CMAF Push Output

lib/cmaf.cpp

@@ -1,14 +1,20 @@
 #include "cmaf.h"
 
 namespace CMAF{
-  size_t payloadSize(const DTSC::Meta &M, size_t track, size_t fragment){
+  /// Function to determine the payload size of a CMAF fragment.
+  /// \parm isKeyIndex indicates whether we are sending DTSC Fragment or DTSC Key based CMAF fragments.
+  size_t payloadSize(const DTSC::Meta &M, size_t track, size_t index, bool isKeyIndex){
     DTSC::Fragments fragments(M.fragments(track));
     DTSC::Keys keys(M.keys(track));
     DTSC::Parts parts(M.parts(track));
 
-    size_t firstKey = fragments.getFirstKey(fragment);
+    size_t firstKey = (isKeyIndex ? index : fragments.getFirstKey(index));
     size_t endKey = keys.getEndValid();
-    if (fragment + 1 < fragments.getEndValid()){endKey = fragments.getFirstKey(fragment + 1);}
+    if (isKeyIndex) {
+      if (index + 1 < keys.getEndValid()){endKey = index + 1;}
+    } else {
+      if (index + 1 < fragments.getEndValid()){endKey = fragments.getFirstKey(index + 1);}
+    }
 
     size_t firstPart = keys.getFirstPart(firstKey);
     size_t endPart = parts.getEndValid();
@@ -22,13 +28,13 @@ namespace CMAF{
     // EDTS Box needed? + 36
     size_t res = 36 + 8 + 108 + 8 + 92 + 8 + 32 + 33 + 44 + 8 + 20 + 16 + 16 + 16 + 40;
 
-    res += M.getTrackIdentifier(track).size();
+    res += M.getType(track).size();
 
     // Type-specific boxes
     std::string tType = M.getType(track);
-    if (tType == "video"){res += 20 + 16 + 86 + 16 + 8 + M.getInit(track).size();}
+    if (tType == "video"){res += 20 + 16 + 86 + 16 + 8 + M.getInit(track).size() + 20;}//20 for btrt box
     if (tType == "audio"){
-      res += 16 + 16 + 36 + 35 + (M.getInit(track).size() ? 2 + M.getInit(track).size() : 0);
+      res += 16 + 16 + 36 + 35 + (M.getInit(track).size() ? 2 + M.getInit(track).size() : 0) + 20;//20 for btrt box
     }
     if (tType == "meta"){res += 12 + 16 + 64;}
 
@@ -37,7 +43,15 @@ namespace CMAF{
     return res;
   }
   
-  std::string trackHeader(const DTSC::Meta &M, size_t track){
+  size_t simplifiedTrackId(const DTSC::Meta & M, size_t idx) { 
+    std::string type = M.getType(idx);
+    if (type == "video") {return 1;}
+    if (type == "audio") {return 2;}
+    if (type == "meta") {return 3;}
+    return idx;
+  }
+
+  std::string trackHeader(const DTSC::Meta &M, size_t track, bool simplifyTrackIds){
     std::string tType = M.getType(track);
 
     std::stringstream header;
@@ -53,12 +67,15 @@ namespace CMAF{
     MP4::MOOV moovBox;
 
     MP4::MVHD mvhdBox(0);
-    mvhdBox.setTrackID(track + 2); // This value needs to point to an unused trackid
+    mvhdBox.setTrackID(0xFFFFFFFF); // This value needs to point to an unused trackid
     moovBox.setContent(mvhdBox, 0);
 
     MP4::TRAK trakBox;
 
     MP4::TKHD tkhdBox(M, track);
+    if (simplifyTrackIds){
+      tkhdBox.setTrackID(simplifiedTrackId(M, track));
+    }
     tkhdBox.setDuration(0);
     trakBox.setContent(tkhdBox, 0);
 
@@ -67,7 +84,7 @@ namespace CMAF{
     MP4::MDHD mdhdBox(0, M.getLang(track));
     mdiaBox.setContent(mdhdBox, 0);
 
-    MP4::HDLR hdlrBox(tType, M.getTrackIdentifier(track));
+    MP4::HDLR hdlrBox(tType, M.getType(track));
     mdiaBox.setContent(hdlrBox, 1);
 
     MP4::MINF minfBox;
@@ -95,9 +112,21 @@ namespace CMAF{
     MP4::STSD stsdBox(0);
     if (tType == "video"){
       MP4::VisualSampleEntry sampleEntry(M, track);
+      MP4::BTRT btrtBox;
+      btrtBox.setDecodingBufferSize(0xFFFFFFFFull);
+      btrtBox.setAverageBitrate(M.getBps(track));
+      btrtBox.setMaxBitrate(M.getMaxBps(track));
+
+      sampleEntry.setBoxEntry(sampleEntry.getBoxEntryCount(),btrtBox);
       stsdBox.setEntry(sampleEntry, 0);
     }else if (tType == "audio"){
       MP4::AudioSampleEntry sampleEntry(M, track);
+      MP4::BTRT btrtBox;
+      btrtBox.setDecodingBufferSize(0xFFFFFFFFull);
+      btrtBox.setAverageBitrate(M.getBps(track));
+      btrtBox.setMaxBitrate(M.getMaxBps(track));
+
+      sampleEntry.setBoxEntry(sampleEntry.getBoxEntryCount(),btrtBox);
       stsdBox.setEntry(sampleEntry, 0);
     }else if (tType == "meta"){
       MP4::TextSampleEntry sampleEntry(M, track);
@@ -132,6 +161,9 @@ namespace CMAF{
     }
 
     MP4::TREX trexBox(track + 1);
+    if (simplifyTrackIds){
+      trexBox.setTrackID(simplifiedTrackId(M, track));
+    }
     trexBox.setDefaultSampleDuration(1000);
     mvexBox.setContent(trexBox, M.getVod() ? 1 : 0);
 
@@ -196,7 +228,7 @@ namespace CMAF{
     return tmpRes;
   }
 
-  std::string fragmentHeader(const DTSC::Meta &M, size_t track, size_t fragment){
+  std::string fragmentHeader(const DTSC::Meta &M, size_t track, size_t fragment, bool simplifyTrackIds, bool UTCTime){
 
     DTSC::Fragments fragments(M.fragments(track));
     DTSC::Keys keys(M.keys(track));
@@ -258,18 +290,21 @@ namespace CMAF{
 
     tfhdBox.setFlags(MP4::tfhdSampleFlag | MP4::tfhdBaseIsMoof | MP4::tfhdSampleDesc);
     tfhdBox.setTrackID(track + 1);
+    if (simplifyTrackIds){
+      tfhdBox.setTrackID(simplifiedTrackId(M, track));
+    }
     tfhdBox.setDefaultSampleDuration(444);
     tfhdBox.setDefaultSampleSize(444);
     tfhdBox.setDefaultSampleFlags((M.getType(track) == "video") ? (MP4::noIPicture | MP4::noKeySample)
                                                                 : (MP4::isIPicture | MP4::isKeySample));
-    tfhdBox.setSampleDescriptionIndex(0);
+    tfhdBox.setSampleDescriptionIndex(1);
     trafBox.setContent(tfhdBox, 0);
 
     MP4::TFDT tfdtBox;
     if (M.getVod()){
       tfdtBox.setBaseMediaDecodeTime(M.getTimeForFragmentIndex(track, fragment) - M.getFirstms(track));
     }else{
-      tfdtBox.setBaseMediaDecodeTime(M.getTimeForFragmentIndex(track, fragment));
+      tfdtBox.setBaseMediaDecodeTime((UTCTime ? Util::epoch()*1000 : M.getTimeForFragmentIndex(track, fragment)));
     }
     trafBox.setContent(tfdtBox, 1);
 
@@ -299,4 +334,106 @@ namespace CMAF{
 
     return header.str();
   }
+
+  /// Calculates the full size of a 'moof' box for a DTSC::Key based fragment.
+  /// Used when building the 'moof' box to calculate the relative data offsets.
+  size_t keyHeaderSize(const DTSC::Meta &M, size_t track, size_t key){
+    uint64_t tmpRes = 8 + 16 + 32 + 20;
+
+    DTSC::Keys keys(M.keys(track));
+    DTSC::Parts parts(M.parts(track));
+
+    size_t firstPart = keys.getFirstPart(key);
+    size_t endPart = parts.getEndValid();
+    if (key + 1 < keys.getEndValid()){
+      endPart = keys.getFirstPart(key + 1);
+    }
+
+    tmpRes += 24 + ((endPart - firstPart) * 12);
+    return tmpRes;
+  }
+
+  /// Generates the 'moof' box for a DTSC::Key based CMAF fragment.
+  std::string keyHeader(const DTSC::Meta &M, size_t track, size_t key, bool simplifyTrackIds, bool UTCTime){
+    DTSC::Keys keys(M.keys(track));
+    DTSC::Parts parts(M.parts(track));
+
+    size_t firstPart = keys.getFirstPart(key);
+    size_t endPart = parts.getEndValid();
+    if (key + 1 < keys.getEndValid()){
+      endPart = keys.getFirstPart(key + 1);
+    }
+
+    std::stringstream header;
+
+    MP4::MOOF moofBox;
+    MP4::MFHD mfhdBox(key + 1);
+    moofBox.setContent(mfhdBox, 0);
+
+
+    std::set<sortPart> trunOrder;
+
+    //We use keyHeaderSize here to determine the relative offsets of the data in the 'mdat' box. 
+    uint64_t relativeOffset = keyHeaderSize(M, track, key) + 8;
+
+    sortPart temp;
+    temp.time = keys.getTime(key);
+    temp.partIndex = firstPart;
+    temp.bytePos = relativeOffset;
+
+    for (size_t p = firstPart; p < endPart; p++){
+      trunOrder.insert(temp);
+      temp.time += parts.getDuration(p);
+      temp.partIndex++;
+      temp.bytePos += parts.getSize(p);
+    }
+
+    MP4::TRAF trafBox;
+    MP4::TFHD tfhdBox;
+
+    tfhdBox.setFlags(MP4::tfhdSampleFlag | MP4::tfhdBaseIsMoof | MP4::tfhdSampleDesc);
+    tfhdBox.setTrackID(track + 1);
+    if (simplifyTrackIds){
+      tfhdBox.setTrackID(simplifiedTrackId(M, track));
+    }
+    tfhdBox.setDefaultSampleDuration(444);
+    tfhdBox.setDefaultSampleSize(444);
+    tfhdBox.setDefaultSampleFlags((M.getType(track) == "video") ? (MP4::noIPicture | MP4::noKeySample)
+                                                                : (MP4::isIPicture | MP4::isKeySample));
+    tfhdBox.setSampleDescriptionIndex(1);
+    trafBox.setContent(tfhdBox, 0);
+
+    MP4::TFDT tfdtBox;
+    if (M.getVod()){
+      tfdtBox.setBaseMediaDecodeTime(keys.getTime(key) - M.getFirstms(track));
+    }else{
+      tfdtBox.setBaseMediaDecodeTime((UTCTime ? Util::epoch()*1000 : keys.getTime(key) ));
+    }
+    trafBox.setContent(tfdtBox, 1);
+
+    MP4::TRUN trunBox;
+    trunBox.setFlags(MP4::trundataOffset | MP4::trunfirstSampleFlags | MP4::trunsampleSize |
+                     MP4::trunsampleDuration | MP4::trunsampleOffsets);
+
+    trunBox.setDataOffset(trunOrder.begin()->bytePos);
+
+    trunBox.setFirstSampleFlags(MP4::isIPicture | MP4::isKeySample);
+
+    size_t trunOffset = 0;
+
+    for (std::set<sortPart>::iterator it = trunOrder.begin(); it != trunOrder.end(); it++){
+      MP4::trunSampleInformation sampleInfo;
+      sampleInfo.sampleSize = parts.getSize(it->partIndex);
+      sampleInfo.sampleDuration = parts.getDuration(it->partIndex);
+      sampleInfo.sampleOffset = parts.getOffset(it->partIndex);
+      trunBox.setSampleInformation(sampleInfo, trunOffset++);
+    }
+    trafBox.setContent(trunBox, 2);
+
+    moofBox.setContent(trafBox, 1);
+
+    header.write(moofBox.asBox(), moofBox.boxedSize());
+
+    return header.str();
+  }
 }// namespace CMAF

lib/cmaf.h

@@ -4,9 +4,11 @@
 #include <set>
 
 namespace CMAF{
-  size_t payloadSize(const DTSC::Meta &M, size_t track, size_t fragment);
+  size_t payloadSize(const DTSC::Meta &M, size_t track, size_t index, bool isKeyIndex = false);
   size_t trackHeaderSize(const DTSC::Meta &M, size_t track);
-  std::string trackHeader(const DTSC::Meta &M, size_t track);
+  std::string trackHeader(const DTSC::Meta &M, size_t track, bool simplifyTrackIds = false);
   size_t fragmentHeaderSize(const DTSC::Meta &M, size_t track, size_t fragment);
-  std::string fragmentHeader(const DTSC::Meta &M, size_t track, size_t fragment);
+  std::string fragmentHeader(const DTSC::Meta &M, size_t track, size_t fragment, bool simplifyTrackIds = false, bool UTCTime = false);
+  size_t keyHeaderSize(const DTSC::Meta &M, size_t track, size_t key);
+  std::string keyHeader(const DTSC::Meta &M, size_t track, size_t key, bool simplifyTrackIds = false, bool UTCTime = false);
 }// namespace CMAF

lib/mp4.cpp

@@ -308,6 +308,7 @@ namespace MP4{
     case 0x74656E63: return ((TENC *)this)->toPrettyString(indent); break;
     case 0x7361697A: return ((SAIZ *)this)->toPrettyString(indent); break;
     case 0x7361696F: return ((SAIO *)this)->toPrettyString(indent); break;
+    case 0x62747274: return ((BTRT *)this)->toPrettyString(indent); break;
     /*LTS-END*/
     default: INFO_MSG("no code found: 0x%.8x", Bit::btohl(data + 4)); break;
     }

lib/mp4_generic.cpp

@@ -75,6 +75,38 @@ namespace MP4{
     return r.str();
   }
 
+  BTRT::BTRT() {
+    memcpy(data + 4, "btrt", 4);
+  }
+
+  uint32_t BTRT::getDecodingBufferSize(){
+    return getInt32(0);
+  }
+  void BTRT::setDecodingBufferSize(uint32_t val){
+    setInt32(val, 0);
+  }
+  uint32_t BTRT::getMaxBitrate(){
+    return getInt32(4);
+  }
+  void BTRT::setMaxBitrate(uint32_t val){
+    setInt32(val, 4);
+  }
+  uint32_t BTRT::getAverageBitrate(){
+    return getInt32(8);
+  }
+  void BTRT::setAverageBitrate(uint32_t val){
+    setInt32(val, 8);
+  }
+
+  std::string BTRT::toPrettyString(uint32_t indent) {
+    std::stringstream r;
+    r << std::string(indent, ' ') << "[btrt] Bitrate Box (" << boxedSize() << ")" << std::endl;
+    r << std::string(indent+2, ' ') << "DecodingBufferSize: " << getDecodingBufferSize() << std::endl;
+    r << std::string(indent+2, ' ') << "Maximum Bitrate: " << getMaxBitrate() << std::endl;
+    r << std::string(indent+2, ' ') << "Average Bitrate: " << getAverageBitrate() << std::endl;
+    return r.str();
+  }
+
   TRUN::TRUN(){memcpy(data + 4, "trun", 4);}
 
   void TRUN::setFlags(uint32_t newFlags){setInt24(newFlags, 1);}
@@ -1217,6 +1249,14 @@ namespace MP4{
     memcpy(data + payloadOffset + 4, newMinorVersion, 4);
   }
 
+  std::string FTYP::getMinorVersionHex(){
+    static char zero[4] ={0, 0, 0, 0};
+    if (memcmp(zero, data + payloadOffset + 4, 4) == 0){return "";}
+    char val[20];
+    snprintf(val, 20, "%.2X%.2X%.2X%.2X", data[payloadOffset + 4], data[payloadOffset + 5], data[payloadOffset + 6], data[payloadOffset + 7]);
+    return std::string(val);
+  }
+
   std::string FTYP::getMinorVersion(){
     static char zero[4] ={0, 0, 0, 0};
     if (memcmp(zero, data + payloadOffset + 4, 4) == 0){return "";}
@@ -1241,7 +1281,7 @@ namespace MP4{
     std::stringstream r;
     r << std::string(indent, ' ') << "[ftyp] File Type (" << boxedSize() << ")" << std::endl;
     r << std::string(indent + 1, ' ') << "MajorBrand: " << getMajorBrand() << std::endl;
-    r << std::string(indent + 1, ' ') << "MinorVersion: " << getMinorVersion() << std::endl;
+    r << std::string(indent + 1, ' ') << "MinorVersion: 0x" << getMinorVersionHex() << std::endl;
     r << std::string(indent + 1, ' ') << "CompatibleBrands (" << getCompatibleBrandsCount()
       << "):" << std::endl;
     for (unsigned int i = 0; i < getCompatibleBrandsCount(); i++){
@@ -1765,7 +1805,7 @@ namespace MP4{
       if (i != getMatrixCount() - 1){r << ", ";}
     }
     r << std::endl;
-    r << std::string(indent + 1, ' ') << "TrackID: " << getTrackID() << std::endl;
+    r << std::string(indent + 1, ' ') << "next_track_ID: " << getTrackID() << std::endl;
     return r.str();
   }
 
@@ -2887,6 +2927,55 @@ namespace MP4{
   }
   /*LTS-END*/
 
+  size_t AudioSampleEntry::getBoxEntryCount(){
+    if (payloadSize() < 36){// if the EntryBox is not big enough to hold any box
+      return 0;
+    }
+    size_t count = 0;
+    size_t offset = 28;
+    while (offset < payloadSize()){
+      offset += getBoxLen(offset);
+      count++;
+    }
+    return count;
+  }
+
+  Box &AudioSampleEntry::getBoxEntry(size_t index){
+    static Box ret = Box((char *)"\000\000\000\010erro", false);
+    if (index >= getBoxEntryCount()){return ret;}
+    size_t count = 0;
+    size_t offset = 28;
+    while (offset < payloadSize()){
+      if (count == index){return getBox(offset);}
+      offset += getBoxLen(offset);
+      count++;
+    }
+    return ret;
+  }
+
+  void AudioSampleEntry::setBoxEntry(size_t index, Box &box){
+    if (index > getBoxEntryCount()){
+      index = getBoxEntryCount();
+      WARN_MSG("This function can not leave empty spaces, appending at index %zu nstead!", index);
+    }
+    size_t count = 0;
+    size_t offset = 28;
+    while (offset < payloadSize()){
+      if (count == index){
+        setBox(box, offset);
+        return;
+      }
+      offset += getBoxLen(offset);
+      count++;
+    }
+    if (count == index){
+      setBox(box, offset);
+    }else{
+      INFO_MSG("Should not be here! Index is %zu, count is %zu, offset is %zu, payloadSize is %zu",
+               index, count, offset, payloadSize());
+    }
+  }
+
   std::string AudioSampleEntry::toPrettyAudioString(uint32_t indent, std::string name){
     std::stringstream r;
     r << std::string(indent, ' ') << name << " (" << boxedSize() << ")" << std::endl;
@@ -2895,10 +2984,13 @@ namespace MP4{
     r << std::string(indent + 1, ' ') << "SampleSize: " << getSampleSize() << std::endl;
     r << std::string(indent + 1, ' ') << "PreDefined: " << getPreDefined() << std::endl;
     r << std::string(indent + 1, ' ') << "SampleRate: " << getSampleRate() << std::endl;
-    r << getCodecBox().toPrettyString(indent + 1) << std::endl;
+    size_t firstBox = 0; 
-    /*LTS-START*/
+    if (getBoxEntryCount() > firstBox){
-    if (isType("enca")){r << getSINFBox().toPrettyString(indent + 1);}
+      for (size_t index = firstBox; index < getBoxEntryCount(); ++index){
-    /*LTS-END*/
+        MP4::Box tmpBox = getBoxEntry(index);
+        r << tmpBox.toPrettyString(indent + 1);
+      }
+    }
     return r.str();
   }
 

lib/mp4_generic.h

@@ -31,7 +31,19 @@ namespace MP4{
   };
   // TRAF Box
 
-  struct trunSampleInformation{
+  class BTRT: public Box {
+    public:
+      BTRT();
+      uint32_t getDecodingBufferSize();
+      void setDecodingBufferSize(uint32_t val);
+      uint32_t getMaxBitrate();
+      void setMaxBitrate(uint32_t val);
+      uint32_t getAverageBitrate();
+      void setAverageBitrate(uint32_t val);
+      std::string toPrettyString(uint32_t indent = 0);
+  };
+
+  struct trunSampleInformation {
     uint32_t sampleDuration;
     uint32_t sampleSize;
     uint32_t sampleFlags;
@@ -273,6 +285,7 @@ namespace MP4{
     void setMajorBrand(const char *newMajorBrand);
     std::string getMajorBrand();
     void setMinorVersion(const char *newMinorVersion);
+    std::string getMinorVersionHex();
     std::string getMinorVersion();
     size_t getCompatibleBrandsCount();
     void setCompatibleBrands(const char *newCompatibleBrand, size_t index);
@@ -719,6 +732,11 @@ namespace MP4{
     void setCodecBox(Box &newBox);
     Box &getCodecBox();
     Box &getSINFBox(); /*LTS*/
+
+    size_t getBoxEntryCount();
+    Box &getBoxEntry(size_t index);
+    void setBoxEntry(size_t index, Box &box);
+
     std::string toPrettyAudioString(uint32_t indent = 0, std::string name = "");
   };
 

src/output/output_cmaf.cpp

@@ -16,13 +16,80 @@
 uint64_t bootMsOffset;
 
 namespace Mist{
+  void CMAFPushTrack::connect(std::string debugParam) {
+    D.setHeader("Transfer-Encoding", "chunked");
+    D.prepareRequest(url, "POST");
+
+    HTTP::Parser & http = D.getHTTP();
+    http.sendingChunks = true;
+    http.SendRequest(D.getSocket());
+
+    if (debugParam.length()){
+      if (debugParam[debugParam.length()-1] != '/'){
+        debugParam += '/';
+      }
+      debug = true;
+      std::string filename = url.getUrl();
+      filename.erase(0, filename.rfind("/")+1);
+      snprintf(debugName, 500, "%s%s-%" PRIu64, debugParam.c_str(), filename.c_str(), Util::bootMS());
+      INFO_MSG("CMAF DEBUG FILE: %s", debugName);
+      debugFile = fopen(debugName, "wb");
+    }
+  }
+
+  void CMAFPushTrack::disconnect() {
+    Socket::Connection & sock = D.getSocket();
+
+    MP4::MFRA mfraBox;
+    send(mfraBox.asBox(), mfraBox.boxedSize());
+    send("");
+    sock.close();
+
+    if (debugFile) {
+      fclose(debugFile);
+      debugFile = 0;
+    }
+  }
+
+  void CMAFPushTrack::send(const char * data, size_t len){
+    D.getHTTP().Chunkify(data, len, D.getSocket());
+    if (debug && debugFile) {
+      fwrite(data, 1, len, debugFile);
+
+    }
+  }
+
+  void CMAFPushTrack::send(const std::string & data){
+    send(data.data(), data.size());
+  }
 
   OutCMAF::OutCMAF(Socket::Connection &conn) : HTTPOutput(conn){
     uaDelay = 0;
-    realTime = 0;
+    if (config->getString("target").size()){
+      needsLookAhead = 5000;
+
+      streamName = config->getString("streamname");
+      std::string target = config->getString("target");
+      target.replace(0, 4, "http");//Translate to http for cmaf:// or https for cmafs://
+      pushUrl = HTTP::URL(target);
+
+      INFO_MSG("About to push stream %s out. Host: %s, port: %d, location: %s", streamName.c_str(),
+               pushUrl.host.c_str(), pushUrl.getPort(), pushUrl.path.c_str());
+      initialize();
+      initialSeek();
+      startPushOut();
+    } else {
+      realTime = 0;
+    }
+    INFO_MSG("Out of constructor now");
   }
 
-  OutCMAF::~OutCMAF(){}
+  //Properly end all tracks on shutdown.
+  OutCMAF::~OutCMAF() {
+    for (std::map<size_t, Comms::Users>::iterator it = userSelect.begin(); it != userSelect.end(); it++){
+      onTrackEnd(it->first);
+    }
+  }
 
   void OutCMAF::init(Util::Config *cfg){
     HTTPOutput::init(cfg);
@@ -66,6 +133,16 @@ namespace Mist{
         "Disables chunked transfer encoding, forcing per-segment buffering. Reduces performance "
         "significantly, but increases compatibility somewhat.";
     capa["optional"]["nonchunked"]["option"] = "--nonchunked";
+
+    capa["push_urls"].append("cmaf://*");
+    capa["push_urls"].append("cmafs://*");
+
+    JSON::Value opt;
+    opt["arg"] = "string";
+    opt["default"] = "";
+    opt["arg_num"] = 1;
+    opt["help"] = "Target CMAF URL to push out towards.";
+    cfg->addOption("target", opt);
   }
 
   void OutCMAF::onHTTP(){
@@ -157,7 +234,7 @@ namespace Mist{
     uint64_t fragmentIndex = M.getFragmentIndexForTime(idx, startTime);
     targetTime = M.getTimeForFragmentIndex(idx, fragmentIndex + 1);
 
-    std::string headerData = CMAF::fragmentHeader(M, idx, fragmentIndex);
+    std::string headerData = CMAF::fragmentHeader(M, idx, fragmentIndex, false, false);
     H.Chunkify(headerData.c_str(), headerData.size(), myConn);
 
     uint64_t mdatSize = 8 + CMAF::payloadSize(M, idx, fragmentIndex);
@@ -172,7 +249,13 @@ namespace Mist{
     parseData = true;
   }
 
+
+
   void OutCMAF::sendNext(){
+    if (isRecording()){
+      pushNext();
+      return;
+    }
     if (thisPacket.getTime() >= targetTime){
       HIGH_MSG("Finished playback to %" PRIu64, targetTime);
       wantRequest = true;
@@ -682,6 +765,122 @@ namespace Mist{
     r << "</SmoothStreamingMedia>\n";
 
     return toUTF16(r.str());
-  }// namespace Mist
+  }
+
+  /**********************************/
+  /* CMAF Push Output functionality */
+  /**********************************/
+
+  //When we disconnect a track, or when we're done pushing out, send an empty 'mfra' box to indicate track end.
+  void OutCMAF::onTrackEnd(size_t idx) {
+    if (!isRecording()){return;}
+    if (!pushTracks.count(idx) || !pushTracks.at(idx).D.getSocket()){return;}
+    INFO_MSG("Disconnecting track %zu", idx);
+    pushTracks[idx].disconnect();
+    
+    pushTracks.erase(idx);
+  }
+  
+  //Create the connections and post request needed to start pushing out a track.
+  void OutCMAF::setupTrackObject(size_t idx) {
+    CMAFPushTrack & track = pushTracks[idx];
+    track.url = pushUrl;
+    if (targetParams.count("usp") && targetParams["usp"] == "1"){
+      std::string usp_path = "Streams(" + M.getType(idx) + + "_" + JSON::Value(idx).asString() + ")"; 
+      track.url = track.url.link(usp_path);
+    }else{
+      track.url.path += "/"; 
+      track.url = track.url.link(M.getTrackIdentifier(idx));
+    }
+
+    track.connect(targetParams["debug"]);
+
+    std::string header = CMAF::trackHeader(M, idx, true);
+    track.send(header);
+  }
+
+
+  /// Function that waits at most `maxWait` ms (in steps of 100ms) for the next keyframe to become available.
+  /// Uses thisIdx and thisPacket to determine track and current timestamp respectively.
+  bool OutCMAF::waitForNextKey(uint64_t maxWait){
+    size_t currentKey = M.getKeyIndexForTime(thisIdx, thisPacket.getTime());
+    DTSC::Keys keys(M.keys(thisIdx));
+    size_t waitTimes = maxWait / 100; 
+    for (size_t i = 0; i < waitTimes; ++i){
+      if (keys.getEndValid() > currentKey + 1){return true;}
+      Util::wait(100);
+      //Make sure we don't accidentally timeout while waiting - runs approximately every second.
+      if (i % 10 == 0){
+        for (std::map<size_t, Comms::Users>::iterator it = userSelect.begin(); it != userSelect.end(); ++it){
+          it->second.keepAlive();
+          stats();
+        }
+      }
+    }
+    return (keys.getEndValid() > currentKey + 1);
+  }
+
+  //Set up an empty connection to the target to make sure we can push data towards it.
+  void OutCMAF::startPushOut(){
+    myConn.close();
+    myConn.Received().clear();
+    myConn.open(pushUrl.host, pushUrl.getPort(), true);
+    wantRequest = false;
+    parseData = true;
+  }
+
+  //CMAF Push output uses keyframe boundaries instead of fragment boundaries, to allow for lower latency
+  void OutCMAF::pushNext() {
+    //Set up a new connection if this is a new track, or if we have been disconnected.
+    if (!pushTracks.count(thisIdx) || !pushTracks.at(thisIdx).D.getSocket()){
+      CMAFPushTrack & track = pushTracks[thisIdx];
+      size_t keyIndex = M.getKeyIndexForTime(thisIdx, thisPacket.getTime());
+      track.headerFrom = M.getTimeForKeyIndex(thisIdx, keyIndex);
+      if (track.headerFrom < thisPacket.getTime()){
+        track.headerFrom = M.getTimeForKeyIndex(thisIdx, keyIndex + 1);
+      }
+
+      HIGH_MSG("Starting track %zu at %" PRIu64 "ms into the stream, current packet at %" PRIu64 "ms", thisIdx, track.headerFrom, thisPacket.getTime());
+
+      setupTrackObject(thisIdx);
+      track.headerUntil = 0;
+
+    }
+    CMAFPushTrack & track = pushTracks[thisIdx];
+    if (thisPacket.getTime() < track.headerFrom){return;}
+    if (thisPacket.getTime() > track.headerUntil || !track.headerUntil){
+      size_t keyIndex = M.getKeyIndexForTime(thisIdx, thisPacket.getTime());
+      uint64_t keyTime = M.getTimeForKeyIndex(thisIdx, keyIndex);
+      if (keyTime != thisPacket.getTime()){
+        WARN_MSG("Corruption probably occured, initiating reconnect %" PRIu64 " != %" PRIu64, keyTime, thisPacket.getTime());
+        onTrackEnd(thisIdx);
+        track.headerFrom = M.getTimeForKeyIndex(thisIdx, keyIndex + 1);
+        track.headerUntil = 0;
+        pushNext();
+        return;
+      }
+      track.headerFrom = keyTime;
+      if (!waitForNextKey()){
+        onTrackEnd(thisIdx);
+        dropTrack(thisIdx, "No next keyframe available");
+        return;
+      }
+      track.headerUntil = M.getTimeForKeyIndex(thisIdx, keyIndex + 1) - 1;
+      std::string keyHeader = CMAF::keyHeader(M, thisIdx, keyIndex, true, true);
+
+      uint64_t mdatSize = 8 + CMAF::payloadSize(M, thisIdx, keyIndex, true);
+      char mdatHeader[] ={0x00, 0x00, 0x00, 0x00, 'm', 'd', 'a', 't'};
+      Bit::htobl(mdatHeader, mdatSize);
+
+      track.send(keyHeader);
+      track.send(mdatHeader, 8);
+    }
+    char *data;
+    size_t dataLen;
+    thisPacket.getString("data", data, dataLen);
+
+    track.send(data, dataLen);
+  }
+
 
 }// namespace Mist

src/output/output_cmaf.h

@@ -1,8 +1,30 @@
 #include "output_http.h"
 #include <mist/http_parser.h>
+#include <mist/downloader.h>
 #include <mist/mp4_generic.h>
 
 namespace Mist{
+  /// Keeps track of the state of an outgoing CMAF Push track.
+  class CMAFPushTrack {
+    public:
+      CMAFPushTrack() {debug = false; debugFile = 0;}
+      ~CMAFPushTrack() {disconnect();}
+      void connect(std::string debugParam = "");
+      void disconnect();
+
+      void send(const char * data, size_t len);
+      void send(const std::string & data);
+
+      HTTP::Downloader D;
+      HTTP::URL url;
+      uint64_t headerFrom;
+      uint64_t headerUntil;
+
+      bool debug;
+      char debugName[500];
+      FILE * debugFile;
+  };
+
   class OutCMAF : public HTTPOutput{
   public:
     OutCMAF(Socket::Connection &conn);
@@ -13,6 +35,8 @@ namespace Mist{
     void sendHeader(){};
 
   protected:
+    void onTrackEnd(size_t idx);
+
     void sendDashManifest();
     void dashAdaptationSet(size_t id, size_t idx, std::stringstream &r);
     void dashRepresentation(size_t id, size_t idx, std::stringstream &r);
@@ -37,6 +61,16 @@ namespace Mist{
 
     std::string h264init(const std::string &initData);
     std::string h265init(const std::string &initData);
+
+    // For CMAF push out
+    void startPushOut();
+    void pushNext();
+
+    HTTP::URL pushUrl;
+    std::map<size_t, CMAFPushTrack> pushTracks; 
+    void setupTrackObject(size_t idx);
+    bool waitForNextKey(uint64_t maxWait = 5000);
+    // End CMAF push out
   };
 }// namespace Mist