MPEG-2 is as close to an Absolute encoder as there ever will be. MPEG-4 and such are Perceptual encoders; it only encodes what the average ho hum person can perceive in a 320x240 on a computer screen.
You dont really see any improment in an MPEG 4 past 1Mbps in SP or ASP; the only profiles in current use. Now, if it was an MPEG4 at Studio Profile @ 38Mbps; then yes, it would look better.(4000x4000 resolution). But, MPEG2 at 38Mbps is dam nice. Hell, MPEG2 @ 25Mbps is nice. Most Direct TV talking head crap is MPEG2 @ 2Mbps. This is were the bitrate is too small for the enocder to work properly; but there is no motion, so it works. Thats why most sporting events on DirectTV are at 9 to 12Mbps; too much motion. And, all those stupid digital cable providers are crushing the shit out of everything; you cant even see the puck during a hocky game, its gone.
So, back to your point; you weren't comparing apples to apples. You took MPEG2 at near its bottom limit to do anything worth while and compared it to MPEG4 at its useful max. Well, I would believe also that the MPEG 4 will look better. But its still a perceptual encoder.
You say that the codec determines the quality. Well, MPEG4 is a lossy encoder, MPEG2 isn't.
As far as bitrates go, they must correspond to the codec's intent. MPEG2@2.5Mbps is like MPEG4@50Kps. Now, I would rather watch the MPEG2 file at 480x400@30fps than the MPEG4 at 160x80@10fps.
Here is the kicker though, people will watch a crappy picture, but they will NOT tolerate bad audio. Our ears have more "resolution" than our eyes do.
Sonic depth of field. Stereo seperation. ie 3dimensional imaging. Frequency Range. Harmonics. All of this is lost in a low bitrate lossy encoder. Try a lamemp3 with a vbr range of 192-256 @ 48Khz with minimum bitrate enforced with a low pass filter set at 19.5K and disable the temporal masking effects. File size is about the same, and the quality is great; but still missing some harmonics.
What will really get you is listening to an actual Vinyl Album and compare it to a CD.
Than how is it that almost all radio broadcast attennas are set up over bodies of water/wetlands??
Of course, FM and AM are just that; they are not in the GHz range.
Hmm, you said "Water actually causes greater atmospheric disturbances than over land. "
No shit sherlock, but we aint talkin bout no flyin water in da atomsphere.
I am talking about a lake.
Over a cold body of water, a "Surface Duct" can occur just fine, allowing a channeling effect of the signal. This "ducting" provides shelter from other spurious signals above the duct to interfere; ala the sun, other nearby microwave channels. Submarines use a similar principal by changing there depth to different Thermal levels to escape sonar. The Thermal barriers channel the sound waves.
OK then, lets see: The 70 mile attempt was done from Promontory to Magna. Almost 90% over water. I am guessing that these guys got good results and said, "shit" its still flat as hell out to Draper, lets try it there. And , they got good results.
Now then, to kayen, yes, I did see their map vs mapquests version, and it does seem to show that the portion of lake they shot it across is dry; but is it dry now? It is winter. The pictures they had of the day they did it, there were some nasty clouds in the air.
To the Anonymous coward: Check this out http://classes.weber.edu/wireless/News.htm It even says in the Article you guys shot it directly over the lake. And if there wasn't any wind to cause white caps, all the better.
Umm, this was line of sight. For that distance, you are not gonna get much out of any spurious reflections. And no, you would not be able to punch it through a mountain, or any type of dirt based hill. Not with the power levels you used.
Again, air borne water is another subject completely. Yes, Snow, rain, Misty fog all cause problems with Microwave Broadcasts.
So, NO, there is no "Hence the reason" support that airborne water is the same as a lake. They/You didn't punch the signal through the lake; just directly above it.
Big friggen differnece!! Btw, thanks for the RF review there @ ce.rit.edu. But, if you want a real primer on RF, I will let you borrow my College Textbook.
Now then, what I would really like to know is, What are the exact modifications to the feed horns. (other than a Weber University sticker slapped on) What kind of test Eq. was used to make these modifications. I see that the final link speed was 1 and 2 Mbps.
My guess Coward, is that you are an Junior in college with less than half of you first semester in an RF class.
At best, your major is Telecommunications; hardcore RF stuff. But, more than likely, you are a Computer Science major, all juiced about some RF stuff.
Stick to ripping Jenna Jamison dvd's in your dormroom while mastering the latest Shockwave utilities.
Slashdot Mirror
Hmm,
Lets refresh.
MPEG-2 is as close to an Absolute encoder as there ever will be.
MPEG-4 and such are Perceptual encoders; it only encodes what the average ho hum person can perceive in a 320x240 on a computer screen.
You dont really see any improment in an MPEG 4 past 1Mbps in SP or ASP; the only profiles in current use. Now, if it was an MPEG4 at Studio Profile @ 38Mbps; then yes, it would look better.(4000x4000 resolution). But, MPEG2 at 38Mbps is dam nice. Hell, MPEG2 @ 25Mbps is nice.
Most Direct TV talking head crap is MPEG2 @ 2Mbps. This is were the bitrate is too small for the enocder to work properly; but there is no motion, so it works. Thats why most sporting events on DirectTV are at 9 to 12Mbps; too much motion.
And, all those stupid digital cable providers are crushing the shit out of everything; you cant even see the puck during a hocky game, its gone.
So, back to your point; you weren't comparing apples to apples.
You took MPEG2 at near its bottom limit to do anything worth while and compared it to MPEG4 at its useful max.
Well, I would believe also that the MPEG 4 will look better. But its still a perceptual encoder.
You say that the codec determines the quality.
Well, MPEG4 is a lossy encoder, MPEG2 isn't.
As far as bitrates go, they must correspond to the codec's intent.
MPEG2@2.5Mbps is like MPEG4@50Kps.
Now, I would rather watch the MPEG2 file at 480x400@30fps than the MPEG4 at 160x80@10fps.
Here is the kicker though, people will watch a crappy picture, but they will NOT tolerate bad audio. Our ears have more "resolution" than our eyes do.
Sonic depth of field.
Stereo seperation. ie 3dimensional imaging.
Frequency Range.
Harmonics.
All of this is lost in a low bitrate lossy encoder.
Try a lamemp3 with a vbr range of 192-256 @ 48Khz with minimum bitrate enforced with a low pass filter set at 19.5K and disable the temporal masking effects.
File size is about the same, and the quality is great; but still missing some harmonics.
What will really get you is listening to an actual Vinyl Album and compare it to a CD.
not when its cold.
hmm , winter olympics in salt lake.
typically, if there's a lot of snow on the ground, the air is pretty dry.
it's not texas
Than how is it that almost all radio broadcast attennas are set up over bodies of water/wetlands??
Of course, FM and AM are just that; they are not in the GHz range.
Hmm, you said "Water actually causes greater atmospheric disturbances than over land. "
No shit sherlock, but we aint talkin bout no flyin water in da atomsphere.
I am talking about a lake.
Over a cold body of water, a "Surface Duct" can occur just fine, allowing a channeling effect of the signal. This "ducting" provides shelter from other spurious signals above the duct to interfere; ala the sun, other nearby microwave channels.
Submarines use a similar principal by changing there depth to different Thermal levels to escape sonar.
The Thermal barriers channel the sound waves.
OK then, lets see:
The 70 mile attempt was done from Promontory to Magna. Almost 90% over water.
I am guessing that these guys got good results and said, "shit" its still flat as hell out to Draper, lets try it there.
And , they got good results.
Now then, to kayen, yes, I did see their map vs mapquests version, and it does seem to show that the portion of lake they shot it across is dry; but is it dry now? It is winter. The pictures they had of the day they did it, there were some nasty clouds in the air.
To the Anonymous coward:
Check this out http://classes.weber.edu/wireless/News.htm
It even says in the Article you guys shot it directly over the lake. And if there wasn't any wind to cause white caps, all the better.
Umm, this was line of sight. For that distance, you are not gonna get much out of any spurious reflections.
And no, you would not be able to punch it through a mountain, or any type of dirt based hill. Not with the power levels you used.
Again, air borne water is another subject completely. Yes, Snow, rain, Misty fog all cause problems with Microwave Broadcasts.
So, NO, there is no "Hence the reason" support that airborne water is the same as a lake. They/You didn't punch the signal through the lake; just directly above it.
Big friggen differnece!!
Btw, thanks for the RF review there @ ce.rit.edu.
But, if you want a real primer on RF, I will let you borrow my College Textbook.
Now then, what I would really like to know is, What are the exact modifications to the feed horns. (other than a Weber University sticker slapped on)
What kind of test Eq. was used to make these modifications.
I see that the final link speed was 1 and 2 Mbps.
My guess Coward, is that you are an Junior in college with less than half of you first semester in an RF class.
At best, your major is Telecommunications; hardcore RF stuff.
But, more than likely, you are a Computer Science major, all juiced about some RF stuff.
Stick to ripping Jenna Jamison dvd's in your dormroom while mastering the latest Shockwave utilities.
Big F'n Deal.
If you look at the map, they punched the signal over water.
No wonder these eTards were able to get the distance out of it.
Try it over land and get back to me.