timecode: introduce timecode and honor it in MPEG-1/2.

This is based on the original work by Baptiste Coudurier.

1 files changed, 56 insertions, 0 deletions

diff --git a/libavcodec/timecode.c b/libavcodec/timecode.c
new file mode 100644
index 0000000000..d9c3f7d8d2
--- /dev/null
+++ b/libavcodec/timecode.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ * Copyright (C) 2011 Smartjog S.A.S, Clément Bœsch      <clement.boesch@smartjog.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation;
+ * version 2 of the License.
+ *
+ * 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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
+ * Timecode helpers
+ */
+
+#include <stdio.h>
+#include "timecode.h"
+#include "libavutil/log.h"
+
+int ff_init_smtpe_timecode(void *avcl, struct ff_timecode *tc)
+{
+    int hh, mm, ss, ff, fps;
+    char c;
+
+    if (sscanf(tc->str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
+        av_log(avcl, AV_LOG_ERROR, "unable to parse timecode, "
+                                   "syntax: hh:mm:ss[:;.]ff\n");
+        return -1;
+    }
+
+    fps       = (tc->rate.num + tc->rate.den/2) / tc->rate.den;
+    tc->start = (hh*3600 + mm*60 + ss) * fps + ff;
+    tc->drop  = c != ':'; // drop if ';', '.', ...
+
+    if (tc->drop) { /* adjust frame number */
+        int tmins = 60*hh + mm;
+        if (tc->rate.den != 1001 || fps != 30) {
+            av_log(avcl, AV_LOG_ERROR, "error: drop frame is only allowed with"
+                                       "30000/1001 FPS");
+            return -2;
+        }
+        tc->start -= 2 * (tmins - tmins/10);
+    }
+    return 0;
+}