segment: introduce segmented chain muxer

It behaves similarly to image2 muxer

Changelog

@@ -109,6 +109,7 @@ easier to use. The changes are:
 - Dxtory capture format decoder
 - v410 QuickTime uncompressed 4:4:4 10-bit encoder and decoder
 - OpenMG Audio muxer
+- Simple segmenting muxer
 
 
 version 0.7:

doc/muxers.texi

@@ -90,6 +90,7 @@ avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
 
 See also the @ref{crc} muxer.
 
+@anchor{image2}
 @section image2
 
 Image file muxer.
@@ -267,4 +268,35 @@ For example a 3D WebM clip can be created using the following command line:
 avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm
 @end example
 
+@section segment
+
+Basic stream segmenter.
+
+The segmenter muxer outputs streams to a number of separate files of nearly
+fixed duration. Output filename pattern can be set in a fashion similar to
+@ref{image2}.
+
+Every segment starts with a video keyframe, if a video stream is present.
+The segment muxer works best with a single constant frame rate video.
+
+Optionally it can generate a flat list of the created segments, one segment
+per line.
+
+@table @option
+@item segment_format @var{format}
+Override the inner container format, by default it is guessed by the filename
+extension.
+@item segment_time @var{t}
+Set segment duration to @var{t} seconds.
+@item segment_list @var{name}
+Generate also a listfile named @var{name}.
+@item segment_list_size @var{size}
+Overwrite the listfile once it reaches @var{size} entries.
+@end table
+
+@example
+avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
+@end example
+
+
 @c man end MUXERS

libavformat/Makefile

@@ -268,6 +268,7 @@ OBJS-$(CONFIG_SAP_DEMUXER)               += sapdec.o
 OBJS-$(CONFIG_SAP_MUXER)                 += sapenc.o rtpenc_chain.o
 OBJS-$(CONFIG_SDP_DEMUXER)               += rtsp.o
 OBJS-$(CONFIG_SEGAFILM_DEMUXER)          += segafilm.o
+OBJS-$(CONFIG_SEGMENT_MUXER)             += segment.o
 OBJS-$(CONFIG_SHORTEN_DEMUXER)           += rawdec.o
 OBJS-$(CONFIG_SIFF_DEMUXER)              += siff.o
 OBJS-$(CONFIG_SMACKER_DEMUXER)           += smacker.o

libavformat/allformats.c

@@ -197,6 +197,7 @@ void av_register_all(void)
     av_register_rdt_dynamic_payload_handlers();
 #endif
     REGISTER_DEMUXER  (SEGAFILM, segafilm);
+    REGISTER_MUXER    (SEGMENT, segment);
     REGISTER_DEMUXER  (SHORTEN, shorten);
     REGISTER_DEMUXER  (SIFF, siff);
     REGISTER_DEMUXER  (SMACKER, smacker);

libavformat/segment.c

+/*
+ * Generic segmenter
+ * Copyright (c) 2011, Luca Barbato
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <strings.h>
+#include <float.h>
+
+#include "avformat.h"
+#include "internal.h"
+
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+#include "libavutil/avstring.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/mathematics.h"
+
+typedef struct {
+    const AVClass *class;  /**< Class for private options. */
+    int number;
+    AVFormatContext *avf;
+    char *format;          /**< Set by a private option. */
+    char *list;            /**< Set by a private option. */
+    float time;            /**< Set by a private option. */
+    int  size;             /**< Set by a private option. */
+    int64_t offset_time;
+    int64_t recording_time;
+    int has_video;
+    AVIOContext *pb;
+} SegmentContext;
+
+static int segment_start(AVFormatContext *s)
+{
+    SegmentContext *c = s->priv_data;
+    AVFormatContext *oc = c->avf;
+    int err = 0;
+
+    if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
+                              s->filename, c->number++) < 0)
+        return AVERROR(EINVAL);
+
+    if ((err = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
+                          &s->interrupt_callback, NULL)) < 0)
+        return err;
+
+    if (!oc->priv_data && oc->oformat->priv_data_size > 0) {
+        oc->priv_data = av_mallocz(oc->oformat->priv_data_size);
+        if (!oc->priv_data) {
+            avio_close(oc->pb);
+            return AVERROR(ENOMEM);
+        }
+        if (oc->oformat->priv_class) {
+            *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
+            av_opt_set_defaults(oc->priv_data);
+        }
+    }
+
+    if ((err = oc->oformat->write_header(oc)) < 0) {
+        goto fail;
+    }
+
+    return 0;
+
+fail:
+    avio_close(oc->pb);
+    av_freep(&oc->priv_data);
+
+    return err;
+}
+
+static int segment_end(AVFormatContext *oc)
+{
+    int ret = 0;
+
+    if (oc->oformat->write_trailer)
+        ret = oc->oformat->write_trailer(oc);
+
+    avio_close(oc->pb);
+    if (oc->oformat->priv_class)
+        av_opt_free(oc->priv_data);
+    av_freep(&oc->priv_data);
+
+    return ret;
+}
+
+static int seg_write_header(AVFormatContext *s)
+{
+    SegmentContext *seg = s->priv_data;
+    AVFormatContext *oc;
+    int ret, i;
+
+    seg->number = 0;
+    seg->offset_time = 0;
+    seg->recording_time = seg->time * 1000000;
+
+    if (seg->list)
+        if ((ret = avio_open2(&seg->pb, seg->list, AVIO_FLAG_WRITE,
+                              &s->interrupt_callback, NULL)) < 0)
+            return ret;
+
+    for (i = 0; i< s->nb_streams; i++)
+        seg->has_video +=
+            (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO);
+
+    if (seg->has_video > 1)
+        av_log(s, AV_LOG_WARNING,
+               "More than a single video stream present, "
+               "expect issues decoding it.\n");
+
+    oc = avformat_alloc_context();
+
+    if (!oc) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    oc->oformat = av_guess_format(seg->format, s->filename, NULL);
+
+    if (!oc->oformat) {
+        ret = AVERROR_MUXER_NOT_FOUND;
+        goto fail;
+    }
+    if (oc->oformat->flags & AVFMT_NOFILE) {
+        av_log(s, AV_LOG_ERROR, "format %s not supported.\n",
+               oc->oformat->name);
+        ret = AVERROR(EINVAL);
+        goto fail;
+    }
+
+    seg->avf = oc;
+
+    oc->streams = s->streams;
+    oc->nb_streams = s->nb_streams;
+
+    if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
+                              s->filename, seg->number++) < 0) {
+        ret = AVERROR(EINVAL);
+        goto fail;
+    }
+
+    if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
+                          &s->interrupt_callback, NULL)) < 0)
+        goto fail;
+
+    if ((ret = avformat_write_header(oc, NULL)) < 0) {
+        avio_close(oc->pb);
+        goto fail;
+    }
+
+    if (seg->list) {
+        avio_printf(seg->pb, "%s\n", oc->filename);
+        avio_flush(seg->pb);
+    }
+
+fail:
+    if (ret) {
+        oc->streams = NULL;
+        oc->nb_streams = 0;
+        if (seg->list)
+            avio_close(seg->pb);
+        avformat_free_context(oc);
+    }
+    return ret;
+}
+
+static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    SegmentContext *seg = s->priv_data;
+    AVFormatContext *oc = seg->avf;
+    AVStream *st = oc->streams[pkt->stream_index];
+    int64_t end_pts = seg->recording_time * seg->number;
+    int ret;
+
+    if ((seg->has_video && st->codec->codec_type == AVMEDIA_TYPE_VIDEO) &&
+        av_compare_ts(pkt->pts, st->time_base,
+                      end_pts, AV_TIME_BASE_Q) >= 0 &&
+        pkt->flags & AV_PKT_FLAG_KEY) {
+
+        av_log(s, AV_LOG_DEBUG, "Next segment starts at %d %"PRId64"\n",
+               pkt->stream_index, pkt->pts);
+
+        ret = segment_end(oc);
+
+        if (!ret)
+            ret = segment_start(s);
+
+        if (ret)
+            goto fail;
+
+        if (seg->list) {
+            avio_printf(seg->pb, "%s\n", oc->filename);
+            avio_flush(seg->pb);
+            if (!(seg->number % seg->size)) {
+                avio_close(seg->pb);
+                if ((ret = avio_open2(&seg->pb, seg->list, AVIO_FLAG_WRITE,
+                                      &s->interrupt_callback, NULL)) < 0)
+                    goto fail;
+
+            }
+        }
+    }
+
+    ret = oc->oformat->write_packet(oc, pkt);
+
+fail:
+    if (ret < 0) {
+        oc->streams = NULL;
+        oc->nb_streams = 0;
+        if (seg->list)
+            avio_close(seg->pb);
+        avformat_free_context(oc);
+    }
+
+    return ret;
+}
+
+static int seg_write_trailer(struct AVFormatContext *s)
+{
+    SegmentContext *seg = s->priv_data;
+    AVFormatContext *oc = seg->avf;
+    int ret = segment_end(oc);
+    if (seg->list)
+        avio_close(seg->pb);
+    oc->streams = NULL;
+    oc->nb_streams = 0;
+    avformat_free_context(oc);
+    return ret;
+}
+
+#define OFFSET(x) offsetof(SegmentContext, x)
+#define E AV_OPT_FLAG_ENCODING_PARAM
+static const AVOption options[] = {
+    { "segment_format",    "container format used for the segments",  OFFSET(format),  AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
+    { "segment_time",      "segment length in seconds",               OFFSET(time),    AV_OPT_TYPE_FLOAT,  {.dbl = 2},     0, FLT_MAX, E },
+    { "segment_list",      "output the segment list",                 OFFSET(list),    AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
+    { "segment_list_size", "maximum number of playlist entries",      OFFSET(size),    AV_OPT_TYPE_INT,    {.dbl = 5},     0, INT_MAX, E },
+    { NULL },
+};
+
+static const AVClass seg_class = {
+    .class_name = "segment muxer",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+
+AVOutputFormat ff_segment_muxer = {
+    .name           = "segment",
+    .long_name      = NULL_IF_CONFIG_SMALL("segment muxer"),
+    .priv_data_size = sizeof(SegmentContext),
+    .flags          = AVFMT_GLOBALHEADER | AVFMT_NOFILE,
+    .write_header   = seg_write_header,
+    .write_packet   = seg_write_packet,
+    .write_trailer  = seg_write_trailer,
+    .priv_class     = &seg_class,
+};