RealVideo 3 decoder functions

Originally committed as revision 11130 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/rv30.c

+/*
+ * RV30 decoder
+ * Copyright (c) 2007 Konstantin Shishkov
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file rv30.c
+ * RV30 decoder.
+ */
+
+#include "avcodec.h"
+#include "dsputil.h"
+#include "mpegvideo.h"
+
+#include "rv34.h"
+#include "rv30data.h"
+
+
+static int rv30_parse_slice_header(RV34DecContext *r, GetBitContext *gb, SliceInfo *si)
+{
+    int mb_bits;
+    int w = r->s.width, h = r->s.height;
+    int mb_size;
+
+    memset(si, 0, sizeof(SliceInfo));
+    skip_bits(gb, 3);
+    si->type = get_bits(gb, 2);
+    if(si->type == 1) si->type = 0;
+    if(get_bits1(gb))
+        return -1;
+    si->quant = get_bits(gb, 5);
+    skip_bits1(gb);
+    skip_bits(gb, 13); // timestamp
+    skip_bits(gb, r->rpr);
+    si->width  = w;
+    si->height = h;
+    mb_size = ((w + 15) >> 4) * ((h + 15) >> 4);
+    mb_bits = ff_rv34_get_start_offset(gb, mb_size);
+    si->start = get_bits(gb, mb_bits);
+    skip_bits1(gb);
+    return 0;
+}
+
+/**
+ * Decode 4x4 intra types array
+ */
+static int rv30_decode_intra_types(RV34DecContext *r, GetBitContext *gb, int *dst)
+{
+    int i, j, k;
+
+    for(i = 0; i < 4; i++, dst += r->s.b4_stride - 4){
+        for(j = 0; j < 4; j+= 2){
+            int code = (ff_rv34_get_gamma(gb) - 1) << 1;
+            if(code >= 81*2){
+                av_log(r->s.avctx, AV_LOG_ERROR, "Incorrect intra prediction code\n");
+                return -1;
+            }
+            for(k = 0; k < 2; k++){
+                int A = dst[-r->s.b4_stride] + 1;
+                int B = dst[-1] + 1;
+                *dst++ = rv30_itype_from_context[A * 90 + B * 9 + rv30_itype_code[code + k]];
+                if(dst[-1] == 9){
+                    av_log(r->s.avctx, AV_LOG_ERROR, "Incorrect intra prediction mode\n");
+                    return -1;
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+/**
+ * Decode macroblock information
+ */
+static int rv30_decode_mb_info(RV34DecContext *r)
+{
+    static const int rv30_p_types[6] = { RV34_MB_SKIP, RV34_MB_P_16x16, RV34_MB_P_8x8, -1, RV34_MB_TYPE_INTRA, RV34_MB_TYPE_INTRA16x16 };
+    static const int rv30_b_types[6] = { RV34_MB_SKIP, RV34_MB_B_DIRECT, RV34_MB_B_FORWARD, RV34_MB_B_BACKWARD, RV34_MB_TYPE_INTRA, RV34_MB_TYPE_INTRA16x16 };
+    MpegEncContext *s = &r->s;
+    GetBitContext *gb = &s->gb;
+    int code = ff_rv34_get_gamma(gb) - 1;
+
+    if(code > 11){
+        av_log(s->avctx, AV_LOG_ERROR, "Incorrect MB type code\n");
+        return -1;
+    }
+    if(code > 5){
+        av_log(s->avctx, AV_LOG_ERROR, "dquant needed\n");
+        code -= 6;
+    }
+    if(s->pict_type != B_TYPE)
+        return rv30_p_types[code];
+    else
+        return rv30_b_types[code];
+}
+
+/**
+ * Initialize decoder
+ */
+static int rv30_decode_init(AVCodecContext *avctx)
+{
+    RV34DecContext *r = avctx->priv_data;
+
+    r->rv30 = 1;
+    ff_rv34_decode_init(avctx);
+    if(avctx->extradata_size < 2){
+        av_log(avctx, AV_LOG_ERROR, "Extradata is too small\n");
+        return -1;
+    }
+    r->rpr = (avctx->extradata[1] & 7) >> 1;
+    r->rpr = FFMIN(r->rpr + 1, 3);
+    r->parse_slice_header = rv30_parse_slice_header;
+    r->decode_intra_types = rv30_decode_intra_types;
+    r->decode_mb_info     = rv30_decode_mb_info;
+    r->luma_dc_quant_i = rv30_luma_dc_quant;
+    r->luma_dc_quant_p = rv30_luma_dc_quant;
+    return 0;
+}
+
+AVCodec rv30_decoder = {
+    "rv30",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_RV30,
+    sizeof(RV34DecContext),
+    rv30_decode_init,
+    NULL,
+    ff_rv34_decode_end,
+    ff_rv34_decode_frame,
+};