[linux-dvb] Fusion HDTV5, US cable, and pid filtering

Andrew Gallatin gallatin at cs.duke.edu
Sat Sep 3 22:33:25 CEST 2005


Hi,

I just got a Fusion HDTV5 Gold.  I am attempting to use it to tune US
Cable (QAM 256).  It somewhat works.  I have some feedback about cable
if anybody is interested.

I'm using 2.6.13 release, and the dvb/video4linux drivers
as outlined in the "how to build from CVS" link posted in
an earlier Fusion HDTV5 thread.

I'm watching captured streams with mplayer.

There seem to be 2 classes of channels I can get.  One class seems to
work, and the other has too much noise / uncorrectible errors to watch
(though it works fine on my older LG-based HDTV's integrated tuner).

When I tune a working channel like our PBS affiliate, which has 4 "SD"
and 1 "HD" subchannels, and I capture a .ts file with test_dvr, the
resulting stream is nearly unwatchable if I don't filter pids (eg, 
I use 0x2000).  If I filter just the pids I want, then the resulting
stream is nearly perfect.  


Here is azap & dvbtraffic output from a good channel (Cable 90):
status 1f | signal 0000 | snr fcae | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0000 | snr fc90 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0000 | snr fc9e | ber 00000000 | unc 00000000 | FE_HAS_LOCK
status 1f | signal 0000 | snr fc7e | ber 00000000 | unc 00000000 | FE_HAS_LOCK

-PID--FREQ-----BANDWIDTH-BANDWIDTH-
0000    10 p/s     1 kb/s    16 kbit
0020    16 p/s     2 kb/s    25 kbit
0021  4650 p/s   853 kb/s  6993 kbit
0022   130 p/s    23 kb/s   196 kbit
0023   130 p/s    23 kb/s   196 kbit
0024    16 p/s     2 kb/s    25 kbit
0025  9975 p/s  1831 kb/s 15002 kbit
0026   262 p/s    48 kb/s   394 kbit
0030    16 p/s     2 kb/s    25 kbit
0031   993 p/s   182 kb/s  1493 kbit
0034   130 p/s    23 kb/s   196 kbit
0035    87 p/s    15 kb/s   132 kbit
0040    16 p/s     2 kb/s    25 kbit
0041  1199 p/s   220 kb/s  1804 kbit
0044   130 p/s    23 kb/s   196 kbit
0045    68 p/s    12 kb/s   103 kbit
0050    33 p/s     6 kb/s    50 kbit
0051  3104 p/s   569 kb/s  4669 kbit
0054   131 p/s    24 kb/s   198 kbit
0055    86 p/s    15 kb/s   130 kbit
00a0    16 p/s     2 kb/s    25 kbit
00a4    69 p/s    12 kb/s   105 kbit
00f0    65 p/s    11 kb/s    99 kbit
00f1   665 p/s   122 kb/s  1000 kbit
00f2   730 p/s   134 kb/s  1098 kbit
00f4    29 p/s     5 kb/s    44 kbit
1ffb     9 p/s     1 kb/s    14 kbit
1fff  3043 p/s   558 kb/s  4577 kbit
2000 25830 p/s  4742 kb/s 38848 kbit


When I tune to our CBS affiliate (1 HD, and 3 SD channels), I get
nothing but noise when I play back the full stream, and I can't
find the correct pids to filter to try filter just one channel. 

Here is azap output from a bad channel (C85):
status 1f | signal 0000 | snr fa03 | ber 00000000 | unc 00005e45 | FE_HAS_LOCK
status 1f | signal 0000 | snr fa0b | ber 00000000 | unc 00005ed0 | FE_HAS_LOCK
status 1f | signal 0000 | snr fa00 | ber 00000000 | unc 00005ea4 | FE_HAS_LOCK
status 1f | signal 0000 | snr fa1c | ber 00000000 | unc 00005f60 | FE_HAS_LOCK


I won't waste space with dvbtraffic because it is huge.., but it sums to
 around 25830 p/s, and there are tons of pids like this:
0006     0 p/s     0 kb/s     1 kbit


So .. my questions:

1) Is the the fact that I can get a watchable stream using pid
   filtering a sign that the Fusion5 doesn't have enough
   internal bandwidth the capture a full QAM256 stream?  Or some other
   problem?

2) Is there any way to get the "bad" channels to behave?  They work
   fine on my TV's integrated LG tuner, and even my old Air2PC can
   pull those "bad" channels in quite a bit better than the LG.  (Though
   the LG wins hands down on the good channels).

Thanks for your help,

Drew



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