Metadata muxer

Dumps all metadata to a text file for easy manual editing.

Originally committed as revision 26101 to svn://svn.ffmpeg.org/ffmpeg/trunk

Makefile

@@ -116,7 +116,7 @@ documentation: $(addprefix doc/, developer.html faq.html general.html libavfilte
 
 $(HTMLPAGES) $(PODPAGES): doc/fftools-common-opts.texi
 
-doc/ffmpeg.pod doc/ffmpeg.html: doc/bitstream_filters.texi doc/eval.texi doc/indevs.texi doc/filters.texi doc/outdevs.texi doc/protocols.texi
+doc/ffmpeg.pod doc/ffmpeg.html: doc/bitstream_filters.texi doc/eval.texi doc/indevs.texi doc/filters.texi doc/outdevs.texi doc/protocols.texi doc/metadata.texi
 doc/ffplay.pod doc/ffplay.html: doc/eval.texi doc/indevs.texi doc/filters.texi doc/outdevs.texi doc/protocols.texi
 doc/ffprobe.pod doc/ffprobe.html: doc/indevs.texi doc/protocols.texi
 doc/libavfilter.html: doc/filters.texi

doc/ffmpeg.texi

@@ -949,6 +949,7 @@ file to which you want to add them.
 @include protocols.texi
 @include bitstream_filters.texi
 @include filters.texi
+@include metadata.texi
 
 @ignore
 

doc/general.texi

@@ -118,6 +118,8 @@ library:
     @tab VR native stream format, used by Leitch/Harris' video servers.
 @item Matroska                  @tab X @tab X
 @item Matroska audio            @tab X @tab
+@item FFmpeg metadata           @tab X @tab
+    @tab Metadata in text format.
 @item MAXIS XA                  @tab   @tab X
     @tab Used in Sim City 3000; file extension .xa.
 @item MD Studio                 @tab   @tab X

doc/metadata.texi

+@chapter Metadata
+@c man begin METADATA
+
+FFmpeg is able to dump metadata from media files into a simple UTF-8-encoded
+INI-like text file and then load it back using the metadata muxer/demuxer.
+
+The file format is as follows:
+@enumerate
+
+@item
+A file consists of a header and a number of metadata tags divided into sections,
+each on its own line.
+
+@item
+The header is a ';FFMETADATA' string, followed by a version number (now 1).
+
+@item
+Metadata tags are of the form 'key=value'
+
+@item
+Immediately after header follows global metadata
+
+@item
+After global metadata there may be sections with per-stream/per-chapter
+metadata.
+
+@item
+A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in
+brackets ('[', ']') and ends with next section or end of file.
+
+@item
+At the beginning of a chapter section there may be an optional timebase to be
+used for start/end values. It must be in form 'TIMEBASE=num/den', where num and
+den are integers. If the timebase is missing then start/end times are assumed to
+be in milliseconds.
+Next a chapter section must contain chapter start and end times in form
+'START=num', 'END=num', where num is a positive integer.
+
+@item
+Empty lines and lines starting with ';' or '#' are ignored.
+
+@item
+Metadata keys or values containing special characters ('=', ';', '#', '\' and a
+newline) must be escaped with a backslash '\'.
+
+@item
+Note that whitespace in metadata (e.g. foo = bar) is considered to be a part of
+the tag (in the example above key is 'foo ', value is ' bar').
+@end enumerate
+
+A ffmetadata file might look like this:
+@example
+;FFMETADATA1
+title=bike\\shed
+;this is a comment
+artist=FFmpeg troll team
+
+[CHAPTER]
+TIMEBASE=1/1000
+START=0
+#chapter ends at 0:01:00
+END=60000
+title=chapter \#1
+[STREAM]
+title=multi\
+line
+@end example
+@c man end METADATA

libavformat/Makefile

@@ -71,6 +71,7 @@ OBJS-$(CONFIG_EAC3_DEMUXER)              += ac3dec.o rawdec.o
 OBJS-$(CONFIG_EAC3_MUXER)                += rawenc.o
 OBJS-$(CONFIG_FFM_DEMUXER)               += ffmdec.o
 OBJS-$(CONFIG_FFM_MUXER)                 += ffmenc.o
+OBJS-$(CONFIG_FFMETADATA_MUXER)          += metaenc.o
 OBJS-$(CONFIG_FILMSTRIP_DEMUXER)         += filmstripdec.o
 OBJS-$(CONFIG_FILMSTRIP_MUXER)           += filmstripenc.o
 OBJS-$(CONFIG_FLAC_DEMUXER)              += flacdec.o rawdec.o \

libavformat/allformats.c

@@ -85,6 +85,7 @@ void av_register_all(void)
     REGISTER_DEMUXER  (EA_CDATA, ea_cdata);
     REGISTER_MUXDEMUX (EAC3, eac3);
     REGISTER_MUXDEMUX (FFM, ffm);
+    REGISTER_MUXER    (FFMETADATA, ffmetadata);
     REGISTER_MUXDEMUX (FILMSTRIP, filmstrip);
     REGISTER_MUXDEMUX (FLAC, flac);
     REGISTER_DEMUXER  (FLIC, flic);

libavformat/meta.h

+/*
+ * Common data for metadata muxer/demuxer
+ * Copyright (c) 2010 Anton Khirnov
+ *
+ * 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
+ */
+
+#ifndef AVFORMAT_META_H
+#define AVFORMAT_META_H
+
+#define ID_STRING  ";FFMETADATA"
+#define ID_CHAPTER "[CHAPTER]"
+#define ID_STREAM  "[STREAM]"
+
+#endif /* AVFORMAT_META_H */

libavformat/metaenc.c

+/*
+ * Metadata muxer
+ * Copyright (c) 2010 Anton Khirnov
+ *
+ * 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 "avformat.h"
+#include "meta.h"
+
+
+static void write_escape_str(ByteIOContext *s, const uint8_t *str)
+{
+    const uint8_t *p = str;
+
+    while (*p) {
+        if (*p == '#' || *p == ';' || *p == '=' || *p == '\\' || *p == '\n')
+            put_byte(s, '\\');
+        put_byte(s, *p);
+        p++;
+    }
+}
+
+static void write_tags(ByteIOContext *s, AVMetadata *m)
+{
+    AVMetadataTag *t = NULL;
+    while ((t = av_metadata_get(m, "", t, AV_METADATA_IGNORE_SUFFIX))) {
+        write_escape_str(s, t->key);
+        put_byte(s, '=');
+        write_escape_str(s, t->value);
+        put_byte(s, '\n');
+    }
+}
+
+static int write_header(AVFormatContext *s)
+{
+    put_tag(s->pb, ID_STRING);
+    put_byte(s->pb, '1');          // version
+    put_byte(s->pb, '\n');
+    put_flush_packet(s->pb);
+    return 0;
+}
+
+static int write_trailer(AVFormatContext *s)
+{
+    int i;
+
+    write_tags(s->pb, s->metadata);
+
+    for (i = 0; i < s->nb_streams; i++) {
+        put_tag(s->pb, ID_STREAM);
+        put_byte(s->pb, '\n');
+        write_tags(s->pb, s->streams[i]->metadata);
+    }
+
+    for (i = 0; i < s->nb_chapters; i++) {
+        AVChapter *ch = s->chapters[i];
+        put_tag(s->pb, ID_CHAPTER);
+        put_byte(s->pb, '\n');
+        url_fprintf(s->pb, "TIMEBASE=%d/%d\n", ch->time_base.num, ch->time_base.den);
+        url_fprintf(s->pb, "START=%lld\n", ch->start);
+        url_fprintf(s->pb, "END=%lld\n",   ch->end);
+        write_tags(s->pb, ch->metadata);
+    }
+
+    put_flush_packet(s->pb);
+
+    return 0;
+}
+
+static int write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    return 0;
+}
+
+AVOutputFormat ffmetadata_muxer = {
+    .name          = "ffmetadata",
+    .long_name     = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text format"),
+    .extensions    = "ffmeta",
+    .video_codec   = CODEC_ID_NONE,
+    .audio_codec   = CODEC_ID_NONE,
+    .write_header  = write_header,
+    .write_packet  = write_packet,
+    .write_trailer = write_trailer,
+    .flags         = AVFMT_NOTIMESTAMPS | AVFMT_NOSTREAMS,
+};