playrtp: --dump support for ALSA and OSS backends

diff --git a/clients/playrtp-alsa.c b/clients/playrtp-alsa.c
index 263ab40045186ec7ddaeda7ff0bfac0ed8646c1e..142f1eef72823dbbfbd43c2e4aa1727a1c203888 100644 (file)
--- a/clients/playrtp-alsa.c
+++ b/clients/playrtp-alsa.c
@@ -30,6 +30,7 @@
 #include <alsa/asoundlib.h>
 #include <assert.h>
 #include <pthread.h>
+#include <arpa/inet.h>
 
 #include "mem.h"
 #include "log.h"
@@ -141,6 +142,15 @@ static int playrtp_alsa_writei(const void *s, size_t n) {
   } else {
     /* Success */
     next_timestamp += frames_written * 2;
+    if(dump_buffer) {
+      snd_pcm_sframes_t count;
+      const int16_t *sp = s;
+      
+      for(count = 0; count < frames_written * 2; ++count) {
+        dump_buffer[dump_index++] = (int16_t)ntohs(*sp++);
+        dump_index %= dump_size;
+      }
+    }
     return 0;
   }
 }

diff --git a/clients/playrtp-oss.c b/clients/playrtp-oss.c
index 7281e1559851371d7daea32952ef1393275774c3..b40947d69db41092e42bf58365fd732248ddd991 100644 (file)
--- a/clients/playrtp-oss.c
+++ b/clients/playrtp-oss.c
@@ -38,6 +38,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
+#include <arpa/inet.h>
 
 #include "mem.h"
 #include "log.h"
@@ -138,6 +139,15 @@ static int playrtp_oss_flush(void) {
       if(nbyteswritten < playrtp_oss_bufsize)
         error(0, "%s: short write (%d/%d)",
               device, nbyteswritten, playrtp_oss_bufsize);
+      if(dump_buffer) {
+        int count;
+        const int16_t *sp = (const int16_t *)playrtp_oss_buffer;
+        
+        for(count = 0; count < playrtp_oss_bufsize; count += sizeof(int16_t)) {
+          dump_buffer[dump_index++] = (int16_t)ntohs(*sp++);
+          dump_index %= dump_size;
+        }
+      }
       playrtp_oss_bufused = 0;
       return 0;
     }

diff --git a/clients/playrtp.c b/clients/playrtp.c
index 1263d7a012cc000085cb359a63a9d8ad20fae205..54107da94a3b9e8f09d960eb59c70736215375f3 100644 (file)
--- a/clients/playrtp.c
+++ b/clients/playrtp.c
@@ -192,9 +192,26 @@ HEAP_DEFINE(pheap, struct packet *, lt_packet);
 /** @brief Control socket or NULL */
 const char *control_socket;
 
+/** @brief Buffer for debugging dump
+ *
+ * The debug dump is enabled by the @c --dump option.  It records the last 20s
+ * of audio to the specified file (which will be about 3.5Mbytes).  The file is
+ * written as as ring buffer, so the start point will progress through it.
+ *
+ * Use clients/dump2wav to convert this to a WAV file, which can then be loaded
+ * into (e.g.) Audacity for further inspection.
+ *
+ * All three backends (ALSA, OSS, Core Audio) now support this option.
+ *
+ * The idea is to allow the user a few seconds to react to an audible artefact.
+ */
 int16_t *dump_buffer;
+
+/** @brief Current index within debugging dump */
 size_t dump_index;
-size_t dump_size = 44100 * 2 * 20; /* 20s */
+
+/** @brief Size of debugging dump in samples */
+size_t dump_size = 44100/*Hz*/ * 2/*channels*/ * 20/*seconds*/;
 
 static const struct option options[] = {
   { "help", no_argument, 0, 'h' },