Some B-frames support (parsing and decoding only, no motion compesation is done)

Originally committed as revision 5820 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vc1.c

@@ -316,8 +316,9 @@ typedef struct VC1Context{
     VLC *cbpcy_vlc;               ///< CBPCY VLC table
     int tt_index;                 ///< Index for Transform Type tables
     uint8_t* mv_type_mb_plane;    ///< bitplane for mv_type == (4MV)
-//    BitPlane direct_mb_plane;     ///< bitplane for "direct" MBs
+    uint8_t* direct_mb_plane;     ///< bitplane for "direct" MBs
     int mv_type_is_raw;           ///< mv type mb plane is not coded
+    int dmb_is_raw;               ///< direct mb plane is raw
     int skip_is_raw;              ///< skip mb plane is not coded
     uint8_t luty[256], lutuv[256]; // lookup tables used for intensity compensation
     int rnd;                      ///< rounding control
@@ -897,7 +898,7 @@ static void vc1_put_block(VC1Context *v, DCTELEM block[6][64])
 /** Do motion compensation over 1 macroblock
  * Mostly adapted hpel_motion and qpel_motion from mpegvideo.c
  */
-static void vc1_mc_1mv(VC1Context *v)
+static void vc1_mc_1mv(VC1Context *v, int dir)
 {
     MpegEncContext *s = &v->s;
     DSPContext *dsp = &v->s.dsp;
@@ -910,9 +911,15 @@ static void vc1_mc_1mv(VC1Context *v)
     my = s->mv[0][0][1];
     uvmx = (mx + ((mx & 3) == 3)) >> 1;
     uvmy = (my + ((my & 3) == 3)) >> 1;
+    if(!dir) {
         srcY = s->last_picture.data[0];
         srcU = s->last_picture.data[1];
         srcV = s->last_picture.data[2];
+    } else {
+        srcY = s->next_picture.data[0];
+        srcU = s->next_picture.data[1];
+        srcV = s->next_picture.data[2];
+    }
 
     src_x = s->mb_x * 16 + (mx >> 2);
     src_y = s->mb_y * 16 + (my >> 2);
@@ -1312,6 +1319,13 @@ static int vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
 
     if(v->s.pict_type == I_TYPE)
         get_bits(gb, 7); // skip buffer fullness
+    if(v->s.pict_type == B_TYPE) {
+        v->bfraction = get_vlc2(gb, vc1_bfraction_vlc.table, VC1_BFRACTION_VLC_BITS, 1);
+        v->bfraction = vc1_bfraction_lut[v->bfraction];
+        if(v->bfraction == -1) {
+            v->s.pict_type = BI_TYPE;
+        }
+    }
 
     /* calculate RND */
     if(v->s.pict_type == I_TYPE)
@@ -1436,6 +1450,44 @@ static int vc1_parse_frame_header(VC1Context *v, GetBitContext* gb)
         }
         break;
     case B_TYPE:
+        if (v->pq < 5) v->tt_index = 0;
+        else if(v->pq < 13) v->tt_index = 1;
+        else v->tt_index = 2;
+
+        lowquant = (v->pq > 12) ? 0 : 1;
+        v->mv_mode = get_bits1(gb) ? MV_PMODE_1MV : MV_PMODE_1MV_HPEL_BILIN;
+        v->s.quarter_sample = (v->mv_mode == MV_PMODE_1MV);
+
+        status = bitplane_decoding(v->direct_mb_plane, &v->dmb_is_raw, v);
+        if (status < 0) return -1;
+        av_log(v->s.avctx, AV_LOG_DEBUG, "MB Direct Type plane encoding: "
+               "Imode: %i, Invert: %i\n", status>>1, status&1);
+        status = bitplane_decoding(v->s.mbskip_table, &v->skip_is_raw, v);
+        if (status < 0) return -1;
+        av_log(v->s.avctx, AV_LOG_DEBUG, "MB Skip plane encoding: "
+               "Imode: %i, Invert: %i\n", status>>1, status&1);
+
+        v->s.mv_table_index = get_bits(gb, 2);
+        v->cbpcy_vlc = &vc1_cbpcy_p_vlc[get_bits(gb, 2)];
+
+        if (v->dquant)
+        {
+            av_log(v->s.avctx, AV_LOG_DEBUG, "VOP DQuant info\n");
+            vop_dquant_decoding(v);
+        }
+
+        v->ttfrm = 0;
+        if (v->vstransform)
+        {
+            v->ttmbf = get_bits(gb, 1);
+            if (v->ttmbf)
+            {
+                v->ttfrm = ttfrm_to_tt[get_bits(gb, 2)];
+            }
+        } else {
+            v->ttmbf = 1;
+            v->ttfrm = TT_8X8;
+        }
         break;
     }
 
@@ -1675,6 +1727,46 @@ static inline void vc1_pred_mv(MpegEncContext *s, int n, int dmv_x, int dmv_y, i
     }
 }
 
+/** Reconstruct motion vector for B-frame and do motion compensation
+ */
+static inline void vc1_b_mc(VC1Context *v, int dmv_x[2], int dmv_y[2], int direct, int mode)
+{
+    MpegEncContext *s = &v->s;
+    int mx[4], my[4], mv_x, mv_y;
+    int i;
+
+    /* scale MV difference to be quad-pel */
+    dmv_x[0] <<= 1 - s->quarter_sample;
+    dmv_y[0] <<= 1 - s->quarter_sample;
+    dmv_x[1] <<= 1 - s->quarter_sample;
+    dmv_y[1] <<= 1 - s->quarter_sample;
+
+    if(direct || mode == BMV_TYPE_INTERPOLATED) {
+        /* TODO */
+        return;
+    }
+
+    if(mode == BMV_TYPE_BACKWARD) {
+        for(i = 0; i < 4; i++) {
+            mx[i] = s->last_picture.motion_val[0][s->block_index[i]][0];
+            my[i] = s->last_picture.motion_val[0][s->block_index[i]][1];
+        }
+    } else {
+        for(i = 0; i < 4; i++) {
+            mx[i] = s->next_picture.motion_val[0][s->block_index[i]][0];
+            my[i] = s->next_picture.motion_val[0][s->block_index[i]][1];
+        }
+    }
+
+    /* XXX: not right but how to determine 4-MV intra/inter in another frame? */
+    mv_x = median4(mx[0], mx[1], mx[2], mx[3]);
+    mv_y = median4(my[0], my[1], my[2], my[3]);
+    s->mv[0][0][0] = mv_x;
+    s->mv[0][0][1] = mv_y;
+
+    vc1_mc_1mv(v, (mode == BMV_TYPE_FORWARD));
+}
+
 /** Get predicted DC value for I-frames only
  * prediction dir: left=0, top=1
  * @param s MpegEncContext
@@ -2455,7 +2547,7 @@ static int vc1_decode_p_mb(VC1Context *v)
             if (!v->ttmbf && !s->mb_intra && mb_has_coeffs)
                 ttmb = get_vlc2(gb, vc1_ttmb_vlc[v->tt_index].table,
                                 VC1_TTMB_VLC_BITS, 2);
-            if(!s->mb_intra) vc1_mc_1mv(v);
+            if(!s->mb_intra) vc1_mc_1mv(v, 0);
             dst_idx = 0;
             for (i=0; i<6; i++)
             {
@@ -2501,7 +2593,7 @@ static int vc1_decode_p_mb(VC1Context *v)
             s->current_picture.mb_type[mb_pos] = MB_TYPE_SKIP;
             s->current_picture.qscale_table[mb_pos] = 0;
             vc1_pred_mv(s, 0, 0, 0, 1, v->range_x, v->range_y, v->mb_type[0]);
-            vc1_mc_1mv(v);
+            vc1_mc_1mv(v, 0);
             return 0;
         }
     } //1MV mode
@@ -2616,6 +2708,146 @@ static int vc1_decode_p_mb(VC1Context *v)
     return -1;
 }
 
+/** Decode one B-frame MB (in Main profile)
+ */
+static void vc1_decode_b_mb(VC1Context *v)
+{
+    MpegEncContext *s = &v->s;
+    GetBitContext *gb = &s->gb;
+    int i, j;
+    int mb_pos = s->mb_x + s->mb_y * s->mb_stride;
+    int cbp; /* cbp decoding stuff */
+    int mqdiff, mquant; /* MB quantization */
+    int ttmb = v->ttfrm; /* MB Transform type */
+
+    static const int size_table[6] = { 0, 2, 3, 4, 5, 8 },
+      offset_table[6] = { 0, 1, 3, 7, 15, 31 };
+    int mb_has_coeffs = 0; /* last_flag */
+    int index, index1; /* LUT indices */
+    int val, sign; /* temp values */
+    int first_block = 1;
+    int dst_idx, off;
+    int skipped, direct;
+    int dmv_x[2], dmv_y[2];
+    int bmvtype = BMV_TYPE_BACKWARD; /* XXX: is it so? */
+
+    mquant = v->pq; /* Loosy initialization */
+    s->mb_intra = 0;
+
+    if (v->dmb_is_raw)
+        direct = get_bits1(gb);
+    else
+        direct = v->direct_mb_plane[mb_pos];
+    if (v->skip_is_raw)
+        skipped = get_bits1(gb);
+    else
+        skipped = v->s.mbskip_table[mb_pos];
+
+    s->dsp.clear_blocks(s->block[0]);
+    dmv_x[0] = dmv_x[1] = dmv_y[0] = dmv_y[1] = 0;
+    for(i = 0; i < 6; i++) {
+        v->mb_type[0][s->block_index[i]] = 0;
+        s->dc_val[0][s->block_index[i]] = 0;
+    }
+    s->current_picture.qscale_table[mb_pos] = 0;
+
+    if (!direct) {
+        if (!skipped) {
+            GET_MVDATA(dmv_x[0], dmv_y[0]);
+        }
+        if(skipped || !s->mb_intra) {
+            bmvtype = decode012(gb);
+            switch(bmvtype) {
+            case 0:
+                bmvtype = (v->bfraction >= (B_FRACTION_DEN/2)) ? BMV_TYPE_BACKWARD : BMV_TYPE_FORWARD;
+                break;
+            case 1:
+                bmvtype = (v->bfraction >= (B_FRACTION_DEN/2)) ? BMV_TYPE_FORWARD : BMV_TYPE_BACKWARD;
+                break;
+            case 2:
+                bmvtype = BMV_TYPE_INTERPOLATED;
+            }
+        }
+    }
+
+    if (skipped) {
+        vc1_b_mc(v, dmv_x, dmv_y, direct, bmvtype);
+        return;
+    }
+    if (direct) {
+        cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);
+        GET_MQUANT();
+        s->current_picture.qscale_table[mb_pos] = mquant;
+        if(!v->ttmbf && !s->mb_intra && mb_has_coeffs)
+            ttmb = get_vlc2(gb, vc1_ttmb_vlc[v->tt_index].table, VC1_TTMB_VLC_BITS, 2);
+        vc1_b_mc(v, dmv_x, dmv_y, direct, bmvtype);
+    } else {
+        if(!mb_has_coeffs && !s->mb_intra) {
+            /* no coded blocks - effectively skipped */
+            vc1_b_mc(v, dmv_x, dmv_y, direct, bmvtype);
+            return;
+        }
+        if(s->mb_intra && !mb_has_coeffs) {
+            GET_MQUANT();
+            s->current_picture.qscale_table[mb_pos] = mquant;
+            s->ac_pred = get_bits1(gb);
+            cbp = 0;
+        } else {
+            if(bmvtype == BMV_TYPE_INTERPOLATED) {
+                GET_MVDATA(dmv_x[1], dmv_y[1]);
+                if(!mb_has_coeffs) {
+                    /* interpolated skipped block */
+                    vc1_b_mc(v, dmv_x, dmv_y, direct, bmvtype);
+                    return;
+                }
+            }
+            if(!s->mb_intra)
+                vc1_b_mc(v, dmv_x, dmv_y, direct, bmvtype);
+            if(s->mb_intra)
+                s->ac_pred = get_bits1(gb);
+            cbp = get_vlc2(&v->s.gb, v->cbpcy_vlc->table, VC1_CBPCY_P_VLC_BITS, 2);
+            GET_MQUANT();
+            s->current_picture.qscale_table[mb_pos] = mquant;
+            if(!v->ttmbf && !s->mb_intra && mb_has_coeffs)
+                ttmb = get_vlc2(gb, vc1_ttmb_vlc[v->tt_index].table, VC1_TTMB_VLC_BITS, 2);
+        }
+    }
+    dst_idx = 0;
+    for (i=0; i<6; i++)
+    {
+        s->dc_val[0][s->block_index[i]] = 0;
+        dst_idx += i >> 2;
+        val = ((cbp >> (5 - i)) & 1);
+        off = (i & 4) ? 0 : ((i & 1) * 8 + (i & 2) * 4 * s->linesize);
+        v->mb_type[0][s->block_index[i]] = s->mb_intra;
+        if(s->mb_intra) {
+            /* check if prediction blocks A and C are available */
+            v->a_avail = v->c_avail = 0;
+            if(i == 2 || i == 3 || !s->first_slice_line)
+                v->a_avail = v->mb_type[0][s->block_index[i] - s->block_wrap[i]];
+            if(i == 1 || i == 3 || s->mb_x)
+                v->c_avail = v->mb_type[0][s->block_index[i] - 1];
+
+            vc1_decode_intra_block(v, s->block[i], i, val, mquant, (i&4)?v->codingset2:v->codingset);
+            vc1_inv_trans(s->block[i], 8, 8);
+            for(j = 0; j < 64; j++) s->block[i][j] += 128;
+            s->dsp.put_pixels_clamped(s->block[i], s->dest[dst_idx] + off, s->linesize >> ((i & 4) >> 2));
+            /* TODO: proper loop filtering */
+            if(v->pq >= 9 && v->overlap) {
+                if(v->a_avail)
+                    vc1_v_overlap(s->dest[dst_idx] + off, s->linesize >> ((i & 4) >> 2));
+                if(v->c_avail)
+                    vc1_h_overlap(s->dest[dst_idx] + off, s->linesize >> ((i & 4) >> 2));
+            }
+        } else if(val) {
+            vc1_decode_p_block(v, s->block[i], i, mquant, ttmb, first_block);
+            if(!v->ttmbf && ttmb < 8) ttmb = -1;
+            first_block = 0;
+            s->dsp.add_pixels_clamped(s->block[i], s->dest[dst_idx] + off, (i&4)?s->uvlinesize:s->linesize);
+        }
+    }
+}
+
 /** Decode blocks of I-frame
  */
 static void vc1_decode_i_blocks(VC1Context *v)
@@ -2769,6 +3001,54 @@ static void vc1_decode_p_blocks(VC1Context *v)
     }
 }
 
+static void vc1_decode_b_blocks(VC1Context *v)
+{
+    MpegEncContext *s = &v->s;
+
+    /* select codingmode used for VLC tables selection */
+    switch(v->c_ac_table_index){
+    case 0:
+        v->codingset = (v->pqindex <= 8) ? CS_HIGH_RATE_INTRA : CS_LOW_MOT_INTRA;
+        break;
+    case 1:
+        v->codingset = CS_HIGH_MOT_INTRA;
+        break;
+    case 2:
+        v->codingset = CS_MID_RATE_INTRA;
+        break;
+    }
+
+    switch(v->c_ac_table_index){
+    case 0:
+        v->codingset2 = (v->pqindex <= 8) ? CS_HIGH_RATE_INTER : CS_LOW_MOT_INTER;
+        break;
+    case 1:
+        v->codingset2 = CS_HIGH_MOT_INTER;
+        break;
+    case 2:
+        v->codingset2 = CS_MID_RATE_INTER;
+        break;
+    }
+
+    ff_er_add_slice(s, 0, 0, s->mb_width - 1, s->mb_height - 1, (AC_END|DC_END|MV_END));
+    s->first_slice_line = 1;
+    for(s->mb_y = 0; s->mb_y < s->mb_height; s->mb_y++) {
+        for(s->mb_x = 0; s->mb_x < s->mb_width; s->mb_x++) {
+            ff_init_block_index(s);
+            ff_update_block_index(s);
+            s->dsp.clear_blocks(s->block[0]);
+
+            vc1_decode_b_mb(v);
+            if(get_bits_count(&s->gb) > v->bits || get_bits_count(&s->gb) < 0) {
+                av_log(s->avctx, AV_LOG_ERROR, "Bits overconsumption: %i > %i at %ix%i\n", get_bits_count(&s->gb), v->bits,s->mb_x,s->mb_y);
+                return;
+            }
+        }
+        ff_draw_horiz_band(s, s->mb_y * 16, 16);
+        s->first_slice_line = 0;
+    }
+}
+
 static void vc1_decode_blocks(VC1Context *v)
 {
 
@@ -2781,6 +3061,9 @@ static void vc1_decode_blocks(VC1Context *v)
     case P_TYPE:
         vc1_decode_p_blocks(v);
         break;
+    case B_TYPE:
+        vc1_decode_b_blocks(v);
+        break;
     }
 }
 
@@ -2839,6 +3122,7 @@ static int vc1_decode_init(AVCodecContext *avctx)
 
     /* Allocate mb bitplanes */
     v->mv_type_mb_plane = av_malloc(s->mb_stride * s->mb_height);
+    v->direct_mb_plane = av_malloc(s->mb_stride * s->mb_height);
 
     /* allocate block type info in that way so it could be used with s->block_index[] */
     v->mb_type_base = av_malloc(s->b8_stride * (s->mb_height * 2 + 1) + s->mb_stride * (s->mb_height + 1) * 2);
@@ -2897,7 +3181,7 @@ static int vc1_decode_frame(AVCodecContext *avctx,
     if(vc1_parse_frame_header(v, &s->gb) == -1)
         return -1;
 
-    if(s->pict_type != I_TYPE && s->pict_type != P_TYPE)return -1;
+//    if(s->pict_type != I_TYPE && s->pict_type != P_TYPE)return -1;
 
     // for hurry_up==5
     s->current_picture.pict_type= s->pict_type;
@@ -2967,6 +3251,7 @@ static int vc1_decode_end(AVCodecContext *avctx)
     av_freep(&v->hrd_buffer);
     MPV_common_end(&v->s);
     av_freep(&v->mv_type_mb_plane);
+    av_freep(&v->direct_mb_plane);
     av_freep(&v->mb_type_base);
     return 0;
 }

libavcodec/vc1data.h

@@ -6,6 +6,9 @@
 #ifndef VC1DATA_H
 #define VC1DATA_H
 
+/* Denominator used for vc1_bfraction_lut */
+#define B_FRACTION_DEN  840
+
 /* bfraction is fractional, we scale to the GCD 3*5*7*8 = 840 */
 const int16_t vc1_bfraction_lut[23] = {
   420 /*1/2*/, 280 /*1/3*/, 560 /*2/3*/, 210 /*1/4*/,