From 91744a1f148ef6d8dbaaf74ae3b331b1faf34b6b Mon Sep 17 00:00:00 2001
From: Lyubomir Marinov <lyubomir.marinov@jitsi.org>
Date: Wed, 4 Jun 2014 20:23:18 +0300
Subject: [PATCH] Fixes a false reporting of SSRC audio levels when such are
negotiated but not sent.
---
src/org/jitsi/impl/neomedia/RawPacket.java | 63 +++++++++++++------
.../transform/csrc/SsrcTransformEngine.java | 2 +-
2 files changed, 46 insertions(+), 19 deletions(-)
diff --git a/src/org/jitsi/impl/neomedia/RawPacket.java b/src/org/jitsi/impl/neomedia/RawPacket.java
index b2929221..c4f4805b 100644
--- a/src/org/jitsi/impl/neomedia/RawPacket.java
+++ b/src/org/jitsi/impl/neomedia/RawPacket.java
@@ -240,7 +240,14 @@ public long[] extractCsrcAudioLevels(byte csrcExtID)
int csrcLevelsIndex = 2 * i;
csrcLevels[csrcLevelsIndex] = 0xFFFFFFFFL & readInt(csrcStartIndex);
- csrcLevels[csrcLevelsIndex + 1] = getCsrcAudioLevel(csrcExtID, i);
+ /*
+ * The audio levels generated by Jitsi are not in accord with the
+ * respective specification, they are backwards with respect to the
+ * value domain. Which means that the audio level generated from a
+ * muted audio source is 0/zero.
+ */
+ csrcLevels[csrcLevelsIndex + 1]
+ = getCsrcAudioLevel(csrcExtID, i, (byte) 0);
}
return csrcLevels;
@@ -267,13 +274,29 @@ public long[] extractCsrcList()
return csrcList;
}
+ /**
+ * Extracts the source audio level reported by the remote party which sent
+ * this packet and carried in this packet.
+ *
+ * @param ssrcExtID the ID of the extension that's transporting ssrc audio
+ * levels in the session that this <tt>RawPacket</tt> belongs to
+ * @return the source audio level reported by the remote party which sent
+ * this packet and carried in this packet or a negative value if this packet
+ * contains no extension such as the specified by <tt>ssrcExtID</tt>
+ */
public byte extractSsrcAudioLevel(byte ssrcExtID)
{
/*
* The method getCsrcAudioLevel(byte, int) is implemented with the
* awareness that there may be a flag bit V with a value other than 0.
*/
- return getCsrcAudioLevel(ssrcExtID, 0);
+ /*
+ * The audio levels sent by Google Chrome are in accord with the
+ * specification i.e. the audio level generated from a muted audio
+ * source is 127 and the values are non-negative. If there is no source
+ * audio level in this packet, return a negative value.
+ */
+ return getCsrcAudioLevel(ssrcExtID, 0, Byte.MIN_VALUE);
}
/**
@@ -375,26 +398,30 @@ public byte[] getBuffer()
* @return the CSRC audio level at the specified index of the csrc audio
* level option or <tt>0</tt> if there was no level at that index.
*/
- private byte getCsrcAudioLevel(byte csrcExtID, int index)
+ private byte getCsrcAudioLevel(byte csrcExtID, int index, byte defaultValue)
{
- if( !getExtensionBit() || getExtensionLength() == 0)
- return 0;
-
- int levelsStart = findExtension(csrcExtID);
+ byte level = defaultValue;
- if(levelsStart == -1)
- return 0;
-
- int levelsCount = getLengthForExtension(levelsStart);
-
- if(levelsCount < index)
+ if (getExtensionBit() && getExtensionLength() != 0)
{
- //apparently the remote side sent more CSRCs than levels.
- // ... yeah remote sides do that now and then ...
- return 0;
- }
+ int levelsStart = findExtension(csrcExtID);
- return (byte) (0x7F & buffer[levelsStart + index]);
+ if (levelsStart != -1)
+ {
+ int levelsCount = getLengthForExtension(levelsStart);
+
+ if (levelsCount < index)
+ {
+ //apparently the remote side sent more CSRCs than levels.
+ // ... yeah remote sides do that now and then ...
+ }
+ else
+ {
+ level = (byte) (0x7F & buffer[levelsStart + index]);
+ }
+ }
+ }
+ return level;
}
/**
diff --git a/src/org/jitsi/impl/neomedia/transform/csrc/SsrcTransformEngine.java b/src/org/jitsi/impl/neomedia/transform/csrc/SsrcTransformEngine.java
index d940ea44..17ce4251 100644
--- a/src/org/jitsi/impl/neomedia/transform/csrc/SsrcTransformEngine.java
+++ b/src/org/jitsi/impl/neomedia/transform/csrc/SsrcTransformEngine.java
@@ -239,7 +239,7 @@ public RawPacket reverseTransform(RawPacket pkt)
* Notify the AudioMediaStream associated with this instance about
* the received audio level.
*/
- if (!dropPkt && (csrcAudioLevelDispatcher != null))
+ if (!dropPkt && (csrcAudioLevelDispatcher != null) && (level >= 0))
{
long[] levels = new long[2];
--
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