Divx
Re: Divx
Weren't they saying that 10 years ago?
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Re: Divx
Jrecee wrote:When will we have so much speed and harddrive space that we don't need compression anymore? 10 years?
Never, I hope. That's a big part of my field (Digital Signal Processing).
But really, I don't expect we'll every stop using compression, for a few reasons.
1. Data Hunger: We keep wanting to store more data, and data is constantly being generated.
2. Video Quality trade-off: Why store uncompressed video when one can use perceptually-lossless compression and store higher-quality compressed video? Rather than stick with our current HD resolution, we can use compression and use that space to boost the resolution or color-depth.
3. Communication: This is actually the big one. I can actually see up reaching limits on data generation or our quest for higher-quality video. However, storage isn't really the big bottle-neck. Communication is-- getting data from one point to another, particularly for wireless communication. RF bandwidth is a very limited resource. Modulation schemes get better and better, but there are still hard limits to deal with there.
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Re: Divx
so an avi ca be a divx?
excuse my lack of knowledge, but I always thought the video codec is the file extension.
Like a divx codec is .divx , an avi codec is .avi ,and so on. I never know(and still don't understand) how divx is avi, but I get the idea now that its embedded within.
excuse my lack of knowledge, but I always thought the video codec is the file extension.
Like a divx codec is .divx , an avi codec is .avi ,and so on. I never know(and still don't understand) how divx is avi, but I get the idea now that its embedded within.
Re: Divx
The file extension is the container for the video, while the codec is how the video is actually encoded. Your media player has to understand both to be able to play the file.
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Re: Divx
That's the crux of it really. A container is a file encapsulating the media comprising the movie in question. AVI is a very old spec that has been there since Win3.x, and even though it's been improved it's still severely lacking. It's also among the most common (along with Microsoft's own WMV, or Windows Media Video). Usually there's an MPEG-4 ASP video inside it (Xvid, DivX, MP4V... Slighlty different implementations but essentially synonymous in real world applications) along with an MP3 audio track.
MP4 on the other hand is a more recent container, chiefly advocated by Apple, that can encapsulate more stream types. Most often it'll be MPEG4-AVC (aka H.264 or x264 among other things) video inside it which is vastly superior to ASP thanks to its optimised compression routines (Which also requires more computing power to execute, therefore explaining why it's not mainstream yet in DVD players) along with an AAC track (again, superior to MP3). As an example you can store a DVD-quality rip with surround audio in less space than it would require ASP/Xvid to achieve comparable quality. Youtube HD videos are encoded in H.264 and are a testimony to AVC's superior encoding capabilities.
Finally there's Matroska (MKV) which is an open-source container that supports even more formats than MP4, along with native 'chapter' and custom caption support. It is basically the future of non-streamed video storage but studios are reluctant to support open-source solutions.
People have often been confused by the (nonexistent) discrepancies between containers and AV formats which is why they're often recommended to use all-in-on solutions like VLC Player or the K-Lite codec pack to take care of their playback needs. Hardware players are another story though, but you'll find that the 360/PS3 can play back many file types if you encode them in a 'conventional' manner.
MP4 on the other hand is a more recent container, chiefly advocated by Apple, that can encapsulate more stream types. Most often it'll be MPEG4-AVC (aka H.264 or x264 among other things) video inside it which is vastly superior to ASP thanks to its optimised compression routines (Which also requires more computing power to execute, therefore explaining why it's not mainstream yet in DVD players) along with an AAC track (again, superior to MP3). As an example you can store a DVD-quality rip with surround audio in less space than it would require ASP/Xvid to achieve comparable quality. Youtube HD videos are encoded in H.264 and are a testimony to AVC's superior encoding capabilities.
Finally there's Matroska (MKV) which is an open-source container that supports even more formats than MP4, along with native 'chapter' and custom caption support. It is basically the future of non-streamed video storage but studios are reluctant to support open-source solutions.
People have often been confused by the (nonexistent) discrepancies between containers and AV formats which is why they're often recommended to use all-in-on solutions like VLC Player or the K-Lite codec pack to take care of their playback needs. Hardware players are another story though, but you'll find that the 360/PS3 can play back many file types if you encode them in a 'conventional' manner.
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lost_within
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Re: Divx
Divx:
I once had a job where I worked the same place as a friend...one day I saw divx on the computer...and I thought of an idea to trick my friend:
Me: Man I hate divx I can never figure it out
Friend: lol
Me: Hey...do you ever watch porn at work?
friend: Turns red and stops laughing
Divx....just porn spelled differently to play different video files.
I once had a job where I worked the same place as a friend...one day I saw divx on the computer...and I thought of an idea to trick my friend:
Me: Man I hate divx I can never figure it out
Friend: lol
Me: Hey...do you ever watch porn at work?
friend: Turns red and stops laughing
Divx....just porn spelled differently to play different video files.
Yep, I know im the one ya love to hate.
Re: Divx
Speaking of the original Divx, it was destined to become a DVD rental scheme but the idea itself was ridiculous, which lead to its demise. You can read more about it here - http://www.dvdjournal.com/extra/divx.html
Thy ban hammer shalt strike
Re: Divx
It's definitely still used and (Xvid) still one of the better video compression standards for people that:
a) Have older PC's/hardware available to them to watch the stuff on. It doesn't take a workhorse to decode Divx/Xvid avi's. A lot of entry level DVD players will play them burned to a disc or from a USB stick as well.
b) Still have SD TV's. Most 1 click Xvid encoding programs are designed around backing up video like DVDs to fit onto CD's and to fit several onto DVD's. The aspect ratios and resolution are usually made to accommodate 4:3 480i/p.
I know a few people that still use XBMC on a original XBOX to view their Xvids on their SDTVs.
That said, most people I know have moved on to h.264 or x264. It, like Xvid, is a Mpeg-4 codec, but it is much more efficient and has a much better video quality to file size ratio than Xvid does. Most of these are found in .mp4 or .mkv container due to the ability of those containers to handle multiple audio streams. The stuff that you download from itunes or the 360/PSN marketplaces are using the h.264 codec. These look pretty damn good on a HDTV or computer monitor where Xvids show a lot of macroblocking and quality loss. You just don't notice it on the old 480i TV sets.
The 1 click programs (like handbrake) have a default setting for game consoles and apple TVs that produce a video with comparable quality at less than 1/2 the file size of the original DVD.
The problem with these is that it takes a more powerful PC to play them back and if you want to view them on your TV, you either need to hook your PC to your TV, or buy a device that has the proper hardware to view them as no DVD players have been made that i know of that will read them.
The original XBOX running XBMC wont do it. (I think it does if you keep the bit rate so low when encoding it, but then it doesn't look better than a Xvid so whats the point). You need to either get a specialized device like the WDTV live or Popcorn hour to play them (off a network share) or as long as you stick with the right formatting, a PS3, 360, or AppleTV will do it.
As the resolution increases with 720p/1080p Blu Ray/HD-DVD rips, the higher the system requirements are to decode.
a) Have older PC's/hardware available to them to watch the stuff on. It doesn't take a workhorse to decode Divx/Xvid avi's. A lot of entry level DVD players will play them burned to a disc or from a USB stick as well.
b) Still have SD TV's. Most 1 click Xvid encoding programs are designed around backing up video like DVDs to fit onto CD's and to fit several onto DVD's. The aspect ratios and resolution are usually made to accommodate 4:3 480i/p.
I know a few people that still use XBMC on a original XBOX to view their Xvids on their SDTVs.
That said, most people I know have moved on to h.264 or x264. It, like Xvid, is a Mpeg-4 codec, but it is much more efficient and has a much better video quality to file size ratio than Xvid does. Most of these are found in .mp4 or .mkv container due to the ability of those containers to handle multiple audio streams. The stuff that you download from itunes or the 360/PSN marketplaces are using the h.264 codec. These look pretty damn good on a HDTV or computer monitor where Xvids show a lot of macroblocking and quality loss. You just don't notice it on the old 480i TV sets.
The 1 click programs (like handbrake) have a default setting for game consoles and apple TVs that produce a video with comparable quality at less than 1/2 the file size of the original DVD.
The problem with these is that it takes a more powerful PC to play them back and if you want to view them on your TV, you either need to hook your PC to your TV, or buy a device that has the proper hardware to view them as no DVD players have been made that i know of that will read them.
The original XBOX running XBMC wont do it. (I think it does if you keep the bit rate so low when encoding it, but then it doesn't look better than a Xvid so whats the point). You need to either get a specialized device like the WDTV live or Popcorn hour to play them (off a network share) or as long as you stick with the right formatting, a PS3, 360, or AppleTV will do it.
As the resolution increases with 720p/1080p Blu Ray/HD-DVD rips, the higher the system requirements are to decode.
Re: Divx
Everytime we get close to it, there are advances in video/audio that take us back to it.Jrecee wrote:When will we have so much speed and harddrive space that we don't need compression anymore? 10 years?
In the age of TB hard drives 6-7GB doesn't seem like a lot when you are backing up a few DVD's to your PC so you dont have to fiddle with the discs anymore, but when you back up a Blu Ray to your PC for the same purpose, 25-40GB a disc adds up quickly.