|author||Christophe Fergeau <email@example.com>||2010-08-17 20:27:55 +0200|
|committer||Christophe Fergeau <firstname.lastname@example.org>||2010-08-17 20:27:55 +0200|
|parent||describe "first" behaviour for RTP packets (diff)|
improve description of NTP timestamps
1 files changed, 5 insertions, 2 deletions
diff --git a/airtunes2.rst b/airtunes2.rst
index 195d178..f82f558 100644
@@ -164,8 +164,11 @@ RtpHeader
-This is an NTP Timestamp as described in RFC 3450 Section 4. and RFC 1305
-(TODO: check this is actually true)
+This is an NTP Timestamp as described in RFC 3450 Section 4. and RFC 1305.
+The timestamps used by iTunes and the device seems to come from a monotonic
+clock which starts at 0 when they just started/booted. This monotonic clock's
+origin of time is the unix epoch, which corresponds to 0x83aa7e80 seconds
+in NTP time.