When will a video called 240p/360p/480p/720p/1080p

[psycholyzern]

hi. I am newbie to video conversion.. Can anyone help me understanding about correct resolution for 240p/360p/720p/1080p.

1280x720 >> 720p
1280x528 >> 720p

from googling, I found that resolution for 720p is 1280x720. But, a video is still called 720p even it has 1280x528 resolution.
what about 240,360, and 480p?? do they restricted to height? we take 360p as example:

640x360 called 360p but,
640x272, are they called 360p???

1080p also called 1080p as long as the height is 1920..
can anyone made all these clear for me as simple as you can??
Im sorry if my question is not clear enough, I tried my best to express this situation.
thanks

[manono]

You're mixing things up. 1280x528 is just 1280x720 with the black bars cropped away (although it was possibly reencoded from a 1080p source).

1080p also called 1080p as long as the height is 1920..

I think you mean to say 'as long as the width is 1920'. Which isn't true. Some 1.33:1 ratio such as 1440x1080 might also be 1080p.

640x272, are they called 360p???

No.

[deadrats]

just to mess with the OP's head a bit more:

the first number refers to the width in pixels, the second number to the height in pixels, so 1920x1080 means that you have 1920 pixels across the screen and 1080 pixels vertically.

here's where those other silly resolutions come from...movie piracy. let's say someone wants to share a copy of the latest batman movie, they can either share the whole dvd or blu-ray, but that file would be huge and many people don't have connections fast enough to allow them to upload and download a 20+ gb file anywhere near what the consider an exceptional time frame or maybe they don't want a file that big on their hdd, so what eventually evolved was people would re-encode the dvd or blu-ray to a lower bit rate. but re-encoding to a lower bit rate lowers the quality so people also decided to reduce the resolution.

here's where it gets tricky, even though the blu-ray may be 1920x1080 this works out to an aspect ratio of 16:9 or 1.78:1. problem is that if you go to the IMBD and look to see what the aspect ratio the movie was shot in and ultimately transferred to dvd or blu-ray in is usually 2.35:1 or 2.40:1. so, when you are resizing you need to recalculate the target resolution in order to maintain the aspect ratio of the source.

you do this by first cropping out the black bars at the top and the bottom of the source that act as padding to bring the resolution to 1920x1080 and then you resize to the appropriate smaller resolution that have the same aspect ration. in the 720p range that usually ends up being 1280x536 or something similar.

[jagabo]

Forget calling video files 1080p, 720p etc. Just name both frame dimensions. Then there's no guessing.

[hello_hello]

1080p = 1920x1080 (16:9)
1080p = 1440x1080 (4:3) - Not an official "Blu-ray" resolution
720p = 1280x720 (16:9)
720p = 960x720 (4:3) - Not an official "Blu-ray" resolution

However when encoding, if the movie contains black borders top and bottom most people remove them, so in order to stick with the above standard (even though it may be counter-intuitive at first) the descriptions of 1080p and 720p are still used.

If you take a (16:9) video which is 1920x1080 including the back borders, but the actual picture area is 2.4:1, you'll be left with 1920x800 after the black borders are removed, but either way, it's still referred to as 1080p. The resolution of the actual picture is exactly the same whether it's encoded as 1920x1080 with black borders or 1920x800 without, a reason why they should both be described the same way (1080p). Once you understand the logic behind it, describing a 1920x800 video as 800p would probably make it more confusing as after-all, the picture area has exactly the same resolution as the 1920x1080 version, only the latter has back borders included.

On playback when using a 16:9 display, the player adds the black borders back if they were removed when encoding, so you're effectively still watching the same 1080p or 720p video, the difference is only whether the black borders are encoded as part of the video or added back on playback.

576p is used to describe PAL DVDs (720x576)
480p for NTSC (720x480).

One commonly used exception to the above rules seems to be the use of 480p. It's often (technically incorrectly) used to describe DVD video which has been resized to square pixel resolutions such as 704x400 or 720x304 etc. Because there's no "industry standard" for resolutions below 480p, often it's used when technically the encoded video is really 400p or 360p etc.

Ideally when describing video, you'd use 1080p or 720p etc to describe what it is, but as jagabo said, it's probably best to qualify that with the exact resolution and aspect ratio. ie 720p, 1280x544, 2.35:1

640x360 called 360p but,
640x272, are they called 360p???

If the former is 360p with black bars, then using the naming convention for 1080p and 720p etc, the latter could be referred to as 360p if it's still the same video, only the black bars have been removed.

When it comes to HD, most people use 1080p or resize down to 720p as there's not too much ambiguity. For video with a 16:9 or wider aspect ratio, you'd expect the width to always be 1920 or 1280 while the height varies according to the aspect ratio of the picture. For video with an aspect ratio less than 16:9 you'd expect the height to always be either 1080 or 720 while the width then varies accordingly.

[El Heggunte]

Forget calling video files 1080p, 720p etc. Just name both frame dimensions. Then there's no guessing.

Therefore, I cannot agree very-much with the definitions proposed by hello_hello in post #5, because then

352x480, 480x480, 544x480, 640x480, etc., could not be called 480p, and

352x576, 480x576, 544x576, 768x576, etc., could not be called 576p.

[hello_hello]

Yes they could. Well mostly... I thought about it and edited the last paragraph of my post after submitting it to hopefully make it clearer.

The OP was asking to have the definitions, as they're commonly used, explained. I wasn't "proposing" them. Maybe I didn't do it well, but anyway...........

The commonly used naming conventions for HD video are based on the "industry standard" naming conventions, which it could be argued are incorrect (marketing) when only the actual picture area is taken into account. A 1080p video might contain a 16:9 video which is 1080p, but it might also contain a picture which has a 2.4:1 aspect ratio. The "industry standard" includes the black borders in the 1080p description but the actual picture area is only 800p, so when removing the back borders most people follow the same "industry standard" naming convention and refer to it as 1080p to avoid (even more) ambiguity.

For HD (1080p and 720p) the naming convention is fairly simple. If the aspect ratio is 16:9 or wider, the width should always be 1920 (1080p) or 1280 (720p) while the height will vary according to the aspect ratio.
If the aspect ratio is less than 16:9, then the usual naming convention after the pillarboxing is removed means the height will always be 1080 (for 1080p) or 720 (for 720p) while the width will vary according to the aspect ratio.

The same principle applies to 480p or 576p. It's the "industry" who's adding black borders to the picture and then including them in the description of the resolution, the "encoding naming convention" just follows the same standard.

I sometimes resize video to 900p, so following the "industry standard" naming convention, I call a video 900p if the width is 1600 and the aspect ratio is 16:9 or wider. The height varies according to the aspect ratio. If the aspect ratio is less than 16:9, then the height must be 900 while the width will vary.

[musopark]

Hi there, i am totally new to forums, but basically i have a 5 gig video i want to put on youtube. You tube is 2 gig max. I downloaded handbrake, but when compressed it went down 90% to half a gig with the quality not the same as many claim.

Q1. How can i reduce it down less % to end up with 2 gig, so the quality is better.


Q2. Is there a great software out there that the quality is the same when reducing/compressing.


I would appreciate any help

Thanks Michael


07525 067 368

[hello_hello]

musopark,
It might pay to start your own thread as your question is totally unrelated to this discussion. Others will no doubt be willing to help if you start a new thread.

[musopark]

Hi there, i'm sorry to ask you this, but its my first time....how do i start a new thread, i've looked everywhere

Thank you

[Baldrick]

Hi there, i'm sorry to ask you this, but its my first time....how do i start a new thread, i've looked everywhere

Thank you

Click on https://forum.videohelp.com/forums/18-Newbie-General-discussions and on Post new thread at top left.

[musopark]

Thank you friend

[psycholyzern]

the conclusion is, the 720p, 1080p definitions with 1280x536, 1920x988 or something similar, came out from the silly piracy movies so they can keep up with the standard??
then, I agree with #4, naming the video with both frame dimension is a better way...
thank you for giving me those explaination

[hello_hello]

Technically it's the "standard" which is "silly", unless you're happy to have black bars included in the description of your video's resolution.

I don't know if I'd refer to it as "keeping up with the standard", but rather "following it", even though the standard is technically incorrect much of the time. The "standard" is to take a wide screen movie, add black bars top and bottom, stick it in a 16:9 frame and call it 1080p. The entire 16:9 frame is included in the 1080p description whether it contains picture or not. The commonly used "encoding definition" of 1080p describes it the same way, taking the entire 16:9 frame into account, only the black bars are added on playback and not encoded along with the picture.

Some people object to the 1080p definition when a video is 1920x800 (black bars removed), yet if I encode the same video with black bars top and bottom to make it 1920x1080 they're happy with an "industry standard" 1080p description, even though the picture itself is exactly the same. I agree it's technically not 1080p either way, but given the "industry standard" is to take the whole 16:9 frame into account, whether it contains actual picture or not, the "encoding standard" uses the same method.