From b78e9bc5626e663681fc5d58690debe34022d079 Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Thu, 14 Nov 2013 12:24:11 +0100
Subject: [PATCH] Finally fixed long standing RTMP sync issue. Also added
 support for getting/setting FLV tag offsets.

---
 lib/flv_tag.cpp    | 28 +++++++++++++++++++++-------
 lib/flv_tag.h      |  6 ++++--
 lib/rtmpchunks.cpp |  5 ++++-
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/lib/flv_tag.cpp b/lib/flv_tag.cpp
index 6f296941..49643ba1 100644
--- a/lib/flv_tag.cpp
+++ b/lib/flv_tag.cpp
@@ -262,6 +262,25 @@ std::string FLV::Tag::tagType(){
   return R.str();
 } //FLV::Tag::tagtype
 
+/// Returns the 24-bit offset of this tag.
+/// Returns 0 if the tag isn't H264
+int FLV::Tag::offset(){
+  if (data[11] & 0x0F == 7){
+    return (((data[13] << 16) + (data[14] << 8) + data[15]) << 8) >> 8;
+  }else{
+    return 0;
+  }
+} //offset getter
+
+/// Sets the 24-bit offset of this tag.
+/// Ignored if the tag isn't H264
+void FLV::Tag::offset(int o){
+  if (data[11] & 0x0F != 7){return;}
+  data[13] = (o >> 16) & 0xFF;
+  data[14] = (o >> 8) & 0XFF;
+  data[15] = o & 0xFF;
+} //offset setter
+
 /// Returns the 32-bit timestamp of this tag.
 unsigned int FLV::Tag::tagTime(){
   return (data[4] << 16) + (data[5] << 8) + data[6] + (data[7] << 24);
@@ -401,10 +420,7 @@ bool FLV::Tag::DTSCLoader(DTSC::Stream & S){
           }else{
             data[12] = 2;
           }
-          int offset = S.getPacket()["offset"].asInt();
-          data[13] = (offset >> 16) & 0xFF;
-          data[14] = (offset >> 8) & 0XFF;
-          data[15] = offset & 0xFF;
+          offset(S.getPacket()["offset"].asInt());
         }
         data[11] = 0;
         if (track.isMember("codec") && track["codec"].asStringRef() == "H264"){
@@ -1174,9 +1190,7 @@ JSON::Value FLV::Tag::toJSON(JSON::Value & metadata){
           pack_out["nalu_end"] = 1;
           break;
       }
-      int offset = (data[13] << 16) + (data[14] << 8) + data[15];
-      offset = (offset << 8) >> 8;
-      pack_out["offset"] = offset;
+      pack_out["offset"] = offset();
       if (len < 21){
         return JSON::Value();
       }
diff --git a/lib/flv_tag.h b/lib/flv_tag.h
index b2815aee..1c1e0446 100644
--- a/lib/flv_tag.h
+++ b/lib/flv_tag.h
@@ -35,8 +35,10 @@ namespace FLV {
       const char * getAudioCodec(); ///< Returns a c-string with the audio codec name.
       const char * getVideoCodec(); ///< Returns a c-string with the video codec name.
       std::string tagType(); ///< Returns a std::string describing the tag in detail.
-      unsigned int tagTime(); ///< Returns the 32-bit timestamp of this tag.
-      void tagTime(unsigned int T); ///< Sets the 32-bit timestamp of this tag.
+      unsigned int tagTime();
+      void tagTime(unsigned int T);
+      int offset();
+      void offset(int o);
       Tag(); ///< Constructor for a new, empty, tag.
       Tag(const Tag& O); ///< Copy constructor, copies the contents of an existing tag.
       Tag & operator=(const Tag& O); ///< Assignment operator - works exactly like the copy constructor.
diff --git a/lib/rtmpchunks.cpp b/lib/rtmpchunks.cpp
index a9dd78cb..25e0dbf8 100644
--- a/lib/rtmpchunks.cpp
+++ b/lib/rtmpchunks.cpp
@@ -423,7 +423,10 @@ std::string & RTMPStream::SendMedia(unsigned char msg_type_id, unsigned char * d
 /// \param tag FLV::Tag with media to send.
 std::string & RTMPStream::SendMedia(FLV::Tag & tag){
   static RTMPStream::Chunk ch;
-  ch.cs_id = ((unsigned char)tag.data[0]);
+  //Commented bit is more efficient and correct according to RTMP spec.
+  //Simply passing "4" is the only thing that actually plays correctly, though.
+  //Adobe, if you're ever reading this... wtf? Seriously.
+  ch.cs_id = 4;//((unsigned char)tag.data[0]);
   ch.timestamp = tag.tagTime();
   ch.len = tag.len - 15;
   ch.real_len = tag.len - 15;