Saturday, June 18, 2011

Q: Is there any technical data available to support claims of “best HD picture quality” when choosing a satellite, cable or IPTV service provider?

I have done a real-time comparison between the HDTV signals transmitted by local broadcasters in the Boston area (NBC, ABC, CBS) over broadcast ATSC and the corresponding signals transmitted over Comcast service in QAM digital cable.

The two streams were bit-for-bit identical.

I'm sure it is true for at least some and maybe most "cable-only" channels, the different providers do vary in signal quality and how much they "re-compress" the signal.

But I can tell you that for the over-the-air channels, at least in Boston on Comcast, there is no difference between getting the signal over the air and getting it from cable. The two streams were exactly the same.[*]

A rigorous comparison of "cable-only" channels would be more difficult because it's hard to get these in unencrypted form from any provider. Just counting the bitrate (if available on a set-top box) is probably a reasonable proxy, but keep in mind that some providers (like DirecTV) use H.264 (aka MPEG-4 part 10) for at least some channels. That's much more efficient than the MPEG-2 part 2 used by digital cable and broadcast HDTV channels.

[*] The MPEG-2 video elementary stream was bit-for-bit identical. I didn't examine the audio but suspect it was the same. The systems-layer framing and other streams were different, if only because Comcast's channels are at 38.8 Mbps and broadcast ATSC is 19.4 Mbps and because the program IDs were rearranged.


  1. It was a wonderful chance to visit this kind of site and I am happy to know. thank you so much for giving us a chance to have this opportunity! I will be back soon for updates.visit here

  2. Check out Dissertationteam rating of different sources for finding out the best picture quality. You can compare the results and make your own decision what to use.

  3. The administrators must be associated with defininig the groups, yet additionally in characterizing the measurements, informational collections, inputs, kinds of examination, and the significance of the outcomes and so forth throughout the undertaking. Data Analytics Course

  4. Truly, this article is really one of the very best in the history of articles. I am a antique ’Article’ collector and I sometimes read some new articles if I find them interesting. And I found this one pretty fascinating and it should go into my collection. Very good work!
    data science course in malaysia
    best tableau training
    data analytics course malaysia

  5. I have to search sites with relevant information on given topic and provide them to teacher our opinion and the article.

    data science course

  6. I am looking for and I love to post a comment that "The content of your post is awesome" Great work!

    Simple Linear Regression

    Correlation vs Covariance

  7. I have been searching for a useful post like this on salesforce course details, it is highly helpful for me and I have a great experience with this Salesforce Training who are providing certification and job assistance. Salesforce training institute in Gurgaon

  8. Really nice and interesting post. I was looking for this kind of information and enjoyed reading this one. Keep posting. Thanks for sharing.
    Data Science Institute in Bangalore

  9. It is perfect time to make some plans for the future and it is time to be happy. I've read this post and if I could I desire to suggest you some interesting things or suggestions. Perhaps you could write next articles referring to this article. I want to read more things about it!

    Data Science Course

  10. I’m happy I located this blog! From time to time, students want to cognitive the keys of productive literary essays composing. Your first-class knowledge about this good post can become a proper basis for such people. nice one

    Data Science Training


Note: Only a member of this blog may post a comment.