lavf: add tee pseudo-muxer.

Changelog

@@ -14,6 +14,7 @@ version <next>:
   and treble audio filter
 - improved showspectrum filter, with multichannel support and sox-like colors
 - histogram filter
+- tee muxer
 
 
 version 1.1:

doc/muxers.texi

@@ -749,4 +749,39 @@ situations, giving a small seek granularity at the cost of additional container
 overhead.
 @end table
 
+@section tee
+
+The tee muxer can be used to write the same data to several files or any
+other kind of muxer. It can be used, for example, to both stream a video to
+the network and save it to disk at the same time.
+
+It is different from specifying several outputs to the @command{ffmpeg}
+command-line tool because the audio and video data will be encoded only once
+with the tee muxer; encoding can be a very expensive process. It is not
+useful when using the libavformat API directly because it is then possible
+to feed the same packets to several muxers directly.
+
+The slave outputs are specified in the file name given to the muxer,
+separated by '|'. If any of the slave name contains the '|' separator,
+leading or trailing spaces or any special character, it must be
+@ref{quoting_and_escaping, escaped}.
+
+Options can be specified for each slave by prepending them as a list of
+@var{key}=@var{value} pairs separated by ':', between square brackets. If
+the options values contain a special character or the ':' separator, they
+must be @ref{quoting_and_escaping, escaped}; note that this is a second
+level escaping.
+
+Example: encode something and both archive it in a WebM file and stream it
+as MPEG-TS over UDP:
+
+@example
+ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee
+  "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"
+@end example
+
+Note: some codecs may need different options depending on the output format;
+the auto-detection of this can not work with the tee muxer. The main example
+is the @option{global_header} flag.
+
 @c man end MUXERS

libavformat/Makefile

@@ -358,6 +358,7 @@ OBJS-$(CONFIG_SWF_DEMUXER)               += swfdec.o swf.o
 OBJS-$(CONFIG_SWF_MUXER)                 += swfenc.o swf.o
 OBJS-$(CONFIG_TAK_DEMUXER)               += takdec.o apetag.o img2.o rawdec.o
 OBJS-$(CONFIG_TEDCAPTIONS_DEMUXER)       += tedcaptionsdec.o
+OBJS-$(CONFIG_TEE_MUXER)                 += tee.o
 OBJS-$(CONFIG_THP_DEMUXER)               += thp.o
 OBJS-$(CONFIG_TIERTEXSEQ_DEMUXER)        += tiertexseq.o
 OBJS-$(CONFIG_MKVTIMESTAMP_V2_MUXER)     += mkvtimestamp_v2.o

libavformat/allformats.c

@@ -263,6 +263,7 @@ void av_register_all(void)
     REGISTER_DEMUXER (SUBVIEWER,        subviewer);
     REGISTER_MUXDEMUX(SWF,              swf);
     REGISTER_DEMUXER (TAK,              tak);
+    REGISTER_MUXER   (TEE, tee);
     REGISTER_DEMUXER (TEDCAPTIONS,      tedcaptions);
     REGISTER_MUXER   (TG2,              tg2);
     REGISTER_MUXER   (TGP,              tgp);

libavformat/tee.c

@@ -0,0 +1,278 @@
+/*
+ * Tee pesudo-muxer
+ * Copyright (c) 2012 Nicolas George
+ *
+ * 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 "libavutil/avutil.h"
+#include "libavutil/avstring.h"
+#include "libavutil/opt.h"
+#include "avformat.h"
+
+#define MAX_SLAVES 16
+
+typedef struct TeeContext {
+    const AVClass *class;
+    unsigned nb_slaves;
+    AVFormatContext *slaves[MAX_SLAVES];
+} TeeContext;
+
+static const char *const slave_delim     = "|";
+static const char *const slave_opt_open  = "[";
+static const char *const slave_opt_close = "]";
+static const char *const slave_opt_delim = ":]"; /* must have the close too */
+
+static const AVClass tee_muxer_class = {
+    .class_name = "Tee muxer",
+    .item_name  = av_default_item_name,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static int parse_slave_options(void *log, char *slave,
+                               AVDictionary **options, char **filename)
+{
+    const char *p;
+    char *key, *val;
+    int ret;
+
+    if (!strspn(slave, slave_opt_open)) {
+        *filename = slave;
+        return 0;
+    }
+    p = slave + 1;
+    if (strspn(p, slave_opt_close)) {
+        *filename = (char *)p + 1;
+        return 0;
+    }
+    while (1) {
+        ret = av_opt_get_key_value(&p, "=", slave_opt_delim, 0, &key, &val);
+        if (ret < 0) {
+            av_log(log, AV_LOG_ERROR, "No option found near \"%s\"\n", p);
+            goto fail;
+        }
+        ret = av_dict_set(options, key, val,
+                          AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
+        if (ret < 0)
+            goto fail;
+        if (strspn(p, slave_opt_close))
+            break;
+        p++;
+    }
+    *filename = (char *)p + 1;
+    return 0;
+
+fail:
+    av_dict_free(options);
+    return ret;
+}
+
+static int open_slave(AVFormatContext *avf, char *slave, AVFormatContext **ravf)
+{
+    int i, ret;
+    AVDictionary *options = NULL;
+    AVDictionaryEntry *entry;
+    char *filename;
+    char *format = NULL;
+    AVFormatContext *avf2 = NULL;
+    AVStream *st, *st2;
+
+    if ((ret = parse_slave_options(avf, slave, &options, &filename)) < 0)
+        return ret;
+    if ((entry = av_dict_get(options, "f", NULL, 0))) {
+        format = entry->value;
+        entry->value = NULL; /* prevent it from being freed */
+        av_dict_set(&options, "f", NULL, 0);
+    }
+
+    avformat_alloc_output_context2(&avf2, NULL, format, filename);
+    if (ret < 0)
+        goto fail;
+    av_free(format);
+
+    for (i = 0; i < avf->nb_streams; i++) {
+        st = avf->streams[i];
+        if (!(st2 = avformat_new_stream(avf2, NULL))) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        st2->id = st->id;
+        st2->r_frame_rate        = st->r_frame_rate;
+        st2->time_base           = st->time_base;
+        st2->start_time          = st->start_time;
+        st2->duration            = st->duration;
+        st2->nb_frames           = st->nb_frames;
+        st2->disposition         = st->disposition;
+        st2->sample_aspect_ratio = st->sample_aspect_ratio;
+        st2->avg_frame_rate      = st->avg_frame_rate;
+        av_dict_copy(&st2->metadata, st->metadata, 0);
+        if ((ret = avcodec_copy_context(st2->codec, st->codec)) < 0)
+            goto fail;
+    }
+
+    if (!(avf2->oformat->flags & AVFMT_NOFILE)) {
+        if ((ret = avio_open(&avf2->pb, filename, AVIO_FLAG_WRITE)) < 0) {
+            av_log(avf, AV_LOG_ERROR, "Slave '%s': error opening: %s\n",
+                   slave, av_err2str(ret));
+            goto fail;
+        }
+    }
+
+    if ((ret = avformat_write_header(avf2, &options)) < 0) {
+        av_log(avf, AV_LOG_ERROR, "Slave '%s': error writing header: %s\n",
+               slave, av_err2str(ret));
+        goto fail;
+    }
+    if (options) {
+        entry = NULL;
+        while ((entry = av_dict_get(options, "", entry, AV_DICT_IGNORE_SUFFIX)))
+            av_log(avf2, AV_LOG_ERROR, "Unknown option '%s'\n", entry->key);
+        ret = AVERROR_OPTION_NOT_FOUND;
+        goto fail;
+    }
+
+    *ravf = avf2;
+    return 0;
+
+fail:
+    av_dict_free(&options);
+    return ret;
+}
+
+static void close_slaves(AVFormatContext *avf)
+{
+    TeeContext *tee = avf->priv_data;
+    AVFormatContext *avf2;
+    unsigned i;
+
+    for (i = 0; i < tee->nb_slaves; i++) {
+        avf2 = tee->slaves[i];
+        avio_close(avf2->pb);
+        avf2->pb = NULL;
+        avformat_free_context(avf2);
+        tee->slaves[i] = NULL;
+    }
+}
+
+static int tee_write_header(AVFormatContext *avf)
+{
+    TeeContext *tee = avf->priv_data;
+    unsigned nb_slaves = 0, i;
+    const char *filename = avf->filename;
+    char *slaves[MAX_SLAVES];
+    int ret;
+
+    while (*filename) {
+        if (nb_slaves == MAX_SLAVES) {
+            av_log(avf, AV_LOG_ERROR, "Maximum %d slave muxers reached.\n",
+                   MAX_SLAVES);
+            ret = AVERROR_PATCHWELCOME;
+            goto fail;
+        }
+        if (!(slaves[nb_slaves++] = av_get_token(&filename, slave_delim))) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        if (strspn(filename, slave_delim))
+            filename++;
+    }
+
+    for (i = 0; i < nb_slaves; i++) {
+        if ((ret = open_slave(avf, slaves[i], &tee->slaves[i])) < 0)
+            goto fail;
+        av_freep(&slaves[i]);
+    }
+
+    tee->nb_slaves = nb_slaves;
+    return 0;
+
+fail:
+    for (i = 0; i < nb_slaves; i++)
+        av_freep(&slaves[i]);
+    close_slaves(avf);
+    return ret;
+}
+
+static int tee_write_trailer(AVFormatContext *avf)
+{
+    TeeContext *tee = avf->priv_data;
+    AVFormatContext *avf2;
+    int ret_all = 0, ret;
+    unsigned i;
+
+    for (i = 0; i < tee->nb_slaves; i++) {
+        avf2 = tee->slaves[i];
+        if ((ret = av_write_trailer(avf2)) < 0)
+            if (!ret_all)
+                ret_all = ret;
+        if (!(avf2->oformat->flags & AVFMT_NOFILE)) {
+            if ((ret = avio_close(avf2->pb)) < 0)
+                if (!ret_all)
+                    ret_all = ret;
+            avf2->pb = NULL;
+        }
+    }
+    close_slaves(avf);
+    return ret_all;
+}
+
+static int tee_write_packet(AVFormatContext *avf, AVPacket *pkt)
+{
+    TeeContext *tee = avf->priv_data;
+    AVFormatContext *avf2;
+    AVPacket pkt2;
+    int ret_all = 0, ret;
+    unsigned i, s;
+    AVRational tb, tb2;
+
+    for (i = 0; i < tee->nb_slaves; i++) {
+        avf2 = tee->slaves[i];
+        s = pkt->stream_index;
+        if (s >= avf2->nb_streams) {
+            if (!ret_all)
+                ret_all = AVERROR(EINVAL);
+            continue;
+        }
+        if ((ret = av_copy_packet(&pkt2, pkt)) < 0 ||
+            (ret = av_dup_packet(&pkt2))< 0)
+            if (!ret_all) {
+                ret = ret_all;
+                continue;
+            }
+        tb  = avf ->streams[s]->time_base;
+        tb2 = avf2->streams[s]->time_base;
+        pkt2.pts      = av_rescale_q(pkt->pts,      tb, tb2);
+        pkt2.dts      = av_rescale_q(pkt->dts,      tb, tb2);
+        pkt2.duration = av_rescale_q(pkt->duration, tb, tb2);
+        if ((ret = av_interleaved_write_frame(avf2, &pkt2)) < 0)
+            if (!ret_all)
+                ret_all = ret;
+    }
+    return ret_all;
+}
+
+AVOutputFormat ff_tee_muxer = {
+    .name              = "tee",
+    .long_name         = NULL_IF_CONFIG_SMALL("Multiple muxer tee"),
+    .priv_data_size    = sizeof(TeeContext),
+    .write_header      = tee_write_header,
+    .write_trailer     = tee_write_trailer,
+    .write_packet      = tee_write_packet,
+    .priv_class        = &tee_muxer_class,
+    .flags             = AVFMT_NOFILE,
+};

libavformat/version.h

@@ -30,8 +30,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 54
-#define LIBAVFORMAT_VERSION_MINOR 61
-#define LIBAVFORMAT_VERSION_MICRO 104
+#define LIBAVFORMAT_VERSION_MINOR 62
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \