[vlc-devel] [PATCH v6 1/3] access: srt: introduce srt input module

Justin Kim justin.kim at collabora.com
Thu Sep 14 11:43:38 CEST 2017


Secure Reliable Transport (SRT) is a proprietary transport technology
that optimizes streaming performance across unpredictable networks.
This patch is an imlementation of input module which works as a SRT
client based on SRT Library[0].

[0] https://github.com/Haivision/srt/releases

Signed-off-by: Justin Kim <justin.kim at collabora.com>
---
 NEWS                       |   1 +
 configure.ac               |   5 +
 modules/MODULES_LIST       |   1 +
 modules/access/Makefile.am |   9 ++
 modules/access/srt.c       | 312 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 328 insertions(+)
 create mode 100644 modules/access/srt.c

diff --git a/NEWS b/NEWS
index cab32bfd5a..31c61baab1 100644
--- a/NEWS
+++ b/NEWS
@@ -60,6 +60,7 @@ Access:
  * Improvements on DVB scanning
  * BluRay module can open ISO over network and has full BD-J support
  * Support for DVD ISO over network
+ * New SRT access module using libsrt
 
 Decoder:
  * OMX GPU-zerocopy support for decoding and display on Android using OpenMax IL
diff --git a/configure.ac b/configure.ac
index 5b7437b8df..0014629c92 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3881,6 +3881,11 @@ AS_IF([test "${enable_lirc}" = "yes"], [
 ])
 AM_CONDITIONAL([HAVE_LIRC], [test "${have_lirc}" = "yes"])
 
+dnl
+dnl  SRT plugin
+dnl
+PKG_ENABLE_MODULES_VLC([SRT], [access_srt], [srt >= 1.2.0], [SRT input plugin], [auto])
+
 EXTEND_HELP_STRING([Visualisations and Video filter plugins:])
 dnl
 dnl  goom visualization plugin
diff --git a/modules/MODULES_LIST b/modules/MODULES_LIST
index 28dac0289f..0e117115a7 100644
--- a/modules/MODULES_LIST
+++ b/modules/MODULES_LIST
@@ -17,6 +17,7 @@ $Id$
  * access_output_udp: UDP Network access_output module
  * access_qtsound: Quicktime Audio Capture
  * access_realrtsp: Real RTSP access
+ * access_srt: SRT(Secure Reliable Transport) access module
  * access_wasapi: WASAPI audio input
  * accesstweaks: access control tweaking module (dev tool)
  * adaptive: Unified adaptive streaming module (DASH/HLS)
diff --git a/modules/access/Makefile.am b/modules/access/Makefile.am
index dd485a2767..51ac1157c5 100644
--- a/modules/access/Makefile.am
+++ b/modules/access/Makefile.am
@@ -417,3 +417,12 @@ libaccess_mtp_plugin_la_LIBADD = $(MTP_LIBS)
 libaccess_mtp_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(accessdir)'
 access_LTLIBRARIES += $(LTLIBaccess_mtp)
 EXTRA_LTLIBRARIES += libaccess_mtp_plugin.la
+
+### SRT ###
+
+libaccess_srt_plugin_la_SOURCES = access/srt.c
+libaccess_srt_plugin_la_CPPFLAGS = $(AM_CPPFLAGS) $(SRT_CPPFLAGS)
+libaccess_srt_plugin_la_LIBADD = $(SRT_LIBS)
+libaccess_srt_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(accessdir)'
+access_LTLIBRARIES += $(LTLIBaccess_srt)
+EXTRA_LTLIBRARIES += libaccess_srt_plugin.la
diff --git a/modules/access/srt.c b/modules/access/srt.c
new file mode 100644
index 0000000000..ca38d3d6d6
--- /dev/null
+++ b/modules/access/srt.c
@@ -0,0 +1,312 @@
+/*****************************************************************************
+ * srt.c: SRT (Secure Reliable Transport) input module
+ *****************************************************************************
+ * Copyright (C) 2017, Collabora Ltd.
+ *
+ * Authors: Justin Kim <justin.kim at collabora.com>
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <errno.h>
+#include <sys/eventfd.h>
+#include <sys/epoll.h>
+
+#include <vlc_common.h>
+#include <vlc_interrupt.h>
+#include <vlc_plugin.h>
+#include <vlc_access.h>
+
+#include <vlc_network.h>
+#include <vlc_url.h>
+
+#include <srt/srt.h>
+
+/* libsrt defines default packet size as 1316 internally
+ * so srt module takes same value. */
+#define SRT_DEFAULT_CHUNK_SIZE 1316
+/* The default timeout is -1 (infinite) */
+#define SRT_DEFAULT_POLL_TIMEOUT -1
+
+struct stream_sys_t
+{
+    SRTSOCKET   sock;
+    int         i_poll_id;
+    int         i_poll_timeout;
+    size_t      i_chunk_size;
+    int         i_event_fd;
+    vlc_mutex_t lock;
+};
+
+static void srt_wait_interrupted(void *p_data)
+{
+    stream_t *p_stream = p_data;
+    stream_sys_t *p_sys = p_stream->p_sys;
+    vlc_mutex_lock( &p_sys->lock );
+    msg_Dbg( p_stream, "Waking up srt_epoll_wait");
+    if ( write( p_sys->i_event_fd, &( bool ) { true }, sizeof( bool ) ) < 0 )
+    {
+        msg_Err( p_stream, "Failed to send data to event fd");
+    }
+    vlc_mutex_unlock( &p_sys->lock );
+}
+
+static int Control(stream_t *p_stream, int i_query, va_list args)
+{
+    stream_sys_t *p_sys = p_stream->p_sys;
+    int i_ret = VLC_SUCCESS;
+
+    vlc_mutex_lock( &p_sys->lock );
+
+    switch( i_query )
+    {
+        case STREAM_CAN_SEEK:
+        case STREAM_CAN_FASTSEEK:
+        case STREAM_CAN_PAUSE:
+        case STREAM_CAN_CONTROL_PACE:
+            *va_arg( args, bool * ) = false;
+            break;
+        case STREAM_GET_PTS_DELAY:
+            *va_arg( args, int64_t * ) = INT64_C(1000)
+                   * var_InheritInteger(p_stream, "network-caching");
+            break;
+        default:
+            i_ret = VLC_EGENERIC;
+            break;
+    }
+
+    vlc_mutex_unlock( &p_sys->lock );
+
+    return i_ret;
+}
+
+static block_t *BlockSRT(stream_t *p_stream, bool *restrict eof)
+{
+    stream_sys_t *p_sys = p_stream->p_sys;
+
+    block_t *pkt = block_Alloc( p_sys->i_chunk_size );
+
+    if ( unlikely( pkt == NULL ) )
+    {   
+        return NULL;
+    }
+
+    vlc_interrupt_register( srt_wait_interrupted, p_stream);
+    vlc_mutex_lock( &p_sys->lock );
+
+    SRTSOCKET ready[2];
+    struct epoll_event event[1] = { 0 };
+
+    if ( srt_epoll_wait( p_sys->i_poll_id,
+        ready, &(int) { 2 }, 0, 0, p_sys->i_poll_timeout,
+        &(int) { p_sys->i_event_fd }, &(int) { 1 }, 0, 0 ) == -1 )
+    {
+        int srt_err = srt_getlasterror( NULL );
+
+        /* Assuming that timeout error is normal when SRT socket is connected. */
+        if ( srt_err == SRT_ETIMEOUT && srt_getsockstate( p_sys->sock ) == SRTS_CONNECTED )
+        {
+            goto skip;
+        }
+
+        msg_Err( p_stream, "released poll wait (reason : %s)", srt_getlasterror_str() );
+        goto endofstream;
+    }
+
+    if ( event[0].events & EPOLLIN ) {
+        bool cancel = 0;
+        int ret = read( event[0].data.fd, &cancel, sizeof( bool ) );
+        if ( ret < 0 )
+        {
+            goto skip;
+        }
+
+        if ( cancel )
+        {
+            msg_Dbg( p_stream, "Cancelled running" );
+            goto endofstream;
+        }
+    }
+
+    int stat = srt_recvmsg( p_sys->sock, (char *)pkt->p_buffer, p_sys->i_chunk_size );
+
+    if ( stat == SRT_ERROR )
+    {
+        msg_Err( p_stream, "failed to recevie SRT packet (reason: %s)", srt_getlasterror_str() );
+        goto endofstream;
+    }
+
+    pkt->i_buffer = stat;
+    vlc_mutex_unlock( &p_sys->lock );
+    vlc_interrupt_unregister();
+    return pkt;
+
+endofstream:
+    msg_Dbg( p_stream, "EOS");
+   *eof = true;
+skip:
+    block_Release(pkt);
+    srt_clearlasterror();
+    vlc_mutex_unlock( &p_sys->lock );
+    vlc_interrupt_unregister();
+
+    return NULL;
+}
+
+static int Open(vlc_object_t *p_this)
+{
+    stream_t     *p_stream = (stream_t*)p_this;
+    stream_sys_t *p_sys = NULL;
+    vlc_url_t     parsed_url = { 0 };
+    struct addrinfo hints = {
+        .ai_socktype = SOCK_DGRAM,
+    }, *res = NULL;
+    int stat;
+
+    p_sys = vlc_malloc( p_this, sizeof( *p_sys ) );
+    if( unlikely( p_sys == NULL ) )
+        return VLC_ENOMEM;
+
+    if ( vlc_UrlParse( &parsed_url, p_stream->psz_url ) == -1 )
+    {
+        msg_Err( p_stream, "Failed to parse a given URL (%s)", p_stream->psz_url );
+        goto failed;
+    }
+
+    p_sys->i_chunk_size = var_InheritInteger( p_stream, "chunk-size" );
+    p_sys->i_poll_timeout = var_InheritInteger( p_stream, "poll-timeout" );
+    p_sys->i_poll_id = -1;
+    p_sys->i_event_fd = -1;
+    p_stream->p_sys = p_sys;
+    p_stream->pf_block = BlockSRT;
+    p_stream->pf_control = Control;
+
+    vlc_mutex_init( &p_sys->lock );
+
+    stat = vlc_getaddrinfo( parsed_url.psz_host, parsed_url.i_port, &hints, &res );
+    if ( stat )
+    {
+        msg_Err( p_stream, "Cannot resolve [%s]:%d (reason: %s)",
+                 parsed_url.psz_host,
+                 parsed_url.i_port,
+                 gai_strerror( stat ) );
+            
+        goto failed;
+    }
+
+    p_sys->sock = srt_socket( res->ai_family, SOCK_DGRAM, 0 );
+    if ( p_sys->sock == SRT_ERROR )
+    {
+        msg_Err( p_stream, "Failed to open socket." );
+        goto failed;
+    }
+
+    /* Make SRT non-blocking */
+    srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN, &(bool) { false }, sizeof( bool ) );
+
+    p_sys->i_poll_id = srt_epoll_create();
+    if ( p_sys->i_poll_id == -1 )
+    {
+        msg_Err( p_stream, "Failed to create poll id for SRT socket." );
+        goto failed;
+    }
+    srt_epoll_add_usock( p_sys->i_poll_id, p_sys->sock, &(int) { SRT_EPOLL_IN } );
+
+    p_sys->i_event_fd = eventfd( 0, EFD_NONBLOCK );
+    srt_epoll_add_ssock( p_sys->i_poll_id, p_sys->i_event_fd, &(int) { EPOLLIN } );
+
+    stat = srt_connect( p_sys->sock, res->ai_addr, sizeof (struct sockaddr) );
+
+    if ( stat == SRT_ERROR )
+    {
+        msg_Err( p_stream, "Failed to connect to server." );
+        goto failed;
+    } 
+
+    vlc_UrlClean( &parsed_url );
+    freeaddrinfo( res );
+
+    return VLC_SUCCESS;
+
+failed:
+
+    if ( parsed_url.psz_host != NULL
+      && parsed_url.psz_buffer != NULL)
+    {
+        vlc_UrlClean( &parsed_url );
+    }
+
+    if ( res != NULL )
+    {
+        freeaddrinfo( res );
+    }
+
+    if ( p_sys->i_event_fd != -1 )
+    {
+        close( p_sys->i_event_fd );
+        p_sys->i_event_fd = -1;
+    }
+
+    if ( p_sys->i_poll_id != -1 )
+    {
+        srt_epoll_release( p_sys->i_poll_id );
+        p_sys->i_poll_id = -1;
+    }
+    srt_close( p_sys->sock );
+
+    return VLC_EGENERIC;
+}
+
+static void Close(vlc_object_t *p_this)
+{
+    stream_t     *p_stream = (stream_t*)p_this;
+    stream_sys_t *p_sys = p_stream->p_sys;
+
+    if ( p_sys->i_poll_id != -1 )
+    {
+        srt_epoll_release( p_sys->i_poll_id );
+        p_sys->i_poll_id = -1;
+    }
+    msg_Dbg( p_stream, "closing server" );
+    srt_close( p_sys->sock );
+
+    if ( p_sys->i_event_fd != -1 )
+    {
+        close( p_sys->i_event_fd );
+        p_sys->i_event_fd = -1;
+    }
+
+    vlc_mutex_destroy( &p_sys->lock );
+}
+
+/* Module descriptor */
+vlc_module_begin ()
+    set_shortname( N_("SRT") )
+    set_description( N_("SRT input") )
+    set_category( CAT_INPUT )
+    set_subcategory( SUBCAT_INPUT_ACCESS )
+
+    add_integer( "chunk-size", SRT_DEFAULT_CHUNK_SIZE, N_("SRT chunk size (bytes)"), NULL, true )
+    add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT, N_("Return poll wait after timeout miliseconds (-1 = infinite)"), NULL, true )
+
+    set_capability( "access", 0 )
+    add_shortcut( "srt" )
+
+    set_callbacks( Open, Close )
+vlc_module_end ()
-- 
2.14.1



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