avformat/libsrt: add snddropdelay parameter for srt

Reviewed-by: "zhilizhao(赵志立)" <quinkblack@foxmail.com>
Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

2 files changed, 13 insertions, 0 deletions

diff --git a/doc/protocols.texi b/doc/protocols.texi
index 726e5f1c44..c100f23f17 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -1496,6 +1496,12 @@ when the old encryption key is decommissioned. Default is -1.
 -1 means auto (0x1000 in srt library). The range for
 this option is integers in the 0 - @code{INT_MAX}.
 
+@item snddropdelay=@var{microseconds}
+The sender's extra delay before dropping packets. This delay is
+added to the default drop delay time interval value.
+
+Special value -1: Do not drop packets on the sender at all.
+
 @item payload_size=@var{bytes}
 Sets the maximum declared size of a packet transferred
 during the single call to the sending function in Live
diff --git a/libavformat/libsrt.c b/libavformat/libsrt.c
index c6308d1f6a..145eea2f7c 100644
--- a/libavformat/libsrt.c
+++ b/libavformat/libsrt.c
@@ -65,6 +65,7 @@ typedef struct SRTContext {
     int enforced_encryption;
     int kmrefreshrate;
     int kmpreannounce;
+    int64_t snddropdelay;
 #endif
     int mss;
     int ffs;
@@ -111,6 +112,7 @@ static const AVOption libsrt_options[] = {
     { "enforced_encryption", "Enforces that both connection parties have the same passphrase set",                              OFFSET(enforced_encryption), AV_OPT_TYPE_BOOL,  { .i64 = -1 }, -1, 1,         .flags = D|E },
     { "kmrefreshrate",       "The number of packets to be transmitted after which the encryption key is switched to a new key", OFFSET(kmrefreshrate),       AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
     { "kmpreannounce",       "The interval between when a new encryption key is sent and when switchover occurs",               OFFSET(kmpreannounce),       AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
+    { "snddropdelay",        "The sender's extra delay(in microseconds) before dropping packets",                                     OFFSET(snddropdelay),        AV_OPT_TYPE_INT64,   { .i64 = -2 }, -2, INT64_MAX,   .flags = D|E },
 #endif
     { "mss",            "The Maximum Segment Size",                                             OFFSET(mss),              AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, 1500,      .flags = D|E },
     { "ffs",            "Flight flag size (window size) (in bytes)",                            OFFSET(ffs),              AV_OPT_TYPE_INT,      { .i64 = -1 }, -1, INT_MAX,   .flags = D|E },
@@ -318,6 +320,7 @@ static int libsrt_set_options_pre(URLContext *h, int fd)
     int latency = s->latency / 1000;
     int rcvlatency = s->rcvlatency / 1000;
     int peerlatency = s->peerlatency / 1000;
+    int snddropdelay = s->snddropdelay > 0 ? s->snddropdelay / 1000 : s->snddropdelay;
     int connect_timeout = s->connect_timeout;
 
     if ((s->mode == SRT_MODE_RENDEZVOUS && libsrt_setsockopt(h, fd, SRTO_RENDEZVOUS, "SRTO_RENDEZVOUS", &yes, sizeof(yes)) < 0) ||
@@ -334,6 +337,7 @@ static int libsrt_set_options_pre(URLContext *h, int fd)
 #endif
         (s->kmrefreshrate >= 0 && libsrt_setsockopt(h, fd, SRTO_KMREFRESHRATE, "SRTO_KMREFRESHRATE", &s->kmrefreshrate, sizeof(s->kmrefreshrate)) < 0) ||
         (s->kmpreannounce >= 0 && libsrt_setsockopt(h, fd, SRTO_KMPREANNOUNCE, "SRTO_KMPREANNOUNCE", &s->kmpreannounce, sizeof(s->kmpreannounce)) < 0) ||
+        (s->snddropdelay  >=-1 && libsrt_setsockopt(h, fd, SRTO_SNDDROPDELAY,  "SRTO_SNDDROPDELAY",  &snddropdelay, sizeof(snddropdelay)) < 0) ||
 #endif
         (s->mss >= 0 && libsrt_setsockopt(h, fd, SRTO_MSS, "SRTO_MSS", &s->mss, sizeof(s->mss)) < 0) ||
         (s->ffs >= 0 && libsrt_setsockopt(h, fd, SRTO_FC, "SRTO_FC", &s->ffs, sizeof(s->ffs)) < 0) ||
@@ -549,6 +553,9 @@ static int libsrt_open(URLContext *h, const char *uri, int flags)
         if (av_find_info_tag(buf, sizeof(buf), "kmpreannounce", p)) {
             s->kmpreannounce = strtol(buf, NULL, 10);
         }
+        if (av_find_info_tag(buf, sizeof(buf), "snddropdelay", p)) {
+            s->snddropdelay = strtoll(buf, NULL, 10);
+        }
 #endif
         if (av_find_info_tag(buf, sizeof(buf), "mss", p)) {
             s->mss = strtol(buf, NULL, 10);