[opendtv] Re: Ride in the Harris-LG MPH bus
- From: Mark Schubin <tvmark@xxxxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 17 Apr 2007 18:50:18 -0500 (GMT-05:00)
They provided audio monitoring for only the most robust channel.
TTFN,
Mark
-----Original Message-----
>From: John Willkie <johnwillkie@xxxxxxxxxxxxx>
>Sent: Apr 17, 2007 12:41 PM
>To: opendtv@xxxxxxxxxxxxx
>Subject: [opendtv] Re: Ride in the Harris-LG MPH bus
>
>Thansk, Mark.
>
>Screen size might have been relevant if you were watching on a 2" screen.
>
>Was the same audio service used for all services?
>
>John
>----- Original Message -----
>From: "Mark Schubin" <tvmark@xxxxxxxxxxxxx>
>To: <opendtv@xxxxxxxxxxxxx>
>Sent: Tuesday, April 17, 2007 7:20 AM
>Subject: [opendtv] Re: Ride in the Harris-LG MPH bus
>
>
>> Screen size should be irrelevant. There was a large flat-screen TV
>> divided into four segments: the output of the 5th-generation LG
>> receiver, the outputs of the two MPH prototype receivers, and a spectrum
>> analyzer. Everything was SD. When the main signal failed, it was
>> pretty obvious -- no need to see macroblocks. The robust sub-channels
>> were low quality, but they're limited only by what can be encoded and
>> decoded into that data rate. Harris and LG are not making the encoders
>> (at least not yet).
>>
>> Actually, there's an error in my previous message. The quarter-rate
>> subchannel did take one hit in a sort of tunnel.
>>
>> TTFN,
>> Mark
>>
>> John Willkie wrote:
>> > Mark;
>> >
>> > Screen size? Apparent quality of the video?
>> >
>> > John Willkie
>> > ----- Original Message -----
>> > From: "Mark Schubin" <tvmark@xxxxxxxxxxxxx>
>> > To: "Open DTV Forum" <opendtv@xxxxxxxxxxxxx>
>> > Sent: Monday, April 16, 2007 10:04 PM
>> > Subject: [opendtv] Ride in the Harris-LG MPH bus
>> >
>> >
>> >
>> >> Transmission was from Sinclair's KVCW, channel 29, broadcasting from
>> >> Black Mountain at 750 kW ERP at 1086 feet HAAT. Two 2.2 Mbps
>> >> sub-channels were used for the robust transmission leaving 15 Mbps for
>> >> the main transmission. One sub-channel, using "half-rate"
>transmission,
>> >> had a payload of 557 kbps; the other, with "quarter rate," had 299
>> >> kbps. MPEG-4 AVC coding was used for those sub-channels.
>> >>
>> >> The antenna was one 6-inch untuned whip split four ways
>> >>
>> >> It was interesting to me that the main channel failed when the bus was
>> >> barely creeping. FYI, it was using a 5th-generation LG receiver.
>> >> Sometimes it seemed okay at speed. The "half-rate" sub-channel took a
>> >> few hits in the worst reception conditions. I take their word for it
>> >> that the "quarter-rate" sub-channel never took a hit (the decoder,
>> >> however, froze).
>> >>
>> >> The white-noise threshold is said to be 8 dB for the half-rate channel
>> >> and 4 dB for the quarter-rate.
>> >>
>> >> I'm told the A-VSB demo also uses two 2.2 Mbps robust sub-channels.
>> >> Their "half-rate" is about 1 Mbps and "quarter-rate" about 500 kbps,
>but
>> >> they take a his of another 2.89 Mbps for the SRS signal.
>> >>
>> >> TTFN,
>> >> Mark
>> >>
>> >>
>> >>
>> >> ----------------------------------------------------------------------
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>> >
>> > ----------------------------------------------------------------------
>> > You can UNSUBSCRIBE from the OpenDTV list in two ways:
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>FreeLists.org
>> >
>> > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
>unsubscribe in the subject line.
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>> >
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>>
>> ----------------------------------------------------------------------
>> You can UNSUBSCRIBE from the OpenDTV list in two ways:
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>
>----------------------------------------------------------------------
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