Why is my HD TV grainy when there is fast motion on the screen?

When ever I'm on an HD channel, if there is a very fast motion on the show I'm watching, the picture will get grainy and pix elated a little bit. It is really annoying, and I'm wondering if there is something wrong with it. Please help. What could this be. Is that just how HD TVs are?Why is my HD TV grainy when there is fast motion on the screen?RT is right. It's not your TV, it's a problem with the original encoding. Digital TV uses Mpeg-2 compression, the same thing that's on DVDs.



Mpeg compression depends heavily on motion detection for reducing the data rate. The process works by starting with an initial frame, called an I-frame, and then in succeeding frames noting where image features move, in units of 8x8 blocks. It then encodes just this "motion vector", with a code representing a delta-x and delta-y for the whole 8x8 block.



This gives enormous compression, and works well as long as substantial areas of the scene are relatively stable or changing in a slow, smooth manner. Fast action scenes cause major problems for this motion prediction scheme. As long as there are plenty of bits to go around, its not a big issue. But if the encoder is starved for bits, then you get the kind of effects that you're seeing.



I'd suggest that you complain to your provider about this, since they are responsible for it. If they don't hear from their customers, then they may feel they can just cram more channels in their signal without worrying about quality. You're paying for "all digital quality", so you should demand that they provide sufficient bandwidth to deliver it.Why is my HD TV grainy when there is fast motion on the screen?Are you on cable or satellite?



That is usually caused by too low of a bit rate for the amount of motion (the picture is not updating fast enough). This is a problem on the transmission side, it's not your TV.



More data takes more room in the signal. Cable and satellite are notorious for compressing (cutting back on the amount of data) to make room for more channels.



Sometimes this effect also happens from over the air TV stations that are operating a number of sub-channels, although the station engineers usually make an effort to avoid this.