Seating distance is very important even for HD content. I sit about 8 feet away from a 50" tv and I can see artifacts and fuzziness. When I go out of the room and stand about 11 feet away, everything looks near perfect and there are no visible flaws for most HD content.
HD Picture Quality
- Thread starter redelephants
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Seating has nothing to do with pq. (unless your standing right up next to it) If the picture is clear @5ft, it will always be clear. I was at the brother in laws house this weekend. They have a 46 samsung tv. I was siting 6 ft away and the picture was great. I get home and sit the same distance away from my 46 inch samsung and the picture is fuzzy. Here is what that tells me. It about the source. They have twc, I have dish.
Of course, the station your watching and the programming they've put on also factor into it. So what station were you watching at the BILs? At home? And which show?
BTW, I was watching NFL on my local Fox (OTA... the only local station the still has ONE channel, so no "bit stealing" needed). Stepped to about 1 foot away (as another poster did for his "test") and saw artifacts and macroblocking.
Looks like CBS OTA during football games.
Yep, CBS OTA sucks for football games.
It is about the source, but seating distance has an effect on the PQ we see. It can make it better or worse.
What? It sure does. Tell me your picture looks just as clear at 1ft from the screen as it does from 10ft. Maybe perceived PQ would be better. Granted if it was perfect at 1ft it would be perfect at nay distance, but 99% of the time that is not the case. 720p looks so,so at 10ft on my 57" vis Dish....Blu-Ray looks fantastic. So higher resolution and less compression allow me to have better PQ at same viewing distance.
Or it is about the TV processing, TV calibration and the program you were watching.
Again, how can viewing distance not factor in. At 1 ft ESPN-HD is not watchable on Dish. At 10ft where I normally sit (57" screen) it is average. At 15ft it looks flawless. Your eyes play a part in the PQ and distance affects what your eyes are able to see.
That is the reality of compression. I have not seen one source that looks great at 1ft from the screen........you get into pixel structure, scan lines, etc.
Sure it may not directly affect PQ, but it does determine what you see and the perceived PQ. If you sat 5ft from a 110" screen everything would look like garbage.
I know mircoblocking you will see at one foot. My point is that dish pq in hd is not the same as twc at the bil house. my tv looks flawless will the ps3 blue ray.
I have called dish twice about my local cbs staion. It is soo horible. i cant lock in with the ota all the time, but when I do, it looks 10 times better than the crap that dish gives me.
I have called dish twice about my local cbs staion. It is soo horible. i cant lock in with the ota all the time, but when I do, it looks 10 times better than the crap that dish gives me.
OTA Signal lock problem?
What is the channel & real channel that they are using? It could be multi-path or as I discovered recently that the OTA was using VHF channel and FM was causing the problem.
What is the channel & real channel that they are using? It could be multi-path or as I discovered recently that the OTA was using VHF channel and FM was causing the problem.
Here's a comparison for you relating picture quality to bit rate (Comcast vs. Fios but the principle is the same.
Comcast HD Quality Reduction: Details, Screenshots - AVS Forum
Again, that is comparing how bit rate affects PQ. No one disputes that. Now show me something like that with signal strength to back up your claim.
Your understanding of FEC is incorrect. This time I will not use my words but the words of others. The source link is included beneath each quote.
Sorry this stuff is technical, but I've tried to simplify it and it seems I don't explain it well enough.
Here are some references:
If we compare direct broadcast satellite (DBS) to older analog satellite services, when signal conditions have high signal-to-noise ratio (SNR), the DBS system outperforms any analog television receive-only (TVRO) with laser-disc picture quality and CD-equivalent audio. But when signal conditions are poor, primarily due to rain, lower SNR compromises the error correction capability and error concealment capability of MPEG-2 algorithms.
And
Basic principles of the Reed-Solomon (RS) error correction method are presented with parameters that can be inquired from a QPSK network interface module (NIM), such as acquisition state, signal strength, SNR, and the number of corrected and uncorrected errors used to get a full status of conditions in a communication channel. http://www.commsdesign.com/main/feat9801.htm
Next:
The coupling between BER and SNR is a logical one. In general, the higher the SNR, the fewer the errors in the channel transmission; or simply stated, as the SNR increases, the BER decreases. Conversely, as the SNR decreases, the BER will increase, at which point the communications channel typically reduces the data rate (making each bit a little longer) in an attempt to reduce the number of errors in the transmission.
AND
Notice that as the SNR decreases, there is a graceful degradation, or roll-off, in channel performance. For example, as a 5.8 GHz signal's SNR is degraded, the channel will tend to remain operational, albeit at a reduced data rate.
Asset Tracking in Industrial Settings?A Review of Wireless Technologies Part 1: The Basics | Sensors Magazine
More:
The bit error rate performance is an important quality in communication systems. In this section we will analyze the wissce receiver to find a relation between the bit error rate (ber) and the input snr to the analog-to-digital conversion stage. This relation needs to be known to formulate requirements for the front-end and the received signal strength. http://sit.iitkgp.ernet.in/archive/teaching/internetTech/wireless/cdma/cas.et.tudelft.nl/%257Eglas/thesis/node27.html
Still more:
At the lower bit rates in this range, the impairments introduced by the MPEG-2 coding and decoding process become increasingly objectionable. AND
[FONT=HELVETICA, SWISS, ARIAL]Buffer control[/FONT]
By removing much of the redundancy from the source images, the coder outputs a variable bit rate. The bit rate depends on the complexity and predictability of the source picture and the effectiveness of the motion-compensated prediction. For many applications, the bitstream must be carried in a fixed bit rate channel. In these cases, a buffer store is placed between the coder and the channel. The buffer is filled at a variable rate by the coder, and emptied at a constant rate by the channel.
AND
Reducing the buffer size will reduce the delay, but may affect picture quality (Note: The converse is also true; increasing buffer size will increase delay but increase picture quality. Along with the signal meter "improvement", Dish expanded the buffer size which increased the delay in channel changes. This was done to compensate for known poor signal reception issues.) MPEG-2 video compression
Still more:
Q. Why should I care about Picture Quality since "bits is bits"?
A. Since Picture Quality is monitored at the video (program) layer, even if you receive all your bits you may still be facing Picture Quality issues. First, if the video signal entering your network has noise, your signal may already be compromised and at risk of deteriorating even more if you are compressing the signal in any way: blockiness, blurriness, etc. Second, noise and compression defects occupy bits that would normally be allocated to the video signal; thus you are receiving video that is compromised by errors. Why should I care about Picture Quality since "bits is bits"? > Frequently Asked Questions : Tektronix
Yet more:
High C/N ratios provide good quality of reception, for example low bit error rate
(BER) of a digital message signal, or high SNR of an analogue message signal.
And
The C/N ratio is measured in a manner similar to the way the signal-to-noise ratio (S/N) is measured, and both specifications give an indication of the quality of a communications channel.
In the famous Shannon–Hartley theorem, the C/N ratio is equivalently to the S/N ratio.
Carrier-to-noise ratio: Definition from Answers.com
And this:
[SIZE=-1]An accurate measurement of signal levels is very important to ensure that an adequate signal level is available [/SIZE]
AND
[SIZE=-1]A great deal of research has shown that by far the primary cause of degradation of BER in transmission is due to noise and that the relationship between signal to noise ratio and BER is reliable.[/SIZE]
[SIZE=-1]Measuring the signal to noise ratio is the quickest and most meaningful way of knowing the margins available from the transmission.[/SIZE]
Digital Terrestrial - Signal Measurement
Last:
Represented graphically, the general error-performance characteristics of most digital communication systems have a waterfall-shaped appearance. System performance improves (i.e., bit-error rate decreases) as the signal-to-noise ratio increases.
AND
Large redundancy is advantageous because it reduces the likelihood that all of the original data will be wiped out during a single transmission. On the down side, the addition of parity bits will generally increase the transmission bandwidth or the message delay (or both). (Note: remember the increased Dish buffer size) How Forward Error-Correcting Codes Work
While some of this information is MPEG 2, MPEG 4 increases the variability of the picture using SVC or Scalable Video Coding. This says that in the presence of a compromised bit stream (poor signal) that the output can be lower resolution.
Just did. Glad there is no dispute on the bit rate/PQ relationship.
Here's a graph, too.
Attachments
Nope, you missed again.
Show real world examples...screen captures of the same program with high and low signal levels that shows a PQ difference.
Show real world examples...screen captures of the same program with high and low signal levels that shows a PQ difference.
That's over IP NETWORK
FTP is File Transfer Protocol. We don't receive sat via WAN, LAN or Fiber and it doesn't use FTP to do it either. It might relate to the downloads we can get from E* over the net but not coming down thru sat.
FTP is File Transfer Protocol. We don't receive sat via WAN, LAN or Fiber and it doesn't use FTP to do it either. It might relate to the downloads we can get from E* over the net but not coming down thru sat.
