Add Dirac parser from SoC; written by Marco Gerards;

submitted by Anuradha Suraparaju, anuradha rd.bbc.co uk

Originally committed as revision 13041 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 88 insertions, 0 deletions

diff --git a/libavcodec/dirac_parser.c b/libavcodec/dirac_parser.c
new file mode 100644
index 0000000000..199354a9c6
--- /dev/null
+++ b/libavcodec/dirac_parser.c
@@ -0,0 +1,88 @@
+/*
+ * Dirac parser
+ *
+ * Copyright (c) 2007 Marco Gerards <marco@gnu.org>
+ *
+ * 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 dirac_parser.c
+ * Dirac Parser
+ * @author Marco Gerards <marco@gnu.org>
+ */
+
+#include "parser.h"
+
+#define DIRAC_PARSE_INFO_PREFIX 0x42424344
+
+/**
+ * Finds the end of the current frame in the bitstream.
+ * @return the position of the first byte of the next frame or -1
+ */
+static int find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
+{
+    uint32_t state = pc->state;
+    int i;
+
+    for (i = 0; i < buf_size; i++) {
+        state = (state << 8) | buf[i];
+        if (state == DIRAC_PARSE_INFO_PREFIX) {
+            pc->frame_start_found ^= 1;
+            if (!pc->frame_start_found) {
+                pc->state = -1;
+                return i - 3;
+            }
+        }
+    }
+
+    pc->state = state;
+
+    return END_NOT_FOUND;
+}
+
+static int dirac_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                       const uint8_t **poutbuf, int *poutbuf_size,
+                       const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+    int next;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
+        next = buf_size;
+    }else{
+        next = find_frame_end(pc, buf, buf_size);
+
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    *poutbuf = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+AVCodecParser dirac_parser = {
+    { CODEC_ID_DIRAC },
+    sizeof(ParseContext),
+    NULL,
+    dirac_parse,
+    ff_parse_close,
+};