lavu: add public timecode API.

1 files changed, 138 insertions, 0 deletions

diff --git a/libavutil/timecode.h b/libavutil/timecode.h
new file mode 100644
index 0000000000..41e56d6bfa
--- /dev/null
+++ b/libavutil/timecode.h
@@ -0,0 +1,138 @@
+/*
+ * 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_H
+#define AVUTIL_TIMECODE_H
+
+#include <stdint.h>
+#include "rational.h"
+
+#define AV_TIMECODE_STR_SIZE 16
+
+#define AV_TIMECODE_OPTION(ctx, string_field, flags)                     \
+    "timecode", "set timecode value following hh:mm:ss[:;.]ff format, "  \
+                "use ';' or '.' before frame number for drop frame",     \
+    offsetof(ctx, string_field),                                         \
+    AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, flags
+
+enum AVTimecodeFlag {
+    AV_TIMECODE_FLAG_DROPFRAME      = 1<<0, ///< timecode is drop frame
+    AV_TIMECODE_FLAG_24HOURSMAX     = 1<<1, ///< timecode wraps after 24 hours
+    AV_TIMECODE_FLAG_ALLOWNEGATIVE  = 1<<2, ///< negative time values are allowed
+};
+
+typedef struct {
+    int start;          ///< timecode frame start (first base frame number)
+    uint32_t flags;     ///< flags such as drop frame, +24 hours support, ...
+    AVRational rate;    ///< frame rate in rational form
+    unsigned fps;       ///< frame per second; must be consistent with the rate field
+} AVTimecode;
+
+/**
+ * Adjust frame number for NTSC drop frame time code.
+ *
+ * @param framenum frame number to adjust
+ * @return         adjusted frame number
+ * @warning        adjustment is only valid in NTSC 29.97
+ */
+int av_timecode_adjust_ntsc_framenum(int framenum);
+
+/**
+ * Convert frame number to SMPTE 12M binary representation.
+ *
+ * @param tc       timecode data correctly initialized
+ * @param framenum frame number
+ * @return         the SMPTE binary representation
+ *
+ * @note Frame number adjustment is automatically done in case of drop timecode,
+ *       you do NOT have to call av_timecode_adjust_ntsc_framenum().
+ * @note The frame number is relative to tc->start.
+ * @note Color frame (CF), binary group flags (BGF) and biphase mark polarity
+ *       correction (PC) bits are set to zero.
+ */
+uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
+
+/**
+ * Load timecode string in buf.
+ *
+ * @param buf      destination buffer, must be at least AV_TIMECODE_STR_SIZE long
+ * @param tc       timecode data correctly initialized
+ * @param framenum frame number
+ * @return         the buf parameter
+ *
+ * @note Timecode representation can be a negative timecode and have more than
+ *       24 hours, but will only be honored if the flags are correctly set.
+ * @note The frame number is relative to tc->start.
+ */
+char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum);
+
+/**
+ * Get the timecode string from the SMPTE timecode format.
+ *
+ * @param buf        destination buffer, must be at least AV_TIMECODE_STR_SIZE long
+ * @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
+ * @return           the buf parameter
+ */
+char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df);
+
+/**
+ * Get the timecode string from the 25-bit timecode format (MPEG GOP format).
+ *
+ * @param buf     destination buffer, must be at least AV_TIMECODE_STR_SIZE long
+ * @param tc25bit the 25-bits timecode
+ * @return        the buf parameter
+ */
+char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit);
+
+/**
+ * Init a timecode struct with the passed parameters.
+ *
+ * @param log_ctx     a pointer to an arbitrary struct of which the first field
+ *                    is a pointer to an AVClass struct (used for av_log)
+ * @param tc          pointer to an allocated AVTimecode
+ * @param rate        frame rate in rational form
+ * @param flags       miscellaneous flags such as drop frame, +24 hours, ...
+ *                    (see AVTimecodeFlag)
+ * @param frame_start the first frame number
+ * @return            0 on success, AVERROR otherwise
+ */
+int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx);
+
+/**
+ * Parse timecode representation (hh:mm:ss[:;.]ff).
+ *
+ * @param log_ctx a pointer to an arbitrary struct of which the first field is a
+ *                pointer to an AVClass struct (used for av_log).
+ * @param tc      pointer to an allocated AVTimecode
+ * @param rate    frame rate in rational form
+ * @param str     timecode string which will determine the frame start
+ * @return        0 on success, AVERROR otherwise
+ */
+int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx);
+
+#endif /* AVUTIL_TIMECODE_H */