On Sun, 2011-06-05 at 17:25 -0700, Greg Fruth wrote: > Andy, > > > Thanks for the pointers! What I'm trying to get working is the > unencrypted channels that are available > on my terrestrial digital cable, which are evidently QAM-256.
Yes, from what little I've seen, QAM-64 is not used very much. Note that re-broadcasts of you local Over-The-Air digital channels may be on the cable as ATSC 8-VSB. Cable companies may choose to not convert them to QAM. > > I used "w_scan -fa -A2 -c US -X -o 7" to generate a channels.conf > file. w_scan successfully finds all the > digital channels I expect to see, both HD and SD. I've never used w_scan myself. Please be advised, that unless you have a very recent w_scan, ATSC 8-VSB scanning might have problems. See here for the discussion and fixes, if needed: http://www.kernellabs.com/blog/?p=1494 I normally use "scandvb" (name may vary with your distro) and a frequency file: $ locate 8VSB | grep us /usr/share/dvb-apps/atsc/us-ATSC-center-frequencies-8VSB /usr/share/dvb-apps/atsc/us-NTSC-center-frequencies-8VSB $ locate QAM | grep us /usr/share/dvb-apps/atsc/us-Cable-EIA-542-HRC-center-frequencies-QAM256 /usr/share/dvb-apps/atsc/us-Cable-EIA-542-IRC-center_frequencies-QAM256 /usr/share/dvb-apps/atsc/us-Cable-HRC-center-frequencies-QAM256 /usr/share/dvb-apps/atsc/us-Cable-IRC-center-frequencies-QAM256 /usr/share/dvb-apps/atsc/us-Cable-Standard-center-frequencies-QAM256 > I then use azap to tune, Hmmm. I was under the impression that czap was needed for cable QAM DTV. (I don't have cable myself.) Maybe that matters? > but it seems the audio portion > is missing. The "audio pid" that azap reports is 0x0000: The audio pid should be listed in your channels.conf. Open it up with a text editor and take a look. > > > % azap -c channels.conf -r 'KABC HD' > using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0' > tuning to 783000000 Hz > video pid 0x1556, audio pid 0x0000 I'll bet you a $1 that the audio pid is 0x1557. It's just the way people seem to do things. Just edit the line for 'KABC HD' in your channels.conf and wing in 0x1557. > status 07 | signal 0186 | snr 0186 | ber 00000000 | unc 00000000 | > status 1f | signal 0190 | snr 0190 | ber 000000b4 | unc 000000b4 | > FE_HAS_LOCK > status 1f | signal 0190 | snr 0190 | ber 00000000 | unc 00000000 | > FE_HAS_LOCK You have a lock, that's good. I see the s5h1411 driver needs some work on proper status reporting of signal/SNR and BER/unc. Right now, a BER/unc count of 0 is what you want for error free reception. > etc. > > > dvbtraffic reports this: I can eyeball three DTV "channels" on this frequency > -PID--FREQ-----BANDWIDTH-BANDWIDTH- > 0000 10 p/s 1 kb/s 16 kbit > 1555 15 p/s 2 kb/s 23 kbit > 1556 9901 p/s 1817 kb/s 14891 kbit <--- Video > 1557 262 p/s 48 kb/s 394 kbit <--- Audio ? > 1558 133 p/s 24 kb/s 200 kbit > 155f 15 p/s 2 kb/s 23 kbit > 1560 8998 p/s 1651 kb/s 13532 kbit <--- Video > 1561 260 p/s 47 kb/s 391 kbit <--- Audio ? > 1562 133 p/s 24 kb/s 200 kbit > 1569 15 p/s 2 kb/s 23 kbit > 156a 4720 p/s 866 kb/s 7099 kbit <--- Video > 156b 309 p/s 56 kb/s 464 kbit <--- Audio ? > 156c 265 p/s 48 kb/s 399 kbit > 1aa0 2 p/s 0 kb/s 4 kbit > 1aa1 2 p/s 0 kb/s 4 kbit > 1aa2 2 p/s 0 kb/s 4 kbit > 1aa3 2 p/s 0 kb/s 4 kbit > 1ffb 8 p/s 1 kb/s 13 kbit > 1fff 892 p/s 163 kb/s 1342 kbit > 2000 25956 p/s 4765 kb/s 39038 kbit > Then (as a consequence, I guess) Mplayer says "no audio": Just hand edit your channels.conf with a good guess for the audio pid. > % mplayer /dev/dvb/adapter0/dvr0 > MPlayer SVN-r33254-snapshot-4.5.1 (C) 2000-2011 MPlayer Team > Can't open joystick device /dev/input/js0: No such file or directory > Can't init input joystick > mplayer: could not connect to socket > mplayer: No such file or directory > Failed to open LIRC support. You will not be able to use your remote > control. > > Playing /dev/dvb/adapter0/dvr0. > TS file format detected. > VIDEO MPEG2(pid=5462) NO AUDIO! NO SUBS (yet)! PROGRAM N. 0 > VIDEO: MPEG2 1280x720 (aspect 3) 59.940 fps 38810.4 kbps (4851.3 > kbyte/s) > Load subtitles in /dev/dvb/adapter0/ > ========================================================================== > Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family > Selected video codec: [ffmpeg2] vfm: ffmpeg (FFmpeg MPEG-2) > ========================================================================== > Audio: no sound > > > > The HD video playback looks great, however. (I'm not worrying about > joystick or LIRC controls at > this point, as this is a desktop PC.) > > > > I don't see any obvious errors in dmesg, except this: > cx18-0: Unreasonably low latency timer, setting to 64 (was 32) That's an information message, not an error. No worries.... > But it looks like the driver automatically fixed that problem. You are free to change the PCI latency for the CX23418 (maximum burst of PCI clock cycles the CX23418 is allowed to use the PCI bus segment at a time) to whatever you need using 'setpci'. Most people don't, unless they really need to tune PCI bus performance. > Hmm, is there supposed to be > a /dev/dvb/adapter0/audio0 file? Nope. > All I have is demux0, dvr0, frontend0 and net0. I don't know why your channels.conf doesn't have the correct audio pid. I'm guessing: 1. w_scan isn't outputing the right channels.conf format for mplayer. (channels.conf is *not* standardized across apps :( ) 2. w_scan has a bug 3. Someone recently introduced a bug into the linux kernel DVB subsystem, which causes w_scan to miss information. (The media build process builds the bleeding edge DVB modules.) 4. Your cable service provider is providing the information in some unexpected manner, or relying on implicit association of the pid following the video pid. Regards, Andy > > ______________________________________________________________ > From: Andy Walls <[email protected]> > To: Greg Fruth <[email protected]>; User discussion about IVTV > <[email protected]> > Cc: "[email protected]" <[email protected]>; > [email protected] > Sent: Saturday, June 4, 2011 5:53 AM > Subject: Re: [ivtv-users] HVR-1600 analog no signal > > On Fri, 2011-06-03 at 23:01 -0700, Greg Fruth wrote: > > I have the reverse problem in Fedora 14 (HVR-1600 model > 1388): the > > analog side > > works totally fine (at /dev/video0) while I can't get the > digital side > > to tune properly. > > The digital side has occasionally been able to record in SD > and HD, > > but since the tuning > > is wrong Mythtv refuses to record, or it records the wrong > program. > > Does your digital > > side work? > > > MythTV is not a good troubleshooting tool - too many moving > parts, so to > speak. > > Instead, use the basic dvb utilities to create a channels.conf > file from > the stdout of [dvb]scan and do some basic tests: > > http://www.linuxtv.org/wiki/index.php/User_Information > http://www.linuxtv.org/wiki/index.php/Testing_your_DVB_device > > > You can then put the channels.conf file into > ~/.mplayer/channels.conf > and use mplayer to test DTV: > > (kill the mythbackend and then...) > > $ mplayer dvb://WJLA-HD -cache 8192 > MPlayer SVN-r31628-4.4.4 (C) 2000-2010 MPlayer Team > ... > Playing dvb://WJLA-HD. > dvb_tune Freq: 177028615 > Cache fill: 19.82% (1662976 bytes) > TS file format detected. > VIDEO MPEG2(pid=49) AUDIO A52(pid=52) NO SUBS (yet)! PROGRAM > N. 0 > VIDEO: MPEG2 1280x720 (aspect 3) 59.940 fps 17782.8 kbps > (2222.8 kbyte/s) > ... > A:28772.1 V:28771.8 A-V: 0.289 ct: -0.785 1452/1452 54% 0% > 2.1% 5 0 13% > > > "WJLA-HD" is a channel name in my channels.conf file. (The > first field > on each line is a channel name.) > > > If [dvb]scan can't a decent channels.conf, either the digital > tuner > drivers need work, or you have signal quality problems. > Please check > the list of items here, just in case: > > http://ivtvdriver.org/index.php/Howto:Improve_signal_quality > > > Unfortunately my only late model HVR-1600 is in Europe with > Hans for > worldwide analog signal tuning verification. I don't have one > in hand > at the moment. (Maybe I'll just go buy another one this > week). > > > Regards, > Andy _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
