added separate entropy context for alt_ref

This commit added code to keep track of separate entropy contexts for
normal frames and alt ref frames. The underly assumption was that the
two type of frames have different entropy characteristics given they
typically have quite different quantization levels. By keeping entropy
contexts separate, it helps the entropy context distribution to be more
closely adapted to each frame type.

Tests on derf set showed a good and very consistent gain on all clips
on all metrics, avg psnr: 0.89%, overall psnr: 0.84% and ssim 0.93%.

http://www.corp.google.com/~yaowu/no_crawl/mulcontext.html

Change-Id: I15bc9697f6ff7829042911fe0c62930585d7e65d

7 files changed, 95 insertions, 12 deletions

diff --git a/vp8/common/onyxc_int.h b/vp8/common/onyxc_int.h
index d85cad0a2..7329e3869 100644
--- a/vp8/common/onyxc_int.h
+++ b/vp8/common/onyxc_int.h
@@ -199,7 +199,9 @@ typedef struct VP8Common
     vp8_prob i8x8_mode_prob [VP8_UV_MODES-1];
 #endif
 
-
+#if CONFIG_MULCONTEXT
+    FRAME_CONTEXT lfc_a; /* last alt ref entropy */
+#endif
     FRAME_CONTEXT lfc; /* last frame entropy */
     FRAME_CONTEXT fc;  /* this frame entropy */
 
diff --git a/vp8/decoder/decodemv.c b/vp8/decoder/decodemv.c
index 68044f4d5..7e3137fd2 100644
--- a/vp8/decoder/decodemv.c
+++ b/vp8/decoder/decodemv.c
@@ -854,4 +854,4 @@ void vp8_decode_mode_mvs(VP8D_COMP *pbi)
 #endif
 
 
-}
+}
\ No newline at end of file
diff --git a/vp8/decoder/decodframe.c b/vp8/decoder/decodframe.c
index 5e8925286..f3da2d0b5 100644
--- a/vp8/decoder/decodframe.c
+++ b/vp8/decoder/decodframe.c
@@ -830,9 +830,16 @@ static void init_frame(VP8D_COMP *pbi)
          */
         pc->ref_frame_sign_bias[GOLDEN_FRAME] = 0;
         pc->ref_frame_sign_bias[ALTREF_FRAME] = 0;
+
+#if CONFIG_MULCONTEXT
+        vpx_memcpy(&pc->lfc, &pc->fc, sizeof(pc->fc));
+        vpx_memcpy(&pc->lfc_a, &pc->fc, sizeof(pc->fc));
+#endif
+
     }
     else
     {
+
         if (!pc->use_bilinear_mc_filter)
             pc->mcomp_filter_type = SIXTAP;
         else
@@ -1206,6 +1213,13 @@ int vp8_decode_frame(VP8D_COMP *pbi)
             pc->refresh_alt_ref_frame = 0;
 #endif
 
+#if CONFIG_MULCONTEXT
+        if(pc->refresh_alt_ref_frame)
+            vpx_memcpy(&pc->fc, &pc->lfc_a, sizeof(pc->fc));
+        else
+            vpx_memcpy(&pc->fc, &pc->lfc, sizeof(pc->fc));
+#endif
+
         /* Buffer to buffer copy flags. */
         pc->copy_buffer_to_gf = 0;
 
@@ -1391,12 +1405,21 @@ int vp8_decode_frame(VP8D_COMP *pbi)
     {
         pc->last_kf_gf_q = pc->base_qindex;
     }
-
+#if CONFIG_MULCONTEXT
+    if(pc->refresh_entropy_probs)
+    {
+        if(pc->refresh_alt_ref_frame)
+            vpx_memcpy(&pc->lfc_a, &pc->fc, sizeof(pc->fc));
+        else
+            vpx_memcpy(&pc->lfc, &pc->fc, sizeof(pc->fc));
+    }
+#else
     if (pc->refresh_entropy_probs == 0)
     {
         vpx_memcpy(&pc->fc, &pc->lfc, sizeof(pc->fc));
         pbi->independent_partitions = prev_independent_partitions;
     }
+#endif
 
 #ifdef PACKET_TESTING
     {
diff --git a/vp8/decoder/onyxd_if.c b/vp8/decoder/onyxd_if.c
index a45d692d0..7862cbf90 100644
--- a/vp8/decoder/onyxd_if.c
+++ b/vp8/decoder/onyxd_if.c
@@ -80,6 +80,7 @@ void vp8_recon_write_yuv_frame(char *name, YV12_BUFFER_CONFIG *s)
     fclose(yuv_file);
 }
 #endif
+//#define WRITE_RECON_BUFFER 1
 #if WRITE_RECON_BUFFER
 void write_dx_frame_to_file(YV12_BUFFER_CONFIG *frame, int this_frame)
 {
@@ -93,21 +94,24 @@ void write_dx_frame_to_file(YV12_BUFFER_CONFIG *frame, int this_frame)
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->y_height; i++)
-        fwrite(frame->y_buffer + i * frame->y_stride, frame->y_width, 1, yframe);
+        fwrite(frame->y_buffer + i * frame->y_stride,
+            frame->y_width, 1, yframe);
 
     fclose(yframe);
     sprintf(filename, "dx\\u%04d.raw", this_frame);
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->uv_height; i++)
-        fwrite(frame->u_buffer + i * frame->uv_stride, frame->uv_width, 1, yframe);
+        fwrite(frame->u_buffer + i * frame->uv_stride,
+            frame->uv_width, 1, yframe);
 
     fclose(yframe);
     sprintf(filename, "dx\\v%04d.raw", this_frame);
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->uv_height; i++)
-        fwrite(frame->v_buffer + i * frame->uv_stride, frame->uv_width, 1, yframe);
+        fwrite(frame->v_buffer + i * frame->uv_stride,
+            frame->uv_width, 1, yframe);
 
     fclose(yframe);
 }
@@ -579,9 +583,17 @@ int vp8dx_receive_compressed_data(VP8D_PTR ptr, unsigned long size, const unsign
 
 #if WRITE_RECON_BUFFER
         if(cm->show_frame)
+<<<<<<< HEAD
             write_dx_frame_to_file(cm->frame_to_show, cm->current_video_frame);
         else
             write_dx_frame_to_file(cm->frame_to_show, cm->current_video_frame+1000);
+=======
+            write_dx_frame_to_file(cm->frame_to_show,
+                cm->current_video_frame);
+        else
+            write_dx_frame_to_file(cm->frame_to_show,
+                cm->current_video_frame+1000);
+>>>>>>> added separate entropy context for alt_ref
 #endif
 
         if(cm->filter_level)
diff --git a/vp8/encoder/bitstream.c b/vp8/encoder/bitstream.c
index 6171492c6..b19d58e3c 100644
--- a/vp8/encoder/bitstream.c
+++ b/vp8/encoder/bitstream.c
@@ -2222,10 +2222,11 @@ void vp8_pack_bitstream(VP8_COMP *cpi, unsigned char *dest, unsigned long *size)
 
     //************************************************
     // save a copy for later refresh
+#if !CONFIG_MULCONTEXT
     {
         vpx_memcpy(&cpi->common.lfc, &cpi->common.fc, sizeof(cpi->common.fc));
     }
-
+#endif
     update_coef_probs(cpi);
 
 #ifdef ENTROPY_STATS
diff --git a/vp8/encoder/onyx_if.c b/vp8/encoder/onyx_if.c
index 867c4bdec..829906a1c 100644
--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -3364,7 +3364,7 @@ static void Pass1Encode(VP8_COMP *cpi, unsigned long *size, unsigned char *dest,
     vp8_first_pass(cpi);
 }
 #endif
-
+//#define WRITE_RECON_BUFFER 1
 #if WRITE_RECON_BUFFER
 void write_cx_frame_to_file(YV12_BUFFER_CONFIG *frame, int this_frame)
 {
@@ -3378,21 +3378,24 @@ void write_cx_frame_to_file(YV12_BUFFER_CONFIG *frame, int this_frame)
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->y_height; i++)
-        fwrite(frame->y_buffer + i * frame->y_stride, frame->y_width, 1, yframe);
+        fwrite(frame->y_buffer + i * frame->y_stride,
+            frame->y_width, 1, yframe);
 
     fclose(yframe);
     sprintf(filename, "cx\\u%04d.raw", this_frame);
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->uv_height; i++)
-        fwrite(frame->u_buffer + i * frame->uv_stride, frame->uv_width, 1, yframe);
+        fwrite(frame->u_buffer + i * frame->uv_stride,
+            frame->uv_width, 1, yframe);
 
     fclose(yframe);
     sprintf(filename, "cx\\v%04d.raw", this_frame);
     yframe = fopen(filename, "wb");
 
     for (i = 0; i < frame->uv_height; i++)
-        fwrite(frame->v_buffer + i * frame->uv_stride, frame->uv_width, 1, yframe);
+        fwrite(frame->v_buffer + i * frame->uv_stride,
+            frame->uv_width, 1, yframe);
 
     fclose(yframe);
 }
@@ -4154,7 +4157,13 @@ static void encode_frame_to_data_rate
             resize_key_frame(cpi);
             vp8_setup_key_frame(cpi);
         }
-
+#if CONFIG_MULCONTEXT
+        else
+        {
+            /* setup entropy for nonkey frame */
+            vp8_setup_inter_frame(cpi);
+        }
+#endif
         // transform / motion compensation build reconstruction frame
         vp8_encode_frame(cpi);
 
@@ -4512,9 +4521,17 @@ static void encode_frame_to_data_rate
 
 #if WRITE_RECON_BUFFER
     if(cm->show_frame)
+<<<<<<< HEAD
         write_cx_frame_to_file(cm->frame_to_show, cm->current_video_frame);
     else
         write_cx_frame_to_file(cm->frame_to_show, cm->current_video_frame+1000);
+=======
+        write_cx_frame_to_file(cm->frame_to_show,
+            cm->current_video_frame);
+    else
+        write_cx_frame_to_file(cm->frame_to_show,
+            cm->current_video_frame+1000);
+>>>>>>> added separate entropy context for alt_ref
 #endif
 
 #if CONFIG_MULTITHREAD
@@ -5309,10 +5326,23 @@ int vp8_get_compressed_data(VP8_PTR ptr, unsigned int *frame_flags, unsigned lon
 
     }
 
+
+
+#if CONFIG_MULCONTEXT
+    if(cm->refresh_entropy_probs)
+    {
+        if(cm->refresh_alt_ref_frame)
+            vpx_memcpy(&cm->lfc_a, &cm->fc, sizeof(cm->fc));
+        else
+            vpx_memcpy(&cm->lfc, &cm->fc, sizeof(cm->fc));
+    }
+#else
     if (cm->refresh_entropy_probs == 0)
     {
         vpx_memcpy(&cm->fc, &cm->lfc, sizeof(cm->fc));
     }
+#endif
+
 
     // if its a dropped frame honor the requests on subsequent frames
     if (*size > 0)
diff --git a/vp8/encoder/ratectrl.c b/vp8/encoder/ratectrl.c
index 9a7907e65..de6ccaf0f 100644
--- a/vp8/encoder/ratectrl.c
+++ b/vp8/encoder/ratectrl.c
@@ -247,7 +247,22 @@ void vp8_setup_key_frame(VP8_COMP *cpi)
 
     cpi->common.refresh_golden_frame = TRUE;
     cpi->common.refresh_alt_ref_frame = TRUE;
+
+#if CONFIG_MULCONTEXT
+    vpx_memcpy(&cpi->common.lfc, &cpi->common.fc, sizeof(cpi->common.fc));
+    vpx_memcpy(&cpi->common.lfc_a, &cpi->common.fc, sizeof(cpi->common.fc));
+#endif
+
 }
+#if CONFIG_MULCONTEXT
+void vp8_setup_inter_frame(VP8_COMP *cpi)
+{
+    if(cpi->common.refresh_alt_ref_frame)
+        vpx_memcpy(&cpi->common.fc, &cpi->common.lfc_a, sizeof(cpi->common.fc));
+    else
+        vpx_memcpy(&cpi->common.fc, &cpi->common.lfc, sizeof(cpi->common.fc));
+}
+#endif
 
 
 static int estimate_bits_at_q(int frame_kind, int Q, int MBs,