1992*4##111 (gimmick_game) wrote in go_nin,

Video Compression - The Difference Between SD Analog and HDTV - A Primer

This is something that has been bugging me for a while, and I think the biggest problem right now is people don't understand the differences in the way video is produced. More than once, I've had someone ask me for the "HD" of a pv, even though I've uploaded the DVD rip, which is just about the highest quality you can get.

So I've decided to explain it a bit to help people understand the differences between DVD rips, Television Streams (Analog and HDTV) and why some things are in huge frame size while others aren't, but of the same quality.

A few years ago, HDTV was starting to get big but there weren't a whole lot of things broadcast in it. It required Digital signal to be able to be seen and most countries/homes relied still on an analog broadcast signal. Cable companies have been using digital cable for years and jumped on the bandwagon, but it was still just a shiny thing to show off to your friends on the Discovery Channel. Once LCD HDTVs became more of a commonplace in homes, cable and broadcast companies started broadcasting in HD signals. Once the digital conversion happened here in the states, even rabbit ears had to be digital and could receive HD signals.

In Japan, things are still broadcast in both resolutions.

Analog files are typically 720x480, a non-widescreen resolution. The quality can be grainy and just...not good. Unless I have no other choice, I choose to not work with analog streams anymore. This aspect ratio is called 4:3.

HDTV files, when first broadcast are typically broadcast in 720p or 1280x720 and 1080p or 1920x1080. MOST stations broadcast in 720p as it is almost completely unnecessary to broadcast in 1080p at times.

HDTV files are crisper, cleaner and wide screen. They are also a BITCH to work with when first captured in a transport stream or .ts file. This is why you will frequently see 13gb .ts files. They are completely interlaced and uncompressed, which is fine for the station to broadcast by, but shit for your computer to try and work with.

Video compression has always been a tricky thing. No two files ever turn out quite exactly the same despite all of your different tries. HDTV has just gone and messed that up more.

Back in the day of just DVD rips and analog streams, .mpg and .avi were just fine. Most people used XVID or DVIX to encode their files, and everything was juuuust fine. Then came video iPods and Apple got a chance to push their .mp4 video file format up to at least a bit more recognition.

Then came HDTV. HD was the death of xvid, I think, as it's just nearly impossible to keep picture quality by using it. Xvid is still a fantastic tool for converting dvd to .avi, but when it comes to .ts or .mp4 or HD .avi...it falls flat.

Enter x264. I was wary of it at first, but I quickly learned the joys. Smaller file sizes, less jumping of the frames and pixles and just an overall clearer picture. And thus, .avi was saved from a horrible, horrible death.

Personally, .mp4 files, when properly converted to from .ts for HDTV stream are the best, but not everyone can run them smoothly. They take a lot of processing and let's face it, most people don't have a brand new macBook Pro sitting on their lap to run it without any hiccups at all.

I find .mp4s to be a fantastic tool. They create very nice files from the chaos that is .ts and are the best stepping stone for .ts to .avi. There are still issues with audio streams on them though, and until fandom as a whole ...upgrades, .avi will remain the standard for file sharing.

First of all, it doesn't matter if something is 704x396 in frame size, if the original stream was HD. For most of us, you would be hard-pressed to be able to find the difference between the two files when watched in full screen on most laptops. It is still a file just made a smaller "resolution", but still an HD quality file. Most DVDs are around this aspect ratio.

Is it true HD? No, but it's damned high quality for the filesize.

Until Johnny starts releasing things via BluRay, you're not going to see "HD" concerts or PVs. And I honestly don't see that happening for a gooood long time. Japanese DVDs are expensive enough, please don't make them more expensive...T___T

I still remember the days when people were BEGGING for DVD rips of PVs. I for one was ECSTATIC when 5x10 DVD was announced because it meant I could have DVD quality of all of the PVs thus far, not just the ones that had been released with a DVD disc.

Still, I get people asking for "HD" pvs. Sure, you may find tv rips that are technically of the HD variety, in the 1280x720 frame size, but that will also most likely not be a true 1280x720.

I like to think of it this way: sure, your scan is 6000x6000 pixles big, but the quality is shit because all of the pixles are an inch apart. It's the same with videos. The more you stretch the image, the less compressed and clear the picture will be.

Provided the ripping and encoding are done properly, DVD quality is about the best damned quality you'll find of anything, aside from BluRay and true HDTV streams (Music Station for one broadcasts beautifully.

Well, first of all...the reason is COLOR. The more color and movement in a video, the larger it has to be to keep all of the video data smooth and seamless. This is the reason why the first few episodes of VS available are so hard to watch. They're huge and disgustingly fuzzy.

Our main source for VS now has been uploading her mp4 in 704x396 framesize. Other uploaders who take longer (particularly at jpopsuki.eu and are not very consistent) still upload at 1280x720, but the size is ridiculous. Most of us can't afford to dedicate 3 gigs of harddrive space a week to three weekly shows. And that's on a good week with no specials. My first computer HD was 3 gigs, if that tells you anything.

VS Arashi will always be a larger file size than the others for the sheer fact it's so COLORFUL.

To put it simply, no.

I've spent many years learning the ins and outs of video ripping, encoding and compression, and there are so many factors that it is almost impossible for anyone else to replicate my particular style to the T. Even hontowa and I, who work on the same model machine for the most part, end up with differences even though we're using the same software and settings to encode.

There are plenty of tutorials around if you use your google-fu, and I'm certain that with time and practice you'll get the hang of it. That's what I did!

I hope this has been at least somewhat informative and not just a lot of babble as it may well be.
Tags: !information, !notice
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