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Discussion in 'DIRECTV Programming' started by vurbano, Oct 18, 2007.
Or like the guys who can hear the difference bettween a $4000 audio cable and a $5000 one...
But that doesn't mean it is!
There are plenty of awful film->HDTV conversions out there. And actually film doesn't compress that well because the natural grain from the silver particles puts random noise into the image, and random noise compresses very poorly.
Just another way that there really can be a big difference in how content is shot, recorded, processed and compressed.
I'll show you the first DVD I ever bought (the first one sold, Twister) and you can see it is crap compared to later ones, even though it plays on all the same hardware using all the same technology, later discs just use the system better and look tons better.
So, similarly, HD content is still in the phase where it is getting rapidly better. It'll level out quite a bit after another year or two, but even then incremental improvements in encoding will still be made for quite some time.
You also have to remember that all the encoders that encode for one transpoder use stat mux variable bit rate so they all talk to each other. Dish has been doing this with their mpeg2 channels from what I read.
Plus mpeg4/h.264 is much more efficient.
We need to remember Satguys is an E* site
PQ looks great to me!!
No more than this is an E* or D* site.
But let us return to the topic at hand. How many licks does it take to get to the center of a Tootsie Pop? Or something like that.
+1...my TV allows all resolutions and the HR20 cycles though to native seamlessly each time!!!
Mr owl........ one....two....three.....
Bottom line it is all subjective. I can tell the difference between Mpg 2 and 4. The picture quality in my eyes is fantastic.
Im starting to see pixellation on HGTVHD! Anyone else seeing this who has a 55 to 65" HD set?
I agree with almost everyone here. As Directv has awsome PQ and sound quality. I couldn't be happier. I don't care how many channels they put on a transponder as long as they keep great PQ and Sound quality.
As, for the OP. There are always people out there that got to complain about everything. Hey, it is a beautiful sunny day in the mid 70's. Man this weather stinks it is to sunny and to cool out there. There is one in every crowd. I just shake my head at the negative nancy. :nono2:
Just out of curiosity more than anything: I have done some transcoding of DVD to MPEG4 using multipass - and that takes forever. Granted the movie houses or broadcasters are going to have optimized equipment, etc - still imagine it takes them a while to work thru a movie. So what happens in the case of a sporting event for example. They pretty much have just enough time shoot it and transmit - when does the conversion take place and would it be enough time to use the advanced compression tools? Based on how long I see on a dual core - they would need one of those Blue Gene computers IBM builds on every truck .
It's done in real time, and therefore it's not compressed as efficiently as it could be. It's a tradeoff.
1st post in the thread
Edit: (Tom Robertson) I removed the link. DBSTalk prefers links to information be available to all users, not sites that require registration.
Unconfirmed and unofficial but seems to be accurate .... http://www.dbstalk.com/showthread.php?p=1191378#post1191378
For some reason claims of "xxx bps" at some undefined point in the signal path make me crazy. Maybe a rundown of what goes on to transmit and receive a D* mpeg4 channel might be of some help.
You've got the following data path (and it may actually be more complicated):
1. Channel is encoded mpeg4 depending on the statistics for that channel. Talks shows get more compressed than sports, and some channels may get more/less compression by choice, contract or other reason. The output bitrate of this process varies second by second, depending on variations in image. Sound data is added, also compressed. For some prerecorded material (e.g. movies), all this is done ahead of time, with multiple passes of compression.
2. Channel data is statistically multiplexed with several other channel's data. This means that the mpeg4 streams are opportunistically merged so that, even though each channel's data needs vary, the sum is as close to constant and maximum as possible. An individual channel's data may move ahead or fall behind to help with this. This may feed back into the compression stage depending on fullness. Buffers in the receivers will fix any time variations.
3. The raw multiplexed data has headers and other framing added (DVB-S2 in this case) and is then fed into a convolutional encoder that produces more bits out than bits in. This is for error correction. Ken says 2/3rds; so 2 bits in, a rather different 3 bits out. The raw data is now carried by redundant strands of bits rather than by individual bits.
4. The encoded, multiplexed, compressed data is fed into a baud encoder, QPSK or 8PSK. These bauds, or symbols, are by now quite different than the bits that make up the channel data.
5. These get modulated onto some carrier and sent to the satellite which retransmits them on down on some other frequency in the band.
6. Your LNB downshifts the modulated signal to some intermediate frequency and passes it down the cable to your box, where it is demodulated and decoded to produce error-corrected multiplexed data, which hopefully contains the data for your requested channel.
7. The headers and framing are read, the multiplexing undone and the channel data recovered. This is then mpeg4 decompressed (which includes guessing at some of the output bits), and then sent to your display at the required rate.
8. The TV takes this data and may scale or otherwise alter it before it puts it up.
Now, at what point does the concept of "bitrate" have a lot of meaning? Almost nowhere, which is why simplistic assertions that bitrate defines quality are so madding.
All that is important is how well the compression operates on the channel, and how efficient the multiplexing and line coding are. In the end, all that matters is how good the resulting picture is. A jillion bps and a bad picture isn't going to satisfy.
Bitrate is all relative. The bitrate of a whole string of up-convert channels could easily be half of the bitrate of a full HD channels.
I really would like to keep this thread open. Could you all please help me and stick to bits, bitrates, and tech? I find that far more interesting than the local internet gossip and name calling.
Sorry to interupt this thread with a silly Q, but what does FUD stand for?