ffmpeg source update for sep 09

source/patched-ffmpeg-mt/libavformat/h261dec.c

+/*
+ * RAW H.261 video demuxer
+ * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+#include "libavcodec/get_bits.h"
+#include "avformat.h"
+#include "rawdec.h"
+
+static int h261_probe(AVProbeData *p)
+{
+    uint32_t code= -1;
+    int i;
+    int valid_psc=0;
+    int invalid_psc=0;
+    int next_gn=0;
+    int src_fmt=0;
+    GetBitContext gb;
+
+    init_get_bits(&gb, p->buf, p->buf_size*8);
+
+    for(i=0; i<p->buf_size*8; i++){
+        if ((code & 0x01ff0000) || !(code & 0xff00)) {
+            code = (code<<8) + get_bits(&gb, 8);
+            i += 7;
+        } else
+            code = (code<<1) + get_bits1(&gb);
+        if ((code & 0xffff0000) == 0x10000) {
+            int gn= (code>>12)&0xf;
+            if(!gn)
+                src_fmt= code&8;
+            if(gn != next_gn) invalid_psc++;
+            else              valid_psc++;
+
+            if(src_fmt){ // CIF
+                next_gn= (gn+1     )%13;
+            }else{       //QCIF
+                next_gn= (gn+1+!!gn)% 7;
+            }
+        }
+    }
+    if(valid_psc > 2*invalid_psc + 6){
+        return 50;
+    }else if(valid_psc > 2*invalid_psc + 2)
+        return 25;
+    return 0;
+}
+
+AVInputFormat h261_demuxer = {
+    "h261",
+    NULL_IF_CONFIG_SMALL("raw H.261"),
+    0,
+    h261_probe,
+    ff_raw_video_read_header,
+    ff_raw_read_partial_packet,
+    .flags= AVFMT_GENERIC_INDEX,
+    .extensions = "h261",
+    .value = CODEC_ID_H261,
+};