[opendtv] Re: How About Portable ATSC Receivers?
- From: "John Willkie" <JohnWillkie@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 1 Apr 2005 10:36:17 -0800
First off, I don't understand your post.
Could you explain what PIDs are in the VCT, and just how these are
mismatched to PIDs that you assert are in the PMT? (I suspect that you mean
the SLD in the EIT-0 (missing events, apparently) versus the PMT PIDs, but I
see none of that here.
I have developed an application that can assess the MPEG-SI and PSIP in a
transport stream. I particularly love bad ts's. If you'd like me to run
this stream (I need at least 60 seconds) through my system, let me know.
Here's what I see in your print out (which I cannot vouch for, since I do
not know the system)
MGT; 4 EITS (0-3); RRT for region 1
The EITs are 15 bytes in length. That means they either indicate 0 events
and provide no event information, or they list up to 255 events are listed
in each EIT instance, but provide no event information. (14 bytes is the
minimum size of a PSIP table; 9 bytes for MPEG-2 header, 1 byte for ATSC
header, 4 bytes for CRC-32.)
Only two of the EITs are listed in the MGT.
The NIT listing is a hint that the encoder is probably a Tandberg (with the
factory settings on NIT not changed), which is only confirmed by the lowest
program_number in service being 3. (That's also the major PSIP problem;
mismatch of the program_number between TVCT and PMT.)
NO PID mismatch; items listed n the MGT which are not found in the
transport stream segment provided. How long in time is the number of
frames?
I've seen EIT-s with duty cycles of 11000 ms (recommendation 500 ms). Means
that people tuning to the channel have to wait up to 11 seconds for EPG
information. Kinda slows down channel surfing.
John Willkie
----- Original Message -----
From: "Ron Economos" <k6mpg@xxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Friday, April 01, 2005 3:23 AM
Subject: [opendtv] Re: How About Portable ATSC Receivers?
> Here's my favorite example of DTV apathy. I've
> dumped the Transport Stream from KFSF-DT below.
> KFSF-DT transmits from Sutro tower in San Francisco
> with 150 kW ERP. It's a TeleFutura affiliate.
> They have a great signal in Milpitas (tons better
> than the analog channel) and their SD video quality
> is really quite nice.
>
> As you can see, the TVCT PID's are mismatched from
> the PMT PID's. This will cause almost every ATSC
> receiver to display a black screen and no audio.
> It's been like this since January when they attempted
> to meet the 0x30 and above PID requirement.
>
> I think it may be possible that this DTV station
> has zero viewers.
>
> Ron
>
> program = 3, video channel = 1, audio channel = 1
>
> MGT tables defined = 6
>
> MGT table type = 0x0000
> MGT table type pid = 0x1ffb
> MGT table type version = 0x04
> MGT table bytes = 0x0000006d
> MGT table desc bytes = 0x0000
>
> MGT table type = 0x0100
> MGT table type pid = 0x1d00
> MGT table type version = 0x00
> MGT table bytes = 0x0000000e
> MGT table desc bytes = 0x0000
>
> MGT table type = 0x0101
> MGT table type pid = 0x1d01
> MGT table type version = 0x00
> MGT table bytes = 0x0000000e
> MGT table desc bytes = 0x0000
>
> MGT table type = 0x0102
> MGT table type pid = 0x1d02
> MGT table type version = 0x00
> MGT table bytes = 0x0000000e
> MGT table desc bytes = 0x0000
>
> MGT table type = 0x0103
> MGT table type pid = 0x1d03
> MGT table type version = 0x00
> MGT table bytes = 0x0000000e
> MGT table desc bytes = 0x0000
>
> MGT table type = 0x0301
> MGT table type pid = 0x1ffb
> MGT table type version = 0x00
> MGT table bytes = 0x000003e0
> MGT table desc bytes = 0x0000
>
> MGT desc bytes = 0x0000
> MGT CRC = 0x1b88f79a, 74, 74
>
> EIT0 events defined = 0
>
> Program Number = 0 (0x0000), Program Map PID = 4094 (0x0ffe)
> Program Number = 3 (0x0003), Program Map PID = 48 (0x0030)
> program descriptor = 0x05, 0x04, 0x47, 0x41, 0x39, 0x34
> program descriptor = 0x10, 0x06, 0xc0, 0xaf, 0xc8, 0xc0, 0x02, 0x00
> program descriptor = 0xa3, 0x0d, 0x01, 0x73, 0x70, 0x61, 0x01, 0x00, 0x00,
0x05, 0x50, 0x72, 0x6f, 0x67, 0x31
> ES descriptor for stream type 0x02 = 0x02, 0x03, 0x22, 0x48, 0x5f
> ES descriptor for stream type 0x02 = 0x06, 0x01, 0x02
> ES descriptor for stream type 0x81 = 0x05, 0x04, 0x41, 0x43, 0x2d, 0x33
> ES descriptor for stream type 0x81 = 0x81, 0x06, 0x08, 0x39, 0x05, 0x00,
0x00, 0x00
> ES descriptor for stream type 0x81 = 0x0a, 0x04, 0x73, 0x70, 0x61, 0x00
> ES descriptor for stream type 0x81 = 0x06, 0x01, 0x01
> ES descriptor for stream type 0x81 = 0x05, 0x04, 0x41, 0x43, 0x2d, 0x33
> ES descriptor for stream type 0x81 = 0x81, 0x06, 0x08, 0x31, 0x05, 0x00,
0x00, 0x00
> ES descriptor for stream type 0x81 = 0x0a, 0x04, 0x73, 0x70, 0x61, 0x00
> ES descriptor for stream type 0x81 = 0x06, 0x01, 0x01
>
> TVCT number of channels = 1
>
> TVCT short name = KFSF -
> TVCT channel number = 66.1
> TVCT modulation mode = 0x04
> TVCT channel TSID = 0x0000
> TVCT program number = 0x0001
> TVCT service type = 0x0002
> TVCT source id = 0x0001
> TVCT desc bytes = 0x003d
>
> SLD PCR pid = 0x0011
> SLD stream type = 0x02
> SLD elementary pid = 0x0011
> SLD language code =
>
> SLD stream type = 0x81
> SLD elementary pid = 0x0014
> SLD language code = spa
>
> SLD stream type = 0x81
> SLD elementary pid = 0x0015
> SLD language code = spa
>
> Extended Channel Name = (Identification and Address)
>
> TVCT additional desc bytes = 0x0000
> TVCT CRC = 0xda1c46d0, 100, 100
>
> Sequence Header found
> 11 frames before first Sequence Header
> Horizontal size = 704
> Vertical size = 480
> Aspect ratio = 4:3
> Frame rate = 29.97
> Sequence header bitrate = 9200000 bps
> Progressive Sequence = 0
> First Video PTS = 0x52962519
> First Audio PTS = 0x52962ecd, -396
> Audio Bitrate = 384000, Audio Sampling Rate = 48000
> Audio Mode = 2/0, bsid = 8, bsmod = 0
>
> EIT1 events defined = 0
>
> packets for pid 0 <0x0000> = 157, first = 869, last = 186713
> packets for pid 48 <0x0030> = 158, first = 273, last = 187309
> packets for pid 49 <0x0031> = 80614, first = 2, last = 187390
> packets for pid 52 <0x0034> = 4087, first = 14, last = 187373
> packets for pid 53 <0x0035> = 2718, first = 26, last = 187385
> packets for pid 7424 <0x1d00> = 502, first = 251, last = 186805
> packets for pid 7425 <0x1d01> = 1, first = 24338, last = 24338
> packets for pid 8187 <0x1ffb> = 195, first = 250, last = 186679
> packets for pid 8191 <0x1fff> = 98960, first = 1, last = 187392
> mpeg frames = 432, video fields = 864
>
> Terry Harvey wrote:
>
> >One consideration was left out of the flawed thought process below. As
with
> >Cable and Satellite STBs: why would anyone want one of those? The answer,
> >of course, is to receive services one cannot receive with an integrated
> >receiving device. Perhaps the real problem with DTV OTA is that there is
> >very little which is compelling to watch which would justify the
expenditure.
> >
> >Blaming the 8VSB transmission system to me is a cop out: there is little
> >mention of the struggle many local broadcaster's are facing with having
to
> >manipulate the DTV stream BEFORE 8VSB modulation. I can tell you from
> >experience that many broadcasters are having problems with the elements
of
> >their stream which prevent clear reception and seamless channel
navigation.
> >Matching MPEG-2 PSI tables with the PSIP TVCT, ensuring descriptors are
> >correct, that the TSID is inserted correctly in the PAT and TVCT etc, etc
> >will greatly affect the way the variety of DTV receivers will function.
> >Unfortunately, many local broadcasters are not investing in proper stream
> >management as well as proper 8VSB monitoring tools.
> >
> >The bottom line is that many broadcasters do not take DTV OTA seriously:
in
> >many cases, the transmitter was installed four years ago and the
> >manufacturer has to be called to make routine adjustments. Bear in mind
> >that any sophisticated digital modulation scheme depends upon a proper
> >analog setup adjustment to ensure adequate audience reach.
> >
> >So before jumping to superficial conclusions, please consider the above.
> >
> >Terry Harvey
> >
> >At 04:11 PM 3/31/2005, BenWebber@xxxxxxx wrote:
> >
> >
> >>John Shutt wrote:
> >>
> >>
> >>
> >>>If the United States were 90% wired (and/or DBS),
> >>>and Australia were0% wired, that would still make
> >>>a market of 10 million US TVHHs, and only 7
> >>>million AU TVHHs.
> >>>
> >>>Where is your logic? Mine says every manufacturer
> >>>that has tried to make an ATSC box has found out
> >>>they are difficult and expensive to make, don't work
> >>>very well, and there is too high of a return rate.
> >>>Therefore there is no profit in them. Yes, it is
> >>>market forces, but with, as the CEA claims, over
> >>>16.5 million DTV sets sold in the United States
> >>>since 1998, shouldn't that be a big enough market?
> >>>Bigger than Australia, and they have plenty of STBs
> >>>to choose from.
> >>>
> >>>
> >>Demand and market size are two different things. It doesn't matter how
> >>many dogs live in your town if they won't eat the dog food you're
> >>selling.
> >>
> >>There is negligible demand for standalone ATSC tuners (i.e., STBs) at
> >>present. Why? As a thought experiment, ask yourself what subset of U.S
> >>TVHHs would actually want to buy a standalone ATSC STB. Basically, that
> >>subset would include:
> >>
> >>a) a few thousand hobbyist and engineer types; and
> >>
> >>b) people who own a tuner-less DTV set AND for some reason don't want to
> >>watch HD via cable or satellite.
> >>
> >>
> >>Everybody else either:
> >>
> >>a) watches TV via cable or satellite;
> >>
> >>b) buys a DTV set with an integrated tuner;
> >>
> >>c) cannot afford a DTV set to begin with; or,
> >>
> >>d) is content with NTSC, and will only switch when forced by government
> >>fiat or attracted by a significantly better value proposition (e.g.,
> >>multiplex).
> >>
> >>
> >>Notice, I haven't said one word about manufacturing costs, receiver
> >>performance, or modulation scheme. Even if ATSC worked really well (I
> >>have no idea if it does or not), demand for standalone ATSC tuners would
> >>still be negligible.
> >>
> >>Regards,
> >>
> >>B.
> >>
> >>------------------------------------------
> >>Ben Webber Managing Director
> >>Psychofish, LLC ben@xxxxxxxxxxxxx
> >>180 N Stetson Ave #810 312-819-4042(v)
> >>Chicago, IL 60601 USA 312-819-4041(f)
> >>------------------------------------------
> >>
> >>
>
>
>
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