@@ -44,7 +44,7 @@ version <next>:

 - blackframe filter

 - Demuxer for Leitch/Harris' VR native stream format (LXF)

 - RTP depacketization of the X-QT QuickTime format

-- SAP (Session Announcement Protocol, RFC 2974) muxer

+- SAP (Session Announcement Protocol, RFC 2974) muxer and demuxer

 - cropdetect filter

@@ -1363,6 +1363,7 @@ ogg_demuxer_select="golomb"

 psp_muxer_select="mov_muxer"

 rtsp_demuxer_select="http_protocol sdp_demuxer"

 rtsp_muxer_select="rtp_muxer http_protocol sdp_demuxer"

+sap_demuxer_select="sdp_demuxer"

 sap_muxer_select="rtp_muxer rtp_protocol"

 sdp_demuxer_select="asf_demuxer rm_demuxer rtp_protocol mpegts_demuxer mov_demuxer"

 spdif_muxer_select="aac_parser"

@@ -217,7 +217,7 @@ library:

     @tab Output is performed by publishing stream to RTMP server

 @item RTP                       @tab X @tab

 @item RTSP                      @tab X @tab X

-@item SAP                       @tab X @tab

+@item SAP                       @tab X @tab X

 @item SDP                       @tab   @tab X

 @item Sega FILM/CPK             @tab   @tab X

     @tab Used in many Sega Saturn console games.

@@ -290,10 +290,12 @@ ffmpeg -re -i @var{input} -f rtsp -muxdelay 0.1 rtsp://server/live.sdp

 @section sap

 Session Announcement Protocol (RFC 2974). This is not technically a

-protocol handler in libavformat, it is a muxer.

+protocol handler in libavformat, it is a muxer and demuxer.

 It is used for signalling of RTP streams, by announcing the SDP for the

 streams regularly on a separate port.

+@subsection Muxer

+

 The syntax for a SAP url given to the muxer is:

 @example

 sap://@var{destination}[:@var{port}][?@var{options}]

@@ -325,6 +327,8 @@ If set to 1, send all RTP streams on the same port pair. If zero (the

 default), all streams are sent on unique ports, with each stream on a

 port 2 numbers higher than the previous.

 VLC/Live555 requires this to be set to 1, to be able to receive the stream.

+The RTP stack in libavformat for receiving requires all streams to be sent

+on unique ports.

 @end table

 Example command lines follow.

@@ -335,6 +339,46 @@ To broadcast a stream on the local subnet, for watching in VLC:

 ffmpeg -re -i @var{input} -f sap sap://224.0.0.255?same_port=1

 @end example

+Similarly, for watching in ffplay:

+

+@example

+ffmpeg -re -i @var{input} -f sap sap://224.0.0.255

+@end example

+

+And for watching in ffplay, over IPv6:

+

+@example

+ffmpeg -re -i @var{input} -f sap sap://[ff0e::1:2:3:4]

+@end example

+

+@subsection Demuxer

+

+The syntax for a SAP url given to the demuxer is:

+@example

+sap://[@var{address}][:@var{port}]

+@end example

+

+@var{address} is the multicast address to listen for announcements on,

+if omitted, the default 224.2.127.254 (sap.mcast.net) is used. @var{port}

+is the port that is listened on, 9875 if omitted.

+

+The demuxers listens for announcements on the given address and port.

+Once an announcement is received, it tries to receive that particular stream.

+

+Example command lines follow.

+

+To play back the first stream announced on the normal SAP multicast address:

+

+@example

+ffplay sap://

+@end example

+

+To play back the first stream announced on one the default IPv6 SAP multicast address:

+

+@example

+ffplay sap://[ff0e::2:7ffe]

+@end example

+

 @section tcp

 Trasmission Control Protocol.

@@ -231,6 +231,7 @@ OBJS-$(CONFIG_RTP_MUXER)                 += rtp.o         \

                                             avc.o

 OBJS-$(CONFIG_RTSP_DEMUXER)              += rtsp.o httpauth.o

 OBJS-$(CONFIG_RTSP_MUXER)                += rtsp.o rtspenc.o httpauth.o

+OBJS-$(CONFIG_SAP_DEMUXER)               += sapdec.o

 OBJS-$(CONFIG_SAP_MUXER)                 += sapenc.o rtpenc_chain.o

 OBJS-$(CONFIG_SDP_DEMUXER)               += rtsp.o        \

                                             rdt.o         \

@@ -181,7 +181,7 @@ void av_register_all(void)

     REGISTER_MUXDEMUX (RSO, rso);

     REGISTER_MUXER    (RTP, rtp);

     REGISTER_MUXDEMUX (RTSP, rtsp);

-    REGISTER_MUXER    (SAP, sap);

+    REGISTER_MUXDEMUX (SAP, sap);

     REGISTER_DEMUXER  (SDP, sdp);

 #if CONFIG_SDP_DEMUXER

     av_register_rtp_dynamic_payload_handlers();

@@ -22,7 +22,7 @@

 #define AVFORMAT_AVFORMAT_H

 #define LIBAVFORMAT_VERSION_MAJOR 52

-#define LIBAVFORMAT_VERSION_MINOR 81

+#define LIBAVFORMAT_VERSION_MINOR 82

 #define LIBAVFORMAT_VERSION_MICRO  0

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,238 @@

+/*

+ * Session Announcement Protocol (RFC 2974) demuxer

+ * Copyright (c) 2010 Martin Storsjo

+ *

+ * 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 "libavutil/avstring.h"

+#include "libavutil/intreadwrite.h"

+#include "network.h"

+#include "os_support.h"

+#include "internal.h"

+#if HAVE_SYS_SELECT_H

+#include <sys/select.h>

+#endif

+

+struct SAPState {

+    URLContext *ann_fd;

+    AVFormatContext *sdp_ctx;

+    ByteIOContext sdp_pb;

+    uint16_t hash;

+    char *sdp;

+    int eof;

+};

+

+static int sap_probe(AVProbeData *p)

+{

+    if (av_strstart(p->filename, "sap:", NULL))

+        return AVPROBE_SCORE_MAX;

+    return 0;

+}

+

+static int sap_read_close(AVFormatContext *s)

+{

+    struct SAPState *sap = s->priv_data;

+    if (sap->sdp_ctx)

+        av_close_input_stream(sap->sdp_ctx);

+    if (sap->ann_fd)

+        url_close(sap->ann_fd);

+    av_freep(&sap->sdp);

+    ff_network_close();

+    return 0;

+}

+

+static int sap_read_header(AVFormatContext *s,

+                           AVFormatParameters *ap)

+{

+    struct SAPState *sap = s->priv_data;

+    char host[1024], path[1024], url[1024];

+    uint8_t recvbuf[1500];

+    int port;

+    int ret, i;

+    AVInputFormat* infmt;

+

+    if (!ff_network_init())

+        return AVERROR(EIO);

+

+    av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,

+                 path, sizeof(path), s->filename);

+    if (port < 0)

+        port = 9875;

+

+    if (!host[0]) {

+        /* Listen for announcements on sap.mcast.net if no host was specified */

+        av_strlcpy(host, "224.2.127.254", sizeof(host));

+    }

+

+    ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",

+                port);

+    ret = url_open(&sap->ann_fd, url, URL_RDONLY);

+    if (ret)

+        goto fail;

+

+    while (1) {

+        int addr_type, auth_len;

+        int pos;

+

+        ret = url_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);

+        if (ret == AVERROR(EAGAIN))

+            continue;

+        if (ret < 0)

+            goto fail;

+        recvbuf[ret] = '\0'; /* Null terminate for easier parsing */

+        if (ret < 8) {

+            av_log(s, AV_LOG_WARNING, "Received too short packet\n");

+            continue;

+        }

+

+        if ((recvbuf[0] & 0xe0) != 0x20) {

+            av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "

+                                      "received\n");

+            continue;

+        }

+

+        if (recvbuf[0] & 0x04) {

+            av_log(s, AV_LOG_WARNING, "Received stream deletion "

+                                      "announcement\n");

+            continue;

+        }

+        addr_type = recvbuf[0] & 0x10;

+        auth_len  = recvbuf[1];

+        sap->hash = AV_RB16(&recvbuf[2]);

+        pos = 4;

+        if (addr_type)

+            pos += 16; /* IPv6 */

+        else

+            pos += 4; /* IPv4 */

+        pos += auth_len * 4;

+        if (pos + 4 >= ret) {

+            av_log(s, AV_LOG_WARNING, "Received too short packet\n");

+            continue;

+        }

+#define MIME "application/sdp"

+        if (strcmp(&recvbuf[pos], MIME) == 0) {

+            pos += strlen(MIME) + 1;

+        } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {

+            // Direct SDP without a mime type

+        } else {

+            av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",

+                                      &recvbuf[pos]);

+            continue;

+        }

+

+        sap->sdp = av_strdup(&recvbuf[pos]);

+        break;

+    }

+

+    av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);

+    init_put_byte(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,

+                  NULL, NULL);

+

+    infmt = av_find_input_format("sdp");

+    if (!infmt)

+        goto fail;

+    sap->sdp_ctx = avformat_alloc_context();

+    if (!sap->sdp_ctx) {

+        ret = AVERROR(ENOMEM);

+        goto fail;

+    }

+    sap->sdp_ctx->max_delay = s->max_delay;

+    ap->prealloced_context = 1;

+    ret = av_open_input_stream(&sap->sdp_ctx, &sap->sdp_pb, "temp.sdp",

+                               infmt, ap);

+    if (ret < 0)

+        goto fail;

+    if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)

+        s->ctx_flags |= AVFMTCTX_NOHEADER;

+    for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {

+        AVStream *st = av_new_stream(s, i);

+        if (!st) {

+            ret = AVERROR(ENOMEM);

+            goto fail;

+        }

+        avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);

+        st->time_base = sap->sdp_ctx->streams[i]->time_base;

+    }

+

+    return 0;

+

+fail:

+    sap_read_close(s);

+    return ret;

+}

+

+static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)

+{

+    struct SAPState *sap = s->priv_data;

+    int fd = url_get_file_handle(sap->ann_fd);

+    int n, ret;

+    fd_set rfds;

+    struct timeval tv;

+    uint8_t recvbuf[1500];

+

+    if (sap->eof)

+        return AVERROR_EOF;

+

+    while (1) {

+        FD_ZERO(&rfds);

+        FD_SET(fd, &rfds);

+        tv.tv_sec = tv.tv_usec = 0;

+        n = select(fd + 1, &rfds, NULL, NULL, &tv);

+        if (n <= 0 || !FD_ISSET(fd, &rfds))

+            break;

+        ret = url_read(sap->ann_fd, recvbuf, sizeof(recvbuf));

+        if (ret >= 8) {

+            uint16_t hash = AV_RB16(&recvbuf[2]);

+            /* Should ideally check the source IP address, too */

+            if (recvbuf[0] & 0x04 && hash == sap->hash) {

+                /* Stream deletion */

+                sap->eof = 1;

+                return AVERROR_EOF;

+            }

+        }

+    }

+    ret = av_read_frame(sap->sdp_ctx, pkt);

+    if (ret < 0)

+        return ret;

+    if (s->ctx_flags & AVFMTCTX_NOHEADER) {

+        while (sap->sdp_ctx->nb_streams > s->nb_streams) {

+            int i = s->nb_streams;

+            AVStream *st = av_new_stream(s, i);

+            if (!st) {

+                av_free_packet(pkt);

+                return AVERROR(ENOMEM);

+            }

+            avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);

+            st->time_base = sap->sdp_ctx->streams[i]->time_base;

+        }

+    }

+    return ret;

+}

+

+AVInputFormat sap_demuxer = {

+    "sap",

+    NULL_IF_CONFIG_SMALL("SAP input format"),

+    sizeof(struct SAPState),

+    sap_probe,

+    sap_read_header,

+    sap_fetch_packet,

+    sap_read_close,

+    .flags = AVFMT_NOFILE,

+};

+