[opendtv] Re: No Commentary on Fox/NASCAR Broadcast
- From: "John Shutt" <shuttj@xxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 31 May 2007 12:56:28 -0400
Dan,
Refer these questions to the Chief Engineer of your local Fox affiliate.
Offer to mail him the VHS tape if he so desires so he can hear what you're
hearing. It sounds like a 2.0 to 5.1 switching error somewhere in the
chain, and I would give it a 99% chance that it is at the local affiliate.
When decoding 2.0 Dolby Digital to AES audio, you get Left on channel 1 and
Right on channel 2 of the first AES pair.
When decoding 5.1 Dolby Digital to AES audio, you have Left on channel 1 and
Right on channel 2 of the first AES pair, Center on channel 1 and Low
Frequency Effects on channel 2 of the second AES pair, and Left Rear on
channel 1 and Right Rear on channel 2 of the third AES pair.
If your local affiliate is only using the first AES pair for their NTSC
transmission, you will have normal audio during any 2.0 programming (or
program segments,) and have only the Left and Right effects of the 5.1 mix
during the 5.1 programming. Announcers are almost always in the Center
channel during 5.1, which would not make it to air with this problem at the
station.
I bet that if you listened to the ATSC broadcasts, there would be no audio
problems at all.
John Shutt
----- Original Message -----
From: <dan.grimes@xxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, May 31, 2007 12:17 PM
Subject: [opendtv] Re: No Commentary on Fox/NASCAR Broadcast
First, regarding my problem recording NASCAR races on FOX and getting only
natural sounds and not commentary, I listened a little more carefully and
found out a couple of things. They are in the answers to John Wilkie's,
Dale Kelly's and Richard Hollandsworth's questions and comments.
John Wilkie's Quesitions:
JW: Does your VCR record the SAP audio on other programming events on that
station? On other stations? Does your VCR permit to select
which audio service to record on a program-by-program basis?
DG: I don't know. I didn't think it would so I need to test it to find
out if this is even a possibility. There is a button on the remote to
select SAP/HiFi. This button does not control SAP during playback, only
for the receiver. During playback, it can select HiFi Stereo, HiFi Left,
HiFi Right, and Mono. It makes no difference which setting it is on, the
audio is the same. So I need to test if setting the live receiver to SAP
causes SAP to be recorded into the HiFi L/R tracks.
JW: What do you mean by "bleep?" Is this a click, a more refined sound, a
consistent sound, or are you just using that term to signify "something
different?"
DG: Remeber those TV remotes that used sound to change the channel by
hitting a couple of metal rods, creating a high pitch "chink"? That is the
sound only faint and only for a split second (about the same duration as
the remote) and only when the commentary comes in or out. The length can
be very short to the point that it is not noticeable.
JW: This interspersed commentary. Does it come in and go out in the
middle of a sentence, at the beginning or end of what a single person says,
or is it a coherent exchange between announcers?
DG: The commentary is there when the cars are not racing, completely
coherent. As soon as the cars take off, the loudness of the engines cuts
out the commentary in a gate fashion. And I mean completely cuts it out
and the racing noise is full loud. If the shot is an in-car cam, the
in-car audio is constant and there will be no commentary. If the shot is a
fixed camera and the cars go by the camera every so often, there is
commentary in between the cars but when a car races by, the commentary cuts
out and it goes full location sound. This can make the commentary very
long sometimes and very short, not even on word's length, at others. Also,
when the visual program stream is switched to another camera, the gate is
reset and the commentary comes back but only for a split second if there
are any engine noises.
JW: Is it always the 'play-by-play' person, or is it always the color
person?
DG: I don't know what "color person" means, but it doesn't matter whether
the commentary comes from the booth or in the pits, they are both cut off.
I'm not sure if the Hollywood Hotel gets through, but they usually aren't
racing when they go to that location.
JW: And, are you acquiring the Fox signal using an antenna to the VCR, or
is there cable somewhere?
DG: Here is the setup: Winegard antenna receiving KVVU Fox 5 from Black
Mountain, feeding an NTSC Panasonic VCR via a couple of passive splitters
and Belden RG-6 cable. I have no cable TV or ATSC in my house at this time
(I gave away my ATSC tuner because I couldn't watch NASCAR in HD, it was
too painful. The analog SD looks better on most programming...but that is
for another discussion). The VCR records stereo and the RF output feeds
the RF input of a Sony 13" video, mono audio television set. Just to see
if there was a difference, I played it back in similar Panasonic VCR
connected to a Dolby Pro Logic receiver. With Dolby Pro Logic on, all the
sound is in the center channel and sounds exactly like the mono speaker on
the other set up.
JW: What is HARD to imagine, is you noticing a consistent problem - I'm
assuming across multiple broadcasts - that wasn't heard in the control room
of the station.
DG: I can't imagine it being heard in the control room or they would do
something about it. This has happened on at least two other races I have
recorded. It is about the only thing I record so I don't know if it is in
other broadcasts. I did listen to SAP on other broadcasts, which can be
heard through the VCR, but it was no different than the main stereo
channels.
JW: If you didn't have the interspersed announcements, I'd say that your
just getting the 'b' audio.
DG: Yes, but why would there be any channels that had gated commentary?
JW: By the way, I've noticed a "very similar" problem for a few seconds to
minutes, a few months back, in Cox Cable San Diego carriage of CBS
programming on KFMB-TV: the main audio dropping out, but still being able
to hear the 'mix + effects and music' audio, and the problem disappearing
during commercials. I just turned off the shows - I mean, a sit-com
without dialog? First noticed in on a Friday ("Numbers", in the middle of
a show, corrected during the broadcast), then on a Monday and the following
Tuesday. Haven't seen it since.
DG: This is about what I am experiencing, repeatedly.
JW: The fact that it disappears during commercials is a good clue that the
problem comes out of the station's transmitter.
DG: I thought it might be coming from the live truck, whle the commercials
are good because they come from network headquarters.
JW: Have you thought to call the station?
DG: I sent an email to the station but haven't heard back. I know someone
over there so I am going to try and get a phone number to one of the
engineers to see if they know anything about it.
Dale Kelly's Questions:
DK: When you had this problem were you perhaps monitoring the tape
playback as mono audio or using an audio system with a center channel?
Sounds much like
a stereo phasing issue where left/right channels are 180 out of phase
somewhere. In a typical stereo sports production, announcer audio
isnormally L/R mono (center channel) therefore, when the stereo mix is
monitored on a mono audio system, the announcer audio is canceled while the
stereo stuff comes through. If I' m off base, please ignore!
DG: At first, I would have thought this to be a probability, but now that
I have listened more carefully, the problem is gating of the commentary
during loud engine bursts.
Richard Hollandsworth:
RH: From time to time I have heard programs that had a much reduced level
for the dialog.....this can occur for both DD5.1 and/or Stereo tracks. And
usually has reduced bass levels as well. Sometimes switching to Stereo
cures the problem...and sometimes not....
DG: I switched to stereo and the problem is the same. Like I said, it is
a gate, commentary goes away completely.
RH: Via Cable, there are separate DD5.1 and PCM Stereo data streams, so
sometimes I've noticed that only the DD5.1 signal is affected.....
DG: I briefly listened to the same broadcast off Cox Cable at a friend's
house and didn't notice the problem. I assume that Cox is getting there
feed from the same Black Mountain transmitter as I was receiving. This is
another reason I was looking at SAP being the problem audio.
- - -
Let me know what you think!
Dan Grimes
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