[svn-commits] sruffell: branch 1.4 r293968 - /branches/1.4/codecs/codec_dahdi.c

[SVN commits to the Digium repositories]

Author: sruffell
Date: Thu Nov  4 19:02:53 2010
New Revision: 293968

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=293968
Log:
codecs/codec_dahdi: Prevent "choppy" audio when receiving unexpected frame sizes.

dahdi-linux 2.4.0 (specifically commit 9034) added the capability for
the wctc4xxp to return more than a single packet of data in response to
a read.  However, when decoding packets, codec_dahdi was still assuming
that the default number of samples was in each read.

In other words, each packet your provider sent you, regardless of size,
would result in 20 ms of decoded data (30 ms if decoding G723). If your
provider was sending 60 ms packets then codec_dahdi would end up
stripping 40 ms of data from each transcoded frame resulting in "choppy"
audio.

This would only affect systems where G729 packets are arriving in sizes
greater than 20ms or G723 packets arriving in sizes greater than 30ms.

DAHDI-744.

Modified:
    branches/1.4/codecs/codec_dahdi.c

Modified: branches/1.4/codecs/codec_dahdi.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.4/codecs/codec_dahdi.c?view=diff&rev=293968&r1=293967&r2=293968
==============================================================================
--- branches/1.4/codecs/codec_dahdi.c (original)
+++ branches/1.4/codecs/codec_dahdi.c Thu Nov  4 19:02:53 2010
@@ -120,10 +120,10 @@
 };
 
 /* Only used by a decoder */
-static int ulawtolin(struct ast_trans_pvt *pvt)
-{
-	struct codec_dahdi_pvt *ztp = pvt->pvt;
-	int i = ztp->required_samples;
+static int ulawtolin(struct ast_trans_pvt *pvt, int samples)
+{
+	struct codec_dahdi_pvt *ztp = pvt->pvt;
+	int i = samples;
 	uint8_t *src = &ztp->ulaw_buffer[0];
 	int16_t *dst = (int16_t *)pvt->outbuf + pvt->datalen;
 
@@ -345,7 +345,7 @@
 		}
 	} else {
 		if (ztp->softslin) {
-			ulawtolin(pvt);
+			ulawtolin(pvt, res);
 			pvt->f.datalen = res * 2;
 		} else {
 			pvt->f.datalen = res;
@@ -357,7 +357,7 @@
 		pvt->f.offset = AST_FRIENDLY_OFFSET;
 		pvt->f.src = pvt->t->name;
 		pvt->f.data = pvt->outbuf;
-		pvt->f.samples = ztp->required_samples;
+		pvt->f.samples = res;
 		pvt->samples = 0;
 
 		return ast_frisolate(&pvt->f);