>I have had similar experience like You with the same card (TT DVB C1500) >regarding QAM64. I discovered that there had been a successful fix for >this done for QAM128 by changing the sweeprate, see >http://www.linuxtv.org/pipermail/linux-dvb/2006-February/008439.html >So I made some test to find a working sweeprate for QAM64, see >http://www.linuxtv.org/pipermail/linux-dvb/2006-May/010141.html > >You might have to the same trip for QAM256? >+ case QAM_256: >+ delay = 200; >+ sweeprate = YOUR_SWEEPRATE; >+ break; > > default: > return -EINVAL; I am experiencing same problem with QAM 256 .. Tried putting sweeprate = 250, but it seemed to make no visible difference. Is there any other way to figure out what could be right than just trying different values and recompiling? --Kari Petri Helin wrote: > Hi, > > I am not completely sure if this really is connected to the channel > using QAM256, but that's what I suspect. I use Technotrend's TT-C1500 > budget card with appropriate common interface and Conax CAM. This > combination works flawlessly on every channel which uses QAM64 or > QAM128. Now the Finnish cable company, for which I am subscribed to, > started broadcasting Canal+ Film HD some three months ago. This has > worked otherwise quite well, but I get constant disturbances/artifacts > in the picture. I used to think that it was just because the bit rate > was five times the normal (17 Mbit/s compared to 3-4 Mbit/s). > > But couple of days ago I noticed that this channel is actually the > only one I am receiving that uses QAM256. Searching the Internet > provided me with couple of forum threads/mailing list posts that > suggested that certain DVB-C cards might have problems in receiving > QAM256 modulated broadcast, but the hits were mainly on VDRportal and > in German and I might have lost something in the translation... In > addition to the picture getting garbled every now and then I can > notice the problem also from the high values of UNC (uncorrected > blocks) and BER (bit error rate). On Canal+ Film HD UNC is between 0 > and 20 and BER is about 250. On all other channels UNC is 0 and BER > close to 0. STR ja SNR are the same on all channels, including Canal+ > Film HD. > > Now what I am asking is for any experiences using DVB-C cards to > receive QAM256 modulated broadcasts, no matter if HDTV or not. > > -Petri > > _______________________________________________ > linux-dvb mailing list > linux-dvb@xxxxxxxxxxx > http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
