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PostPosted: Wed Oct 29, 2003 6:22 am Reply with quote
dlarrick
 
Joined: 22 Sep 2003
Posts: 58
Location: Outside Boston, MA




Hey, that's good news that you've got at least 2 stations with data. Like I said, I just have the one.

Alignment issues would not surprise me ... that Multiple String Structure that the various tables use is just weird. It's also possible you're seeing packet errors -- I'm not checking the CRCs on the various tables. There's code dtvscan to compute CRCs if you want to give it a shot.

-Doug
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PostPosted: Wed Oct 29, 2003 9:14 am Reply with quote
elwood
 
Joined: 26 Sep 2003
Posts: 67
Location: Phoenix, AZ




I think I'll take up your torch then. Might be time constrained with out of town visitors, but this is too cool to ignore.

Brad
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PostPosted: Mon Dec 08, 2003 2:56 pm Reply with quote
Taylor
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Have you guys made any progress on getting the PSIP data parsed out?
PostPosted: Tue Dec 09, 2003 2:48 pm Reply with quote
invisi
 
Joined: 29 Oct 2003
Posts: 8
Location: Minnesota




dlarrick wrote:
Hey, that's good news that you've got at least 2 stations with data. Like I said, I just have the one.

Alignment issues would not surprise me ... that Multiple String Structure that the various tables use is just weird. It's also possible you're seeing packet errors -- I'm not checking the CRCs on the various tables. There's code dtvscan to compute CRCs if you want to give it a shot.

-Doug


I also have two stations here with data. But, both are the "PBS" stations, as we have two. One of the two stations has 5 subchannels, while the other just has HD.

_________________
- Tim
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testinfo.C hacked to include CRC32 verification.
PostPosted: Tue Feb 17, 2004 6:27 am Reply with quote
Ulmo
 
Joined: 06 Nov 2003
Posts: 95
Location: Aptos,CA,USA




ftp://ftp.sonic.net/pub/users/ulmo/HW/pcHDTV/HD-2000/tools/choppatch
ftp://ftp.sonic.net/pub/users/ulmo/HW/pcHDTV/HD-2000/tools/hd2000_tools.tar.bz2
ftp://ftp.sonic.net/pub/users/ulmo/HW/pcHDTV/HD-2000/tools/hd2000_tools.tar.bz2.sig
ftp://ftp.sonic.net/pub/users/ulmo/HW/pcHDTV/HD-2000/tools/hd2000_tools.tar.sig

Since my last edit, I figured out the CRC used is the standard one, which is also in Linux kernel, so copied that code. Now it is bit-aligned, well tested, 32 bit efficient, and table oriented. Hopefully it will compile on various endians.

You should get my entire tools directory for the most recent one (URLs above).

---

Since my last edit, I created and verified the CRC32 table, put documentation in, and signed it.

---

I updated testinfo.C to calculate & verify CRC32s. There was a bug, and I implemented the CRC32 thing. Then, I found a table in Google of the data, and it seemed to work. I just re-created the same table, and they're equal, so I know they're both right. I wrote a big description of the CRC32, and also placed it into testinfo.C.

I'm slowly writing my own PSIP reader from nothing in order to find all the data in all my local channels. Meanwhile, I needed to test my CRC32 routine, so I hacked it into testinfo.C, and it works. It took me a while to find a bug in testinfo.C that was missing 3 bytes in the tables, but it's fixed. testinfo.C is a sandbox, definitely --- it's not very pretty inside. That's why I'm trying to rewrite. This is low priority for me; just for fun.

The rest of the tools can be found in this directory:

ftp://ftp.sonic.net/pub/users/ulmo/HW/pcHDTV/HD-2000/tools/


Last edited by Ulmo on Wed Feb 18, 2004 1:38 am; edited 1 time in total
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PostPosted: Wed Feb 18, 2004 1:17 am Reply with quote
Ulmo
 
Joined: 06 Nov 2003
Posts: 95
Location: Aptos,CA,USA




dlarrick wrote:
Hey, that's good news that you've got at least 2 stations with data. Like I said, I just have the one.

Alignment issues would not surprise me ... that Multiple String Structure that the various tables use is just weird. It's also possible you're seeing packet errors -- I'm not checking the CRCs on the various tables. There's code dtvscan to compute CRCs if you want to give it a shot.

-Doug


Oh. Well, that would have saved me some time. I didn't remember that you had said that dtvscan had CRC code in it. Yes, the CRC32 code is right there in dtvscan. At first it was nicer than mine, but my latest version uses a version from the kernel that has endian-aware 32 bit aligning; I wonder if that speeds it up much? I assume it can. Someone ought to make a 64 bit version, and I like the idea of generating the table after loading.

dtvscan has some nice stuff in it. Anyway, I'm going to continue making mine from nothing, so I know how it works and can design it without legacy code, and can diagnose whether or not the other stations are actually sending something or not.
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PostPosted: Thu Jan 06, 2005 12:38 am Reply with quote
Guest
 




Has anyone else noticed that psipguide doesn't work any more? There were some changes stations had to make by January 1st to be more compatible with DVB-T (one change was to move all subchannels to 3 and above). All stations in my area except one made the changes and psipguide doesn't work with them any more. It does still work with the one station that didn't make the changes.
PostPosted: Thu Jan 06, 2005 5:17 am Reply with quote
dlarrick
 
Joined: 22 Sep 2003
Posts: 58
Location: Outside Boston, MA




Anonymous wrote:
Has anyone else noticed that psipguide doesn't work any more?


I just ran psipguide on all my stations (Boston area) last night. It failed on one (WGBH) (no output at all) but I haven't had time to check into why. What symptom are you seeing.

Keep in mind that this program is a major hack, and is mostly intended as a diagnostic tool.
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PostPosted: Thu Jan 06, 2005 4:29 pm Reply with quote
Scott Larson
 
Joined: 15 Oct 2003
Posts: 713
Location: Portland, OR




(That was me, I thought I was logged in)

It's not printing any data except the station's ID. It used to work on all six of my local stations.
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PostPosted: Thu Jan 06, 2005 5:08 pm Reply with quote
dlarrick
 
Joined: 22 Sep 2003
Posts: 58
Location: Outside Boston, MA




Scott Larson wrote:
(That was me, I thought I was logged in)

It's not printing any data except the station's ID. It used to work on all six of my local stations.


I'd guess they're not sending guide data then. If it's printing out the initial MGT (listing all the EITs and ETTs), and all the EITs are the same size, that's a good indication that it's empty or canned guide data.

-Doug
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PostPosted: Thu Jan 06, 2005 6:49 pm Reply with quote
Scott Larson
 
Joined: 15 Oct 2003
Posts: 713
Location: Portland, OR




No every station in my area sends PSIP data and everyone with an STB is still getting it. The stations made a change just before the end of the year that broke it.

I'll debug it over the weekend.
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PostPosted: Sat Jan 22, 2005 12:51 pm Reply with quote
Scott Larson
 
Joined: 15 Oct 2003
Posts: 713
Location: Portland, OR




OK I finally looked at this. It's just a problem of psipguide giving up too early sometimes. If you run it two or more times it will try harder and get all the data.
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PostPosted: Mon Jan 31, 2005 9:41 pm Reply with quote
Scott Larson
 
Joined: 15 Oct 2003
Posts: 713
Location: Portland, OR




I was looking at psipguide.C. Is it possible to see 1000 MGT repetitions and still proceed to print good data or should the code assume the data is bad?
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PostPosted: Tue Feb 01, 2005 8:38 am Reply with quote
dlarrick
 
Joined: 22 Sep 2003
Posts: 58
Location: Outside Boston, MA




Scott Larson wrote:
I was looking at psipguide.C. Is it possible to see 1000 MGT repetitions and still proceed to print good data or should the code assume the data is bad?


There's no reason you can't keep waiting... I chose to limit it because at the time I wrote it, one of my local stations mentioned some ETTs in their VCT but never sent 'em.

-Doug
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PostPosted: Tue Feb 01, 2005 10:29 am Reply with quote
Scott Larson
 
Joined: 15 Oct 2003
Posts: 713
Location: Portland, OR




Yes my PBS station is doing this. You'll wait forever for a PID that never shows up. Even STB's will never get any data from them.

There's also the problem of it giving up quickly. What's happening is that the loop is seeing a high ratio of bad packets vs. good packets. I think the ratio is about 1400/400 on the stations I was seeing. When I run it again, it gets zero bad packets so there's some syncronization problem happening here. Any clues at what I might try here? I can easily have it reopen the device and try again automatically if the bad packet rate is too high.

I hoping to make a simple script that will collect PSIP data from all my local stations every night.
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Guide data in PSIP
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