what resolution does disk turbo hd have and what about directtv

[Onceler2]

I can't seem to find anything about the resolution except turbohd is the ONLY provide giving full HD
I did a search on wiki it didnt turn anything up.I know that there are a lot of knowledgeable people on the forum and someone might give a link explaining the resolutions
Thanks

[misterbill]

Just Google "resolution of directv hd" and read. Then Google "resolution of dish network hd", read and compare.

[Onceler2]

just get a bunch of 1080i/p
nothing is said wether it is 1440 or 1920

[edDV]

just get a bunch of 1080i/p
nothing is said wether it is 1440 or 1920

Are you thinking 1920 is better than 1440 ? It isn't unless bit rate is raised 25% to compensate.

If you increase resolution 25% at the same bitrate, compression errors will be far worse than any benefit from the difference in resolution. This is even more an issue since most HD origination in network television is 1440x1080 HDCAM or 1280x1080 DVCProHD. There is no current 1920x1080p source for broadcast television. For that you need to get Blu-Ray DVD.

I'll look for some references.

[Onceler2]

I am thinking that 1920 is better I would like to see what the real resolutions and bitrate are
I am setting up my HT and will be making purchases very soon

[edDV]

OK, read this one to understand what they are up-linking to the satellite for typical TV network produced material. 1440x1080 is the highest resolution any of this is recorded in the field or studio.
http://library.creativecow.net/articles/kolb_tim/formats.php

The huge difference is these broadcast formats avoid or reduce intraframe compression so that editing is less lossy. Typical bit rates are far higher.

Production formats:
HDCAM 135 Mb/s 1440x1080i or 1280x720p 3:1:1 coding
DVCPro-HD 100 Mb/s 960x1080i or 1280x720p 4:2:2 coding

News/Reality formats:
XDCAM-HD 35Mb/s 1440x1080i or 1280x720p 4:2:0 coding
HDV 25Mb/s 1440x1080i or 1280x720p 4:2:0 coding

After editing, these are distributed from either HDCAM or DVCProHD master formats to playout servers.

DBS and broadcast bitrate transmission to the home is much reduced to between 8 to 19 Mb/s for MPeg2 HD or about 5-15 Mb/s for MPeg4.

There is absolutely no point to upscaling these to 1920x1080i before downlink. It would only decrease quality. The cable/sat tuner makes the conversion to 1920x1080i or 1280x720p in the box for output over HDMI or analog component.

BluRay allows use of 1920x1080p/24 formats at up to 25 Mb/s for added quality. It would be possible to distribute movies over satellite at this bitrate (or ~12Mb/s for MPeg4) but half the channels could be sent over a satellite transponder. Someday this quality may be offered at a premium charge.

ATSC DTV broadcast does upscale to 1920x1080i or 1280x720p for broadcast in anticipation of future enhancement. They are investing in fixed infrastructure intended for decades of life for transmitters and HDTV internal tuners. 1440x1080 was not approved as one of the supported 18 transmission formats. Still the production behind the transmitter is typically recorded at lower resolution. DirectTV and Dish can do what they want because both the downlink and tuner are under their control.

[jagabo]

There is no current 1920x1080p source for broadcast television.

What about film sources? Are saying that all movie broadcasts have been encoded at, or reduced to, 1440x1080 (or less) somewhere along the broadcast chain? That wouldn't surprise me for satellite but even OTA from your local broadcaster?

Are you thinking 1920 is better than 1440 ? It isn't unless bit rate is raised 25% to compensate.

I disagree with this a bit. 1920 will require more bitrate than 1440 but I find the additional bitrate requirement usually isn't linear. 25 percent more resolution (on one axis) may only require half as much additional bitrate, say, 10 to 15 percent. The exact amount varies depending on what type of resizing filter you use. Lanczos3 won't save you much bitrate. Bilinear will save more.

[edDV]

There is no current 1920x1080p source for broadcast television.

What about film sources? Are saying that all movie broadcasts have been encoded at, or reduced to, 1440x1080 (or less) somewhere along the broadcast chain? That wouldn't surprise me for satellite but even OTA from your local broadcaster?

HDCAM tapes have been the typical transfer and distribution media for movies for HD television. HDCAM holds the progressive film image telecined to 8 bit 1440x1080i. It uses 3:1:1 color space and about 3x intraframe DCT compression to a 144 Mb/s data rate vs. 90Mb/s used for SD DigiBeta. Under playback, the 1440x1080i recorded signal is stretched out to 1920x1080i/29.97 or inverse telecined and scaled for 1280x720p/59.94 playback. Later HDCAM models can also play progressive 23.976 PsF tapes out to 1080p/23.976, 1080i/29.97 or 720p/59.94.



There is another tape mastering format called D5 that does store the film transfer image at 10bit 1920x1080i/29.97 4:2:2 with 4x DCT compression but this format is seldom used for distribution.

More recently, film transfers have been mastered as 1920x1080p/24 or 4kx2k/24 progressive data but distribution for HDTV broadcast is still mostly by HDCAM tape. Eventually this will be done as networked data transfers directly to playout servers.

Are you thinking 1920 is better than 1440 ? It isn't unless bit rate is raised 25% to compensate.

I disagree with this a bit. 1920 will require more bitrate than 1440 but I find the additional bitrate requirement usually isn't linear. 25 percent more resolution (on one axis) may only require half as much additional bitrate, say, 10 to 15 percent. The exact amount varies depending on what type of resizing filter you use. Lanczos3 won't save you much bitrate. Bilinear will save more.

Yes, but my main point is that HDCAM distributed movies have already been resolution reduced to 1440x1080 on tape. HDCAM playback is still very high quality with entact frames and 144 Mb/s bit rate.

It seems to me that satellite distribution at 1440x1080i would offer superior compression efficiency. In that case horizontal aspect stretch to 1920 could be done in the tuner.

[edDV]

Here is a picture of the HBO uplink facility in 2003 when all movies were played from tape. Since then I'm guessing it has all gone to hard disk playout servers but ingest is probably still from HDCAM and DigiBeta tape.


Each of the racks on the right contain robotic tape players for one cable channel. There are two redundant playback racks for each uplink to provide backup. The hard drive playout servers on the left handle the breaks and promos.

http://gallery.bostonradio.org/2003-01/nyc/100-00866-lrg.html

[edDV]

Some might ask why do broadcasters use less than full up 1920x1080p/59.94 or 1920x1080p/23.976 formats for everything?

The answers come down to limitations of the technology and facility infrastructure upgrade cost.

I'll explain this for NTSC. At the end I'll explain PAL differences.

During the 90's TV networks and large TV stations converted from analog to uncompressed digital SD 720x480i SDI (SMPTE-259M) routing infrastructure and DigiBeta SD compression recorders. Facility video/audio routing is similar to a telephone switch involving hundreds of A/V lines. The SD serial digital architecture was "HD ready" but only for compressed HD formats not uncompressed. "Full uncompressed HD" requires SMPTE-292M routing (up to 1.4GB/s) which was developed later.

The HDCAM format was introduced in 1997 as the first generation lightly compressed HD format (explained above) which achieved the best possible quality within the 144 Mb/s bitrate limits of the SMPTE-259M routing infrastructure. That allowed HD testing and peripheral conversion to HD using the existing SD digital lines. Uncompressed SMPTE 292M routing could be added for production departments only without changing everything.

While HDCAM offered excellent distribution quality, it had limitations for certain types of layered or graphics intensive production due to the 3:1:1 color space compromise. Panasonic developed the 100Mb/s DVCPro-HD format to fill both the 4:2:2 production need and offered idealized 720p/59.94 field origination for ABC, ESPN and FOX (also the 720p National Geographic cable network). These are the formats currently in use.

The interesting conclusion that resulted from both Sony and Panasonic was color space and minimal interframe compression are more important for editable picture quality than pixel resolution. Sony dropped resolution to 1440x1080i (non-square pixels). Panasonic went to 4:2:2 960x1080i (double wide pixels) and 1280x720p (square pixels) for optimal production. We should remember this for our own camcorder production workflow. For a given bitrate, 1280x720p or 1440x1080i acquisition provides a better quality edited result than more heavily compressed 1920x1080i.

A special enhanced version of HDCAM (called HDCAM-SR) was developed specifically for 24p digital movie and TV series production. It records lightly compressed 1920x1080p/23.976 or 24 fps, 4:4:4 RGB at 440 or 880 Mb/s and is intended as a direct replacement for 35mm film. A new rival format is AVC-Intra which uses H.264 intraframe compression to handle production needs at 100Mb/s and distribution/ENG needs at 50Mb/s.


PAL format variations follows

HDCAM uses 1440x1080i/25 or 1280x720p/50
DVCPro-HD uses 1280x1080i/25 or 1280x720p/50

XDCAM-HD uses 1440x1080i/25 or 1280x720p/50
HDV uses 1440x1080i/25 or 1280x720p/25