Discussion Standard Definition Channels PQ issue solved in Technicolor HD HEVC STB

[TJ_DJ]

But such an effect was not there 1 month back, it's only happening now in more frequency than ever before

Can someone explain exactly what interlacing means in HD channels? Perhaps a screenshot would help. Just want to know if it is the same thing that I am observing too.

 

[Ramesh DthSky]

But such an effect was not there 1 month back, it's only happening now in more frequency than ever before

I have been seeing those interlacing effects for nearly three years since I have started viewing HD channels on Sun Direct (2015), Videocon D2H (2016), Tata Sky (2017) and now on Airtel (2018). Initially I too didn't notice those but only in 2016 I started watching HD channels very keenly and found that in Videocon D2H and then cross checked that with Sun Direct. Interlacing effects will also be visible on the grass outfield of the stadium.

You will notice some graininess on the green outfield when the ball moves faster, especially when the grass is less dense and not cut evenly like in the Wankhede stadium. But this graininess will be very rarely seen when the match happens either in Melbourne or Lord's or Mohali or for that matter, in any other grounds of the Premier League football matches. Also when the TV's motion flow engine is not quite good even though the TV has a refresh rate of 50 Hz or above, then those interlacing effects will be further enhanced or prominently seen, especially for sports.

I see it in Fast Action Scenes in movies too, and also in black / dark backgrounds, especially on Romedy NOW HD Channel, on ADTV. Anyone else observed the same?

I don't watch Romedy Now HD or other English movie channels frequently but the interlacing effects are visible primarily on fast moving scenes with darker background. But again, it depends on the content as well. When an older content is upscaled to HD, the black background will produce some unintended effects like graininess or blurriness, etc.

l have seen that most English movie channels broadcast movies in 16:9 format full screen but actually those movies are shot with different aspect ratio, either 1.85:1 or 2.39:1. When the content is broadcast in the aspect ratio with which it was shot, it would be fine like in Hindi movie channels or other regional movie channels. But once you try to enlarge that to fit the full screen like in English movie channels or Sony Rox HD or MTV Beats HD, the amount of vertical pixels in the content will not match with the original content needed for the 16:9 aspect ratio and some content on the either side of the screen horizontally gets cut/removed as well. This process normally reduces the quality of the content marginally, but the effects will be very much pronounced in the older movies, at least a decade old and that are not shot with advanced cameras like now. So here, the faster actions will show some unintended effects along with interlacing impacts especially on darker background.

To cross check, please download a HD video song or a movie and attempt to change its aspect ratio to fit the screen in a GOM player so that there won't be any black bars and you will find the clarity of the video decreased when compared to the video clarity with black bars.

 

[Ramesh DthSky]

Can someone explain exactly what interlacing means in HD channels? Perhaps a screenshot would help. Just want to know if it is the same thing that I am observing too.

It is quite difficult to explain but you can find a greater reserve of information related to interlaced scanning and progressive scanning along with videos and explanation on YouTube. Interlacing happens for both SD and HD broadcast. Since HD has greater clarity by means of increased pixels, interlacing impacts for fast action scenes will be sometimes visible, may be due to content and some other factors as well can be attributed. But normally you won't see those impacts on general entertainment channels or even for songs.

 

[Sparker0i]

I have been seeing those interlacing effects for nearly three years since I have started viewing HD channels on Sun Direct (2015), Videocon D2H (2016), Tata Sky (2017) and now on Airtel (2018). Initially I too didn't notice those but only in 2016 I started watching HD channels very keenly and found that in Videocon D2H and then cross checked that with Sun Direct. Interlacing effects will also be visible on the grass outfield of the stadium.

You will notice some graininess on the green outfield when the ball moves faster, especially when the grass is less dense and not cut evenly like in the Wankhede stadium. But this graininess will be very rarely seen when the match happens either in Melbourne or Lord's or Mohali or for that matter, in any other grounds of the Premier League football matches. Also when the TV's motion flow engine is not quite good even though the TV has a refresh rate of 50 Hz or above, then those interlacing effects will be further enhanced or prominently seen, especially for sports.



I don't watch Romedy Now HD or other English movie channels frequently but the interlacing effects are visible primarily on fast moving scenes with darker background. But again, it depends on the content as well. When a older content is upscaled to HD, the black background will produce some unintended effects like graininess or blurriness, etc.

l have seen that most English movie channels broadcast movies in 16:9 format full screen but actually those movies are shot with different aspect ratio, either 1.85:1 or 2.39:1. When the content is broadcast in the aspect ratio with which it was shot, it would be fine like in Hindi movie channels or other regional movie channels. But once you try to enlarge that to fit the full screen like in English movie channels or Sony Rox HD or MTV Beats HD, the amount of vertical pixels in the content will not match with the original content needed for the 16:9 aspect ratio and some content on the either side of the screen horizontally gets cut/removed as well. This process normally reduces the quality of the content marginally, but the effects will be very much pronounced in the older movies, at least a decade old and that are not shot with advanced cameras like now. So here, the faster actions will show some unintended effects along with interlacing impacts especially on darker background.

To cross check, please download a HD video song or a movie and attempt to change its aspect ratio to fit the screen in a GOM player so that there won't be any black bars and you will find the clarity of the video decreased when compared to the video clarity with black bars.

Not just the grass, but also when the batsman hits with his bat.

And also for me, some pixels stay as it is for a few microseconds (but visible) and others change, then all pixels are in sync again.

 

[TJ_DJ]

Ok, then what is this issue called? :
In dark scenes, or black background, U will see "Refresh Delay" and ghtostly vertical lines which refresh at a slow frequency. It is not a ghost image of previous scene, but random thick lines/structures due to the dark black background. Very visible on Romedy NOW HD Channel on ADTV. Does not appear at all during bright or colorful scenes.

What is this phenomena called?

 

[Ramesh DthSky]

Not just the grass, but also when the batsman hits with his bat.

And also for me, some pixels stay as it is for a few microseconds (but visible) and others change, then all pixels are in sync again.

It happens sometimes when the camera moves fast along with the ball after being hit and suddenly stops moving when the fielder stops the ball, especially inside the 30 yard circle or even at the boundary line when the fielder slides. The start and stop process happens suddenly and the pixels needed sometime to rearrange. Normally many won't find this, but when we watch the game along with the background, one can easily notice this phenomenon. And it happens very very fast.

Ok, then what is this issue called? :
In dark scenes, or black background, U will see "Refresh Delay" and ghtostly vertical lines which refresh at a slow frequency. It is not a ghost image of previous scene, but random thick lines/structures due to the dark black background. Very visible on Romedy NOW HD Channel on ADTV. Does not appear at all during bright or colorful scenes.

What is this phenomena called?

Not exactly sure what the phenomenon is since I have not watched this Romedy Now HD recently. But black background will always have this issue. The quality of the content also plays a huge role here. I have some older 90's movies in Hindi that were upscaled to HD and whenever black background comes there will be something like noise or blurriness, etc. Hence it may be because of interlacing or content quality or something that we might not be aware of in the video processing technology for the black background.

 

[TJ_DJ]

It happens sometimes when the camera moves fast along with the ball after being hit and suddenly stops moving when the fielder stops the ball, especially inside the 30 yard circle or even at the boundary line when the fielder slides. The start and stop process happens suddenly and the pixels needed sometime to rearrange. Normally many won't find this, but when we watch the game along with the background, one can easily notice this phenomenon. And it happens very very fast.



Not exactly sure what the phenomenon is since I have not watched this Romedy Now HD recently. But black background will always have this issue. The quality of the content also plays a huge role here. I have some older 90's movies in Hindi that were upscaled to HD and whenever black background comes there will be something like noise or blurriness, etc. Hence it may be because of interlacing or content quality or something that we might not be aware of in the video processing technology for the black background.

Good point. I have noted it doesnt happen in all channels. But only in few. Just wanted to know if other ADTV users too have observed the same.

 

[Ramesh DthSky]

Good point. I have noted it doesnt happen in all channels. But only in few. Just wanted to know if other ADTV users too have observed the same.

Yeah. And one more. Please just watch keenly the black sight screen during night on the two ends of the cricket ground especially when the bowler moves. You will find some unevenness or graininess on the screen rather than being uniformly black. And here I believe this may be because of interlacing since the 540 lines are refreshed here alternatively for two frames and hence interlacing is very visible on the black background (screen).

 

[TJ_DJ]

Yeah. And one more. Please just watch keenly the black sight screen during night on the two ends of the cricket ground especially when the bowler moves. You will find some unevenness or graininess on the screen rather than being uniformly black. And here I believe this may be because of interlacing since the 540 lines are refreshed here alternatively for two frames and hence interlacing is very visible on the black background (screen).

Grains is a different issue. I agree. But black background often contains some thick vertical unevenly sized ghostly lines.... which refresh at "one-second" intervals.

 

[Ramesh DthSky]

Grains is a different issue. I agree. But black background often contains some thick vertical unevenly sized ghostly lines.... which refresh at "one-second" intervals.

Yeah. Exactly. Black background or for that matter, the black screen in the ground that I mentioned will not look uniformly black, mostly seen when the bowler moves, and will give an impression like the refresh and rearrangement of pixels are happening with some minute delay.