[FFmpeg-devel] [PATCH v2 1/3] avutil/timecode: add ff_timecode_set_smpte

* [FFmpeg-devel] [PATCH v2 1/3] avutil/timecode: add ff_timecode_set_smpte
@ 2025-02-28 22:46 Timo Rothenpieler
  2025-02-28 22:46 ` [FFmpeg-devel] [PATCH v2 2/3] avcodec/utils: use new ff_timecode_set_smpte function Timo Rothenpieler
  2025-02-28 22:46 ` [FFmpeg-devel] [PATCH v2 3/3] avcodec/nvenc: add time code writing for h264 Timo Rothenpieler
  0 siblings, 2 replies; 4+ messages in thread
From: Timo Rothenpieler @ 2025-02-28 22:46 UTC (permalink / raw)
  To: ffmpeg-devel; +Cc: Timo Rothenpieler

---
 libavutil/timecode.c          | 27 +++----------------
 libavutil/timecode_internal.c | 51 +++++++++++++++++++++++++++++++++++
 libavutil/timecode_internal.h | 51 +++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 24 deletions(-)
 create mode 100644 libavutil/timecode_internal.c
 create mode 100644 libavutil/timecode_internal.h

diff --git a/libavutil/timecode.c b/libavutil/timecode.c
index f454466f97..bca16b6ac2 100644
--- a/libavutil/timecode.c
+++ b/libavutil/timecode.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include "common.h"
 #include "timecode.h"
+#include "timecode_internal.h"
 #include "log.h"
 #include "error.h"
 
@@ -127,32 +128,10 @@ char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum_arg)
     return buf;
 }
 
-static unsigned bcd2uint(uint8_t bcd)
-{
-   unsigned low  = bcd & 0xf;
-   unsigned high = bcd >> 4;
-   if (low > 9 || high > 9)
-       return 0;
-   return low + 10*high;
-}
-
 char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
 {
-    unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
-    unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
-    unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
-    unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
-    unsigned drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not arbitrary bit
-
-    if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
-        ff <<= 1;
-        if (!skip_field) {
-            if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
-                ff += !!(tcsmpte & 1 << 7);
-            else
-                ff += !!(tcsmpte & 1 << 23);
-        }
-    }
+    unsigned hh, mm, ss, ff, drop;
+    ff_timecode_set_smpte(&drop, &hh, &mm, &ss, &ff, rate, tcsmpte, prevent_df, skip_field);
 
     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
              hh, mm, ss, drop ? ';' : ':', ff);
diff --git a/libavutil/timecode_internal.c b/libavutil/timecode_internal.c
new file mode 100644
index 0000000000..259ebf1664
--- /dev/null
+++ b/libavutil/timecode_internal.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ * Copyright (c) 2011-2012 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 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 "timecode_internal.h"
+
+static unsigned bcd2uint(uint8_t bcd)
+{
+   unsigned low  = bcd & 0xf;
+   unsigned high = bcd >> 4;
+   if (low > 9 || high > 9)
+       return 0;
+   return low + 10*high;
+}
+
+void ff_timecode_set_smpte(unsigned *drop, unsigned *hh, unsigned *mm, unsigned *ss, unsigned *ff,
+                           AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
+{
+    *hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
+    *mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
+    *ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
+    *ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
+    *drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not arbitrary bit
+
+    if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
+        *ff <<= 1;
+        if (!skip_field) {
+            if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
+                *ff += !!(tcsmpte & 1 << 7);
+            else
+                *ff += !!(tcsmpte & 1 << 23);
+        }
+    }
+}
diff --git a/libavutil/timecode_internal.h b/libavutil/timecode_internal.h
new file mode 100644
index 0000000000..8ef43d1f98
--- /dev/null
+++ b/libavutil/timecode_internal.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
+ * Copyright (c) 2011-2012 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 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
+ * Timecode helpers header
+ */
+
+#ifndef AVUTIL_TIMECODE_INTERNAL_H
+#define AVUTIL_TIMECODE_INTERNAL_H
+
+#include <stdint.h>
+#include "rational.h"
+
+/**
+ * Convert SMPTE 12M binary representation to sei info.
+ *
+ * @param drop       drop flag output
+ * @param hh         hour output
+ * @param mm         minute output
+ * @param ss         second output
+ * @param ff         frame number output
+ * @param rate       frame rate of the timecode
+ * @param tcsmpte    the 32-bit SMPTE timecode
+ * @param prevent_df prevent the use of a drop flag when it is known the DF bit
+ *                   is arbitrary
+ * @param skip_field prevent the use of a field flag when it is known the field
+ *                   bit is arbitrary (e.g. because it is used as PC flag)
+ */
+void ff_timecode_set_smpte(unsigned *drop, unsigned *hh, unsigned *mm, unsigned *ss, unsigned *ff,
+                           AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field);
+
+#endif /* AVUTIL_TIMECODE_INTERNAL_H */
-- 
2.45.3

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