重写rtp框架

src/Rtsp/Rtsp.cpp

@@ -415,14 +415,101 @@ string printSSRC(uint32_t ui32Ssrc) {
 }
 
 Buffer::Ptr makeRtpOverTcpPrefix(uint16_t size, uint8_t interleaved){
-    auto rtp_tcp = std::make_shared<BufferRaw>(4);
+    auto rtp_tcp = std::make_shared<BufferRaw>(RtpPacket::kRtpTcpHeaderSize);
+    rtp_tcp->setSize(RtpPacket::kRtpTcpHeaderSize);
     auto ptr = rtp_tcp->data();
     ptr[0] = '$';
     ptr[1] = interleaved;
     ptr[2] = (size >> 8) & 0xFF;
     ptr[3] = size & 0xFF;
-    rtp_tcp->setSize(4);
     return rtp_tcp;
 }
 
+#define AV_RB16(x)                           \
+    ((((const uint8_t*)(x))[0] << 8) |          \
+      ((const uint8_t*)(x))[1])
+
+size_t RtpHeader::getCsrcSize() const {
+    //每个csrc占用4字节
+    return csrc << 2;
+}
+
+uint8_t *RtpHeader::getCsrcData() {
+    if (!csrc) {
+        return nullptr;
+    }
+    return &payload;
+}
+
+size_t RtpHeader::getExtSize() const {
+    //rtp有ext
+    if (!ext) {
+        return 0;
+    }
+    auto ext_ptr = &payload + getCsrcSize();
+    uint16_t reserved = AV_RB16(ext_ptr);
+    //每个ext占用4字节
+    return AV_RB16(ext_ptr + 2) << 2;
+}
+
+uint8_t *RtpHeader::getExtData() {
+    if (!ext) {
+        return nullptr;
+    }
+    auto ext_ptr = &payload + getCsrcSize();
+    //多出的4个字节分别为reserved、ext_len
+    return ext_ptr + 4 + getExtSize();
+}
+
+size_t RtpHeader::getPayloadOffset() const {
+    //有ext时，还需要忽略reserved、ext_len 4个字节
+    return getCsrcSize() + (ext ? (4 + getExtSize()) : 0);
+}
+
+uint8_t *RtpHeader::getPayloadData() {
+    return &payload + getPayloadOffset();
+}
+
+size_t RtpHeader::getPaddingSize(size_t rtp_size) const {
+    if (!padding) {
+        return 0;
+    }
+    auto end = (uint8_t *) this + rtp_size;
+    return *end;
+}
+
+size_t RtpHeader::getPayloadSize(size_t rtp_size){
+    auto invalid_size = getPayloadOffset() + getPaddingSize(rtp_size);
+    if (invalid_size + RtpPacket::kRtpHeaderSize >= rtp_size) {
+        return 0;
+    }
+    return rtp_size - invalid_size - RtpPacket::kRtpHeaderSize;
+}
+
+RtpHeader* RtpPacket::getHeader(){
+    //需除去rtcp over tcp 4个字节长度
+    return (RtpHeader*)(data() + RtpPacket::kRtpTcpHeaderSize);
+}
+
+uint16_t RtpPacket::getSeq(){
+    return ntohs(getHeader()->seq);
+}
+
+uint32_t RtpPacket::getStampMS(){
+    return ntohl(getHeader()->stamp) * uint64_t(1000) / sample_rate;
+}
+
+uint32_t RtpPacket::getSSRC(){
+    return ntohl(getHeader()->ssrc);
+}
+
+uint8_t* RtpPacket::getPayload(){
+    return getHeader()->getPayloadData();
+}
+
+size_t RtpPacket::getPayloadSize(){
+    //需除去rtcp over tcp 4个字节长度
+    return getHeader()->getPayloadSize(size() - kRtpTcpHeaderSize);
+}
+
 }//namespace mediakit