for bug #66, refine the api to send h264 frames.

@@ -50,9 +50,13 @@ int read_h264_frame(char* data, int size, char** pp, int fps,
         srs_trace("h264 raw data invalid.");
         return -1;
     }
-    p += pnb_start_code;
     
+    // @see srs_write_h264_raw_frames
+    // each frame prefixed h.264 annexb header, by N[00] 00 00 01, where N>=0, 
+    // for instance, frame = header(00 00 00 01) + payload(67 42 80 29 95 A0 14 01 6E 40)
     *frame = p;
+    p += pnb_start_code;
+    
     for (;p < data + size; p++) {
         if (srs_h264_startswith_annexb(p, size - (p - data), &pnb_start_code)) {
             break;
@@ -162,7 +166,7 @@ int main(int argc, char** argv)
         }
         
         // send out the h264 packet over RTMP
-        if (srs_write_h264_raw_frame(rtmp, data, size, dts, pts) != 0) {
+        if (srs_write_h264_raw_frames(rtmp, data, size, dts, pts) != 0) {
             srs_trace("send h264 raw data failed.");
             goto rtmp_destroy;
         }

@@ -996,21 +996,23 @@ char* srs_amf0_human_print(srs_amf0_t amf0, char** pdata, int* psize)
     return any->human_print(pdata, psize);
 }
 
-int srs_write_h264_raw_frame(srs_rtmp_t rtmp, char* frame, int frame_size, u_int32_t dts, u_int32_t pts)
+int srs_write_h264_raw_frames(srs_rtmp_t rtmp, char* frames, int frames_size, u_int32_t dts, u_int32_t pts)
 {
     int ret = ERROR_SUCCESS;
     
-    srs_assert(frame_size > 1);
+    srs_assert(frames_size > 1);
     
     srs_assert(rtmp != NULL);
     Context* context = (Context*)rtmp;
     
-    // 5bits, 7.3.1 NAL unit syntax, 
+    /*// 5bits, 7.3.1 NAL unit syntax, 
     // H.264-AVC-ISO_IEC_14496-10.pdf, page 44.
     //  7: SPS, 8: PPS, 5: I Frame, 1: P Frame
     u_int8_t nal_unit_type = (char)frame[0] & 0x1f;
     
-    /*// the timestamp in rtmp message header is dts.
+    // the RTMP packet header
+    
+    // the timestamp in rtmp message header is dts.
     u_int32_t timestamp = dts;
     
     // for h264 in RTMP video payload, there is 5bytes header:

@@ -338,21 +338,51 @@ extern char* srs_amf0_human_print(srs_amf0_t amf0, char** pdata, int* psize);
 *************************************************************/
 /**
 * write h.264 raw frame over RTMP to rtmp server.
-* @param frame the input h264 raw data, an encoded h.264 I/P/B frame data.
-*       the frame without h.264 annexb header, by N[00] 00 00 01, where N>=0, 
-*       for instance, header(00 00 00 01) + frame(67 42 80 29 95 A0 14 01 6E 40)
-* @paam frame_size the size of h264 raw data. 
-*       assert frame_size > 1, at least has 1 bytes header.
+* @param frames the input h264 raw data, encoded h.264 I/P/B frames data.
+*       frames can be one or more than one frame,
+*       each frame prefixed h.264 annexb header, by N[00] 00 00 01, where N>=0, 
+*       for instance, frame = header(00 00 00 01) + payload(67 42 80 29 95 A0 14 01 6E 40)
+* @paam frames_size the size of h264 raw data. 
+*       assert frames_size > 1, at least has 1 bytes header.
 * @param dts the dts of h.264 raw data.
 * @param pts the pts of h.264 raw data.
 * 
-* @remark, user should free the frame.
+* @remark, user should free the frames.
 * @remark, the tbn of dts/pts is 1/1000 for RTMP, that is, in ms.
 * 
 * @return 0, success; otherswise, failed.
 */
-extern int srs_write_h264_raw_frame(srs_rtmp_t rtmp, 
-    char* frame, int frame_size, u_int32_t dts, u_int32_t pts
+/**
+For the example file: 
+    http://winlinvip.github.io/srs.release/3rdparty/720p.h264.raw
+The data sequence is:
+    // SPS
+    000000016742802995A014016E40
+    // PPS
+    0000000168CE3880
+    // IFrame
+    0000000165B8041014C038008B0D0D3A071.....
+    // PFrame
+    0000000141E02041F8CDDC562BBDEFAD2F.....
+User can send the SPS+PPS, then each frame:
+    // SPS+PPS
+    srs_write_h264_raw_frame('000000016742802995A014016E400000000168CE3880', size, dts, pts)
+    // IFrame
+    srs_write_h264_raw_frame('0000000165B8041014C038008B0D0D3A071......', size, dts, pts)
+    // PFrame
+    srs_write_h264_raw_frame('0000000141E02041F8CDDC562BBDEFAD2F......', size, dts, pts)
+User also can send one by one:
+    // SPS
+    srs_write_h264_raw_frame('000000016742802995A014016E4', size, dts, pts)
+    // PPS
+    srs_write_h264_raw_frame('00000000168CE3880', size, dts, pts)
+    // IFrame
+    srs_write_h264_raw_frame('0000000165B8041014C038008B0D0D3A071......', size, dts, pts)
+    // PFrame
+    srs_write_h264_raw_frame('0000000141E02041F8CDDC562BBDEFAD2F......', size, dts, pts) 
+*/
+extern int srs_write_h264_raw_frames(srs_rtmp_t rtmp, 
+    char* frames, int frames_size, u_int32_t dts, u_int32_t pts
 );
 /**
 * whether h264 raw data starts with the annexb,