HD Cable

[Adz]

I have HD cablevision. It comes with 13 HD channels. My question is why do certain HD channels come in so much better than other channels. I find there are three levels of picture quality. The worst are the networks such as Fox, CBS, NBC, ESPN, PBS (and within these channels Fox and PBS are much better). The next level are the movie channels with HBOHD taking the prize there (against SHOHD, MAXHD, STARZ HD). "Clearly" the best channel by far is INHD which shows some movies/shows but mostly live events (and w/in INHD, baseball games are the clear winner). Any technical reason why this is the case?

Second question is why the sound sometimes goes in and out at times?

[aud19]

I'm not sure why the sound would go in and out other than a bad signal though you should lose picture at the same time. Being digital it's either there or it isn't. Maybe a bad connection on your end or trouble from your SP?

Could be a few reasons why some channels are better/worse. Some dependent on your display. Do you have a (native) 720p or a 1080i display? Depending on your set the 720p feeds common to sports channels could look better on a native 720 set. Or you may simply prefer them due to the programming you're watching (720p looks better for fast motion ie: sports than 1080i) Also the different channels could be using more or less compression, could be using upsampled SD material or just have inferior equipment, including cameras..? Could be the compression your SP is using on certain channels, perhaps they're transmitting the "better" channels at full bandwidth but decided to scrimp a bit on the network channels to add in that Norwegian Fisherman channel that's so popular :roll: :lol:

Jason

[jimmyp58]

I understand the signal quality issue is because there isn't a 'standard' HD broadcast phenomenon as of yet. I asked this question of numerous folks and all have said the same thing. I don't understand it but the analogy given is similar to CDs. The format is agreed upon but the transference to the disc varies from manufacturer to manufacturer. I noticed the same thing when I had cable (Time Warner) and also now with DISH.

Not sure why the sound would be an issue.

[number17]

Not sure how bad are the 'worse' HD channels ... but you know that not all HD channels are broadcasted with HD content 100% of the times, right?

For example, here in Canada HD TSN (a sports channel) rarely broadcast real HD content program, so even though their HD channel looks better than their analog or digital channel, it is not really HD quality, and thus looks far worse than the other HD channels when they are broadcasting real HD content programs. Not sure if that's what you mean by 'poor quality'.

And, even for 2 channels both broadcasting HD content program, the compression ratio the broadcaster uses determines the quality of the program. Higher compression means lower quality. For sports programs usually very little compression is used (constant action) whereas for a movie broadcast (especially a drama), or say, a talk show broadcast, higher compression ratio can be used with insignificant degradation in picture quality.

Hope that answers you question.

[Adz]

Thanks all. These seem to be plausible reasons such as compression, equipment, etc.

I had thought all cable channels broadcast only at 1080i and my dsplay downconverts the signal to 720p; but if that's not the case and sports, for example, is being broadcast in 720p, then maybe that's why it tends to look crisper and cleaner.

My comparison is based on only "true" HD programming which for the networks, for example, is mostly only at night on certain programming. I consider it to be HD, to answer number17's question, only when I get a 16:9 picture.