1.85 AR movies question...

[poisondeathray]

As I said earlier I don't have any 1.778 (or 1.85) blu-rays to compare. You might be correct in saying this might be a case of studio laziness. I find it odd that DVD version AR in manono's link is done correctly, but the blu-ray is done differenly.

I've used MeGUI extensively through many versions. I can tell for certain that MeGUI's display AR in the preview box doesn't always work depending on which build you are using and the method of entering the avs script. I don't use the auto avisynth generator, because half the time it's broken, and the passthru formula for aspect ratio doesn't work very well - again depending on the version used.

When you use the global MeGUI_darx = X, global MeGUI_dary = Y business in the .avs script again, I've found that works only some of the time.

In my experience, the only 100% sure way to get your encoding aspect ratio correctly in MeGUI is to use --sar x:y, everything done through manually. When this is done, the preview will never show the effects, but the final encode will be proper. Note while the "SAR" in x264 terminology is defined as the sample aspect ratio, in function it is the "pixel aspect ratio." The DAR, FAR, PAR, SAR acronyms are used differently often and can mean different things, but the math is always the same despite what you "label" it

Display Aspect Ratio = Frame Aspect Ratio x Pixel Aspect Ratio (--sar in x264)

1) First step is to determine the AR that you want, and the AR that you actually have (assuming your particular blu-ray is incorrect, you have the opportunity to "fix" it if you are re-encoding). If you want you can upload a tiny <1sec .m2ts sample and I can check it for you.

2) Do you want anamorphic encoding or not? Resized frame or full frame? Cropped or non-cropped? I've never seen any original blu-rays that are encoded with non-square pixels or didn't preserve the AR by not having borders. "deadrats" is completely out to lunch on this. Also, by retaining the borders, you are not saving much space. Jagabo did some comparisons to prove this - I don't have link handy, but PM him for the work. The borders take almost no bitrate - it is just personal preference. Again, the original blu-rays (at least the ones I've seen) don't have anamorphic encoding. They don't have DAR information in the raw video stream or container flags. The active area is always 1920x(some number) with borders to keep the full frame 1920x1080 to meet blu-ray compatibility standards.

3) As manono suggested, definitely consider using DGAVCIndex, the h264 analog to DGIndex.

Assuming your blu-ray is full frame, no borders, find the aspect ratio that you want and determine the --sar x:y value required to balance the equation. You can test this on a 10 sec sample (to minimize encoding time) until you get it right.

[alcOre]

I tried dgavcdec but the project file it created didnt load in MeGUI...maybe I have to do something besides just extract the program and run it? when you hit the open/browse button in MeGUI it doesnt list the dgavcdec project file as an option to open. I told it to search for *.* so I could "see" the dgavcdec project file but when MeGUI attempted to open it, it said it couldn't and maybe I didn't have the correct codec installed...or something along those lines.

[alcOre]

I've never seen any original blu-rays that are encoded with non-square pixels or didn't preserve the AR by not having borders. "deadrats" is completely out to lunch on this.

LOL...that made me laugh.

[poisondeathray]

I tried dgavcdec but the project file it created didnt load in MeGUI...maybe I have to do something besides just extract the program and run it? when you hit the open/browse button in MeGUI it doesnt list the dgavcdec project file as an option to open. I told it to search for *.* so I could "see" the dgavcdec project file but when MeGUI attempted to open it, it said it couldn't and maybe I didn't have the correct codec installed...or something along those lines.

Index it just like you would with DGIndex. This will give you a .dga file (analogous to a .d2v file for MPEG2 sources)

Create a simple .avs to input directly into MeGUI (not using avisynth creator)

LoadPlugin("...\DGAVCDecode.dll")
AVCSource("mystream.dga")

The quick start manual included with DGAVCdec is only 1-page and will get you started

[poisondeathray]

If you wanted anamorphic encoding, assuming your source is indeed 1920x1080, no borders (and it wasn't some display setting or filtering effect), and that you just wanted to "fix" the aspect ratio to what you think looks to be correct

Display Aspect Ratio = Frame Aspect Ratio x Pixel Aspect Ratio
DAR = FAR x PAR

(Again the "PAR" is equivalent to the "--sar" in x264 terminology)

37/20 = 1920/1080 x (x/y)

The 37/20 is the 1.85 DAR goal that you want.
The 1920/1080 is the frame size (I'm assuming you want full frame, no resize, no borders for your output goal)

If my rusty math is correct, the x/y that solves this equation is 333/320, so you would enter --sar 333:320 in the extra command line config in MeGUI.

The preview won't show this in MeGUI, so just encode a few frames to double check if this is correct. You can use Trim (0,100) in the .avs script to encode 100 the 1st 100 frames, for example. Again, when you "check", you have to be certain that it's not a software setting, container flag, splitter, decoder choice, or filter interfering with the proper DAR - they all can skew what you percieve as the DAR, and speaking from experience, I have "forgotten" to reset many times.

If you wanted, say 1280x720 frame instead, you would change the 1920/1080 to 1280/720 in that equation, and solve for x/y...I'm sure you get the idea...

-----------

The other scenario using 1:1 pixels without --sar x:y is just to use AddBorders() to the top and bottom to create the way it "should have been" transferred to blu-ray

This will be off a bit, if you use mod16. 1920x1040 gives 1.846 which is close. So 20 pixels top and bottom:
AddBorders(0,20,0,20)

----------------

Of course, the 3rd option is just to resize to 1920x1040, with square pixels, no borders. Something like:
LanczosResize(1920,1040)


----------------

Option 4 is to set a container flag. e.g. DAR in .mkv with mkvmerge, or SAR in mp4box (YAMB) for .mp4 container. Note not all players/decoders/filters will recognize the flag, but when it does, the container flag will override the stream level DAR information


The option that works in all player/filters/situation is option 3. Hence that is why "deadrats" sees that format so often on legally questionably downloaded items


PS. If you wouldn't mind uploading a .m2ts tiny clip, I would like to add it to my "bizarre" clip collection. You can use tsmuxer to cut a small section

[deadrats]

"deadrats" is completely out to lunch on this

i just opened a 33 gig m2ts blu-ray rip of dead man' chest with kmplayer, nero 7's recode and tmpg express 4.0 and they all say that it is 1920x1080 with a DAR of 16:9 (which equals 1.78 ), procoder 3 further tells me that it has a PAR of 1:1. the back of the blu-ray disk says that it is 1080p/2.35:1 as does the imdb.

when i play this file on my computer there are indeed black borders at the top and bottom, but that is only because the video is being formatted to fit within the maximum resolution that my monitor supports, namely 1280x1024. i just loaded up the blu-ray with my PS3 and tried it on my 2 tv's, one supports FullHD 1920x1080 and one supports 1368x768, one the 1080p tv there are no black borders at all, on the other tv again yes, black borders appear.

further complicating things is this: the movie's printed film format is 35mm anamorphic which has a widescreen industry standard resolution of 1.85:1 as is the film negative.

so in what way does cropping the damn movie to 1920x816 (2.35:1) make any sense at all?

what if you wanted to encode it to 720p, would you resize it to 1280x720 or would you resize it to 1280x544 (2.35:1)?

i'm would love it if someone can explain to me how all of the above points to cropping a movie to 1920x816 or 1280x544.

references:

http://en.wikipedia.org/wiki/Panavision_cameras#Panaflex_Platinum

http://www.imdb.com/title/tt0383574/technical

http://en.wikipedia.org/wiki/Aspect_ratio_(image)#Movie_camera_systems

[poisondeathray]

i just opened a 33 gig m2ts blu-ray rip of dead man' chest with kmplayer, nero 7's recode and tmpg express 4.0 and they all say that it is 1920x1080 with a DAR of 16:9 (which equals 1.78 ), procoder 3 further tells me that it has a PAR of 1:1. the back of the blu-ray disk says that it is 1080p/2.35:1 as does the imdb.

when i play this file on my computer there are indeed black borders at the top and bottom, but that is only because the video is being formatted to fit within the maximum resolution that my monitor supports, namely 1280x1024. i just loaded up the blu-ray with my PS3 and tried it on my 2 tv's, one supports FullHD 1920x1080 and one supports 1368x768, one the 1080p tv there are no black borders at all, on the other tv again yes, black borders appear.

further complicating things is this: the movie's printed film format is 35mm anamorphic which has a widescreen industry standard resolution of 1.85:1 as is the film negative.

so in what way does cropping the damn movie to 1920x816 (2.35:1) make any sense at all?

what if you wanted to encode it to 720p, would you resize it to 1280x720 or would you resize it to 1280x544 (2.35:1)?

i'm would love it if someone can explain to me how all of the above points to cropping a movie to 1920x816 or 1280x544.

references:

http://en.wikipedia.org/wiki/Panavision_cameras#Panaflex_Platinum

http://www.imdb.com/title/tt0383574/technical

http://en.wikipedia.org/wiki/Aspect_ratio_(image)#Movie_camera_systems

Hey deadrats, I was just joking with you btw, and didn't mean anything malicious.

The key here is you what to preserve what is on the blu ray. Sure the aspect ratio may differ from film, to DVD, to blu-ray to the VHS(!) version, but that is dependent on how the studio transferred the master

As I said earlier, all blu rays will be 16:9 frame size with 1:1 pixels - so all your automated tools will show the DAR as 16:9, but the active area is not. There will always be top and bottom borders (for a 2.35 or 2.39 movie) if you have the proper display settings. I can set my TV/monitor/software player to different modes e.g. stretch to window, pan & scan, custom AR, but the default settings will have the borders

The problem is how it is encoded onto the bluray. If you didnt use 1280x544 or whatever, the image will be distorted. Try it for yourself and you will see this is true. I hope this makes sense

These are full frame examples resized on this bulletin board, so save them to desktop and examine it.

NORMAL



CROP RESIZE to mod16 1920x800



What deadrats suggests



Cheers.

[deadrats]

@poisondeathray:

ok, i did as you suggested and viewed a variety of movies, encoded to 1920x1080, 1920x800, 1280x720 and 1280x544 and now i'm more convinced than ever that something is very wrong: there are black areas above and below the video, with the black areas being much more pronounced in the ones that are "correctly cropped" than in the videos where they are at a standard 1080p or 720p.

with the 1080p/800p movies i could attribute the weirdness to the limitations of my monitor, i.e. a max resolution of 1280x1024, but i can make no such excuse with the 720p/544p encoded content.

i also encoded 2 small samples, from an 1920x1080 18Mb/s HDTV capture, one at 1280x720 and one at 1280x544 and i'll be damned if the 544p doesn't look messed up, like the viewing area is too short.

how do you post a screen shot so that i can show you exactly what i am seeing?

[poisondeathray]

Hi deadrats, you maybe right, perhaps they were mastered differently.

There is upload image/file box in videohelp under the reply box. You can also use free hosting sites like tinypic.com

The problem with taking screenshots is I need to know how you took them. The directshow splitter, video decoder, possible filters, renderer, software used and/or settings used can skew the image.

The problem with the encoding example is that I need to know the specifics of the source, and the process you used for the encode (e.g. is it stream level signalling or container level information)

I would rather you upload an unprocessed .m2ts source to a free hosting site like mediafire, megaupload, etc..., and a sample of your encodes that you claim to be messed up.

[jagabo]

Deadrats, is your 1280x1024 monitor a CRT or LCD?

[jagabo]

Double post. Just not my day.

[deadrats]

Deadrats, is your 1280x1024 monitor a CRT or LCD?

LCD, an AOpen F95GS, to be exact.

[jagabo]

Deadrats, is your 1280x1024 monitor a CRT or LCD?

LCD, an AOpen F95GS, to be exact.

Ok, you're using a square pixel 5:4 display. I asked because running a 4:3 CRT monitor at 1280x1024 (non square pixels) would give you yet another layer of aspect ratio problems.

[deadrats]

Hi deadrats, you maybe right, perhaps they were mastered differently.

There is upload image/file box in videohelp under the reply box. You can also use free hosting sites like tinypic.com

The problem with taking screenshots is I need to know how you took them. The directshow splitter, video decoder, possible filters, renderer, software used and/or settings used can skew the image.

The problem with the encoding example is that I need to know the specifics of the source, and the process you used for the encode (e.g. is it stream level signalling or container level information)

I would rather you upload an unprocessed .m2ts source to a free hosting site like mediafire, megaupload, etc..., and a sample of your encodes that you claim to be messed up.

ok, here's the deal: i can't upload an unprocessed .m2ts source, because the source is a 33 gig blu-ray rip, encoded at almost 30 Mb/s H264 with multiple audio streams, including LCPM and a bunch of AC3 streams, so i did the next best thing, i loaded the file into tmpgenc express 4 and cut a short clip and encoded that, using the built in blu-ray template to mpeg-2 1920x1080 with square pixels, at 32 Mb/s with 448 kb/s ac3 audio, i set the motion search precision to 'high', the DC component precision to 10 and the result is a nearly perfect copy of the source, i tested it with media player classic, media player classic hdtv, kmplayer and vlc and i see no difference between the 2.

what you will find linked below is the same clip, using the blu-ray rip as source, encoded to different resolutions, as noted in the file name. when you see '1 1' in the file name it means i used square pixels, when you see '16 9', it means i used 16:9 pixels.

http://www.mediafire.com/?kghcbzg4zqz

http://www.mediafire.com/?5wnqcltozyq

http://www.mediafire.com/?zimukzexoed

http://www.mediafire.com/?uk2w2kojyqy

http://www.mediafire.com/?ivlknyycfym

http://www.mediafire.com/?mjhum2gjn4h

http://www.mediafire.com/?wjizzzi501j

[poisondeathray]

I took a quick look, and I think you forgot to crop in yout "544p" and "816p" examples so it looks like you are not doing it "properly", because there are still top&bottom borders.

I'll have a closer look again tonight when I have more time

PS. it's easier/faster to use TsMuxeR on the .m2ts. When I mean "unprocessed source" I really meant just the video; you can take out the pgs, multiple tracks, etc... and just leave the video by uncheckmarking the other stuff. You can also use the split & cut tab also to cut a 1sec segment and just leave all the junk in which is tiny for a 1 sec clip.

Cheers

[poisondeathray]

Let's pretend that your big file is the blu-ray source, and that we want to make a smaller backup

I cropped 136 from the top and 138 from bottom leaving an "Active area" = 1920x806 which is NonMod16, but this "Active Area" DAR is 2.38.

What's important is to emulate how it is on the source (assuming the source was correct, and circles look like circles, etc...).
This is why Alcore's case is peculiar, because he apparently has an improperly transferred source, so he has opportunity to "fix" it should he choose to re-encode it

Resizing to 1280 width, the corresponding Mod16 reesolution for = 1280x544 ~2.35DAR , which is off by a bit from 2.38, but it's fairly close. This method is using square pixels, no flags, which is the most common method. Thus DAR=frame aspect ratio x 1/1

Compare the "active area" of the "source" to that of your version, and to what is in my opinion the "proper" way to do it

Again, these images are resized from the bulletin board, so save them to your desktop and compare. (They are also .jpg instead of .png, because we are not looking at image quality, just aspect ratios)

"Original"


"Deadrats version"


"Proper" (Cropped & Resized to 1280x544)


And here is the 1st 300 frames from that clip (no audio):
proper%201280x544.mp4

[deadrats]

I took a quick look, and I think you forgot to crop in yout "544p" and "816p" examples so it looks like you are not doing it "properly", because there are still top&bottom borders.

I'll have a closer look again tonight when I have more time

PS. it's easier/faster to use TsMuxeR on the .m2ts. When I mean "unprocessed source" I really meant just the video; you can take out the pgs, multiple tracks, etc... and just leave the video by uncheckmarking the other stuff. You can also use the split & cut tab also to cut a 1sec segment and just leave all the junk in which is tiny for a 1 sec clip.

Cheers

i tried tsmuxer, but like before i didn't have much luck with it, i couldn't get it to cut anything, that software borders on being a head fake with certain codecs.

regardless, i did the next best thing, i again loaded dead man's chest into tmpgenc 4 express, and i re-encoded a number of 10 sec clips:

a 1920x1080p using the built in blu-ray template, again this encode is a flawless match of the original.

http://www.mediafire.com/?ihmutjdt4jn

a 1920x816p, this time i went into the 'picture crop' filter and cropped 132 pixels from top and bottom, for a total of 264 pixels cropped, i also couldn't use the blu-ray template as it doesn't allow such a resolution so i had to use a custom mpeg-2 template, with settings that match, save for the resolution, the blu-ray template. i also chose to use the 16:9 aspect ratio setting, as this is the setting that is used with the blu-ray template (it can't be changed).

http://www.mediafire.com/?xwjwghwtkzz

a 1280x720p using the built in blu-ray template.

http://www.mediafire.com/?ztewwdlvydt

a 1280x544p, this time i went into 'picture crop' and cropped 88 pixels from top and bottom, for a total of 176 pixels, as above i used a custom mpeg-2 template and i used the 16:9 aspect ratio setting, and i set the output resolution as 1280x544. this one looks like crap as far as i'm concerned.

http://www.mediafire.com/?emgxznukzci

interesting side note, when the hi def resolutions were first announced i remember reading that the reason 1920x1080 and 1280x720 were chosen was because they had a display aspect ratio of 16:9, i.e. 1.78 (16/9 = ~1.78 ), which is the industry standard resolution that movies are shot in (most modern movies are shot on 35mm film, and the resolution of said film is 1.78 ), however after reading everything i can find on the net it seems that no one has a clear answer of where 2.40/2.35 comes from.

[deadrats]

@poisondeathray:

of the three pics you posted, the first one, which i created, is an exact copy and looks just like the original. the second one admittedly i screwed up but in my defense i never encoded a 1280x544 before, the third one, which you label as "proper" doesn't look anything like the original, whereas the original blu-ray and my 1080p encode are properly letterboxed and the images are exactly the same your "proper" encode takes up the entire screen.

if you want to see what a true proper 720p encode should look like, check out the 1280x720p encode i just made using the blu-ray template, this encode looks just like the original blu-ray and the 1080p copy i made:

http://www.mediafire.com/?ztewwdlvydt

[jagabo]

the third one, which you label as "proper" doesn't look anything like the original, whereas the original blu-ray and my 1080p encode are properly letterboxed and the images are exactly the same your "proper" encode takes up the entire screen.

That's your player's fault. There's nothing wrong with the MP4 file. It's no less "proper" than your 720p encode.

[poisondeathray]

deadrats - I can't believe you still don't get it . You're confused.

1) If you crop, you use the non-standard resolutions to preserve the aspect ratio e.g. 1280x544

2) If you don't crop, you have to keep the black borders top & bottom (Because that's what not-cropping means )

It's as simple as that

The active area is the same is the same in either case(well a bit off because of mod16). It's not supposed to look identical to the original (except for the active area), because its cropped!

Most people prefer cropped. Some people don't. Some people like red, some people like blue. There is nothing wrong with keeping borders if you want to.

[jagabo]

Note: it's the player's responsibility to see the 1280x544 frame size with square pixels and add borders to fill out the 16:9 frame before sending it to the TV -- so that it looks exactly the same as the original 16:9 frame with black borders.

Cropping away black borders has some benefits as enumerated here:

https://forum.videohelp.com/topic359781.html#1909999

The down side is that some players may not handle it correctly.

[deadrats]

If you crop, you use the non-standard resolutions to preserve the aspect ratio e.g. 1280x544

see that's the thing, you aren't preserving the aspect ratio. near as i can tell all modern movies are shot on 35mm film, which has an aspect ratio of 1.78, and during the transfers to print masters that aspect ratio is maintained, it's an industry standard. 1920x1080 and 1280x720 also have an aspect ratio of 1.78, what i want to know is where the hell the notion that the movies have an aspect ratio of 1.85/2.35/2.40 comes from.

If you don't crop, you have to keep the black borders top & bottom

those black borders are a result of scaling a 1920x1080 image to fit into a screen that doesn't support such a resolution, if you were to play back the commercial blu-ray on an FullHD tv that supports 1920x1080p you wouldn't get said black borders.

furthermore, assume that the blu-ray was in fact authored so that it was letterboxed, i.e. black borders top and bottom, why would anyone crop said borders and in what way does that "preserve the aspect ratio".

Most people prefer cropped. Some people don't. Some people like red, some people like blue. There is nothing wrong with keeping borders if you want to.

if it was just a matter of preference i could almost understand that, but what really gets me is that it doesn't seem to be about preference, it's that people actually believe that what they are doing is the proper way to do things and justify it by citing the need to "preserve aspect ratio" when the damn aspect ratio was correct in the first place.

it drives me up the wall, it's like when people say that pi is equal to 22/7, it's not, pi is a none repeating, never ending decimal, it's not "equal" to anything, not 3.1416, nothing, it has no finite value, well except maybe at the quantum limit, but let's forget about that for now.

[jagabo]

what i want to know is where the hell the notion that the movies have an aspect ratio of 1.85/2.35/2.40 comes from.

Is this a joke? There are almost no movies that are 16:9.

http://www.imdb.com/SearchRatios?2.35%20:%201
http://www.imdb.com/SearchRatios?1.85%20:%201
http://www.imdb.com/SearchRatios?1.78:1
http://www.imdb.com/SearchRatios?1.37%20:%201

35mm film does not have a 16:9 aspect ratio. It's about 4:3 (1.37:1). Anamorphic lenses are used to squeeze other aspect ratios into that frame size. Or the frame is simply masked to the desired AR.

http://en.wikipedia.org/wiki/35mm_film#Common_formats

those black borders are a result of scaling a 1920x1080 image to fit into a screen that doesn't support such a resolution,

No, those black borders are from fitting a non-16:9 movie into a 1920x1080 square-pixel frame.

if you were to play back the commercial blu-ray on an FullHD tv that supports 1920x1080p you wouldn't get said black borders.

A 16:9 movie doesn't show black borders. All other movie aspect ratios will have black borders because they have to fit into a 16:9 1920x1080 frame.

You are right about one thing though. Pi is not equal to 22/7. On the other hand, it is equal to the circumference of a circle divided by the radius of a circle divided by two.

[alcOre]

I opened up a can of worms apparently.

Deadrats...The black borders you see are there for movies that are not 1.778 aspect ratios (which is most movies...look at the box of the movie, it should list the AR)

p.s. Please click on the screenshots here and read what I wrote on the images.

Lets take a 1080p tv as an example. It can display 1920x1080 pixels on the screen. 1920 divided by 1080 = 1.778 aspect ratio.



Now lets look at a frame of the bluray kung fu panda. All blurays are encoded at a 1.778 AR INCLUDING the black borders....most are encoded at 1920x1080, as is this movie.



Now lets put that frame of the movie on the sony hdtv...fits perfect with black borders, because the tv AR is 1.778 and the movie's AR INCLUDING black borders is 1.778. That's why blurays are encoded to 1920x1080, because 1920/1080=1.778 AR, just like the tv. This DOES NOT MEAN the actual movie's AR (active area) is 1.778. In fact, most movies are not 1.778. They add borders above and below the movie to fill up the empty space.



Now, look at the following screenshot. The red square represents the frame INCLUDING black borders...which is 1.778 AR. Now look at the blue border, which is outlining the ACTIVE AREA of the movie...in other words the actual movie (no black bars.) This area has an AR of 2.35.



Now lets crop the black borders off...look at the image.....its still the same movie, still has the 2.35 AR, no stretching. The reason people remove the black borders is for viewing on computers or portable media players like an ipod touch. There's no reason to have the black borders. The only reason the black borders are required on a bluray, or dvd for that matter, is that the bluray/dvd player HAS to have the video at the resolutions it supports. You could re-encode the bluray and remove the black borders and feed it the video at 1920x818 pixels, but the bluray player won't be able to play it. Its expecting resolutions of 1920x1080. Hence the studios have to add black borders to the video. Computers dont have that limitation, therefore why encode the video with the black borders? Hence, people crop the black borders off.



If you're still confused, I'm not sure how else to explain it. And again, no one has to crop. Wether or not the video is cropped, the aspect ratio of the ACTIVE AREA (the actual movie, not the bars) is the same. See screenshots for proof.) Its simply a choice/option when transcoding a video for viewing on a computer, and most people choose to crop useless black bars. And they don't crop "to preserve the aspect ratio." The vertical resolution is chosen to preserve the aspect ratio of the active area. For example the above movie kung fu panda. The AR on the ACTIVE AREA of the film is 2.35. Assuming you did no resizing and no cropping from the left or right side of the film, you can take the width, 1920, and divide it by the AR to get the vertical size of the ACTIVE AREA to preserve the AR. So, 1920 / 2.35 = 817.02. I resized it to 818 since the vertical resolution has to be at least Mod2. Technically I should have gone down to 816, which would make it Mod16, but I'm just using this stuff as an example. So, now you can see if I cropped I would have a movie with a resolution of 1920x816, which is an AR of 2.3529. Now, VERY SLIGHTLY off of the original AR of 2.35 but it would be unnoticeable. So again, they do not crop "to preserve aspect ratio" like you have said. They choose the vertical resolution of their transcode to preserve aspect ratio, otherwise the video would stretch vertically if you cropped the black borders off and chose to keep the vertical resolution at what it originally was. They crop to remove useless black bars. One reason to crop, it can waste at very least a little bit of bitrate encoding that black bar. Another reason as an example, if you didnt crop a movie and played it on an ipod touch, you could not zoom in on the video.

PS : Before someone posts that me taking my 1920 and dividing it by 2.35 is wrong because the stated AR on the box could be wrong...I know that. I was just doing that for the example. That is not the actual way I get my vertical resolution after cropping. I either crop and let MeGUI decide my vertical resolution based on my input AR and how much I cropped, or I select Clever anamorphic encoding, then I look at the DAR it sets. For example, lets take a ITU NTSC 1.822784 Input DAR source, cropped 40 pixels from the top and bottom. MeGUI set DAR to 35/16. Say I want the video to be 480 pixels wide. So I take 480 x 16 / 35 = Vertical Resolution = 219.4....I then just round to the nearest Mod2 value cause I don't care about my vertical resolution being Mod16...I play the videos on my computer and my iPod, and they both support non-mod16 resolutions. And I ran tests and the difference in compressability was not noticable at all for my purposes. Anyways, so for that example I would then uncheck clever anamorphic (I want square pixels) and set my resolution manually to 480x220.

[deadrats]

@alcOre (and everyone else):

my "confusion" arose because i thought that 35mm film had an aspect ratio of 1.778 and that said ratio was an industry standard (i found it some time ago while reading about various types of film on wikipedia) and because when HDTV first started hitting the market it was reported over and over again that the reason 1920x1080 and 1280x720 were chosen was because they matched the aspect ratio of the movies as they are shown in theaters.

however over the last couple of days i have been reading everything i can about how movies are filmed and realize where the 2.35/2.40 comes from, so i can understand the cropping.

on thing though, what if you are capturing a movie from a hi def broadcast, for instance i have about a dozen music videos and high def movies captured from hi def tv and they were all captured at 1920x1080, should they also be cropped, as they have absolutely no black borders in the video stream and quite frankly play beautifully and are of excellent quality.

[manono]

Why would you crop them if they have no black borders? Capping from TV is different, though. Many, if not most, TV programs are created these days in true 1.78:1. And many movies broadcast for Hi-Def TV are panned and scanned or cropped to 1.78:1. This is in contrast to movies found on DVD or Blu-Ray which are often in some aspect ratio other than 1.78:1.

[alcOre]

Well...I hope you read my post and it helped. Like manano said, if there's no black borders, why would you crop? You would be cropping active area of the film. I too am actually right now creating avs scripts for a few different 1920x1080 music video caps. If there's no black borders on any of your content, then there's no reason to crop. THE reason to crop is to get rid of black borders. But, I have quite a few music videos from MTVHD/Palladia that do have black boders...ie they are not 1.778 AR. Those I crop the borders off. What I've seen on some of my HD music video caps is there's actually some black border even on the left and right side of the active area...I'm assuming they put that in to compensate for overscan for people that tune to the HD channel with an SD set.

PS : I'm not "capping" from TV per se. I've got an HD DVR that actually records the original .ts file sent from my cable provider. I then hooked up my HD DVR to my PC via firewire cable, and I can "copy" the exact .ts file. No capping/encoding from the cable company to my dvr to my pc. Keep the quality nice and high. MTV HD/Palladia needs to show more of a variety of damn HD videos though. For the most part they play the same damn videos over and over again every night during their 6 hours of music video content from 12-6am.

[jagabo]

on thing though, what if you are capturing a movie from a hi def broadcast

It depends on the broadcast. For example TBS HD and TNT HD stretch 2.35:1 movies vertically rather than add black borders -- really annoying. In that case you would want to add DAR flags or resize to the correct square pixel AR.

MTV HD/Palladia needs to show more of a variety of damn HD videos though.

That's for sure!

I'm not "capping" from TV per se. I've got an HD DVR that actually records the original .ts file sent from my cable provider. I then hooked up my HD DVR to my PC via firewire cable, and I can "copy" the exact .ts file.

I can do this with standard defintion broadcasts. But my HD "caps" break up into blocky decoding artifacts every second or so. Am I missing something? Do these need to be treated in some way before they can be played on a computer?

[alcOre]

I can do this with standard defintion broadcasts. But my HD "caps" break up into blocky decoding artifacts every second or so. Am I missing something? Do these need to be treated in some way before they can be played on a computer?

I'm using CapDVHS to get the files from my HD DVR to my computer. Is that what you're using jagabo? If so, check the following under settings

1) Check/Enable Convert 188 byes
2) Check/Enable Delete to SyncByte
3) Make all the extentions .ts (ps file ext, ts file ext, etc.)

Another thing....download the latest MPEG2Repair and run each .ts file you "cap" through it. Its easy to figure out. I hit "rec." on CapDVHS about 20-30 seconds before what I want "capped" begins and I hit "stop" about 20-30 seconds after what I want "capped" ends also. So I have things that need to be cut. After I run the original .ts file through MPEG2Repair and it makes a repaired .ts file, I run that repaired .ts file through VideoReDo and cut out the stuff I don't want at the beginning and the end. Not sure what your process is but I don't really have any stuttering/break up on anything other than the very beginning of the "cap." That's why I hit the "Rec." button early, so I can edit that out.

Do me a favor...cap a short HD source clip (like 10-20 seconds) and post the original file (not run through mpeg2repair or edited in any way.) I want to see if it breaks up/stutters on my computers.

[jagabo]

alcOre, thanks for your input. CapDVHS works fine when capturing SD but it crashes within ~5 seconds when capturing HD. So I was using a simple GraphEdit graph (SciAtl tuner device -> dump filter). Since the HD ts files were all corrupt I didn't save any of them. I'll capture some more samples today and upload one for you to look at. Thanks again!