libavformat: Add a muxer wrapping mpegts encoding into RTP

Since this structurally is quite different from normal RTP
(multiple streams are muxed into one single mpegts stream,
which is packetized into one single RTP session), it is kept
as a separate muxer.

Since this structurally also behaves differently than normal
RTP, all of the other muxers that do chained RTP muxing
(rtsp, sap, mp4) would need to be updated similarly to handle
this - in particular, creating one single rtp_mpegts muxer
for the whole presentation instead of one rtp muxer per stream.
Signed-off-by: Martin Storsjö <martin@martin.st>

Changelog

@@ -8,6 +8,7 @@ version <next>:
 - XCB-based screen-grabber
 - creating DASH compatible fragmented MP4, MPEG-DASH segmenting muxer
 - H.261 RTP payload format (RFC 4587) depacketizer and experimental packetizer
+- RTP/mpegts muxer
 
 
 version 11:

libavformat/Makefile

@@ -287,6 +287,7 @@ OBJS-$(CONFIG_ROQ_MUXER)                 += idroqenc.o rawenc.o
 OBJS-$(CONFIG_RSO_DEMUXER)               += rsodec.o rso.o pcm.o
 OBJS-$(CONFIG_RSO_MUXER)                 += rsoenc.o rso.o
 OBJS-$(CONFIG_RPL_DEMUXER)               += rpl.o
+OBJS-$(CONFIG_RTP_MPEGTS_MUXER)          += rtpenc_mpegts.o
 OBJS-$(CONFIG_RTP_MUXER)                 += rtp.o         \
                                             rtpenc_aac.o     \
                                             rtpenc_latm.o    \

libavformat/allformats.c

@@ -212,6 +212,7 @@ void av_register_all(void)
     REGISTER_DEMUXER (RPL,              rpl);
     REGISTER_MUXDEMUX(RSO,              rso);
     REGISTER_MUXDEMUX(RTP,              rtp);
+    REGISTER_MUXER   (RTP_MPEGTS,       rtp_mpegts);
     REGISTER_MUXDEMUX(RTSP,             rtsp);
     REGISTER_MUXDEMUX(SAP,              sap);
     REGISTER_DEMUXER (SDP,              sdp);

libavformat/rtpenc_mpegts.c

+/*
+ * RTP/mpegts muxer
+ * Copyright (c) 2011 Martin Storsjo
+ *
+ * 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 "libavutil/mathematics.h"
+#include "avformat.h"
+
+struct MuxChain {
+    AVFormatContext *mpegts_ctx;
+    AVFormatContext *rtp_ctx;
+};
+
+static int rtp_mpegts_write_close(AVFormatContext *s)
+{
+    struct MuxChain *chain = s->priv_data;
+
+    if (chain->mpegts_ctx) {
+        if (!chain->mpegts_ctx->pb)
+            avio_open_dyn_buf(&chain->mpegts_ctx->pb);
+        if (chain->mpegts_ctx->pb) {
+            uint8_t *buf;
+            av_write_trailer(chain->mpegts_ctx);
+            avio_close_dyn_buf(chain->mpegts_ctx->pb, &buf);
+            av_free(buf);
+        }
+        avformat_free_context(chain->mpegts_ctx);
+    }
+    if (chain->rtp_ctx) {
+        av_write_trailer(chain->rtp_ctx);
+        avformat_free_context(chain->rtp_ctx);
+    }
+    return 0;
+}
+
+static int rtp_mpegts_write_header(AVFormatContext *s)
+{
+    struct MuxChain *chain = s->priv_data;
+    AVFormatContext *mpegts_ctx = NULL, *rtp_ctx = NULL;
+    AVOutputFormat *mpegts_format = av_guess_format("mpegts", NULL, NULL);
+    AVOutputFormat *rtp_format    = av_guess_format("rtp", NULL, NULL);
+    int i, ret = AVERROR(ENOMEM);
+    AVStream *st;
+
+    if (!mpegts_format || !rtp_format)
+        return AVERROR(ENOSYS);
+    mpegts_ctx = avformat_alloc_context();
+    if (!mpegts_ctx)
+        return AVERROR(ENOMEM);
+    mpegts_ctx->oformat   = mpegts_format;
+    mpegts_ctx->max_delay = s->max_delay;
+    for (i = 0; i < s->nb_streams; i++) {
+        AVStream* st = avformat_new_stream(mpegts_ctx, NULL);
+        if (!st)
+            goto fail;
+        st->time_base           = s->streams[i]->time_base;
+        st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
+        avcodec_copy_context(st->codec, s->streams[i]->codec);
+    }
+    if ((ret = avio_open_dyn_buf(&mpegts_ctx->pb)) < 0)
+        goto fail;
+    if ((ret = avformat_write_header(mpegts_ctx, NULL)) < 0)
+        goto fail;
+    for (i = 0; i < s->nb_streams; i++)
+        s->streams[i]->time_base = mpegts_ctx->streams[i]->time_base;
+
+    chain->mpegts_ctx = mpegts_ctx;
+    mpegts_ctx = NULL;
+
+    rtp_ctx = avformat_alloc_context();
+    if (!rtp_ctx) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+    rtp_ctx->oformat = rtp_format;
+    st = avformat_new_stream(rtp_ctx, NULL);
+    st->time_base.num   = 1;
+    st->time_base.den   = 90000;
+    st->codec->codec_id = AV_CODEC_ID_MPEG2TS;
+    chain->rtp_ctx = rtp_ctx;
+    rtp_ctx->pb = s->pb;
+    if ((ret = avformat_write_header(rtp_ctx, NULL)) < 0)
+        goto fail;
+    rtp_ctx = NULL;
+
+    return 0;
+
+fail:
+    if (mpegts_ctx) {
+        if (mpegts_ctx->pb) {
+            uint8_t *buf;
+            avio_close_dyn_buf(mpegts_ctx->pb, &buf);
+            av_free(buf);
+        }
+        avformat_free_context(mpegts_ctx);
+    }
+    if (rtp_ctx)
+        avformat_free_context(rtp_ctx);
+    rtp_mpegts_write_close(s);
+    return ret;
+}
+
+static int rtp_mpegts_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    struct MuxChain *chain = s->priv_data;
+    int ret = 0, size;
+    uint8_t *buf;
+    AVPacket local_pkt;
+
+    if (!chain->mpegts_ctx->pb) {
+        if ((ret = avio_open_dyn_buf(&chain->mpegts_ctx->pb)) < 0)
+            return ret;
+    }
+    if ((ret = av_write_frame(chain->mpegts_ctx, pkt)) < 0)
+        return ret;
+    size = avio_close_dyn_buf(chain->mpegts_ctx->pb, &buf);
+    chain->mpegts_ctx->pb = NULL;
+    if (size == 0) {
+        av_free(buf);
+        return 0;
+    }
+    av_init_packet(&local_pkt);
+    local_pkt.data         = buf;
+    local_pkt.size         = size;
+    local_pkt.stream_index = 0;
+    if (pkt->pts != AV_NOPTS_VALUE)
+        local_pkt.pts = av_rescale_q(pkt->pts,
+                                     s->streams[pkt->stream_index]->time_base,
+                                     chain->rtp_ctx->streams[0]->time_base);
+    if (pkt->dts != AV_NOPTS_VALUE)
+        local_pkt.dts = av_rescale_q(pkt->dts,
+                                     s->streams[pkt->stream_index]->time_base,
+                                     chain->rtp_ctx->streams[0]->time_base);
+    ret = av_write_frame(chain->rtp_ctx, &local_pkt);
+    av_free(buf);
+
+    return ret;
+}
+
+AVOutputFormat ff_rtp_mpegts_muxer = {
+    .name              = "rtp_mpegts",
+    .long_name         = NULL_IF_CONFIG_SMALL("RTP/mpegts output format"),
+    .priv_data_size    = sizeof(struct MuxChain),
+    .audio_codec       = AV_CODEC_ID_AAC,
+    .video_codec       = AV_CODEC_ID_MPEG4,
+    .write_header      = rtp_mpegts_write_header,
+    .write_packet      = rtp_mpegts_write_packet,
+    .write_trailer     = rtp_mpegts_write_close,
+};

libavformat/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
-#define LIBAVFORMAT_VERSION_MINOR  8
+#define LIBAVFORMAT_VERSION_MINOR  9
 #define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \