RealText demuxer and decoder.

1 files changed, 83 insertions, 0 deletions

diff --git a/libavcodec/realtextdec.c b/libavcodec/realtextdec.c
new file mode 100644
index 0000000..d2ac0cd
--- /dev/null
+++ b/libavcodec/realtextdec.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2012 Clément Bœsch
+ *
+ * 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
+ * RealText subtitle decoder
+ * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm
+ */
+
+#include "avcodec.h"
+#include "ass.h"
+#include "libavutil/avstring.h"
+#include "libavutil/bprint.h"
+
+static int rt_event_to_ass(AVBPrint *buf, const char *p)
+{
+    int prev_chr_is_space = 1;
+
+    while (*p) {
+        if (*p != '<') {
+            if (!isspace(*p))
+                av_bprint_chars(buf, *p, 1);
+            else if (!prev_chr_is_space)
+                av_bprint_chars(buf, ' ', 1);
+            prev_chr_is_space = isspace(*p);
+        } else {
+            const char *end = strchr(p, '>');
+            if (!end)
+                break;
+            if (!av_strncasecmp(p, "<br/>", 5) ||
+                !av_strncasecmp(p, "<br>",  4)) {
+                av_bprintf(buf, "\\N");
+            }
+            p = end;
+        }
+        p++;
+    }
+    av_bprintf(buf, "\r\n");
+    return 0;
+}
+
+static int realtext_decode_frame(AVCodecContext *avctx,
+                                 void *data, int *got_sub_ptr, AVPacket *avpkt)
+{
+    AVSubtitle *sub = data;
+    const char *ptr = avpkt->data;
+    AVBPrint buf;
+
+    av_bprint_init(&buf, 0, 4096);
+    // note: no need to rescale pts & duration since they are in the same
+    // timebase than ASS (1/100)
+    if (ptr && avpkt->size > 0 && !rt_event_to_ass(&buf, ptr))
+        ff_ass_add_rect(sub, buf.str, avpkt->pts, avpkt->duration, 0);
+    *got_sub_ptr = sub->num_rects > 0;
+    av_bprint_finalize(&buf, NULL);
+    return avpkt->size;
+}
+
+AVCodec ff_realtext_decoder = {
+    .name           = "realtext",
+    .long_name      = NULL_IF_CONFIG_SMALL("RealText subtitle"),
+    .type           = AVMEDIA_TYPE_SUBTITLE,
+    .id             = CODEC_ID_REALTEXT,
+    .decode         = realtext_decode_frame,
+    .init           = ff_ass_subtitle_header_default,
+};