Changeset 1813

Timestamp:

Feb 21, 2008 4:46:34 PM (17 years ago)

Author:

bennylp

Message:

Ticket #486: Handle G.722 wong clock rate bug and other codec with inconsistent clock rate

Location:

pjproject/trunk/pjmedia

Files:

• include/pjmedia/config.h (modified) (2 diffs)
• src/pjmedia/endpoint.c (modified) (1 diff)
• src/pjmedia/session.c (modified) (1 diff)
• src/pjmedia/stream.c (modified) (18 diffs)

pjproject/trunk/pjmedia/include/pjmedia/config.h

@@ -486 +486 @@
 
 /**
- * SRTP Transport
+ * Enable support for SRTP media transport. This will require linking
+ * with libsrtp from the third_party directory.
+ *
  * By default it is enabled.
  */
@@ -495 +497 @@
 
 /**
+ * Enable support to handle codecs with inconsistent clock rate
+ * between clock rate in SDP/RTP & the clock rate that is actually used.
+ * This happens for example with G.722 and MPEG audio codecs.
+ * See:
+ *  - G.722      : RFC 3551 4.5.2
+ *  - MPEG audio : RFC 3551 4.5.13 & RFC 3119
+ *
+ * Also when this feature is enabled, some handling will be performed
+ * to deal with clock rate incompatibilities of some phones.
+ *
+ * By default it is enabled.
+ */
+#ifndef PJMEDIA_HANDLE_G722_MPEG_BUG
+#   define PJMEDIA_HANDLE_G722_MPEG_BUG             1
+#endif
+
+
+/**
  * @}
  */

pjproject/trunk/pjmedia/src/pjmedia/endpoint.c

@@ -413 +413 @@
 
         rtpmap.pt = *fmt;
+        rtpmap.enc_name = codec_info->encoding_name;
+
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG != 0)
+        if (codec_info->pt == PJMEDIA_RTP_PT_G722)
+            rtpmap.clock_rate = 8000;
+        else
+            rtpmap.clock_rate = codec_info->clock_rate;
+#else
         rtpmap.clock_rate = codec_info->clock_rate;
-        rtpmap.enc_name = codec_info->encoding_name;
-        
+#endif
+
         /* For audio codecs, rtpmap parameters denotes the number
          * of channels, which can be omited if the value is 1.

pjproject/trunk/pjmedia/src/pjmedia/session.c

@@ -389 +389 @@
             si->fmt.clock_rate = rtpmap->clock_rate;
             
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG != 0)
+            /* The session info should have the actual clock rate, because 
+             * this info is used for calculationg buffer size, etc in stream */
+            if (si->fmt.pt == PJMEDIA_RTP_PT_G722)
+                si->fmt.clock_rate = 16000;
+#endif
+
             /* For audio codecs, rtpmap parameters denotes the number of
              * channels.

pjproject/trunk/pjmedia/src/pjmedia/stream.c

@@ -93 +93 @@
                                                  Otherwise it's NULL.       */
 
-    unsigned                 enc_samples_per_frame;
+    unsigned                 enc_samples_per_pkt;
     unsigned                 enc_buf_size;  /**< Encoding buffer size, in
                                                  samples.                   */
@@ -132 +132 @@
     void                    (*dtmf_cb)(pjmedia_stream*, void*, int);
     void                     *dtmf_cb_user_data;
+
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG!=0)
+    /* Enable support to handle codecs with inconsistent clock rate
+     * between clock rate in SDP/RTP & the clock rate that is actually used.
+     * This happens for example with G.722 and MPEG audio codecs.
+     */
+    pj_bool_t                has_g722_mpeg_bug;
+                                            /**< Flag to specify whether 
+                                                 normalization process 
+                                                 is needed                  */
+    unsigned                 rtp_tx_samples_per_pkt;
+                                            /**< Normalized samples per packet 
+                                                 transmitted according to 
+                                                 'erroneous' definition     */
+    unsigned                 rtp_rx_samples_per_frame;
+                                            /**< Normalized samples per frame 
+                                                 received according to 
+                                                 'erroneous' definition     */
+    pj_uint32_t              rtp_rx_last_ts;/**< Last received RTP timestamp
+                                                 for timestamp checking     */
+    unsigned                 rtp_rx_last_cnt;/**< Nb of frames in last pkt  */
+    unsigned                 rtp_rx_check_cnt;
+                                            /**< Counter of remote timestamp
+                                                 checking */
+#endif
+
 };
 
@@ -522 +548 @@
     pj_status_t status = 0;
     pjmedia_frame frame_out;
-    unsigned ts_len, samples_per_frame;
+    unsigned ts_len, rtp_ts_len, samples_per_frame;
     void *rtphdr;
     int rtphdrlen;
@@ -542 +568 @@
     stream->tx_duration += ts_len;
 
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG!=0)
+    /* Handle special case for audio codec with RTP timestamp inconsistence 
+     * e.g: G722, MPEG audio.
+     */
+    if (stream->has_g722_mpeg_bug)
+        rtp_ts_len = stream->rtp_tx_samples_per_pkt;
+    else
+        rtp_ts_len = ts_len;
+#else
+    rtp_ts_len = ts_len;
+#endif
+
     /* Init frame_out buffer. */
     frame_out.buf = ((char*)channel->out_pkt) + sizeof(pjmedia_rtp_hdr);
@@ -547 +585 @@
 
     /* Calculate number of samples per frame */
-    samples_per_frame = stream->enc_samples_per_frame;
+    samples_per_frame = stream->enc_samples_per_pkt;
 
 
@@ -564 +602 @@
         status = pjmedia_rtp_encode_rtp( &channel->rtp, 
                                          stream->tx_event_pt, first, 
-                                         frame_out.size, (first?ts_len:0), 
+                                         frame_out.size,
+                                         (first ? rtp_ts_len : 0), 
                                          (const void**)&rtphdr, 
                                          &rtphdrlen);
@@ -573 +612 @@
              * RTP packets.
              */
-            inc_timestamp = PJMEDIA_DTMF_DURATION - ts_len;
+            inc_timestamp = PJMEDIA_DTMF_DURATION - rtp_ts_len;
         }
 
@@ -641 +680 @@
         status = pjmedia_rtp_encode_rtp( &channel->rtp, 
                                          channel->pt, 0, 
-                                         frame_out.size, ts_len, 
+                                         frame_out.size, rtp_ts_len, 
                                          (const void**)&rtphdr, 
                                          &rtphdrlen);
@@ -649 +688 @@
         status = pjmedia_rtp_encode_rtp( &channel->rtp, 
                                          0, 0, 
-                                         0, ts_len, 
+                                         0, rtp_ts_len, 
                                          (const void**)&rtphdr, 
                                          &rtphdrlen);
@@ -730 +769 @@
     unsigned samples_per_frame;
 
-    samples_per_frame = stream->enc_samples_per_frame;
+    samples_per_frame = stream->enc_samples_per_pkt;
 
     /* http://www.pjsip.org/trac/ticket/56:
@@ -807 +846 @@
              * rebuffer() with NULL frame.
              */
-            if (stream->enc_buf_count >= stream->enc_samples_per_frame) {
+            if (stream->enc_buf_count >= stream->enc_samples_per_pkt) {
 
                 tmp_rebuffer_frame.type = PJMEDIA_FRAME_TYPE_NONE;
@@ -1027 +1066 @@
         pj_timestamp ts;
         unsigned i, count = MAX;
-        unsigned samples_per_frame;
+        unsigned ts_span;
         pjmedia_frame frames[MAX];
 
@@ -1047 +1086 @@
         }
 
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG!=0)
+        /* This code is used to learn the samples per frame value that is put
+         * by remote endpoint, for codecs with inconsistent clock rate such
+         * as G.722 or MPEG audio. We need to learn the samples per frame 
+         * value as it is used as divider when inserting frames into the
+         * jitter buffer.
+         */
+        if (stream->has_g722_mpeg_bug) {
+            if (stream->rtp_rx_check_cnt) {
+                /* Make sure the detection performed only on two consecutive 
+                 * packets with valid RTP sequence and no wrapped timestamp.
+                 */
+                if (seq_st.diff == 1 && stream->rtp_rx_last_ts && 
+                    ts.u64 > stream->rtp_rx_last_ts)
+                {
+                    unsigned peer_frm_ts_diff;
+
+                    peer_frm_ts_diff = 
+                        ((pj_uint32_t)ts.u64-stream->rtp_rx_last_ts) / 
+                        stream->rtp_rx_last_cnt;
+
+                    /* Possibilities remote's samples per frame for G.722 
+                     * are only 160 and 320, this validation is needed
+                     * to avoid wrong decision because of silence frames.
+                     */
+                    if (stream->codec_param.info.pt == PJMEDIA_RTP_PT_G722 &&
+                        (peer_frm_ts_diff==stream->port.info.samples_per_frame
+                         || peer_frm_ts_diff == 
+                                    stream->port.info.samples_per_frame >> 1))
+                    {
+                        if (peer_frm_ts_diff < stream->rtp_rx_samples_per_frame)
+                            stream->rtp_rx_samples_per_frame = peer_frm_ts_diff;
+
+                        if (--stream->rtp_rx_check_cnt == 0) {
+                            PJ_LOG(4, (THIS_FILE, "G722 codec used, remote"
+                                       " samples per frame detected = %d", 
+                                       stream->rtp_rx_samples_per_frame));
+                            
+                            /* Reset jitter buffer once detection done */
+                            pjmedia_jbuf_reset(stream->jb);
+                        }
+                    }
+                }
+
+                stream->rtp_rx_last_ts = (pj_uint32_t)ts.u64;
+                stream->rtp_rx_last_cnt = count;
+            }
+
+            ts_span = stream->rtp_rx_samples_per_frame;
+
+        } else {
+            ts_span = stream->codec_param.info.frm_ptime * 
+                      stream->codec_param.info.clock_rate *
+                      stream->codec_param.info.channel_cnt /
+                      1000;
+        }
+#else
+        ts_span = stream->codec_param.info.frm_ptime * 
+                  stream->codec_param.info.clock_rate *
+                  stream->codec_param.info.channel_cnt /
+                  1000;
+#endif
+
         /* Put each frame to jitter buffer. */
-        samples_per_frame = stream->codec_param.info.frm_ptime * 
-                            stream->codec_param.info.clock_rate *
-                            stream->codec_param.info.channel_cnt /
-                            1000;
-                            
         for (i=0; i<count; ++i) {
             unsigned ext_seq;
 
-            ext_seq = (unsigned)(frames[i].timestamp.u64 /
-                                 samples_per_frame);
+            ext_seq = (unsigned)(frames[i].timestamp.u64 / ts_span);
             pjmedia_jbuf_put_frame(stream->jb, frames[i].buf, 
                                    frames[i].size, ext_seq);
@@ -1190 +1286 @@
     name.ptr = (char*) pj_pool_alloc(pool, M);
     name.slen = pj_ansi_snprintf(name.ptr, M, "strm%p", stream);
-
 
     /* Init some port-info. Some parts of the info will be set later
@@ -1264 +1359 @@
                                         1000;
 
-
     /* Open the codec: */
 
@@ -1280 +1374 @@
         unsigned ptime;
 
-        stream->enc_samples_per_frame = stream->codec_param.info.enc_ptime *
-                                        stream->port.info.clock_rate / 1000;
+        stream->enc_samples_per_pkt = stream->codec_param.info.enc_ptime *
+                                      stream->port.info.clock_rate / 1000;
 
         /* Set buffer size as twice the largest ptime value between
@@ -1304 +1398 @@
 
     } else {
-        stream->enc_samples_per_frame = stream->port.info.samples_per_frame;
-    }
+        stream->enc_samples_per_pkt = stream->port.info.samples_per_frame;
+    }
+
 
     /* Initially disable the VAD in the stream, to help traverse NAT better */
@@ -1322 +1417 @@
 
 
+#if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG!=0)
+    stream->rtp_rx_check_cnt = 5;
+    stream->has_g722_mpeg_bug = PJ_FALSE;
+    stream->rtp_rx_last_ts = 0;
+    stream->rtp_rx_last_cnt = 0;
+    stream->rtp_tx_samples_per_pkt = stream->enc_samples_per_pkt;
+    stream->rtp_rx_samples_per_frame = stream->port.info.samples_per_frame;
+
     /* Init RTCP session: */
 
+    /* Special case for G.722 */
+    if (info->fmt.pt == PJMEDIA_RTP_PT_G722) {
+        pjmedia_rtcp_init(&stream->rtcp, stream->port.info.name.ptr,
+                          8000, 
+                          160,
+                          info->ssrc);
+        stream->has_g722_mpeg_bug = PJ_TRUE;
+        /* RTP clock rate = 1/2 real clock rate */
+        stream->rtp_tx_samples_per_pkt >>= 1;
+    } else {
+        pjmedia_rtcp_init(&stream->rtcp, stream->port.info.name.ptr,
+                          info->fmt.clock_rate, 
+                          stream->port.info.samples_per_frame, 
+                          info->ssrc);
+    }
+#else
     pjmedia_rtcp_init(&stream->rtcp, stream->port.info.name.ptr,
                       info->fmt.clock_rate, 
                       stream->port.info.samples_per_frame, 
                       info->ssrc);
-
+#endif
 
     /* Init jitter buffer parameters: */