Anamorphic dvds leave some space on sides

[Digiface]

Why some anamorphic dvds leave some space on sides? In other words, won't horizontally fill the whole screen.

here's an example: http://i62.tinypic.com/wler6p.jpg

[huhn]

because they have a black boarder in the source.
they most likely let them in because old TVs cropped the boarder anyway

[foxyshadis]

The DVD specs are for 704x video to be transferred onto a 720x picture, 8px black buffer on each side. Your player is supposed to cut that off, or your DVD ripper; what are you playing it with?

Here's wikipedia on the topic (https://en.wikipedia.org/wiki/Safe_area_%28television%29).

[Sharc]

Yes, there is nothing wrong with such (typically older) DVD's. Perhaps few comments:
In this case the pixel aspect ratio (PAR) for the video should be signalled according the ITU specification rather than using the "generic" value. If the player interprets the PAR signalling, the active picture will be played back with the correct aspect ratio, irrespective of any borders.
Unfortunately most DVD/BD HW players disregard the PAR and simply stretch the video (including any borders) to 16:9 (or 4:3) which will leave us with the "famous" (but hardly noticeable) 2.4% horiziontal distortion.
SW players like MPC-HC can read the PAR and play the movie undistorted.
One can however never be 100% sure with such sources unless one would have the information how the DVD has actually been authored (cut, resize) by the studio, or we are back to the "circle test" ....

[huhn]

The DVD specs are for 704x video to be transferred onto a 720x picture, 8px black buffer on each side. Your player is supposed to cut that off, or your DVD ripper; what are you playing it with?

Here's wikipedia on the topic (https://en.wikipedia.org/wiki/Safe_area_%28television%29).

the picture in this case has information in the right part. the wiki link and my knowledge clearly say it's fine to have informations in the hole picture but what about the 8 pixel "rule" is there a wiki too? are they really suppose to be cropped?

[SeeMoreDigital]

are they really suppose to be cropped?Such black areas are not seen when viewed on an old fashioned CRT TV because they are lost to 'over-scan' (http://en.wikipedia.org/wiki/Overscan).

Sufficed to say, all software players display images without over-scan, which is why you're seeing what you're seeing...

[SeeMoreDigital]

Oh, and if you want to see a terrible example of how to get the so-called 'safe area' wrong. Here's a frame grab from the 1997 PAL DVD release of Blade Runner: -

http://i62.tinypic.com/15ocl5j.png


And the 1997 NSTC DVD release did not fair any better: -

http://i61.tinypic.com/flvq52.png

[Digiface]

I use MPC-HC. I tried 'Overscanning' on Nvidia options, but it won't do anything. I found best option fill the areas is to use MPC pan 'n scan option "Increase size". Just one notch is enough.

btw. I use HDMI cable.

[Sharc]

@SMD:
The (PAL) example which you provided is not totally off the kilter from the anamorph point of view IMO.
The only issue I see is that the so-called safe-area has been interpreted too cautious with approximately 2 macroblocks instead of the usual 1. (IIRC there have been questions in the early days of DVD and CRT TVs about how wide it really needs to be in order to be "safe").
Otherwise the anamorph sizing seems quite ok, and if the player would follow ITU PAR (512:351 or more precisely 4600:3159) we would get an almost perfect 2:35 aspect ratio for the picture (within rounding errors).
But anyway, the unnecessary heavy margin for "overscan" will leave us with the unecessary wide black borders in this case.

[Digiface]

Much thanks for all the answers. Wonder if there's any SW players or codec-filters follow this ITU PAR 'Sharc' mentioned? I'm using LAV for DVD (HW)decoding.

[SeeMoreDigital]

Much thanks for all the answers. Wonder if there's any SW players or codec-filters follow this ITU PAR 'Sharc' mentioned? I'm using LAV for DVD (HW)decoding.I can't say I've ever seen an 'add over-scan' option. But it's an interesting idea...

[Sparktank]

I remember Harrison Ford's " Six Days Seven Nights (1998)" movie on DVD had the same horrible problem as Blade Runner.
On older devices, it was not noticeable at all.

Today (era), going to revisit it? I hate it.

Playing from the PC to TV (via HDMI), I did the same thing Digiface did with all the zoom and pan-and-scan settings.
Knowing how bad the transfer was to DVD, I would just convert the video with x264 and zero black borders.

But I'd rather just wait for the blu-ray at this point.

[Sharc]

.....On older devices, it was not noticeable at all.

... which actually justifies the introduction of the borders for these legacy devices. If the full 720 horizontal width would have been filled with active picture content, some portion of the picture would have been cut off (i.e. disappeared in "overscan" on CRT TVs).
To go back to the original question: There is nothing wrong with these 2x8 pixel borders, it's just a bit outdated for current digital playback devices, and the "overscan margin" has historically sometimes been applied over-cautiously as the example of SMD (Blade Runner) indicates. "Six Days Seven Nights" is probably the same.

[Sharc]

I can't say I've ever seen an 'add over-scan' option. But it's an interesting idea...
One always had to add the borders manually AFAIK. Not sure if any encoder has provided this as an option; maybe CCE?
For playback, at least x264 offers the "--overscan" signalling parameter which tells the player how to handle it. But as mentioned in the wiki (http://mewiki.project357.com/wiki/X264_Settings)is "...usually ignored by software decoders". Or as you wrote before ...Sufficed to say, all software players display images without over-scan, which is why you're seeing what you're seeing...

[Sharc]

Interestingly, there is a similar discussion going on here (http://forum.doom9.org/showthread.php?p=1686266#post1686266).
Seems that adding borders has still some significance.
Either you see what you see or you don't miss what you never have seen .... :D

[Digiface]

There is nothing wrong with these 2x8 pixel borders, it's just a bit outdated for current digital playback devices

Yes, those are not too bad. I just find them a bit "ugly". But using pan & scan options i can "fix" it.

[Sharc]

Just in case someone is interested, an excellent explanation which says all is given here (http://en.wikipedia.org/wiki/Overscan):

Analog to digital resolution issues
720 vs. 702 or 704

The sampling (digitising) of standard definition video was defined in Rec. 601 in 1982. In this standard, the existing analogue video signals are sampled at 13.5 MHz. Thus the number of active video pixels per line is equal to the sample rate multiplied by the active line duration (the part of each analogue video line which contains active video, i.e. does not contain sync pulses, blanking etc.).
For 625-line 50 Hz video (usually, though incorrectly, called "PAL"), the active line duration is 52 µs,[10] giving 702 pixels per line.
For 525-line 60 Hz video (usually, though incorrectly, called "NTSC"), the active line duration is 52.856 µs,[11] giving ~713.5 pixels per line.

In order to accommodate both formats within the same line length, and to avoid cutting off parts of the active picture if the timing of the analogue video was at or beyond the tolerances set in the relevant standards, a total digital line length of 720 pixels was chosen. Hence the picture will have thin black bars down each side.

704 is the nearest mod(16) value to the actual analogue line lengths, and avoids having black bars down each side.

The use of 704 can be further justified as follows:
625-line analogue video contains 575 active video lines[12] (this includes two half lines). When the half lines are rounded up to whole lines for ease of digital representation, this gives 576 lines, which is also the nearest mod(16) value to 575. To maintain the same picture aspect ratio, the number of active pixels could be increased to 703.2, which can be rounded up to 704.
525-line analogue video contains 485 active video lines[11] (this include two half lines, though typically only 483 picture lines are present due to Closed Captions data taking up the first "active picture" line on each field). The nearest mod(16) value is 480. To maintain the same picture aspect ratio, the number of active pixels could be decreased to 706.2, which can be rounded down to 704 for mod(16).

The "standard" pixel aspect ratio data found in video editors, certain ITU standards, MPEG etc. is usually based on an approximation of the above, fudged to allow either 704 or 720 pixels to equate to the full 4x3 or 16x9 picture at the whim of the author.

Although standards-compliant video processing software should never fill all 720 pixels with active picture (only the center 704 pixels must contain the actual image, and the remaining 8 pixels on the sides of the image should constitute vertical black bars), recent digitally generated content (e.g. DVDs of recent movies) often disregards this rule. This makes it difficult to tell whether these pixels represent wider than 4x3 or 16x9 (as they would do if following Rec.601), or represent exactly 4x3 or 16x9 (as they would do if created using one of the fudged 720-referenced pixel aspect ratios).

[huhn]

the blue part was that what i was asking before thx a lot.

[hello_hello]

I use MPC-HC. I tried 'Overscanning' on Nvidia options, but it won't do anything. I found best option fill the areas is to use MPC pan 'n scan option "Increase size". Just one notch is enough.

And one tap on the "6" key is pretty much the ITU aspect ratio.

I had a quick play with the Nvidia overscan setting too and it seemed to do nothing. I've got the PC connected to the TV at 1080p so maybe video card over-scanning only works for NTSC/PAL resolutions? My testing motivation didn't extend that far.

For the record, I think most HD TVs do overscan, although you can generally disable it and most people would when the TV is connected to a PC.

[Sharc]

And one tap on the "6" key is pretty much the ITU aspect ratio.

I had a quick play with the Nvidia overscan setting too and it seemed to do nothing. I've got the PC connected to the TV at 1080p so maybe video card over-scanning only works for NTSC/PAL resolutions? My testing motivation didn't extend that far.

For the record, I think most HD TVs do overscan, although you can generally disable it and most people would when the TV is connected to a PC.
I have uploaded 3 AVC testclips (http://www.mediafire.com/download/ax35p9iy5gnljen/AR_and_Overscan_Testclips.zip) which I use for checking overscan and aspect ratio.
- the ellipses indicate the overscan (if any)
- the circles should be exact circles (use a ruler) on the screen

[hello_hello]

I have uploaded 3 AVC testclips (http://www.mediafire.com/download/ax35p9iy5gnljen/AR_and_Overscan_Testclips.zip) which I use for checking overscan and aspect ratio.
- the ellipses indicate the overscan (if any)
- the circles should be exact circles (use a ruler) on the screen

I'll confess my over-scan check involves running a program in a maximised window, and if there's not bits of it disappearing off the edge of the screen.......

I did have a play with your test clips though. With overscanning enabled (1080p) my TV hides 26 pixels from both the top and bottom and 40 pixels each side. Give or take a couple....

1840/1028 = 1.789

It turns out I can resize the desktop in 1080p mode (I was playing with the wrong setting) and according to the Nvidia Control Panel, it was resizing to 1840x1036. Although it'll only resize the width in multiple of 16 and the height in multiples of 8.

In 576p mode (720x576) I set MPC-HC to change the aspect ratio to 5:4 to correct it, which I think is right, and I lose around 32 pixels from each side (although it'd be closer to 28 and 32), and around 18 from both top and bottom. I can't disable overscanning in 576p mode.

(660/540)x(64/45) = 1.738

Thinking about it....

(660/540)x(16/11) = 1.777

So is my TV being all ITU about the aspect ratio in 576p mode, or am I looking at it the wrong way? I've confused myself now.... :)

[Sharc]

Well, I don't have your equipment, but what you do seems overly complicated to me.
- Put the files on an USB and play them via your standalone + TV. What do you get?

When using MPC-HC, use settings:
- Touch window from inside
- Keep aspect ratio
- Aspect ratio => 16:9 or Auto
No need to do any "corrections" like 5:4 or whatever.

Whatever else you are doing, you should finally see:
- the full picture (i.e. without substantial cropping)
- the circles should be exact circles (horizontal = vertical)
Then your settings are correct.

[hello_hello]

I normally leave the PC connected at 1080p, over-scanning disabled, and MPC-HC's settings the same as in your previous post. I'm not sure I've ever connected the PC at 576p until today. I just played around with your test clips because you replied to my post with a link and I thought I'd have a look to see how much my TV overscans when it's enabled. I used the 720x576 test clip with the TV connected at 720x576.

Anyway.... I'm still trying to get my head around the aspect ratio in 576p mode.... just for curiosity's sake.
By changing the aspect ratio to 5:4 in MPC-HC for the 720x576 clip, I'm effectively displaying it as though it compromises square pixels (720x576 = 5:4). Then I connect to the TV at 576p, which stretches it out to 16:9, so when connected at 576p the TV seems to expect PAL video which it needs to stretch itself, or squish to 4:3 itself, depending on which mode you put it in. After overscanning, the TV displays 660x540 worth of video (in 16:9 mode and according to your 720x576 test clip) with gives me an aspect ratio of either 1.73, or 1.77, depending on which pixel aspect ratio I use for the calculation. Obviously if I used the 704x576 test clip the result would be a little different because the borders each side don't seem to be counted in respect to overscanning and I'm not really sure why that is.

Does the above make sense?

All I was trying to do is work was see if I could work out which aspect ratio the TV uses when it stretches 720x576 video out to 16:9. ITU 16:9, or 16:9, or something else. I don't really care.... it was just an exercise.
For the record, if I connect to the TV at 720x576 with MPC-HC ignoring the aspect ratio, the circle in the 720x576 test clip seems nice and round. If I do the same thing using the 704x576 test clip, it's a little squished horizontally.

[Sharc]

Your testing makes sense. Just to mention that Overscan and Pixel Aspect Ratios are basically 2 different things. It just happens that when a 704 picture is padded to 720 by adding borders, the 2x8 borders my get "lost" in overscan and hence are considered as part of the "overscan margin".
For the record, if I connect to the TV at 720x576 with MPC-HC ignoring the aspect ratio, the circle in the 720x576 test clip seems nice and round. If I do the same thing using the 704x576 test clip, it's a little squished horizontally
Voilà!
Just to be clear: The "704x576 test clip" is actually a 704x576 active picture with a pixel aspect ratio 16:11, padded to 720 by adding 2x8 green borders. Means it is still a 720x576 frame.
The squashing indicates that your playback does not obey the sar 16:11 signalling in the stream but plays the full frame (picture+borders) at 16:9. This is quite usual, but it also means that DVD footage which is encoded this way (i.e. 704 with ITU or mpeg4 pixel aspect ratio, + 2x8 borders) will be slightly squashed.
When you play the same file in MPC-HC (with Video Frame/Keep Aspect Ratio ticked) you have the option:
- Video Frame/Override Aspect Ratio/16:9 => slight squashing (as you have now)
- Video Frame/Override Aspect Ratio/Default => no squashing (MPC-HC follows the SAR signalling).
You can toggle between these 2 settings and see the effect.

[hello_hello]

The ITU thing shouldn't be an issue.... at least in respect the the aspect ratio the TV uses.... given I normally only connect the the PC at 1080p and I rarely play 720x576 video. I tend to re-encode first it while resizing to the correct (hopefully most of the time) square pixel aspect ratio. Even the Bluray players are set to always output 1080p, although I'm not sure if that's a good idea for DVDs. I guess it'd be the player's job to upscale and do the picture stretching to fix the aspect ratio, and I have no idea how they resize. Once again though.... re-encoded square pixel video is often played via the TV or Bluray player's USB input.... at least by the rest of the family. Playing discs..... that's somewhat less frequent. I've owned a Bluray player for a few years now and I still haven't put a disc in it. I have no idea why I bought it..... I think it was a "get in before Cinavia", just to be on the safe side, situation.

The squashing indicates that your playback does not obey the sar 16:11 signalling in the stream but plays the full frame (picture+borders) at 16:9.

Initially I thought the pixel aspect ratios should be the other way around, but obviously not.... I just confused myself at the time.

Cheers.