intra_dc_precission>0 encoding support

Originally committed as revision 3093 to svn://svn.ffmpeg.org/ffmpeg/trunk

3 files changed, 33 insertions, 3 deletions

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index a81c865b3f..6a4d223769 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -17,7 +17,7 @@ extern "C" {
 
 #define FFMPEG_VERSION_INT     0x000408
 #define FFMPEG_VERSION         "0.4.8"
-#define LIBAVCODEC_BUILD       4710
+#define LIBAVCODEC_BUILD       4711
 
 #define LIBAVCODEC_VERSION_INT FFMPEG_VERSION_INT
 #define LIBAVCODEC_VERSION     FFMPEG_VERSION
@@ -1584,6 +1584,13 @@ typedef struct AVCodecContext {
      * - decoding: unused
      */
      int mb_threshold;
+
+    /**
+     * 
+     * - encoding: set by user
+     * - decoding: unused
+     */
+     int intra_dc_precision;
 } AVCodecContext;
 
 
diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index 0d6583c890..93e21af100 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -360,7 +360,7 @@ static void common_init(MpegEncContext *s)
 {
 
     s->y_dc_scale_table=
-    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
+    s->c_dc_scale_table= mpeg2_dc_scale_table[s->intra_dc_precision];
 
 }
 
@@ -837,6 +837,27 @@ void ff_mpeg1_encode_init(MpegEncContext *s)
 
 static inline void encode_dc(MpegEncContext *s, int diff, int component)
 {
+  if(((unsigned) (diff+255)) >= 511){
+        int index;
+
+        if(diff<0){
+            index= av_log2_16bit(-2*diff);
+            diff--;
+        }else{
+            index= av_log2_16bit(2*diff);
+        }
+        if (component == 0) {
+            put_bits(
+                &s->pb, 
+                vlc_dc_lum_bits[index] + index,
+                (vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1)));
+        }else{
+            put_bits(
+                &s->pb, 
+                vlc_dc_chroma_bits[index] + index,
+                (vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1)));
+        }
+  }else{
     if (component == 0) {
         put_bits(
 	    &s->pb, 
@@ -848,6 +869,7 @@ static inline void encode_dc(MpegEncContext *s, int diff, int component)
 	    mpeg1_chr_dc_uni[diff+255]&0xFF,
 	    mpeg1_chr_dc_uni[diff+255]>>8);
     }
+  }
 }
 
 static void mpeg1_encode_block(MpegEncContext *s, 
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 772775cdad..1fa39e0f1f 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -890,6 +890,7 @@ int MPV_encode_init(AVCodecContext *avctx)
     s->quarter_sample= (avctx->flags & CODEC_FLAG_QPEL)!=0;
     s->mpeg_quant= avctx->mpeg_quant;
     s->rtp_mode= !!avctx->rtp_payload_size;
+    s->intra_dc_precision= avctx->intra_dc_precision;
 
     if (s->gop_size <= 1) {
         s->intra_only = 1;
@@ -4009,7 +4010,7 @@ static int encode_thread(AVCodecContext *c, void *arg){
     for(i=0; i<3; i++){
         /* init last dc values */
         /* note: quant matrix value (8) is implied here */
-        s->last_dc[i] = 128;
+        s->last_dc[i] = 128 << s->intra_dc_precision;
         
         s->current_picture_ptr->error[i] = 0;
     }