Some cableco's, like Adelphia, reduce OTA HD quality on their systems. Others, like Comcast, don't.
OTA vs Cable box HD quality
Currently I am running an amplified antenna to my build in ATSC tuner on my 32" LCD. I also have a Motorola DCT6200 HD Cable box provided by Adelphia and I am connecting it to the display with some well shielded component cables. Last night I was watching the tonight show on both inputs through picture and picture and I noticed how much better the OTA was. I have heard that the OTA is generally the best in terms of picture quality when it comes to recieving HD but this was a pretty big difference. The OTA looked much sharper and the colors were more virbrant. I was even using the same picture mode preset for both inputs to make sure they were as close as possible.
I purchased some DVI to HDMI cables to try hooking my cable box up that way but I am wondering if I should expect an improvement or if the problem is related to the compression that the cable company does, the quality of the cables I am using to go from the box to my TV, or the signal level that I am getting after all the cable splits between the feed into my house and my room.
I purchased some DVI to HDMI cables to try hooking my cable box up that way but I am wondering if I should expect an improvement or if the problem is related to the compression that the cable company does, the quality of the cables I am using to go from the box to my TV, or the signal level that I am getting after all the cable splits between the feed into my house and my room.
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Well for the record, my DVI to HDMI cable finally came today. I hooked it up and compared the component output to the HDMI and the HDMI was MUCH better. There was no HD content at the time, so I tuned to 708 (NBC's HD feed) and Dr. Phil was on. Everything was sharper and the picture wasn't washed out at all. I'll have to compare it to some real HD stuff tonight to see just how much of a difference there is with HDMI vs. Component vs OTA with my STB and provider.
Spent a few hours once comparing CBS's weekday soap, "The Young and the Restless," between cable and OTA, since CBS was the only OTA station I could tune. Y&R is video taped at 1080/60i (30i), and although the video is heavily filtered, clothing fiber patterns appeared very similar resolution-wise. OTA seemed slightly crisper, but the white image 'fogging' from the cable STB black level was spoiling contrast. Also earlier, someone with the right equipment (member dr1394) compared bit patterns from the same OTA and cable-delivered program and found them identical.
But the many cable companies and head ends (or stations) have such a variety of hardware and processing methods that some variations are likely. Rate shaping , for example, possible for both cable and multicasting (subchannel) OTA, may involve requantization of higher frequencies/resolutions. And reducing the maximum bit rate available by a station or cable head end will automatically trim higher resolutions since lossy MPEG-2 'tosses out' bits to achieve the desired compression.
Also, cable STBs, along with head-end processing, may limit PQ compared to OTA tuners (or vice versa). HDNet's Tuesday 6 am ET test patterns provide a numerical maximum resolution measurement. Readings with various cable hardware here ranged from an appalling 890 lines/PW (16X9) to a typical 1290 lines, to a maximum 1335 lines. CableCard users often cite better overall PQ, although haven't spotted any confirming HDNet test pattern readings. Adequate display resolution is needed to compare the higher readings. -- John
But the many cable companies and head ends (or stations) have such a variety of hardware and processing methods that some variations are likely. Rate shaping , for example, possible for both cable and multicasting (subchannel) OTA, may involve requantization of higher frequencies/resolutions. And reducing the maximum bit rate available by a station or cable head end will automatically trim higher resolutions since lossy MPEG-2 'tosses out' bits to achieve the desired compression.
Also, cable STBs, along with head-end processing, may limit PQ compared to OTA tuners (or vice versa). HDNet's Tuesday 6 am ET test patterns provide a numerical maximum resolution measurement. Readings with various cable hardware here ranged from an appalling 890 lines/PW (16X9) to a typical 1290 lines, to a maximum 1335 lines. CableCard users often cite better overall PQ, although haven't spotted any confirming HDNet test pattern readings. Adequate display resolution is needed to compare the higher readings. -- John
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