Hi Andy, First, I thought you might be interested in some testing I've done. I configured my card to match yours, i.e. standard, bit rates, stream type. And I still had static on channel 29. Then I ran through all the cable channels and tried to quantify the levels of static I heard on each station. It's subjective and I want to repeat it, and spend a little more time on each channel, because sometimes the longer I stay with a channel, there's a chance the static will clear up to some degree. Anyway, here are my notes from my first pass:
No sound on 18, 41 Static not noticeable on 2, 3, 5, 16, 17, 20, 21, 54, 56, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 81, 82, 83, 84 Not noticeable on 22 (although ivtv-tune did not report "Signal detected") Slight on 23, 25, 56, 57, 87 Some on 4, 7, 8, 10, 11, 13, 14, 15, 24, 26, 27, 33, 34, 41, 43, 46, 47, 49, 51, 52, 53, 55 Annoying on 6, 29, 30, 31, 32, 36, 37, 38, 40, 42, 58 Not noticeable to annoying on 19 changed with image and/or speaker Really annoying to annoying on 12, 28 changed with image No sound to really annoying to annoying on 35 White noise & video on 39, 71-80, 85, 86, 88-116, 118-125, same on TV (no signal detected by ivtv-tune) I should get 39 (HSN), 85 (JWLTV), 95 (TBN), 107 (GEMSTV) but not the others No sound to really annoying on 44 No sound to annoying on 45 Really annoying to annoying on 48 Really annoying to some on 50 No sound on 117 (test pattern) Hope they make sense. If it will help, I'll put them in a spreadsheet. Maybe a subjective scale from 0-4? Here are my definitions: 0, Not noticeable: I can't hear static at normal volume 1, Slight: I might not notice it if I weren't listening for it. 2, Some: I notice it, but it's lower than the other sounds. 3, Annoying: About the same volume as other sounds. 4, Really annoying: louder than the other sounds. > Please double check the guidelines here: > > http://www.ivtvdriver.org/index.php/Howto:Improve_signal_quality Will do. > An unterminated splitter output can cause reflections that show up as > elevated noise floor. That is a possibility. I don't think we have TVs hooked up to all the outputs from the 8 way splitter, although I'm 99% sure they all go to one room or another. > First, I have had a 4 way spliteer where one (and only one) of the > output ports was bad. It was a brand new expensive one too. :( That's why I swapped connections between my two boards. It didn't matter. The PVR-150 produced good recordings using what had been the HVR-1600 connection, and the HVR-1600 still produced static on what had been the PVR-150 connection. > You, however, may want to just try bypassing you in line amplifier and > seeing if the static goes away. I can probably do this as a test, move the computer to the office and use the cable modem's unamplified connection. If it works, I'll have to go into the attic to effect a more permanent solution. Not something I look forward to, it's got this fluffy insulation that gets all over the place. >> Hmm, I do have an old Gemini cable box. I think it's 20+ years old. >> Would it be a useful data point if I hooked it up to the HVR-1600? > > Well. We know a cable box will only output on channel 3. There is no > chance for intermodulation products and you will also only exercise the > low VHF part of the analog tuner. Your problem on channel 29 manifests > with the UHF part of the tuner with many channels available. If the > static persists with the cable box attached, we'll know it's not a > signal problem if one assumes the analog tuner is not defective. So it wouldn't be a waste of time, right? I'm afraid I'm not an EE although I do have an engineering degree. I sort of get the gist of what you're saying, but I don't really understand. I'll probably try this first, since it's easier than moving the computer around. > It works, both sliced and raw. I've got to make improvements for > non-NTSC standards though. I've tried to figure out the difference between sliced & raw. I searched a while back, but never found a good explanation. I think I understand what sliced is. It's what MythTV uses. FWIW, I've written a little program that extracts the data and passes it off to libzvbi, used by xawtv. > The interlock on insertion of private packets only in the PS is strictly > a cx18 driver software thing. > > I know the insertion will corrupt the MPEG TS and would likely not do > well with the MPEG-1 streams. So I put in an interlock to only let it > happen with the PS. If there are stream types where you know from > experience ivtv wouldn't corrupt the stream, let me know and I'll add it > back for cx18. > > Here's what I think about enabling private packet insertion without in > depth analysis of anything other than the PS and TS: > > OK 0: MPEG-2 Program Stream > No! 1: MPEG-2 Transport Stream > No? 2: MPEG-1 System Stream > ??? 3: MPEG-2 DVD-compatible Stream > No? 4: MPEG-1 VCD-compatible Stream > ??? 5: MPEG-2 SVCD-compatible Stream Well, I can confirm that the IVTV driver does add the VBI private packets to the DVD compatible stream and that MythTV will display the CCs. I haven't used the MPEG-1 stream types, so can't comment. One way to decide might be how badly it might break applications like mplayer, xine, myth, dvdauthor or ccextractor. For example, it should be possible to author a DVD using DVD compatible streams. However, in practice, dvdauthor, in particular, requires front end applications to separate the video and audio streams, then put them back together using mplex (this is something that mytharchive does). I came across someone who had patched dvdauthor to avoid this CPU and disk intensive step. One of these days, I was going to check it out. If the patch works with DVD streams that have no private VBI streams, but does not work with those DVD streams that have VBI streams, then either that fact should be documented, so people can make intelligent decisions about configuring apps like myth, deciding which is more important, the time it takes to burn a DVD or capturing CCs or Teletext. Burning DVDs with CCs is a feature near and dear to my heart. I think the best solution would be if the Hauppauge hardware encoders embedded CCs in the video stream according to the EIA-608 standard. But they don't. I believe Panasonic DVD recording appliances do. If I play back a DVD burned by a Panasonic on another manufacturer's player, I will get CCs. So they both must implement a common standard like EIA-608. Panasonics also produce better video quality with better compression than the PVR-150. But they're appliances which are a lot less flexible than a computer. OK, I'm rambling, but maybe it will fuel more dialog on the topic? Helen _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
