Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > (HD) DVD, Blu-ray & (S)VCD > DVD & BD Rebuilder

Reply
 
Thread Tools Search this Thread Display Modes
Old 1st May 2017, 13:20   #25881  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
There is no such thing as lossless recoding.
Actually there is. It's typically huge, but you can use a lossless setting in X264 and get an exact duplicate of the original in which the rendered picture will match bit-for-bit. There are also several lossless codecs that will do the same.
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net
jdobbs is offline   Reply With Quote
Old 1st May 2017, 13:25   #25882  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
Originally Posted by Lathe View Post
How then does TSMuxer allow you to change the frame rate for the video track when it is simply remuxing the file...?
I think he's talking about changing the framerate but staying temporally accurate. You can change the frame rate without reencoding by only changing the internal flags (that indicate framerate) -- but (unless it is using pulldown flags and you're doing iVTC) the video will speed up or slow down and not be accurate temporally.

In telecining the video is actually 23.976fps (24fps)... and then pulldown flags are used to repeat fields and a new frame is generated for every 4 that actually exists during playback. In simple iVTC you can just reset those flags and the result comes out at the original frame rate. Telecining was created so that 24fps films could be easily converted to NTSC (29.97fps) for broadcast.

Pulldown flags can also be used for other conversions (like PAL->NTSC or FILM->PAL) but you don't see that as often.
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net

Last edited by jdobbs; 1st May 2017 at 13:33.
jdobbs is offline   Reply With Quote
Old 1st May 2017, 21:36   #25883  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
Actually there is. It's typically huge, but you can use a lossless setting in X264 and get an exact duplicate of the original in which the rendered picture will match bit-for-bit.
Then just copy the original video file.
MrVideo is offline   Reply With Quote
Old 1st May 2017, 21:41   #25884  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
In telecining the video is actually 23.976fps (24fps)... and then pulldown flags are used to repeat fields and a new frame is generated for every 4 that actually exists during playback. In simple iVTC you can just reset those flags and the result comes out at the original frame rate.
The only service that I know of that uses pulldown flags is HBO.
MrVideo is offline   Reply With Quote
Old 1st May 2017, 21:56   #25885  |  Link
Sharc
Registered User
 
Join Date: May 2006
Posts: 3,997
Quote:
Originally Posted by MrVideo View Post
Then just copy the original video file.
And how to convert the format by just copying?
Sharc is offline   Reply With Quote
Old 1st May 2017, 22:40   #25886  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by Sharc View Post
And how to convert the format by just copying?
You can't convert the format and have a bit-for-bit copy. Maybe our ideas of what a format change is, is a little different.
MrVideo is offline   Reply With Quote
Old 1st May 2017, 23:16   #25887  |  Link
Sharc
Registered User
 
Join Date: May 2006
Posts: 3,997
Quote:
Originally Posted by MrVideo View Post
You can't convert the format and have a bit-for-bit copy. Maybe our ideas of what a format change is, is a little different.
I think our ideas of "lossless compression" are different.
The comparison is after decoding, i.e. after reconstruction of the original data.

Last edited by Sharc; 1st May 2017 at 23:25.
Sharc is offline   Reply With Quote
Old 2nd May 2017, 00:34   #25888  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by Sharc View Post
I think our ideas of "lossless compression" are different.
The comparison is after decoding, i.e. after reconstruction of the original data.
It therefore cannot be lossless. As soon as you decode the video, it is turned into raw video. When you then run it through a MPEG-2, H.264 or H.265 encoder, it is compressed. Especially at the bitrates that we typically use.

An example of a lossless compressor is a program that produces TIFF images. MPEG-2, H.264 or H.265 encoders are lossy.

Take a look at: http://stackoverflow.com/questions/7...ss-video-codec

Google lossless video encoder for more places to look.
MrVideo is offline   Reply With Quote
Old 2nd May 2017, 01:43   #25889  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
Originally Posted by MrVideo View Post
The only service that I know of that uses pulldown flags is HBO.
Well, that, and pretty much every DVD that has ever been encoded for US distribution. That's millions...
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net

Last edited by jdobbs; 2nd May 2017 at 01:53.
jdobbs is offline   Reply With Quote
Old 2nd May 2017, 01:44   #25890  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
Originally Posted by MrVideo View Post
You can't convert the format and have a bit-for-bit copy. Maybe our ideas of what a format change is, is a little different.
Listen, I know you think you know what you're talking about -- but you're completely wrong. What, exactly, do you think "lossless" means? It means no loss.
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net
jdobbs is offline   Reply With Quote
Old 2nd May 2017, 01:48   #25891  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
Originally Posted by MrVideo View Post
You can't convert the format and have a bit-for-bit copy. Maybe our ideas of what a format change is, is a little different.
Yes. You can. It's completely silly to say otherwise and just shows that you don't understand how it works. I'm sorry -- but that is a fact.

Example: You display the individual frames and save them with no encoding. Is that not lossless? When you look at the frames after encoding it will match bit-for-bit. Now -- use a lossless encoding method (there are hundreds of them) -- when it recreates the image it is EXACTLY THE SAME BIT-FOR-BIT PICTURE as the original.

Just because you don't understand something doesn't make it any less a fact. H.264, MPEG-2, etc are not typically lossless. But there are many, many encoding methods that reduce size without losing a single bit. When you zip a file, do you expect the same output as input? Yes, because a zip uses lossless compression. There are also video codecs that use lossless compression methods that are designed specifically for video.
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net

Last edited by jdobbs; 2nd May 2017 at 02:00.
jdobbs is offline   Reply With Quote
Old 2nd May 2017, 01:49   #25892  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
Quote:
Originally Posted by Sharc View Post
I think our ideas of "lossless compression" are different.
The comparison is after decoding, i.e. after reconstruction of the original data.
A true lossless encoding doesn't change the original. It is an EXACT duplicate. That's the whole purpose of lossless encoding -- it has no changes between encoding generations. You could do 9000 generations and have absolutely no difference between the original and the 900th encode. I'm not talking about "almost lossless" I mean lossless. You'd probably also find that the intermediate (compressed) files are exact duplicates as well.
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net

Last edited by jdobbs; 2nd May 2017 at 02:02.
jdobbs is offline   Reply With Quote
Old 2nd May 2017, 04:10   #25893  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
Well, that, and pretty much every DVD that has ever been encoded for US distribution. That's millions...
I said service. DVD releases are not a service.
MrVideo is offline   Reply With Quote
Old 2nd May 2017, 04:14   #25894  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
Listen, I know you think you know what you're talking about -- but you're completely wrong. What, exactly, do you think "lossless" means? It means no loss.
Exactly. Yet, posters seem to think that they can get lossless recoding using H.264, which is defined as a lossy codec.
MrVideo is offline   Reply With Quote
Old 2nd May 2017, 04:30   #25895  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
Example: You display the individual frames and save them with no encoding. Is that not lossless? When you look at the frames after encoding it will match bit-for-bit. Now -- use a lossless encoding method (there are hundreds of them) -- when it recreates the image it is EXACTLY THE SAME BIT-FOR-BIT PICTURE as the original.
Yes, using a lossless encoder. We are talking about MPEG-2, H.264 and H.265 encoders. You can't burn lossless encoder output to a Blu-ray using BD-RB. Lossy encoders cannot create lossless output. That is the point I've been trying to make. While you can set the encoders to be as near lossless (not truly lossless), it can create unmanageable file sizes.
Quote:
Just because you don't understand something doesn't make it any less a fact. H.264, MPEG-2, etc are not typically lossless. But there are many, many encoding methods that reduce size without losing a single bit. There are also video codecs that use lossless compression methods that are designed specifically for video.
See above about using lossless encoders by users of BD-RB.

I do understand what I am talking about. I just do not seem to be getting the info across.
MrVideo is offline   Reply With Quote
Old 2nd May 2017, 04:50   #25896  |  Link
jdobbs
Moderator
 
Join Date: Oct 2001
Posts: 20,973
You will also note that X264 has a lossless mode.
Quote:
Lossy encoders cannot create lossless output. That is the point I've been trying to make.
You're misrepresenting your position. Your statement quoted exactly was
Quote:
There is no such thing as lossless recoding. Any time a video is recoded, there are digital losses.
That statement was wrong, no matter how hard to try to change it or its intent.
Quote:
Quote:
Originally Posted by jdobbs View Post
In telecining the video is actually 23.976fps (24fps)... and then pulldown flags are used to repeat fields and a new frame is generated for every 4 that actually exists during playback. In simple iVTC you can just reset those flags and the result comes out at the original frame rate.
The only service that I know of that uses pulldown flags is HBO.
Quote:
I said service. DVD releases are not a service.
Why would you respond to my post talking just about "service" when you know the description is accurate in response to the original subject of how framerate can be changed in a video file without changing the underlying video. Sounds to me, again, like you're trying to misrepresent the intent of your post in order to attempt to be "right". Why even post a response at all?
__________________
Help with development of new apps: Donations.
Website: www.jdobbs.net

Last edited by jdobbs; 2nd May 2017 at 05:09.
jdobbs is offline   Reply With Quote
Old 2nd May 2017, 05:13   #25897  |  Link
AmigaFuture
Registered User
 
AmigaFuture's Avatar
 
Join Date: Apr 2003
Location: Within the main Source.
Posts: 895
Quote:
Originally Posted by MrVideo View Post
There is no such thing as lossless recoding. Any time a video is recoded, there are digital losses. Depending on the bitrate involved, the loss can be so subtle that the viewer cannot see it. But, each and every re-encoding results in added digital artifacts. Initially, the broadcast industry was kinda worried about the re-encoding that goes on from the production stage up thru the broadcast stage. But, that point is kinds moot now that the video that is broadcast (OTA/cable/DBS) is so bit starved that it can look horrible.
CloneDVD 2 with DVD DL active will pass the video/audio through (lossless) and remove Layer Break as well as languages if you choose. I usually don't, I allow other software to remove it. But for ripping, it's a nice GUI.

Quote:
You also cannot have something re-encoded and have it "look better" than the original. It is impossible to create something from nothing. It it like those TV shows where a still image, or surveillance video, is "enhanced" to get a sharp clear image. A crappy pixel image is going to stay a crappy pixel image.
I wasn't meaning it would look better. I meant that I can see the difference in rerendering in transcoding and higher quality. Many people I know don't see it, but I do. Upscaling a video can look really good, but I do agree...not better than the original. Some Star Trek TNG is showing through Cable and they've "upscaled" the video some, and I can see the "fuzziness" but I like the show..so I "ignore it", haha.

Quote:
When you re-encode from 59.94 fps to 29.97 fps, one of two things has to happen: 1) every other frame is dropped, or 2) two consecutive frames are blended together to create a single frame. You didn't say why you want to go to 29.07 fps, instead of keeping the original 59.94 fps video.
File size for storage and making disks...or discs. Also, sometimes, for keeping it closer to "original" framerates. But TV shows I'm starting to think..if it's 59.94 then just remove the commercials and it's in great quality since it IS from TV and they aren't using Blu-ray or HD great quality. That's saved for the series/moves we buy.

The general rule of thumb is that when you re-encode, in order to reduce the added artifacts, is to have at least a 2:1 bitrate difference. That means if the resulting bitrate is 10 Mbps, the source bitrate needs to be 20 Mbps, or more. Keep in mind that 20 Mbps MPEG-2 video is approximately equal to H.264 video at 40 Mbps. So, recoding 10 Mbps MPEG-2 video to 10 Mbps MPEG-2 video does nothing but add digital artifacts. It will not result in a better looking video. Recoding from 10 Mbps MPEG-2 video to 10 Mbps H.264 video will result in fewer digital artifacts due to the 2:1 ratio and the better H.264 encoder. But, in all cases, the resultant recoded video will not look better than the original.[/QUOTE]

Argh, that 2:1 stuff is still very confusing to me. I under 4:3 is SD and 16:9 is Letterbox or HD...but otherwise...

I don't think I'll ever be a fan of MiB and Mbps. I still love and understand MB and KB or Kb. But I get your idea. :-)
__________________
Life is not a journey to the grave; but rather to skid out broadside, thoroughly used, torn and warn and loudly proclaim; WOW; What a ride!!! Soon, I'm going to do it AGAiN in different skin!!
AmigaFuture is offline   Reply With Quote
Old 2nd May 2017, 05:18   #25898  |  Link
AmigaFuture
Registered User
 
AmigaFuture's Avatar
 
Join Date: Apr 2003
Location: Within the main Source.
Posts: 895
Quote:
Originally Posted by jdobbs View Post
Actually there is. It's typically huge, but you can use a lossless setting in X264 and get an exact duplicate of the original in which the rendered picture will match bit-for-bit. There are also several lossless codecs that will do the same.
Okay!! Ahhh, yeah, this I have read and I have used them some years ago. They are uncompressed images. Thanks, JD, I knew I remembered correctly. Like BMP can be compressed or not, same as the old IFF format the Amiga used to name a couple. Indeed, very large. A lot of people don't know what compression is that I know. When I talk about it I'm usually asked what it means. I don't go into the details that MrVideo does but it gets it across.
__________________
Life is not a journey to the grave; but rather to skid out broadside, thoroughly used, torn and warn and loudly proclaim; WOW; What a ride!!! Soon, I'm going to do it AGAiN in different skin!!
AmigaFuture is offline   Reply With Quote
Old 2nd May 2017, 06:06   #25899  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by jdobbs View Post
You will also note that X264 has a lossless mode.
I admit that I didn't know that x264/ffmpeg had a lossless mode. I found the following in the ffmpeg site:
[code]Note that lossless output files will likely be huge, and most non-FFmpeg based players will not be able to decode lossless, so if compatibility or file size issues you should not use lossless. If you're looking for an output that is roughly "visually lossless" but not technically lossless use a -crf value of around 17 or 18 (you'll have to experiment to see which value is acceptable for you). It will likely be indistinguishable from the source and not result in a huge, possibly incompatible file like true lossless mode.[/quote]

A lot of my wording indeed left a lot to be desired. Posts, not just by me, went astray from just changing the frame rate.

I got the impression from posts that usable lossless output could be created for use with BD-RB, or at least desired. Yes, I did not include DVD sources. I limited responses to HD sources and should have said so.

For files that members want to change from 29.97 to 23.976 that do not have pulldown flags (a majority of MPEG-2/H.264 HD videos), lossless recoding is not really a choice. The files will be way too large and more-than-likely not playable. Most certainly can't be burned to Blu-ray by BD-RB, as is.

So, in a broad sense, the way HD videos are used with BD-RB, lossless recoding doesn't exist. As noted in the above quote, "visually lossless" output is very possible. I do it all the time.

Time to move on. We've each made our points.
MrVideo is offline   Reply With Quote
Old 2nd May 2017, 06:15   #25900  |  Link
MrVideo
Registered User
 
MrVideo's Avatar
 
Join Date: May 2007
Location: Wisconsin
Posts: 2,129
Quote:
Originally Posted by AmigaFuture View Post
Argh, that 2:1 stuff is still very confusing to me. I under 4:3 is SD and 16:9 is Letterbox or HD...but otherwise...
Ah, but there is 4:3 HD. Your ST:TNG mention is a prime example. They went back to the original film negatives and rescanned for HD. While the actual video that is displayed is 16:9, the 4:3 content is pillarboxed within the 16:9 frame.

BTW, the 2:1 ratio tends to be moot at extremely high bit rates.
MrVideo is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 09:02.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.