Digital Ugliness on Certain 1080i Broadcasts

[Pookie]

I see this on both Leno and Conan during the music performance. The stage lights seem to blow out the luma levels (I'm guessing), resulting in this:

http://www.uploadhouse.com/images/346720963ws-block.png (http://www.uploadhouse.com/)



When the stage lights don't strobe (aka slower parts of the song) the result is more normal:

http://www.uploadhouse.com/images/621569317ws-noblock.png (http://www.uploadhouse.com/)



You can download a 30Mb clip of the phenomenon at:

ftp://tempclips@avisynth.org:QfJY(86m@avisynth.org/nbc1080i.MPG

(Thanks to Richard Berg for the hosting space)

I'm wondering what the source is of the distortion. Anyone else get this ?

[Emp3r0r]

Welcome to the world of NBC 1080i low definition tv caused by starving bitrate and a crappy hardware mpeg2 encoder. This ugliness can be seen on almost all networks that broadcast 1080i: NBC, CBS, WB. In my area, the WB has the least amount of ugliness. However, NBC is by the far the ugliest 1080i broadcast available.

<19mbps hardware encoded 1080i only looks good when there is very little motion.

[Tio]

Yup. :-(

Their HD airing of the Thanksgiving Day Parade was the worst yet. Any (and I mean ANY) movement in the scene and everything was pixelated. Take a gander at this thread (http://forum.abhdtv.com/showthread.php?t=22116) over on abHDTV. It's enough to piss anyone off...even those without HiDef!

-Tio

[reepa]

At least you're getting high definition. In Europe we're going the route of cramming as many standard definition channels into one multiplex (bandwidth of one analog channel) as possible. The result is something horrible.

edit: On the other hand, this allows us to decide on an MPEG4-based HDTV standard in the future.

[n3rdyguy]

We in EU will nevah enjoy HDTV.. It suckz! We don't have anything to rip lol.

[Emp3r0r]

Here is the avisynth script I use for CBS 1080i material:


Mpeg2Source("{0}",cpu=0) #no deblocking
Telecide(Order=1).Decimate() #convert to progressive
Crop(0,0,-0,-8) #remove gray bar
Deblock(32,8,8) #deblock crap 1080i motion
UnDot() #clean a little
LanczosResize(960,720)

Fox 720p:


Mpeg2Source("{0}",cpu=4) #deblocking
SelectEven().Decimate(cycle=5) #60fps to 24fps
Crop(2, 0, -4, 0)
FillMargins(0,2,0,4) #(left, top, right, bottom)
UnDot()
LanczosResize(960,720) #horizontal resize

The deblocking helps with the ugliness and the anamorphic resolution does most shows well when using mpeg4 ASP from 700MB to 1GB with 5.1 AC3 sound. The 40 minute shows can playback fine on a xbox and still look good on higher resolution displays.

[Pookie]

Thanks for the sympathetic ear, everyone. Tio, I read that thread and see it happens everywhere. Emp3r0r, thanks for the script suggestions. n3rdyguy and reepa, seems like the movement to h264 for European HDTV is going to be a good decision.

[illCP]

seems like the movement to h264 for European HDTV is going to be a good decision.
Maybe.... or maybe not. I'm scared of the day when DVB-Streams come in 1080i AVC-encoded with a bitrate of 3 MBit/s each to get as much channels as possible (even more crappy gameshow-channels) in one transponder bandwith range...:(

So DVB-S2 in AVC may not enhance the quality - not if they use half of the MPEG-2 Bitrates they use nowadays, which are verly low on a lot of channels.

[Pookie]

Maybe.... or maybe not. I'm scared of the day when DVB-Streams come in 1080i AVC-encoded with a bitrate of 3 MBit/s each to get as much channels as possible (even more crappy gameshow-channels) in one transponder bandwith range...:(

So DVB-S2 in AVC may not enhance the quality - not if they use half of the MPEG-2 Bitrates they use nowadays, which are verly low on a lot of channels.

Blocks might be replaced by smears, eh ? Perhaps, but even lower bitrate AVC/h264 might be quite acceptable. Just have a look at the 480p King Kong trailer -> http://www.apple.com/trailers/universal/kingkong/hd/

[Xayd]

At least you're getting high definition. In Europe we're going the route of cramming as many standard definition channels into one multiplex (bandwidth of one analog channel) as possible. The result is something horrible.

edit: On the other hand, this allows us to decide on an MPEG4-based HDTV standard in the future.

i'm convinced that mpeg-4 transitions in the future will largely be a downgrade in quality in the states.

broadcasters don't seem to grasp the fact that with real-time encoding mpeg-4 doesn't offer a whole lot more compression than mpeg-2 in real time. and they will not release their ability to down-res and down-sample everything they receive on the fly to further starve bitrates, so i fully expect mpeg-4 to be on average worse than mpeg-2.