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Topic: "Alt Preset Standard" For Video (Read 4565 times) previous topic - next topic
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"Alt Preset Standard" For Video

Hello all,

As you can see, I am new, but I have been a lurker here on and off for about a year. Hydrogen Audio is always my number one reference for any audio questions and problems.

My question is actually not about audio at all, but about video, more specifically, movies/DVD backups. I currently use the popular MeGUI for all my backups. I process audio seperately using LAME and APS to get transparent audio quality. I use x264 (H.264) for video, using the built-in Bitrate Calculator to make my backups 700MB in size (to be archived on CD) and using the "HQ-Slowest" profile to get the best quality possible at this restricted size. I also backup the video in its full, original resolution to preserve as much quality as possible. Finally, all this is muxed together into an MP4 container. All in all, this method of video encoding has been quite transparent for me for almost all video I have encountered; I cannot tell the difference between my x264 backups and the DVDs (for the most part). I've just recently discovered x264, and this is a HUGE improvement in quality since my DivX days.

I have been encoding video backups for a long time, but ever since I discovered LAME and APS for audio, I have been somewhat ticked that bitrate calculation by final file size is the only way to encode video. Since most video encoding is done ABR, it takes quite some experience to "just know" what bitrate to manually use. Therefore, being new to x264, bitrate calculation by final file size is the only viable option for me.

Here is my question. I am wondering why there is no STANDARD out there for video as there is for audio. Why isn't there a transparent-to-most-people, makes-most-efficient-use-of-bits, VBR video encoding option out there? (As there is for audio.)

Or perhaps THERE IS and I'm just extremely ignorant. If this is the case, someone please enlighten me. Is there an "Alt Preset Standard" equivalent in the video world? (Preferably in DivX or x264.)

I am willing to take a hike in filesize to ensure that I get the highest quality possible/needed. I am a big efficiency junkie and if some of my backups can be less that 700MB while still being transparent, then it is definitely an issue for me. Right now, I don't even know whether or not that's the case. Please begrace me with your knowledge, people.

Thanks for your time, and combined knowledge and expertise.

"Alt Preset Standard" For Video

Reply #1
I think it won't be easy to define such an encoding profile. Video encoding focuses on finding the most efficient way to use a pre-defined amount of space, as most (by far) users think "I want this video to fit perfectly on a CD/DVD/Zip Disk/whatever".
Second, your eyes are not as easily tricked as your ears. Theoretically, you can see every single compression artifact as you can see every single pixel in every single frame. Given the fact, of course, that you have a monitor which you can tell one pixel from another on.
So it is merely a question of transparency to all people (which would be a pixel-by-pixel clone) or none. In video encoding, all you can do is minimizing the annoyance of artifacts to a level where most users don't bother them anymore; you cannot find a level where the artifacts become invisible to most users.

Long story short, I don't think a 100%-equivalent setting can exist. However, in x264 you could take a look at the Single Pass/Quality and Single Pass/Quantizer encoding options, I think they work like the -Qx options in Ogg Vorbis.
Nothing is impossible if you don't need to do it yourself.

"Alt Preset Standard" For Video

Reply #2
DVD is not transparent. Most source material is compressed. Unless you're working from a transparent source, transparency is impossible. Transparency will also require enormous amounts of data be stored.

The concept of audio transparency doesn't analogize easily to video transparency anyhow; if you get close with any video source you'll probably be able to see the format loss, be it analog or digital.

"Alt Preset Standard" For Video

Reply #3
DVD is not transparent. Most source material is compressed. Unless you're working from a transparent source, transparency is impossible.

What is transparency?

The way we use the word "transparent" here, its meaning is "indistinguishable from the original". Transparency is achieved when there are no perceivable differences between two things (video files, in this case). For such a comparison, the "original" source can be whatever you like, and an encoded file can be transparent for this source. You can say a DVD is original, and the encoded file can be transparent for this DVD. The DVD surely is not transparent in comparison to the film roll, and the film roll surely is not transparent compared to reality.

Same goes for audio: Many people say a Vorbis file at Q5 or 6 is transparent to them. They compared it to an audio CD and couldn't hear differences. But the CD is a downsampled version of the studio recording, which itself is a digitized excerpt from reality, nonetheless they call it "original".

The decision whether something is transparent or not is totally independent on the source, yet it is totally limited to it.
Nothing is impossible if you don't need to do it yourself.

"Alt Preset Standard" For Video

Reply #4
I have been encoding video backups for a long time, but ever since I discovered LAME and APS for audio, I have been somewhat ticked that bitrate calculation by final file size is the only way to encode video. Since most video encoding is done ABR, it takes quite some experience to "just know" what bitrate to manually use. Therefore, being new to x264, bitrate calculation by final file size is the only viable option for me.

Here is my question. I am wondering why there is no STANDARD out there for video as there is for audio. Why isn't there a transparent-to-most-people, makes-most-efficient-use-of-bits, VBR video encoding option out there? (As there is for audio.)


I think that the answer to your question is inside your same post. There's no standard for this kind of video encoding because the user always have to change the bitrate according to 2 main elements: the final size of the video and the different lenght of each movie/backup.

A "video standard" will have to adapt and vary the settings everytime according to those 2 elements and, in my opinion, a standard cannot be reached this way because the results will vary from time to time.
[ Commodore 64 Forever...! ]

"Alt Preset Standard" For Video

Reply #5
...lack of models?...

"Alt Preset Standard" For Video

Reply #6
as most (by far) users think "I want this video to fit perfectly on a CD/DVD/Zip Disk/whatever".


Only because up till recently you would put your movie on one (or more cd's). Just think back to the vcd/svcd days when most people did not have dvd burners. The whole "let's fit the entire movie on a cd-rom" philosophy goes back to this time imo. This was the time of affordable standalone dvd-players which could also read cd-roms, remember!

why not put 2 or 3 movies on one dvd-r? Or, with recent devices you can just stream it from your hard-disk. This way you are no longer constrained by limited space on your storage medium.

IMO it makes a lot more sense to encode to a quality level. In the video encoding world people just seem to be brainwashed into squeezing it on a cd-rom.

Remember, back in the days when I used svcd to make dvd backups, you could already encode to a constant quantizer. This was a popular way to to svcd backups but strangely enough mpeg-4 encoding never seemed to attempt this. The notable exception is xvid which allows you to encode to a quality level but it's poorly documented and seems to be generally frowned upon.

For those who absolutely need to use a fixed-size encoding, I ask you: how do you know whether your encode will look good enough or that you needed to use an additional cd-rom? You cannot watch and check every movie completely on a high quality screen all the time!

"Alt Preset Standard" For Video

Reply #7
Here's a thought...

lame aps averages about what? 5:1 compression compared to the source?

5:1 compression for raw video gives you 54Mbps!

(Interestingly, the BBC use 50Mbps MPEG-2 for their playout servers).

Cheers,
David.

"Alt Preset Standard" For Video

Reply #8
Just think back to the vcd/svcd days when most people did not have dvd burners.

I don't have to think far back, because this is still the case. I know some people who don't even have a DVD drive at all.

What video compression tries to achieve is a backup that's as easy to distribute as possible (Arrr, thar be pirates!) while maintaining a good-enough quality. For easy distribution, you are bound to fixed media sizes. So perfect space occupation is far more important than a constant high quality level.
(Note: That's not my own opinion, but what I presume the video encoding "scene"'s is.)

Luckily, audio compression does not have many space limitations. It can combine ease of distribution and a very high quality level. But I'm sure that when a CD-R could only hold about 70 MBytes, we'd see tons of multi-pass ~120 kbit/s ABR audio encodings.
Nothing is impossible if you don't need to do it yourself.

"Alt Preset Standard" For Video

Reply #9
What video compression tries to achieve is a backup that's as easy to distribute as possible (Arrr, thar be pirates!) while maintaining a good-enough quality. For easy distribution, you are bound to fixed media sizes. So perfect space occupation is far more important than a constant high quality level.
(Note: That's not my own opinion, but what I presume the video encoding "scene"'s is.)

There's a major transition underway in terms of the demographic of people who have an interest in DVD transcoding.

Previously as you said, most of the folks ripping DVDs were interested in piracy of some sort.  Now with the advances made in x264, new container formats, and the explosion of cheap, easy media server devices, more and more people are seeing the benefits of ripping their DVD collections to disk.

Projects like MythTV.org bring universal media serving in a user-friendly interface to the masses.

 
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