[FFmpeg-devel] [PATCH 02/12] lavu: add public timecode API.
Clément Bœsch
ubitux at gmail.com
Tue Jan 31 14:39:02 CET 2012
On Thu, Jan 26, 2012 at 01:11:21PM +0100, Clément Bœsch wrote:
> On Wed, Jan 25, 2012 at 07:34:23PM +0100, Alexander Strasser wrote:
> > Hi,
> >
> > Clément Bœsch wrote:
> > > On Tue, Jan 24, 2012 at 10:21:02PM +0100, Alexander Strasser wrote:
> > > > Clément Bœsch wrote:
> > > > > On Tue, Jan 24, 2012 at 01:47:30PM +0100, Stefano Sabatini wrote:
> > > > > [...]
> > > > > > > + * @note Frame number adjustment is automatically done in case of drop timecode,
> > > > > > > + * you do NOT have to call av_adjust_ntsc_framenum().
> > > > > >
> > > > > > nit++: no complete sentence, lowcased and no dot at the end
> > > > > >
> > > > >
> > > > > Most of the the @note I see are of two forms:
> > > > >
> > > > > @note frame number adjust is [...] ...framenum().
> > > > > ==> "note that xxxx."
> > > > > @note Frame number [...] ...framenum().
> > > > > ==> "NOTE: xxxx."
> > > > >
> > > > > I used the second form, but it seems you do not want the first form
> > > > > either. Should I just drop the period? The sentence still has verbs… Could
> > > > > you be a bit more explicit about what you are expecting with an example?
> > > > >
> > > > > [...]
> > > > > > > + */
> > > > > > > +uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
> > > > > >
> > > > > > Nit: get->make is maybe more approriate (as noted by Alexander
> > > > > > Strasser in a recent mail)
> > > >
> > > > First of all thanks to Stefano for caring about naming. Second I appologize to
> > > > you, Clément, as proper naming needs some discussion :(
> > > >
> > >
> > > Proper naming for public is important, better overthink it first.
> >
> > I fear I have another one. Seems I am only causing you work :(
> >
> > But please don't do anything if you think I am not making sense here.
> >
> > I just saw it would be good to have the tc parameter as the first one,
> > for all av_timecode_* functions that use (read/write) its state (I think
> > all others don't have that param at all).
> >
>
> So a read only context would likely have a higher priority than an output
> in the parameters list priority? I don't mind much. I'll update the
> patchset next week. Consider it done locally.
>
OK, new version. Prototypes:
int av_timecode_adjust_ntsc_framenum(int framenum);
uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum);
char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df);
char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit);
int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx);
int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx);
So briefly what's new:
- better comments and doxy of av_timecode_get_smpte_from_framenum()
- add av_timecode_make_smpte_tc_string()
- various renames
- AVTimecode context has a higher priority than output buffer in parameters
list
- log_ctx is now the last parameter
I also attach to this email a patch for the usage of
av_timecode_make_smpte_tc_string() in DV. This function can also be used to
extract the timecode from MXF.
If I see no more comment I'll push the whole patchset by the end of the week.
[...]
--
Clément B.
-------------- next part --------------
From 7bc08b2ef7cf2fc15170988cf2eaef7a2e06a296 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <clement.boesch at smartjog.com>
Date: Mon, 16 Jan 2012 11:20:46 +0100
Subject: [PATCH 02/13] lavu: add public timecode API.
---
doc/APIchanges | 3 +
libavutil/Makefile | 2 +
libavutil/timecode.c | 194 ++++++++++++++++++++++++++++++++++++++++++++++++++
libavutil/timecode.h | 138 +++++++++++++++++++++++++++++++++++
4 files changed, 337 insertions(+), 0 deletions(-)
create mode 100644 libavutil/timecode.c
create mode 100644 libavutil/timecode.h
diff --git a/doc/APIchanges b/doc/APIchanges
index 3c5fe68..1c149fd 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil: 2011-04-18
API changes, most recent first:
+2012-01-xx - xxxxxxx - lavu 51.35.100
+ Add public timecode helpers.
+
2012-01-24 - xxxxxxx - lavfi 2.60.100
Add avfilter_graph_dump.
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 2cd763c..5034f5a 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -37,6 +37,7 @@ HEADERS = adler32.h \
rational.h \
samplefmt.h \
sha.h \
+ timecode.h \
BUILT_HEADERS = avconfig.h
@@ -71,6 +72,7 @@ OBJS = adler32.o \
rc4.o \
samplefmt.o \
sha.o \
+ timecode.o \
tree.o \
utils.o \
diff --git a/libavutil/timecode.c b/libavutil/timecode.c
new file mode 100644
index 0000000..db3c818
--- /dev/null
+++ b/libavutil/timecode.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier at gmail.com>
+ * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch at 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
+ * A few references:
+ * https://en.wikipedia.org/wiki/SMPTE_time_code
+ * http://www.dropframetimecode.org
+ */
+
+#include <stdio.h>
+#include "timecode.h"
+#include "log.h"
+#include "error.h"
+
+int av_timecode_adjust_ntsc_framenum(int framenum)
+{
+ /* only works for NTSC 29.97 */
+ int d = framenum / 17982;
+ int m = framenum % 17982;
+ //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */
+ return framenum + 18 * d + 2 * ((m - 2) / 1798);
+}
+
+uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
+{
+ unsigned fps = tc->fps;
+ int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
+ int hh, mm, ss, ff;
+
+ framenum += tc->start;
+ if (drop)
+ framenum = av_timecode_adjust_ntsc_framenum(framenum);
+ ff = framenum % fps;
+ ss = framenum / fps % 60;
+ mm = framenum / (fps*60) % 60;
+ hh = framenum / (fps*3600) % 24;
+ return 0 << 31 | // color frame flag (0: unsync mode, 1: sync mode)
+ drop << 30 | // drop frame flag (0: non drop, 1: drop)
+ (ff / 10) << 28 | // tens of frames
+ (ff % 10) << 24 | // units of frames
+ 0 << 23 | // PC (NTSC) or BGF0 (PAL)
+ (ss / 10) << 20 | // tens of seconds
+ (ss % 10) << 16 | // units of seconds
+ 0 << 15 | // BGF0 (NTSC) or BGF2 (PAL)
+ (mm / 10) << 12 | // tens of minutes
+ (mm % 10) << 8 | // units of minutes
+ 0 << 7 | // BGF2 (NTSC) or PC (PAL)
+ 0 << 6 | // BGF1
+ (hh / 10) << 4 | // tens of hours
+ (hh % 10); // units of hours
+}
+
+char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
+{
+ int fps = tc->fps;
+ int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
+ int hh, mm, ss, ff, neg = 0;
+
+ framenum += tc->start;
+ if (drop)
+ framenum = av_timecode_adjust_ntsc_framenum(framenum);
+ if (framenum < 0) {
+ framenum = -framenum;
+ neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
+ }
+ ff = framenum % fps;
+ ss = framenum / fps % 60;
+ mm = framenum / (fps*60) % 60;
+ hh = framenum / (fps*3600);
+ if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
+ hh = hh % 24;
+ snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d",
+ neg ? "-" : "",
+ hh, mm, ss, drop ? ';' : ':', ff);
+ 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_string(char *buf, uint32_t tcsmpte, int prevent_df)
+{
+ 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
+ snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
+ hh, mm, ss, drop ? ';' : ':', ff);
+ return buf;
+}
+
+char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
+{
+ snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
+ tc25bit>>19 & 0x1f, // 5-bit hours
+ tc25bit>>13 & 0x3f, // 6-bit minutes
+ tc25bit>>6 & 0x3f, // 6-bit seconds
+ tc25bit & 1<<24 ? ';' : ':', // 1-bit drop flag
+ tc25bit & 0x3f); // 6-bit frames
+ return buf;
+}
+
+static int check_timecode(void *log_ctx, AVTimecode *tc)
+{
+ if (tc->fps <= 0) {
+ av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate must be specified\n");
+ return AVERROR(EINVAL);
+ }
+ if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps != 30) {
+ av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with 30000/1001 FPS\n");
+ return AVERROR(EINVAL);
+ }
+ switch (tc->fps) {
+ case 24:
+ case 25:
+ case 30: return 0;
+
+ default:
+ av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate not supported\n");
+ return AVERROR_PATCHWELCOME;
+ }
+}
+
+static int fps_from_frame_rate(AVRational rate)
+{
+ if (!rate.den || !rate.num)
+ return -1;
+ return (rate.num + rate.den/2) / rate.den;
+}
+
+int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
+{
+ memset(tc, 0, sizeof(*tc));
+ tc->start = frame_start;
+ tc->flags = flags;
+ tc->rate = rate;
+ tc->fps = fps_from_frame_rate(rate);
+ return check_timecode(log_ctx, tc);
+}
+
+int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
+{
+ char c;
+ int hh, mm, ss, ff, ret;
+
+ if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
+ av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
+ "syntax: hh:mm:ss[:;.]ff\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ memset(tc, 0, sizeof(*tc));
+ tc->flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
+ tc->rate = rate;
+ tc->fps = fps_from_frame_rate(rate);
+
+ ret = check_timecode(log_ctx, tc);
+ if (ret < 0)
+ return ret;
+
+ tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
+ if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
+ int tmins = 60*hh + mm;
+ tc->start -= 2 * (tmins - tmins/10);
+ }
+ return 0;
+}
diff --git a/libavutil/timecode.h b/libavutil/timecode.h
new file mode 100644
index 0000000..41e56d6
--- /dev/null
+++ b/libavutil/timecode.h
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier at gmail.com>
+ * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch at 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 */
--
1.7.8.3
-------------- next part --------------
From f176bcecf088711f753bba5be71e0d85d569752e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <clement.boesch at smartjog.com>
Date: Tue, 31 Jan 2012 11:44:27 +0100
Subject: [PATCH 07/13] dv: use new public timecode API.
---
libavformat/dv.c | 38 ++++++++------------------------------
1 files changed, 8 insertions(+), 30 deletions(-)
diff --git a/libavformat/dv.c b/libavformat/dv.c
index 106a878..c6583a8 100644
--- a/libavformat/dv.c
+++ b/libavformat/dv.c
@@ -34,6 +34,7 @@
#include "libavcodec/dvdata.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
+#include "libavutil/timecode.h"
#include "dv.h"
#include "libavutil/avassert.h"
@@ -276,42 +277,19 @@ static int dv_extract_video_info(DVDemuxContext *c, uint8_t* frame)
return size;
}
-static int bcd2int(uint8_t bcd)
+static int dv_extract_timecode(DVDemuxContext* c, uint8_t* frame, char *tc)
{
- int low = bcd & 0xf;
- int high = bcd >> 4;
- if (low > 9 || high > 9)
- return -1;
- return low + 10*high;
-}
-
-static int dv_extract_timecode(DVDemuxContext* c, uint8_t* frame, char tc[32])
-{
- int hh, mm, ss, ff, drop_frame;
const uint8_t *tc_pack;
- tc_pack = dv_extract_pack(frame, dv_timecode);
- if (!tc_pack)
- return 0;
-
- ff = bcd2int(tc_pack[1] & 0x3f);
- ss = bcd2int(tc_pack[2] & 0x7f);
- mm = bcd2int(tc_pack[3] & 0x7f);
- hh = bcd2int(tc_pack[4] & 0x3f);
- drop_frame = tc_pack[1] >> 6 & 0x1;
-
- if (ff < 0 || ss < 0 || mm < 0 || hh < 0)
- return -1;
-
// For PAL systems, drop frame bit is replaced by an arbitrary
// bit so its value should not be considered. Drop frame timecode
// is only relevant for NTSC systems.
- if(c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50) {
- drop_frame = 0;
- }
+ int prevent_df = c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50;
- snprintf(tc, 32, "%02d:%02d:%02d%c%02d",
- hh, mm, ss, drop_frame ? ';' : ':', ff);
+ tc_pack = dv_extract_pack(frame, dv_timecode);
+ if (!tc_pack)
+ return 0;
+ av_timecode_make_smpte_tc_string(tc, AV_RB32(tc_pack + 1), prevent_df);
return 1;
}
@@ -455,7 +433,7 @@ typedef struct RawDVContext {
static int dv_read_timecode(AVFormatContext *s) {
int ret;
- char timecode[32];
+ char timecode[AV_TIMECODE_STR_SIZE];
int64_t pos = avio_tell(s->pb);
// Read 3 DIF blocks: Header block and 2 Subcode blocks.
--
1.7.8.3
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