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
To give you all an update on this matter, all problems with the picture vanished once I removed the common interface and put the subscription card to a smartcard reader. So it looks like either the CI ("BDGTCIS Rev 1.1 TT2004.14") or the CAM (Dual Irdeto & Conax) I used caused the artifacts in the picture.
-Petri _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
