[opendtv] Re: Superbowl XL(1080)I
- From: "Meehan, John" <JMeehan@xxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 7 Feb 2007 17:20:10 -0500
Uh, Oh! I've never seen that RC indicator on other streams.... I guess
I just broke the law by sending that Superbowl thumbnail over the Web,
huh?
I was just wondering if the null rate could be lowered at all.... (I've
seen other stations that are multicasting use rates in the neighborhood
of 1 Mbs for additional channels.)
It'd be nice to reduce the occurrence of null packets as much as
possible, no? (But I can't really say how many is "too many", though -
is there any sort of guideline?)
Too many nulls would mean that the quantizer / rate control settings
weren't optimal, right?
John Meehan
JVC
________________________________
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]
On Behalf Of John Willkie
Sent: Wednesday, February 07, 2007 4:43 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Superbowl XL(1080)I
John;
Null packets are what encoders provide when there is no other data to
send.
If the total data rate is more than 19.39 mb/sec, then you've got a
problem. There has to be a setting on the encoder or mux to specify the
maximum output bit rate and whether to furnish null packets to pad out
that bit rate, which is generally what one wants to do.
Video bps + audio bps + psip/psi bps + null packets bps = total bit rate
(assuming no packetized data streams)
I don't see any issue with bit rate in this sample. The mux rate is
19.39, there are no CRC-32 errors, no continuity_counter errors. If
there were too many bits per second, these would signal it.
I do wonder why the image looks to be 4:3, since HD video by definition
is 16:9.
Notice the redistribution control (rc) on the video?
Hth
John Willkie
EtherGuide Systems
________________________________
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]
On Behalf Of Meehan, John
Sent: Wednesday, February 07, 2007 1:23 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Superbowl XL(1080)I
Hello
The attached TSReader screen capture of the SuperBowl (CBS OTA in NYC),
shows an 18Mbps rate for video... Out of curiosity, has anyone looked at
streams from satellite or cable? Are they at the same rate?
Also, the null-packet rate is 832K - almost 1 Meg. Is there any way to
lower this with encoder settings?
<<cbs_super.gif>>
John Meehan
JVC
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