View Full Version : Does D* still use 'HD-Lite'? Comparing resolutions...
CHaynes112
12-02-09, 11:41 AM
I have been reading various sources, and discovered D* used to (or possibly still does) broadcast 1080i at 1280x1080 instead of 1920x1080. I was wondering if they still use 1280 at all, or did they finally bump everything up to 1920?
It looks like Dish is still at 1440x1080 and FiOS is true 1920x1080?
As far as SD goes, it looks like D* currently uses 480x480, whereas Dish is 544x480, and FiOS is at 528x480 for most channels (they used to be 704x480, but apparently they have compressed most channels down to 528)?
-Thanks
Stuart Sweet
12-02-09, 11:48 AM
DIRECTV uses the resolutions provided to them. If the native broadcast is 1280x720, then DIRECTV sends 1280x720, and the same with 1920x1080. This is true for all MPEG-4 encoded broadcasts. As far as older, MPEG-2 encoded SD channels, the resolution may still be low.
For the most part DIRECTV tries to keep the same quality as original broadcast for all HD programming, but there is some re-encoding going on. Personally I was unable to see any difference between OTA HD and DIRECTV HD, although there is a clear difference between Discovery Channel HD and the same programming on Blu-ray. I don't know if that difference originates at Discovery or DIRECTV.
Greg Alsobrook
12-02-09, 11:49 AM
It is my understanding that DIRECTV broadcasts most, if not all content at source resolution.
Do you think you could provide your sources so we can read up as well?
Justin23
12-02-09, 12:00 PM
although there is a clear difference between Discovery Channel HD and the same programming on Blu-ray. I don't know if that difference originates at Discovery or DIRECTV.
Well...those are 2 different resolutions, right?
It would be very messed up if they sent anything as 1280x1080, that is practically a square instead of 16:9 and would require some major stretching or anamorphic conversion.
1280x720 is a possibility, and it still is HD (720p), but overall I believe it depends on the network. As the others have said, DirecTV sends things in the resolution they get them for the most part from what I have heard/seen.
If you put your receiver in native mode it will change depending on the channel, and there is a mixture of 720p and 1080i in the HD channels.
Well...those are 2 different resolutions, right?
Same resolution (1080), but different bit rates. Bluray will look better because of the higher bitrate.
ARKDTVfan
12-02-09, 01:19 PM
Do you think you could provide your sources so we can read up as well?
swanni?
CHaynes112
12-02-09, 03:34 PM
Here is one link talking about the poor SD resolution of 480x480...
http://www.avsforum.com/avs-vb/showthread.php?t=1062044
I can't post a hyperlink until I reach 5 posts :lol:
wilbur_the_goose
12-02-09, 03:36 PM
SD resolution stinks on any HD TV.
hilmar2k
12-02-09, 03:42 PM
SD resolution stinks on any HD TV.
Actually, my new Vizio LCD does a fantastic job unconverting SD. SD is almost unwatchable on my other HDTV's, but very impressive looking on the Vizio.
BattleZone
12-02-09, 03:51 PM
The handful of remaining MPEG2 mirrors in the 70s are still down-rezzed to 1280x1080 (for 1080 content), but all of the MPEG4 channels, including the MPEG4 mirrors of the channels in the 70s, are resent at the source resolution. For some channels, that is 1280x720, and for others, 1920x1080.
So, if you still have one of the old MPEG2-only HD receivers, the 6 or so HD channels you can still get are "HD-Lite". If you've got an MPEG4 HD receiver (H2x or HR2x), you shouldn't be watching those MPEG2 versions anyway, since there are full-rez MPEG4 versions.
Tony Chick
12-02-09, 05:30 PM
The MPEG4 channels look really good, but if I compare my HD locals with the OTA equivalent using my HR20, the OTA is still just slightly sharper. I suspect thats simply compression algorithm differences between MPEG4 and MPEG2.
The handful of remaining MPEG2 mirrors in the 70s are still down-rezzed to 1280x1080 (for 1080 content), but all of the MPEG4 channels, including the MPEG4 mirrors of the channels in the 70s, are reset and the source resolution. For some channels, that is 1280x720, and for others, 1920x1080.
So, if you still have one of the old MPEG2-only HD receivers, the 6 or so HD channels you can still get are "HD-Lite". If you've got an MPEG4 HD receiver (H2x or HR2x), you shouldn't be watching those MPEG2 versions anyway, since there are full-rez MPEG4 versions.
I am curious where this info comes from...when the switch was taking place and we had both sets of channels active, lots of us did comparisons and saw very little PQ difference between them overall.
I am curious where this info comes from...when the switch was taking place and we had both sets of channels active, lots of us did comparisons and saw very little PQ difference between them overall.
I know people have other ways of doing this but if you have an HD PVR on your computer it will tell you what resolution signal you are getting. So I can say that at least USA and HDNet Movies are the full 1920x1080 and that my local ABC and FOX are their full 1280x720.
sigma1914
12-02-09, 06:06 PM
I am curious where this info comes from...when the switch was taking place and we had both sets of channels active, lots of us did comparisons and saw very little PQ difference between them overall.
I see a big difference, especially between the TNTs.
I know people have other ways of doing this but if you have an HD PVR on your computer it will tell you what resolution signal you are getting. So I can say that at least USA and HDNet Movies are the full 1920x1080 and that my local ABC and FOX are their full 1280x720.
With Directv though the HD has to go through a receiver, so you will never see the signal natively. The exception is setting the receiver to "native", which should show the channel in its native format to your display, but it is always either SD, 720p, 1080i, or 1080p. So if it truly is getting a different "HD-Lite" format, the receiver is doing some scaling/stretching to output it at one of the regular formats.
bonscott87
12-03-09, 09:07 AM
"HD-Lite" hasn't been an issue for over 3 years now with the introduction of MPEG4.
Doug Brott
12-03-09, 09:20 AM
"HD-Lite" hasn't been an issue for over 3 years now with the introduction of MPEG4.
This is the bottom line ...
bobcamp1
12-03-09, 09:45 AM
"HD-Lite" hasn't been an issue for over 3 years now with the introduction of MPEG4.
Yep, it's now all about compression rates. :grin: You'll see the effects of that when there is a lot of movement on the screen.
OTA , FIOS, and C-Band have the least amount of compression. DirecTV and Dish have more compression. Cable varies but usually has the most compression.
Whether or not you can tell the difference is another matter.
I am curious where this info comes from...when the switch was taking place and we had both sets of channels active, lots of us did comparisons and saw very little PQ difference between them overall.Probably depends on the size, resolution and viewing distance from your display. I say this because I just moved from a 50" 768p plasma to a 65" 1080p plasma. On the 50", I couldn't detect any difference between MPEG-4 and OTA MPEG-2 HD on the same channels, except for trickplay smoothness. On the 65", if I look for them, I can now occasionally see some "graininess" in MPEG-4 scene transitions that are not present when viewing OTA. Otherwise, they are hardly noticeable from our normal viewing distances of 10'-12'.
Piratefan98
12-03-09, 09:48 AM
Well...those are 2 different resolutions, right?
Yes. Discovery Channel on DTV is (I assume) 1080i. Blu-Ray is 1080p. Not surprising that Blu Ray would look better.
Jeff
CCarncross
12-03-09, 10:43 AM
Yes. Discovery Channel on DTV is (I assume) 1080i. Blu-Ray is 1080p. Not surprising that Blu Ray would look better.
Jeff
Technically they arent 2 different resolutions...its just a difference between 1080p and 1080i(progressive and interlaced delivery), which is minor compared to the actually bitrates. BD bitrates can be in the 30-40 or higher Mb/s range, distributed tv signal is usually under 10 Mb/s, in many case way under...
hilmar2k
12-03-09, 11:05 AM
Technically they arent 2 different resolutions...its just a difference between 1080p and 1080i(progressive and interlaced delivery), which is minor compared to the actually bitrates. BD bitrates can be in the 30-40 or higher Mb/s range, distributed tv signal is usually under 10 Mb/s, in many case way under...
My math says that DIRECTV mpeg 4 HD is about 9 Mb/s.
kevinwmsn
12-03-09, 12:00 PM
How did you come up with those numbers????
Jeremy W
12-03-09, 12:38 PM
My math says that DIRECTV mpeg 4 HD is about 9 Mb/s.
It's actually a bit lower. 7-8.5 Mbps.
hilmar2k
12-03-09, 12:46 PM
How did you come up with those numbers????
Easy. Assuming an HR20, there is 200GB of space available for recording stuff, and that space holds about 50 hours of mpeg 4 content. From there, it's just math.
GlennDio
12-03-09, 01:40 PM
Yep, it's now all about compression rates. :grin: You'll see the effects of that when there is a lot of movement on the screen.
OTA , FIOS, and C-Band have the least amount of compression. DirecTV and Dish have more compression. Cable varies but usually has the most compression.
Whether or not you can tell the difference is another matter.
this is not what I have always heard ... I have always heard the OTA/FIOS/C-Band/and D* were "full" HD and that Cable and Dish were clearly "HD Lite" and in some cases very very Lite...
hilmar2k
12-03-09, 01:54 PM
this is not what I have always heard ... I have always heard the OTA/FIOS/C-Band/and D* were "full" HD and that Cable and Dish were clearly "HD Lite" and in some cases very very Lite...
DIRECTV is full resolution, but uses higher compression than FIOS/C-Band does. Cable is far, far worse, generally.
GlennDio
12-03-09, 02:15 PM
DIRECTV is full resolution, but uses higher compression than FIOS/C-Band does. Cable is far, far worse, generally.
but the compression technique (MPEG4) is advanced from the technique that FIOS/C-band does so we have full resolution in OTA/FIOS/DirecTV and it doesn't exist in Dish/Cable....correct?
paragon
12-03-09, 02:25 PM
but the compression technique (MPEG4) is advanced from the technique that FIOS/C-band does so we have full resolution in OTA/FIOS/DirecTV and it doesn't exist in Dish/Cable....correct?
I may be wrong, but I believe Dish is also MPEG4 but they use a higher compression rate so they can fit more channels per transponder.
I have been reading various sources, and discovered D* used to (or possibly still does) broadcast 1080i at 1280x1080 instead of 1920x1080. I was wondering if they still use 1280 at all, or did they finally bump everything up to 1920?
It looks like Dish is still at 1440x1080 and FiOS is true 1920x1080?
As far as SD goes, it looks like D* currently uses 480x480, whereas Dish is 544x480, and FiOS is at 528x480 for most channels (they used to be 704x480, but apparently they have compressed most channels down to 528)?
-Thanks
Not sure where you're getting the info about FiOS (I know... this is a DirecTV forum, but still, it should be addressed). Verizon doesn't do any additional compression to either their SD or HD signals. I've been a customer for 2 1/2 years, and their SD PQ really is nice - it looks ok on my HD TV, but on my SD TVs, it really is nice. I've seen no degredation of PQ in the time I've been a customer.
Also, you need to check the dates on those posts. That information is over a year old.
CCarncross
12-03-09, 06:07 PM
How did you come up with those numbers????
I believe he's basing it on what a Tp can handle and how many channels they tend to put on each transponder...but hopefully he'll return and answer himself.
:)
hilmar2k
12-03-09, 06:49 PM
I believe he's basing it on what a Tp can handle and how many channels they tend to put on each transponder...but hopefully he'll return and answer himself.
:)
If he was asking me, which I think he was, I did answer. See post #26.
Jeremy W
12-03-09, 07:25 PM
I may be wrong, but I believe Dish is also MPEG4 but they use a higher compression rate so they can fit more channels per transponder.
Dish does use MPEG4. Not only do they use a higher compression rate (which results in a lower bitrate) but they down-res the 1080i channels to 1440x1080. I've never seen Dish HD for any extended period of time, but I've seen various cable companies. They range from pretty good to downright terrible. Brighthouse is the worst I've seen, by far. But from what I've heard, they're actually not the worst in the country.
texasbrit
12-03-09, 07:33 PM
Yep, it's now all about compression rates. :grin: You'll see the effects of that when there is a lot of movement on the screen.
OTA , FIOS, and C-Band have the least amount of compression. DirecTV and Dish have more compression. Cable varies but usually has the most compression.
Whether or not you can tell the difference is another matter.
Not quite correct. The comment about FIOS is only really relevant when it comes to their transmission of OTA signals. FIOS uses MPEG-2 compression which is the same as the OTA signals. So FIOS just passes the OTA signal through, whereas DirecTV converts from MPEG-2 to MPEG-4 and so there are some losses; the DirecTV picture on the HD locals is sometimes as good as the off-air (and FIOS) picture but often slightly worse. The other HD channels come to the providers in different ways and of course are all compressed using either MPEG-2 or MPEG-4. My own experience of FIOS is that the quality of the HD non-locals is about the same as DirecTV. Cable depends on the local provider but varies from good to poor.
DirecTV uses or transmits satellite signals as it gets them to the customer.
DIRECTV uses the resolutions provided to them. If the native broadcast is 1280x720, then DIRECTV sends 1280x720, and the same with 1920x1080. This is true for all MPEG-4 encoded broadcasts. As far as older, MPEG-2 encoded SD channels, the resolution may still be low.
For the most part DIRECTV tries to keep the same quality as original broadcast for all HD programming, but there is some re-encoding going on. Personally I was unable to see any difference between OTA HD and DIRECTV HD, although there is a clear difference between Discovery Channel HD and the same programming on Blu-ray. I don't know if that difference originates at Discovery or DIRECTV.
the re-encoding means they bit rate starve the shows. 40mb is the maximum you can get with mpeg4. directv uses 5-12 mb usually. that is why the quality suffers.
texasbrit
12-03-09, 07:40 PM
How did you come up with those numbers????
5 channels in the 36 MHz usable bandwidth of a single CONUS transponder equals 7.2 Mbps per channel on average. But the use of statistical multiplexing means channels can instantaneously be using less or more than this number.
Jeremy W
12-03-09, 07:46 PM
DirecTV uses or transmits satellite signals as it gets them to the customer.
That is not true most of the time. Most channels send out their signal in MPEG2 format, so DirecTV has to re-encode the signal to MPEG4, which results in losses.
Jeremy W
12-03-09, 07:47 PM
5 channels in the 36 MHz usable bandwidth of a single CONUS transponder equals 7.2 Mbps per channel on average. But the use of statistical multiplexing means channels can instantaneously be using less or more than this number.
Yep, and that's why the average bitrate of a program will generally be somewhere between 7 and 8.5 Mbps.
texasbrit
12-03-09, 08:00 PM
Yep, and that's why the average bitrate of a program will generally be somewhere between 7 and 8.5 Mbps.
Well, not really. Many channels would be running much lower than that on average. The key is how much bandwidth can the channel get when it needs it (fast movement). I don't know what the max bandwidth is that the stat mux will allocate but it seems reasonable that if a channel needs 8.5Mbps it can usually get it unless all the channels on the stat mux are demanding maximum bandwidth at the same time. I seem to remember that the HBO agreement requires 8Mbps be provided for their MPEG-4 signal.
Most channels send out their signal in MPEG2 format.Is this still true?
CCarncross
12-04-09, 07:19 AM
Is this still true?
Most likely..every OTA station does...
Most likely..every OTA station does...FWIW, HBO is providing both MPEG-4 and MPEG-2 feeds. Contrary to their original 2007 announcement about going strictly MPEG-4, it looks like they decided (or were pressured) to continue to supply both formats, as you can see by the last section of this (http://www.homeboxoffice.com/to/Recently_Updated/HBO_MPEG4_HD_Tech_Summary_B2B_20080916.pdf) tech advisory.
JoeTheDragon
12-04-09, 08:11 AM
FWIW, HBO is providing both MPEG-4 and MPEG-2 feeds. Contrary to their original 2007 announcement about going strictly MPEG-4, it looks like they decided (or were pressured) to continue to supply both formats, as you can see by the last section of this (http://www.homeboxoffice.com/to/Recently_Updated/HBO_MPEG4_HD_Tech_Summary_B2B_20080916.pdf) tech advisory.
I don't think any cable system as mpeg 4 yet and mpeg 4 HD cable boxes just came out and they still have HDMI bugs and the cable co still give old the mepg 2 only HD boxes as well.
paulman182
12-04-09, 08:34 AM
FWIW, HBO is providing both MPEG-4 and MPEG-2 feeds. Contrary to their original 2007 announcement about going strictly MPEG-4, it looks like they decided (or were pressured) to continue to supply both formats, as you can see by the last section of this (http://www.homeboxoffice.com/to/Recently_Updated/HBO_MPEG4_HD_Tech_Summary_B2B_20080916.pdf) tech advisory.
Yes, but the dual HD feeds mentioned are for the main HBO E/W and Cinemax E/W (not all their HD channels,) and the SD channels.
This document is also almost 14 months old.
This document is also almost 14 months old.Yup. Most current one I could locate. If you can find more recent info, please post. Thx! :)
Jeremy W
12-04-09, 02:53 PM
Is this still true?
Yep. Some channels have plans to switch to MPEG4 in the future, but the vast majority are still MPEG2. HBO being the most notable exception, but Smithsonian HD has been MPEG4 since it launched.
Jeremy W
12-04-09, 02:57 PM
Well, not really. Many channels would be running much lower than that on average.
What makes you say that? With 5 channels/transponder, and usable bitrate on each transponder being around 38 Mbps, the average per channel is 7.6. Obviously stat muxing screws with that, but I can't see why the actual average would be much lower. The stat muxing will use the full bitrate constantly, it just changes the mix.
Doug Brott
12-04-09, 03:05 PM
That is not true most of the time. Most channels send out their signal in MPEG2 format, so DirecTV has to re-encode the signal to MPEG4, which results in losses.
technically they transcode it.
Jeremy W
12-04-09, 03:34 PM
technically they transcode it.
That's true. Re-encode is not the proper terminology.
Tom Servo
12-05-09, 01:13 AM
For the most part DIRECTV tries to keep the same quality as original broadcast for all HD programming, but there is some re-encoding going on. Personally I was unable to see any difference between OTA HD and DIRECTV HD, although there is a clear difference between Discovery Channel HD and the same programming on Blu-ray. I don't know if that difference originates at Discovery or DIRECTV.
I personally think that the Discovery Networks have cheaped out on HD broadcast equipment. All of their networks and many of their current shows just have lackluster PQ. IIRC several shows like Mythbusters and Dirty Jobs were shot for a while with 16:9 480i/p and some of the old episodes are noticeably blurry.
And don't get me started on their 14:9 "compromise" zoom on all the SD programming and commercials. Yeeech.
Motion artifacts aside, I think a lot of the quibbles we have with the HD PQ on DirecTV is down to the channel's end of things. Garbage in, garbage out. (I'm looking at you, A&E/Cartoon/TBS and anyone else who stretches SD content.)
texasbrit
12-05-09, 07:56 AM
What makes you say that? With 5 channels/transponder, and usable bitrate on each transponder being around 38 Mbps, the average per channel is 7.6. Obviously stat muxing screws with that, but I can't see why the actual average would be much lower. The stat muxing will use the full bitrate constantly, it just changes the mix.
Usable bitrate is 36 Mbps, so 7.2MBps per channel. If a channel demands more than 7.2MBps, another channel will be less, so it's hard to average above that unless you are one of the channels "locked" to a minimum bitrate like HBO. And the way many (most) stat muxes work, they tend to allocate bandwidth to channels that have demanded high rates in the past. So with that type of stat mux, if there's a channel that only ever needs 6 Mbps, it tends to get that all the time, and might never get the full 7.2MBps or more even though it's available. In that scenario, some channels might average 7.2 or over and some channels might average less than that. I don't know exactly how the DirecTv stat muxes handle that situation.
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