hello everyone,
allow me to begin by pointing out what i think is correct about aspect ratios (my problem may be that i don't actually understand them as well as i think i do):
display aspect ratio refers to the ratio, in pixels between the width and the height of a video stream.
pixel aspect ratio refers to the ratio between the width and height of a pixel.
dvd has par of either 4:3 or 16:9, 1440x1080 has a dar of 4:3 and a par of 1:1 and 1920x1080 and 1280x720 both have dar of 16:9 and all three have a par of 1:1.
so far so good, here is where my head starts spinning:
i keep seeing hi def movies on various torrent sites that are cropped to 1920x800, 1920x816, 1280x544 and a few others, but these are the most common. the explaination i keep seeing is that the original movie had a ratio of 2.35 or 2.40 and so they are trying to maintain the original aspect ratio. i always thought that the 2.35/2.40 refered to the movies aspect ratio while it was still on film but that no longer applies once it was scanned and digitized.
i was told that what is done during the authoring stage is that they take the 1920x800 video steam and encode it to 1920x1080 by adding black bars on the top and bottom of the stream so that it can adhere to the blu-ray standard and as proof they point out that on the back of commercial blu-ray disks the movie is listed as being 1080p/2.35 (or 2.40).
this almost seems plausible, but then i noticed something odd, if i play my official blu-ray of a certain movie (let's use batman begins as an example) on my computer and compare it to a download that's been cropped to 1920x800, they don't look the same, the 1920x800 version looks "squished" just a bit, as if someone had grabbed both ends of the video stream and stretched the image.
so i started checking out all my blu-ray titles and comparing them against downloaded versions and i noticed the same thing.
at first i figured it was a scaling issue that resulted from the encoder being used to create the mkv files i downloaded as well as a problem with the software players i was using (vlc, kmp, media classic and gomplayer) or maybe a problem with ffdshow, as the maximum resolution of my monitor is 1280x1024 and i use 1024x768 for regular use.
at this point i'm somewhat confused, but then it got even worse: i started encoding my own 1280x720p movies using the latest tmpgenc4 express and all the encodes would come out letterboxed, which i assumed was how 720p was supposed to be displayed on my monitor.
then i ran across some HDTV captures that had a resolution of 1280x720p but when i played them they filled up my entire screen!!!
and that's where my confusion took a turn for the worse: i started using procoder 3 and after creating a couple of 720p movies i started poking around the options and saw that there was a slider labeled "scaling and letterboxing" and it allows you to adjust, in terms of percentage whether you want the output letterboxed and/or scaled and cropped.
trying each setting just ended up perplexing me even more: if i chose letterboxing the results where a movie with black borders on the top and bottom of the movie but the entire scene displayed on my monitor; choosing scale and crop resulted in a movie that filled the entire screen but also caused parts of the scene to be outside the boundaries of the monitor, just what you would expect if you where trying to output a stream whose resolution exceeded the abilities of the monitor.
but the odd thin is that analysing both streams it shows that they are both 1280x720 and that they both have pixel aspect ratios of 1:1, i don't understand how 2 streams can have the same resolution, the same par yet have 2 very different playback characterists.
adding to the confusion further is the fact that i download some movie trailers, in full 1920x1080p, to see what a professionally done video should look like and it displayed the same characteristics as the non-letterboxed 720p i created.
so, can someone tell me what is going on, namely:
does it make sense to crop a 1920x1080 commercial blu-ray to 1920x800?
how is it possible for 2 files to have the same par, the same resolution and yet one be letterboxed and one not?
which is the correct way to encode movie, with letterboxing or without and why?
my gut feeling is telling me that sans letterboxing would be the proper way, as then it would fill up the entire screen when viewed on a 1920x1080 capable monitor.
and lastly, what do you guys think is the best software media player for viewing movies on a pc?
sorry for the long post, but the above has been driving me bananas.
rogar-Smoke(DBG):
-deadrats.
allow me to begin by pointing out what i think is correct about aspect ratios (my problem may be that i don't actually understand them as well as i think i do):
display aspect ratio refers to the ratio, in pixels between the width and the height of a video stream.
pixel aspect ratio refers to the ratio between the width and height of a pixel.
dvd has par of either 4:3 or 16:9, 1440x1080 has a dar of 4:3 and a par of 1:1 and 1920x1080 and 1280x720 both have dar of 16:9 and all three have a par of 1:1.
so far so good, here is where my head starts spinning:
i keep seeing hi def movies on various torrent sites that are cropped to 1920x800, 1920x816, 1280x544 and a few others, but these are the most common. the explaination i keep seeing is that the original movie had a ratio of 2.35 or 2.40 and so they are trying to maintain the original aspect ratio. i always thought that the 2.35/2.40 refered to the movies aspect ratio while it was still on film but that no longer applies once it was scanned and digitized.
i was told that what is done during the authoring stage is that they take the 1920x800 video steam and encode it to 1920x1080 by adding black bars on the top and bottom of the stream so that it can adhere to the blu-ray standard and as proof they point out that on the back of commercial blu-ray disks the movie is listed as being 1080p/2.35 (or 2.40).
this almost seems plausible, but then i noticed something odd, if i play my official blu-ray of a certain movie (let's use batman begins as an example) on my computer and compare it to a download that's been cropped to 1920x800, they don't look the same, the 1920x800 version looks "squished" just a bit, as if someone had grabbed both ends of the video stream and stretched the image.
so i started checking out all my blu-ray titles and comparing them against downloaded versions and i noticed the same thing.
at first i figured it was a scaling issue that resulted from the encoder being used to create the mkv files i downloaded as well as a problem with the software players i was using (vlc, kmp, media classic and gomplayer) or maybe a problem with ffdshow, as the maximum resolution of my monitor is 1280x1024 and i use 1024x768 for regular use.
at this point i'm somewhat confused, but then it got even worse: i started encoding my own 1280x720p movies using the latest tmpgenc4 express and all the encodes would come out letterboxed, which i assumed was how 720p was supposed to be displayed on my monitor.
then i ran across some HDTV captures that had a resolution of 1280x720p but when i played them they filled up my entire screen!!!
and that's where my confusion took a turn for the worse: i started using procoder 3 and after creating a couple of 720p movies i started poking around the options and saw that there was a slider labeled "scaling and letterboxing" and it allows you to adjust, in terms of percentage whether you want the output letterboxed and/or scaled and cropped.
trying each setting just ended up perplexing me even more: if i chose letterboxing the results where a movie with black borders on the top and bottom of the movie but the entire scene displayed on my monitor; choosing scale and crop resulted in a movie that filled the entire screen but also caused parts of the scene to be outside the boundaries of the monitor, just what you would expect if you where trying to output a stream whose resolution exceeded the abilities of the monitor.
but the odd thin is that analysing both streams it shows that they are both 1280x720 and that they both have pixel aspect ratios of 1:1, i don't understand how 2 streams can have the same resolution, the same par yet have 2 very different playback characterists.
adding to the confusion further is the fact that i download some movie trailers, in full 1920x1080p, to see what a professionally done video should look like and it displayed the same characteristics as the non-letterboxed 720p i created.
so, can someone tell me what is going on, namely:
does it make sense to crop a 1920x1080 commercial blu-ray to 1920x800?
how is it possible for 2 files to have the same par, the same resolution and yet one be letterboxed and one not?
which is the correct way to encode movie, with letterboxing or without and why?
my gut feeling is telling me that sans letterboxing would be the proper way, as then it would fill up the entire screen when viewed on a 1920x1080 capable monitor.
and lastly, what do you guys think is the best software media player for viewing movies on a pc?
sorry for the long post, but the above has been driving me bananas.
rogar-Smoke(DBG):-deadrats.