Optimizing picture quality on sd-channels

[besit]

Re: Optimizing picture quality on sd-channels

SD channels quality depends on the encoding settings like resolution and bitrate. On my experience TV providers doesn't do nothing to make a high quality picture on SD channels. MPEG2 has some restrictions. If bitrate less then 4 MBit/s you'll see some artifacts. MPEG4 needs less bitrate to maintain good quality. I'm absolutely sure that if they'd encode content one time in h264 with only 1mb bitrate the quality should be very good. But often they get mpeg2 signal then convert to mpeg4 to save the bandwidth. What you'll get? The big disgrace. Also some channels are broadcasted in 540x576 resolution. Using of this resolution intended to reduce bitrate without visible quality degradation. But in fact converting video signal few times (like 1920x1080 to 720x576 then to 540x576) you'll get absolutely distorted image. And if such content is made by feet you won't do nothing to improve it's quality.
About upscale. I have seen what sony and panasonic blueray players make from DVD. But it must be a good DVD. On the other hand I haven't see no DVB-S box with such upscale capabilities.
The best way to upscale SD content - to use windows xp PC and DVBViewer.

[Clark197]

Re: Optimizing picture quality on sd-channels

The real time scaling is still a big challenge and is still object of intensive research.
External components can be copied by all.
The heart of the pucture scaling is in the FPGA. It is this code written in VHDL or Verilog
which make the difference between scaling.
Software (plugin) scaling is not a very good idea because it need more time
to compute the resultant video.

Regards
Clark

[Satphoenix]

Re: Optimizing picture quality on sd-channels

OK, after several testings and reading I found my best combination of all components:

- hdmi and 1080i upscaling from sat-receiver
- overscan off at tv (is always better)
- sharpness up on sat-receiver (if possible)
- other (brightness, contrast...) nearly untouched, only a bit

my experiences untill now...

[gianni253]

Re: Optimizing picture quality on sd-channels

- hdmi and 1080i upscaling from sat-receiver
- overscan off at tv (is always better)

These two are the most critical variables, and they can be both connected to only one choice, that is where to execute upscaling (receiver or tv).
If you have a good interpolation algorithm in receiver (combined with good processing power) I agree it's the best choice.

[Satphoenix]

Re: Optimizing picture quality on sd-channels

...If you have a good interpolation algorithm in receiver (combined with good processing power) I agree it's the best choice.

Normaly cheap receivers (and I have only cheap receivers untill now) don't have such a processor or algorythm. They only strech the picture to 1920*1080 points.
I know there are special processors and software (farudija or reon) which are specialised for this, but they are to expensive for cheaper receivers. So I'm looking for a way with my "limited possibilities".

[BlueIsMyColor]

Re: Optimizing picture quality on sd-channels

The big question is: if the channels broadcasting have bad quality it's very difficult to have good quality pictures in our tvs. To have good quality it's necessary to have good bitrates/resolutions in transmissions. If not there are no miracles.

regards

[aplok]

Re: Optimizing picture quality on sd-channels

Here some comments about faroudja video processing chipset:

Faroudja Video Optimized is a calibration and logo branding program available to TV and Set-Top Box manufacturers who use STMicroelectronics system-on-chip (SoC) solutions with integrated Faroudja video processing algorithms.

The program helps properly initialize the video signal processing and optimize the LCD panel to produce an accurate picture.
The program includes programming and calibration tools.

Calibration steps include

adjusting contrast,
brightness,
gamma levels,
color temperature,
sharpness,
noise reduction filters and backlight levels,
as well as Faroudja Adaptive Contrast Control (ACC2) and Active Color Management (ACM3D),
to insure extended dynamic range and accuracy in shadow details,
as well as natural tone (color quality).

The calibrated settings are stored in a video mode called Faroudja Movie,
optimized for high-end TVs and Blu-ray HD sources.

[Satphoenix]

Re: Optimizing picture quality on sd-channels

Here some comments about faroudja video processing chipset...

And which sat-receiver has such an upscaling processor?

I know that some better av-receivers (e. g. from denon) have this, but for a sat receiver perhaps to expensive.

[aplok]

Re: Optimizing picture quality on sd-channels

Faroudja DVP1500 : Faroudja Digital Videp Processor 1500

abstract


+ sat rcvr
| .S-Video DVI YPrPb
|
|
+ dvp 1500
-i dvp 1500 :: input
. . S-Video DVI YPrPb
.
-o dvp 1500 :: output
. . RGBHV DVI
|
+
|
|
+ hdtv



Connecting HDTV Satellite Receivers

... if we will assume the receiver being used operates as follows:

1. Non HDTV material is output from the receiver via an S-video connection
2. HDTV material is output via YPrPb outputs
3. If available, HDTV material is also output via a DVI connector.
The following diagram offers one way to connect the system.


... different sources is as follows:
Non-HDTV Channels
Native HDTV Channels
Native HDTV Channels with HDCP Encription

... dvp1500 input
S-Video DVI YPrPb

... dvp1500 output
RGBHV DVI

price

More items related to "faroudja dvp 1500"

Faroudja DVP-5000 Digital Video Scaler Processor
$165.00

Faroudja DVP-3000 Digital Video Scaler Processor
$295.00

Faroudja Dvp1010 Digital Video Processor
$495.00

Faroudja DVP3000 Digital Video Processor/Scaler Hi-Def Video Processor
$390.00

[odysseas1991]

Re: Optimizing picture quality on sd-channels

It is quite simple imo opinion to optimise picture quality.

Firstly, switch to your box output and pick a channel on a satellite that broadcasts a high level of detail (judge by your own eye as this is important). Firstly adjust all the settings from the box settings such as colour etc. That should optimise the basic output level.

Secondly, attempt to configure the TV settings in a manner that optimises the source output to give you the best picture quality. Adjust, colour, contrast, brightness etc. Basic stuff.

All this doesn't neccesarily improve the picture but it helps improve what you have.

The discussions in the previous posts relies on add ons and the STB to have features for improving picture quality which some boxes don't have.

Note, some channels broadcast in very bad quality anyway and pixelate so it is not always your channel picture quality settings that may be at fault if you are not happy with what you receive!

[aplok]

Re: Optimizing picture quality on sd-channels

The discussions in the previous posts relies on add ons and the STB to have features for improving picture quality which some boxes don't have.

yes,

so if you let conceptualize the Digital Video Processor as a

video equalizer

and remember, hifi history started with

tuner
tuner + equalizer
tuner + equalizer + dolby + surround + bose extra + ....

all in extra boxes, at extra money,
where all these signal processing algorithms were that time melt into dedicated cpu (called chip)

and today, all these signal processing algorithms are forged into software run by fast cpu

this schema leads obsviously to the idea of a dedicated plugin for video post processing into a wide open linux driven fast cpu, just like new 2x1300 mhz vu+2 processor

just like equalizer did at that time

that is a nice and challenging project for a student thesis: embed these algo into less than 100 Mb open os