Changeset 2850 for pjproject/trunk/pjmedia/src/pjmedia/stream.c

Timestamp:

Aug 1, 2009 9:20:59 AM (15 years ago)

Author:

bennylp

Message:

Initial commit for ticket #929: Improve packet lost concealment (PLC) when handling burst of lost packets

WSOLA improvements:

• Introduce fade-out and fade-in effect
• Limit the number of continuous synthetic samples (only take effect when fading is used)
• Export many settings as macros:
  • PJMEDIA_WSOLA_DELAY_MSEC (was HANNING_PTIME)
  • PJMEDIA_WSOLA_TEMPLATE_LENGTH_MSEC (was TEMPLATE_PTIME)
  • PJMEDIA_WSOLA_MAX_EXPAND_MSEC

PLC:

• added compile time macro PJMEDIA_WSOLA_PLC_NO_FADING to disable fading (default enabled)

Stream:

• fixed bug when stream is not PLC-ing subsequent packet loss (only the first)
• also add maximum PLC limit just as precaution if PLC doesn't limit number of synthetic frames
• unrelated: fixed warning about unused send_keep_alive() function

Delaybuf:

• modified to NOT use fading in WSOLA since we don't expect it to generate many continuous synthetic frames

File:

• pjproject/trunk/pjmedia/src/pjmedia/stream.c (modified) (15 diffs)

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

@@ -44 +44 @@
 #define BYTES_PER_SAMPLE                2
 
+/* Limit the number of synthetic audio samples that are generated by PLC.
+ * Normally PLC should have it's own means to limit the number of
+ * synthetic frames, so we need to set this to a reasonably large value
+ * just as precaution
+ */
+#define MAX_PLC_MSEC                    240
+
 /**
  * Media channel.
@@ -99 +106 @@
     unsigned                 enc_buf_count; /**< Number of samples in the
                                                  encoding buffer.           */
+
+    unsigned                 plc_cnt;       /**< # of consecutive PLC frames*/
+    unsigned                 max_plc_cnt;   /**< Max # of PLC frames        */
 
     unsigned                 vad_enabled;   /**< VAD enabled in param.      */
@@ -198 +208 @@
 }
 
+#if defined(PJMEDIA_STREAM_ENABLE_KA) && PJMEDIA_STREAM_ENABLE_KA != 0
 /*
- * Send keep-alive packet.
+ * Send keep-alive packet using non-codec frame.
  */
 static void send_keep_alive_packet(pjmedia_stream *stream)
 {
-#if defined(PJMEDIA_STREAM_ENABLE_KA) && \
-    PJMEDIA_STREAM_ENABLE_KA == PJMEDIA_STREAM_KA_EMPTY_RTP
+#if PJMEDIA_STREAM_ENABLE_KA == PJMEDIA_STREAM_KA_EMPTY_RTP
 
     /* Keep-alive packet is empty RTP */
@@ -225 +235 @@
     TRC_((stream->port.info.name.ptr, "Keep-alive sent (empty RTP)"));
 
-#elif defined(PJMEDIA_STREAM_ENABLE_KA) && \
-      PJMEDIA_STREAM_ENABLE_KA == PJMEDIA_STREAM_KA_USER
+#elif PJMEDIA_STREAM_ENABLE_KA == PJMEDIA_STREAM_KA_USER
 
     /* Keep-alive packet is defined in PJMEDIA_STREAM_KA_USER_PKT */
@@ -244 +253 @@
 #endif
 }
+#endif  /* defined(PJMEDIA_STREAM_ENABLE_KA) */
 
 /*
@@ -295 +305 @@
             /* Activate PLC */
             if (stream->codec->op->recover && 
-                stream->codec_param.setting.plc) 
+                stream->codec_param.setting.plc &&
+                stream->plc_cnt < stream->max_plc_cnt) 
             {
                 pjmedia_frame frame_out;
@@ -305 +316 @@
                                                        &frame_out);
 
+                ++stream->plc_cnt;
+
             } else {
                 status = -1;
@@ -319 +332 @@
                           "Lost frame recovered"));
             }
-            
+
         } else if (frame_type == PJMEDIA_JB_ZERO_EMPTY_FRAME) {
 
@@ -326 +339 @@
              * the frame. 
              */
-            if (frame_type != stream->jb_last_frm) {
+            //Using this "if" will only invoke PLC for the first packet
+            //lost and not the subsequent ones.
+            //if (frame_type != stream->jb_last_frm) {
+            if (1) {
                 pjmedia_jb_state jb_state;
                 const char *with_plc = "";
@@ -332 +348 @@
                 /* Activate PLC to smoothen the missing frame */
                 if (stream->codec->op->recover && 
-                    stream->codec_param.setting.plc) 
+                    stream->codec_param.setting.plc &&
+                    stream->plc_cnt < stream->max_plc_cnt) 
                 {
                     pjmedia_frame frame_out;
@@ -344 +361 @@
                         if (status != PJ_SUCCESS)
                             break;
+
                         samples_count += samples_per_frame;
-
-                    } while (samples_count < samples_required);
+                        ++stream->plc_cnt;
+
+                    } while (samples_count < samples_required &&
+                             stream->plc_cnt < stream->max_plc_cnt);
 
                     with_plc = ", plc invoked";
@@ -380 +400 @@
             /* Always activate PLC when it's available.. */
             if (stream->codec->op->recover && 
-                stream->codec_param.setting.plc) 
+                stream->codec_param.setting.plc &&
+                stream->plc_cnt < stream->max_plc_cnt) 
             {
                 pjmedia_frame frame_out;
@@ -394 +415 @@
                     samples_count += samples_per_frame;
 
-                } while (samples_count < samples_required);
-
-                if (stream->jb_last_frm != frame_type) {
+                    ++stream->plc_cnt;
+
+                } while (samples_count < samples_required &&
+                         stream->plc_cnt < stream->max_plc_cnt);
+
+                //if (stream->jb_last_frm != frame_type) {
+                if (1) {
                     PJ_LOG(5,(stream->port.info.name.ptr, 
                               "Jitter buffer is bufferring with plc (prefetch=%d)",
@@ -419 +444 @@
             /* Got "NORMAL" frame from jitter buffer */
             pjmedia_frame frame_in, frame_out;
+
+            stream->plc_cnt = 0;
 
             /* Decode */
@@ -1822 +1849 @@
         ++stream->frame_size;
     }
+
+    /* How many consecutive PLC frames can be generated */
+    stream->max_plc_cnt = (MAX_PLC_MSEC+stream->codec_param.info.frm_ptime-1)/
+                            stream->codec_param.info.frm_ptime;
 
 #if defined(PJMEDIA_HANDLE_G722_MPEG_BUG) && (PJMEDIA_HANDLE_G722_MPEG_BUG!=0)