Is it Virgin Media at fault or broadcaster when HD is not HD ?

dante01

Distinguished Member
I set my V6 to output what it is receiving as opposed to using it to either scale or deinterlace content. THe TV will automatically scale it to fit its panel anyway and has to deinterlace it and I doubt that the V6 includes a scaler any better than that onboard my TV.

The settings I posted earlier in the thread should result in the box only outputting the resolution it is receiving.
 

thedude

Distinguished Member
I have my v6 set at whatever it should output. And then my TV or amp whichever I decide to will Process the image.
 

dante01

Distinguished Member
Just leave it to the TV to process and or scale the video. There's no benefit associated with using a scaler onboard an AV receiver either.
 

grahamlthompson

Distinguished Member
I don’t want to comment really on whats best as I don’t know, but beyond bitrate there is also a couple of other factors which determine the quality of the final image we see. The signal received will likely be 1080i. Typically nowadays customers do not set their boxes to match the incoming broadcast signal, firstly there will be deinterlacing going on, in addition users tend to set the resolution to the max capabilities of the STB, which in this instance would be 4K. Both these things (deinterlacing and upscaling) require some picture processing, the capabilities of which will be different dependent on the STB being used

@grahamlthompson told the anecdote of a freesat user using a built in tuner from a 4k TV. I can totally believe the image will be better in this instance as the TV will have better picture processing capabilities compared to the STB’s being discussed.
Frreview-HD can be 1080i 50 fields/second or 1080p 25 fps. It can dynamically switch ie change from interlaced to progressive within the same broadcast. Basically the gop structure is switched to match the source. You physically cannot tell if you are looking at 25 fps or 50 fields/second. Which according to some here is bound to stutter just like they insist 24Hz does. Provided the display exactly matches the source framerate they both look the framerate. As soon as someone mentions pulldown this means that you get the issue generated by the processing. No pulldown is needed to show 23.976 fps provided the display can be switched to show on frame for every one in the source. Result no jerkiness from missing frames, though too low a bitrate will cause fast motion artefacts simply because two much video information has been thrown away.

Freesat tuners cannot handle progressive content it's always interlaced.

As all TV's with a screen of a fixed resolution can only display a progressive frame followed by another.

The full frame is built in a frame store that has 3 transistors for every physical pixel on the actual display. This data is instantly transferred to the screen. Each pixel is comprised of 3 sub pixels (Red Green and Blue). You can see these by looking closely at the screen using a magnifying glass.

You are always looking at progressive video, Only CRT displays generate the upper field lines first followed by the lower field on the same screen. This is purely to avoid flicker as the phosphors from the upper field fade. Effectively creating 100Hz refresh.

There is no fade on a non crt display. one frame is instantly replaced by the next. So if you use two identical frames you don't see the join.

Efectively de-interlacing is not an issue,
 

grahamlthompson

Distinguished Member
I have my v6 set at whatever it should output. And then my TV or amp whichever I decide to will Process the image.
No AVR can change the framerate of a Video source. They can change the resolution up or down. eg upscale Full HD to 2160p. Some TV's can display the source signal refresh rate usually just saying 48Hz or 50 Hz. No point in displaying the output resolution. Whatever the source it will always be the number of pixels on the screen. If wider than 16:9 it will have black pixels top and bottom.
 

thedude

Distinguished Member
I don't use my avr it's just there passing through a signal
 

chopples

Distinguished Member
Efectively de-interlacing is not an issue,
Thanks Graham very informative but I am unsure why it was neseccary. I know a TV only display a progressive frame. My comment was in relation to whether there Is a difference in quality dependent on which device is processing the interlaced signal. In my experience, which granted is based around satellite, is yes it does, as does the device handling any upscaling. I was just trying to offer a reason why image quality can be different across devices and platforms beyond method of encoding and bitrate.
 

grahamlthompson

Distinguished Member
Thanks Graham very informative but I am unsure why it was neseccary. I know a TV only display a progressive frame. My comment was in relation to whether there Is a difference in quality dependent on which device is processing the interlaced signal. In my experience, which granted is based around satellite, is yes it does, as does the device handling any upscaling. I was just trying to offer a reason why image quality can be different across devices and platforms beyond method of encoding and bitrate.
That's easy to show, The older Foxsat-HDR video processing generates a somewhat flat image when compared to the newer G2 Humax boxes,

Using the custom firnware the Foxsat-HDR recording files can be directly viewed using the newer boxes DLNA client. The difference in playback quality is dramatically improved when using the newer box to handle the pictures. It would only take the Virgin box to have poor video processing to generate the same sort of instantly noticeable inferior pictures. Of course both boxes create identical recording files for the same content.

I doubt the Virgin box has a dlna server that you can view the recording files on other kit so no way to compare. I do use Virgin broadband as it's the fastest by a long margin round here.

I also have Vbox IP server box, that can record and can be viewed easily on other kit. (even remotely like a slingbox).

Enigma 2 kit that can use both satellite and terrestrial and have dlna servers would be vastly more capable source and of course no Virgin TV fees either.

Copying the Foxsat-HDR files to a PC and burning them to blu-ray produces the same improvement. In fact if I play them back using my Panasonic 4K HDR player on my LG OLED they look fantastic.

High end player and high end oled makes all the difference.
 
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dante01

Distinguished Member
The V6 can share recorded content with other Virgin boxes on the same LAN or WAN. You can also use the app on an iOS or Android device to play the content stored on an STB if also on the same LAN or WAN.

Virgin are about to expand upon this with new hardware and a mini box cloud based STB.

As noted earlier within this thread, it is perfectly possible to bypass the V6 box's own video processing and there is no requirement to utilise the inbuilt scaler. How would not using something degrade the output? Moving files from one storge location to another has no quality improvements associated witb it. The PC playing the files will not result in better video than using the device the files were originally recorded with and stored on. You are otherwise saying that what you get depends upon the PC and its capabilities and this is only of any importance iof wishing to use that device to process or sale the video? You'd get the same data irrespective of where that data isstored.

I think that you are confusing storage, playback and processing? They are not all the same thing.
 
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dante01

Distinguished Member
Basically, don't use any intermediary device to scale or deinterlace the video and just leave it to the TV to deinterlace it and scale that content to its panel.

The only exception to this is if you've £30K to spend on a pro grade scaler. Even then, there's no real benefit unless the screen you have is inordinately large and the TV's own processing is exceptionally poor?

Scaling up the video can in itself be detrimental and requires additional sharpening and or smoothing. Your TV's manufacturer is far more aware of your TV's abilities to portray an image than any thotd part manufacturer so why use a third party scaling device to scale video that the TV itself can scale and treat in a manner benefitting that TV's capabilities? You are more than likely introducing undesirable effects if processing the video prior to the TV and it is very unlikely that any device apart from very expensive ones will result in better scaling than that which your TV itself can attain. It is easy enough for people to try this for themselves, but I'd be surprised if anyone notices any improvement if processing the video using a scaling device prior to the TV itself?


Some may find this of interest:


It should also be stressed that all resolution less than that of your TVs panel will always be scaled up to fit your TVs panel by the TV. If the TV didn't do this then you'd end up with a nlack border all the wat arounf content if a lesser resolution being displayed upon that higher resourion panel. Interlace video which is commonly associated with TV broadcasts will also be automatocally deinterlaced by all flat panel TV. THe only time you'd get the interlaced image is ig using a CRT display. It could be theoretically dropped, but doing so means severing any backwatd compatability for older CRT TVs as well as causing some of the broadcasters issues associated with then having to supply progessive video feeds.
 
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