Jun  6 02:07:21 2017 +0300| [79b36f27a57dd511eefead6d5422689220c767b5] | committer: Anton Mitrofanov

Fix 8x8dct in lossless encoding

Change V and H intra prediction in lossless (TransformBypassModeFlag == 1)
macroblocks to correctly adhere to the specification. Affects lossless
encoding with 8x8dct or mix of lossless with normal macroblocks.

8x8dct has already been disabled in lossless mode for some time due to
being out-of-spec but this will allow us to re-enable it again.

> http://git.videolan.org/gitweb.cgi/x264.git/?a=commit;h=79b36f27a57dd511eefead6d5422689220c767b5
---

 encoder/macroblock.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/encoder/macroblock.c b/encoder/macroblock.c
index 56d06129..929fcc8e 100644
--- a/encoder/macroblock.c
+++ b/encoder/macroblock.c
@@ -558,9 +558,16 @@ void x264_predict_lossless_4x4( x264_t *h, pixel *p_dst, int p, int idx, int i_m
     pixel *p_src = h->mb.pic.p_fenc_plane[p] + block_idx_x[idx]*4 + block_idx_y[idx]*4 * stride;
 
     if( i_mode == I_PRED_4x4_V )
+    {
         h->mc.copy[PIXEL_4x4]( p_dst, FDEC_STRIDE, p_src-stride, stride, 4 );
+        memcpy( p_dst, p_dst-FDEC_STRIDE, 4*sizeof(pixel) );
+    }
     else if( i_mode == I_PRED_4x4_H )
+    {
         h->mc.copy[PIXEL_4x4]( p_dst, FDEC_STRIDE, p_src-1, stride, 4 );
+        for( int i = 0; i < 4; i++ )
+            p_dst[i*FDEC_STRIDE] = p_dst[i*FDEC_STRIDE-1];
+    }
     else
         h->predict_4x4[i_mode]( p_dst );
 }
@@ -571,9 +578,16 @@ void x264_predict_lossless_8x8( x264_t *h, pixel *p_dst, int p, int idx, int i_m
     pixel *p_src = h->mb.pic.p_fenc_plane[p] + (idx&1)*8 + (idx>>1)*8*stride;
 
     if( i_mode == I_PRED_8x8_V )
+    {
         h->mc.copy[PIXEL_8x8]( p_dst, FDEC_STRIDE, p_src-stride, stride, 8 );
+        memcpy( p_dst, &edge[16], 8*sizeof(pixel) );
+    }
     else if( i_mode == I_PRED_8x8_H )
+    {
         h->mc.copy[PIXEL_8x8]( p_dst, FDEC_STRIDE, p_src-1, stride, 8 );
+        for( int i = 0; i < 8; i++ )
+            p_dst[i*FDEC_STRIDE] = edge[14-i];
+    }
     else
         h->predict_8x8[i_mode]( p_dst, edge );
 }
@@ -581,12 +595,21 @@ void x264_predict_lossless_8x8( x264_t *h, pixel *p_dst, int p, int idx, int i_m
 void x264_predict_lossless_16x16( x264_t *h, int p, int i_mode )
 {
     int stride = h->fenc->i_stride[p] << MB_INTERLACED;
+    pixel *p_dst = h->mb.pic.p_fdec[p];
+
     if( i_mode == I_PRED_16x16_V )
-        h->mc.copy[PIXEL_16x16]( h->mb.pic.p_fdec[p], FDEC_STRIDE, h->mb.pic.p_fenc_plane[p]-stride, stride, 16 );
+    {
+        h->mc.copy[PIXEL_16x16]( p_dst, FDEC_STRIDE, h->mb.pic.p_fenc_plane[p]-stride, stride, 16 );
+        memcpy( p_dst, p_dst-FDEC_STRIDE, 16*sizeof(pixel) );
+    }
     else if( i_mode == I_PRED_16x16_H )
-        h->mc.copy_16x16_unaligned( h->mb.pic.p_fdec[p], FDEC_STRIDE, h->mb.pic.p_fenc_plane[p]-1, stride, 16 );
+    {
+        h->mc.copy_16x16_unaligned( p_dst, FDEC_STRIDE, h->mb.pic.p_fenc_plane[p]-1, stride, 16 );
+        for( int i = 0; i < 16; i++ )
+            p_dst[i*FDEC_STRIDE] = p_dst[i*FDEC_STRIDE-1];
+    }
     else
-        h->predict_16x16[i_mode]( h->mb.pic.p_fdec[p] );
+        h->predict_16x16[i_mode]( p_dst );
 }
 
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