Variable or Constant Framerate?

[enim]

While players will handle the variable framerate and play it back properly, if you use timing sensitive software like Adobe Premiere, your audio and video will desync and it's maddening to work with variable framerate videos because of the sync problems.

With VFR av-sync is biggest issue plus most of professional editors do not like it.

[OnlySublime]

is there a solution for converting these variable framerate videos so that I can work with them without losing a lot of quality?

[kes1802]

I had my first bad experience with variable framerate videos. Do not encode with variable framerate!

While players will handle the variable framerate and play it back properly, if you use timing sensitive software like Adobe Premiere, your audio and video will desync and it's maddening to work with variable framerate videos because of the sync problems.

Software players may handle and play variable framerate properly but NOT all hardware based media players will. Variable framerate screw stuff up so much I don't know why people use it. Or is it the they don't know how to constant framerate? So far I've not seen anyone defend variable framerate and provide good reasons for using it, so I agree with you 100% OnlySublime "Do not encode with variable framerate".

[hello_hello]

So far I've not seen anyone defend variable framerate and provide good reasons for using it, so I agree with you 100% OnlySublime "Do not encode with variable framerate".

I don't use VFR myself as I use an AVISynth based encoder GUI, but when it comes to NTSC stuff.... it seems it's not uncommon for it to be a hybrid of "film" and "NTSC", where parts of it are 23.976fps and parts 29.970fps etc, which means one of them needs to be converted to a different frame rate. So for NTSC stuff I can see the logic being encoding it "as-is"..... but then for video like that I guess you could argue it's more a combination of two different constant frame rates.

[hello_hello]

is there a solution for converting these variable framerate videos so that I can work with them without losing a lot of quality?

If the source is MKV you can re-encode it as though it's constant frame rate, then use the video timecodes from the source MKV as the timecodes for the encoded version, effectively changing it back to the same variable frame rate, but if you're wanting to edit the video, even that probably wouldn't work as you'd have audio sync issues.
I son't use Adobe Premiere so have no idea what it can and can't do, but possibly the best bet would to be convert the video to a constant frame rate while re-encoding it losslessly. You'll end up with a large file, but then you should be able to edit it and re-convert it without two losses of quality due to re-encoding.

What type of source video are you working with?

[kes1802]

So far I've not seen anyone defend variable framerate and provide good reasons for using it, so I agree with you 100% OnlySublime "Do not encode with variable framerate".

I don't use VFR myself as I use an AVISynth based encoder GUI, but when it comes to NTSC stuff.... it seems it's not uncommon for it to be a hybrid of "film" and "NTSC", where parts of it are 23.976fps and parts 29.970fps etc, which means one of them needs to be converted to a different frame rate. So for NTSC stuff I can see the logic being encoding it "as-is"..... but then for video like that I guess you could argue it's more a combination of two different constant frame rates.

Your use of "hybrid" here refers to a program (or so the links takes us) rather than a mix of two frame rates so I don't see its relevance here.

[hello_hello]

I didn't convert the word "hybrid" to a link. The forum did that automatically. I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts.... but I guess on the odd occasion it can lead to confusion.

[Cornucopia]

So far I've not seen anyone defend variable framerate and provide good reasons for using it, so I agree with you 100% OnlySublime "Do not encode with variable framerate".

I don't use VFR myself as I use an AVISynth based encoder GUI, but when it comes to NTSC stuff.... it seems it's not uncommon for it to be a hybrid of "film" and "NTSC", where parts of it are 23.976fps and parts 29.970fps etc, which means one of them needs to be converted to a different frame rate. So for NTSC stuff I can see the logic being encoding it "as-is"..... but then for video like that I guess you could argue it's more a combination of two different constant frame rates.

Occurrences such as this can either be attributed to users/apps misinterpreting a cfr but soft-telecined source, or to sloppiness/incompetence on the part of the encoding producer, whether hobbyist or professional.

The ONLY semi-legit instance I have seen of vfr has been from smartphone captures, and even then I believe there are likely (better) cfr options available.

Scott

[hello_hello]

Occurrences such as this can either be attributed to users/apps misinterpreting a cfr but soft-telecined source, or to sloppiness/incompetence on the part of the encoding producer, whether hobbyist or professional.

No doubt that's all true, but I live in PAL-land and I'm sure I've come across several NTSC DVD videos containing mixed frame rates. It might only be the opening credits vs the actual content, that sort of thing, and because I live in PAL-land I'm struggling to come up with a specific example..... although I recall one problem DVD..... I'll check it later. In the mean time, from the AVIsynth VFR page:
http://avisynth.org/mediawiki/VFR#Variable_framerate_and_hybrid_video
"Examples of hybrid video include many of the modern anime TV Series, many of the Sci-Fi TV Series (such as Stargate: SG1, Star Trek: TNG, and Babylon 5), and many of the "Making Of" documentaries included on DVD."
Actually that's another one I could check.... the extras on the Terminator (TV Series) DVDs were fairly hybrid if I remember correctly.
I guess as DVD players seem to handle mixed frame rates without issue, using them for one reason or another mightn't be considered" bad" by those responsible for a DVD's creation.

On the subject of frame rates, while I'm thinking about it, DGIndex has a "force film" option where if X% of a video is film, it'll treat the rest as film. I think many encoder GUI's use a force film threshold of around 95%. I understand what force film does, but I've never got the point of it. Why not process 100% of the video correctly?
Once of my early ventures into NTSC conversion had me banging my head against the desk. I eventually discovered, when force film is used, DGIndex writes the index file differently and always outputs 23.976. So I could see the bits which weren't right but thought I must be somewhat mentally challenged when nothing I added to a script would fix it, and after analysing the video the GUI kept insisting it was pure film. Eventually I worked out what was going on and created a new index file and from there all was right with the world again, but ever since then I've wondered about the benefit of using "force film".

[kes1802]

I didn't convert the word "hybrid" to a link. The forum did that automatically. I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts.... but I guess on the odd occasion it can lead to confusion.

So your "hybrid" refers to the program and not a mix of frame rates and therefore still irrelevant.

[hello_hello]

It's the forum converting it to a link, not me. I would have thought, after explaining why it's a link, it'd go without saying the program called "hybrid" isn't relevant to the discussion. In case it doesn't go without saying either, the word "hybrid" is because yes, I was referring to a mix of frame rates.

[kes1802]

Oops double post....

[kes1802]

It's the forum converting it to a link, not me. I would have thought, after explaining why it's a link, it'd go without saying the program called "hybrid" isn't relevant to the discussion. In case it doesn't go without saying either, the word "hybrid" is because yes, I was referring to a mix of frame rates.

I know why it is a link but you said " I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts" without saying that in this case it was wrong and that you did not mean to refer to a program. Nothing goes without saying if you don't say it which in this case you didn't. I'm not a mind-reader, I read what is written. The edit button is always available to you to change something, including what is done automatically, to make sure that a post is clear which your post certainly wasn't.

[manono]

I'm not a mind-reader, I read what is written. The edit button is always available to you to change something, including what is done automatically, to make sure that a post is clear which your post certainly wasn't.

What he said was perfectly clear and it's obvious he wasn't referring to a program completely unrelated to a discussion of mixed framerates and you're just being silly by belaboring the point when you have no point to make to begin with.

[hello_hello]

I know why it is a link but you said " I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts" without saying that in this case it was wrong and that you did not mean to refer to a program.

I was trying to avoid insulting you with a statement of the excruciatingly obvious. I said I didn't create the link, you're apparently aware the forum does it automatically, yet here you are still arguing I didn't make it clear enough I hadn't meant to refer to a program.

The edit button is always available to you to change something, including what is done automatically, to make sure that a post is clear which your post certainly wasn't.

Twaddle. I wrote: "it seems it's not uncommon for it to be a hybrid of "film" and "NTSC". Seriously, how could "hybrid" in that context be referring to an encoding program? If I'd said "it seems it's not uncommon for it to be a Handbrake of "film" and "NTSC", or "it seems it's not uncommon for it to be a MeGUI of "film" and "NTSC", or, "it seems it's not uncommon for it to be a Staxrip of "film" and "NTSC", it'd make no sense, yet apparently "a hybrid of "film" and "NTSC" is more likely to refer to a program than not.
I've no idea why it's called common sense when experience tells me not only isn't it very common, it's actually fairly rare.

[kes1802]

I'm not a mind-reader, I read what is written. The edit button is always available to you to change something, including what is done automatically, to make sure that a post is clear which your post certainly wasn't.

What he said was perfectly clear and it's obvious he wasn't referring to a program completely unrelated to a discussion of mixed framerates and you're just being silly by belaboring the point when you have no point to make to begin with.

Sorry it was not clear to me until he, AT LAST, said he was NOT referring to a program. Up until that point it read as if he was. Maybe you can read his mind but I can't, won't try and read only what is written. I consider it silly for you to expect me to do something other than just read what he has written.

[kes1802]

I know why it is a link but you said " I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts" without saying that in this case it was wrong and that you did not mean to refer to a program.

I was trying to avoid insulting you with a statement of the excruciatingly obvious. I said I didn't create the link, you're apparently aware the forum does it automatically, yet here you are still arguing I didn't make it clear enough I hadn't meant to refer to a program.

The edit button is always available to you to change something, including what is done automatically, to make sure that a post is clear which your post certainly wasn't.

Twaddle. I wrote: "it seems it's not uncommon for it to be a hybrid of "film" and "NTSC". Seriously, how could "hybrid" in that context be referring to an encoding program? If I'd said "it seems it's not uncommon for it to be a Handbrake of "film" and "NTSC", or "it seems it's not uncommon for it to be a MeGUI of "film" and "NTSC", or, "it seems it's not uncommon for it to be a Staxrip of "film" and "NTSC", it'd make no sense, yet apparently "a hybrid of "film" and "NTSC" is more likely to refer to a program than not.
I've no idea why it's called common sense when experience tells me not only isn't it very common, it's actually fairly rare.

Because you said links referring to programs was a good idea but failed to say that in this instance that was not the case. You may be clear in what you wanted to say but you did not write it clear.

Your "if I said" is totally irrelevant as that is NOT what you said. You left you post referring to a program which you now say had nothing to do with what you were talking about. If that is the case why didn't you edit your post so that was made clear. Even your second post after I queried "the link" STILL did not say that the link was irrelevant leaving even more confusion on my part. You are now trying to justify your posts with utter nonsense rather than simply apologize for the confusion you caused.

As I now at last understand what it is that you were trying to say and that it HAD nothing to do with a program I see no need to continue this discussion.

[hello_hello]

I'm starting to think sometimes people put their common sense neural pathways to so little use, the brain must eventually decommission them and replace them with neural pathways for something else. Creating forum signatures with maximum irony seems to be one possibility.

You are now trying to justify your posts with utter nonsense rather than simply apologize for the confusion you caused.

Did I mention I didn't create the link? I think I might have. On behalf of the videohelp forum I apologise for forum software incapable of checking the context of every word it automatically converts to a link, and specifically for the amount of confusion it caused you as a result.

[kes1802]

I'm starting to think sometimes people put their common sense neural pathways to so little use, the brain must eventually decommission them and replace them with neural pathways for something else. Creating forum signatures with maximum irony seems to be one possibility.

Ditto ditto for those who fail to write properly so people don't understand and then try to justify it with further nonsense.

You are now trying to justify your posts with utter nonsense rather than simply apologize for the confusion you caused.

Did I mention I didn't create the link? I think I might have. On behalf of the videohelp forum I apologise for forum software incapable of checking the context of every word it automatically converts to a link, and specifically for the amount of confusion it caused you as a result.

No need to apologize to the forum software it was only doing its job. You could have edited the mistake it made and turned off the automatic creation of link. Or are you saying that the software is supposed to be more intelligent than you. The software made no confusion to me, your inability to use it correctly did.

[_Al_]

My English suck, I need to read things more than once sometimes, but that original hello_hello reaction was clear as a day to me, meaning that word h y b r i d he used had nothing to do with h y b r i d software. It is pretty stupid to drag this along as if it was his fault or that he did not fix it. He did. His last appology was ironic btw.

This automatic hyper link putter is restless , I interlace a spaces there but anyway it insists to include that link there ...

[kes1802]

My English suck, I need to read things more than once sometimes, but that original hello_hello reaction was clear as a day to me, meaning that word h y b r i d he used had nothing to do with h y b r i d software. It is pretty stupid to drag this along as if it was his fault or that he did not fix it. He did. His last appology was ironic btw.

This automatic hyper link putter is restless , I interlace a spaces there but anyway it insists to include that link there ...

Not until hello_hello's third post did he state clearly that the word "hybrid" had nothing to do with software. Turning off links is a simple click on the edit page. So simple any idiot can do it. But it seems too hard for some.

[_Al_]

you seem to have problem that nobody else does ...

[kes1802]

I didn't convert the word "hybrid" to a link. The forum did that automatically. I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts.... but I guess on the odd occasion it can lead to confusion.

Explain to me where/how the above states that the linked word hybrid should not have been a link but just a word. All I can see is praise to the software for doing it and a statement about confusion that leads me to more confusion especially as "hybrid" is STILL linked.

[hello_hello]

Or are you saying that the software is supposed to be more intelligent than you. The software made no confusion to me, your inability to use it correctly did.

No, but apparently you're no more intelligent than the software. It hasn't been written to examine the context in which words are used before converting them to links, just as you're apparently unable to look at a linked word in context and decide for yourself whether it's likely the software's automated process got it wrong, no matter how painfully obvious it might be.

I didn't convert the word "hybrid" to a link. The forum did that automatically. I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts.... but I guess on the odd occasion it can lead to confusion.

Explain to me where/how the above states that the linked word hybrid should not have been a link but just a word. All I can see is praise to the software for doing it and a statement about confusion that leads me to more confusion especially as "hybrid" is STILL linked.

When I replied to your first post, the forum "incorrectly" converted the same word to a link again, yet not only did the penny still fail to drop, an exact repetition of the forum software's behaviour only managed to increase your confusion? It's almost hard to believe.

I'm really starting to think there must be something wrong with you. You stated "my use" of the linked word referred to a program without first ensuring you had your facts straight. I corrected you, twice. It wasn't my use of the link. If you required specific information to end your confusion you should have asked a specific question instead of making a statement and then complaining when the reply didn't have the level of clarity you obviously require.

[kes1802]

Or are you saying that the software is supposed to be more intelligent than you. The software made no confusion to me, your inability to use it correctly did.

No, but apparently you're no more intelligent than the software. It hasn't been written to examine the context in which words are used before converting them to links, just as you're apparently unable to look at a linked word in context and decide for yourself whether it's likely the software's automated process got it wrong, no matter how painfully obvious it might be.

I didn't convert the word "hybrid" to a link. The forum did that automatically. I think it's a fairly good idea.... the automatic creating of links to programs mentioned in posts.... but I guess on the odd occasion it can lead to confusion.

Explain to me where/how the above states that the linked word hybrid should not have been a link but just a word. All I can see is praise to the software for doing it and a statement about confusion that leads me to more confusion especially as "hybrid" is STILL linked.

When I replied to your first post, the forum "incorrectly" converted the same word to a link again, yet not only did the penny still fail to drop, an exact repetition of the forum software's behaviour only managed to increase your confusion? It's almost hard to believe.

I'm really starting to think there must be something wrong with you. You stated "my use" of the linked word referred to a program without first ensuring you had your facts straight. I corrected you, twice. It wasn't my use of the link. If you required specific information to end your confusion you should have asked a specific question instead of making a statement and then complaining when the reply didn't have the level of clarity you obviously require.

And you're not intelligent enough to edit your post and correct the forum software mistake. And now it is MY job to spend time and decipher what has been written by you rather than you write it properly. A bad workman always blames his tools. All I ever did was ask for clarification. The clarification was still unclear to me so I asked for further clarification. This has obviously got you riled as you've been nothing but rude ever since trying desperately to justify why I should have understood your confusing messages.


As for the second part you have explained nothing. You have not answered the question. You are being evasive just as you were in your second post. It was "your use" of the link. The post was written by YOU. The forum software made an edit to YOUR post. The post still remained YOURS. You failed to notice that the edit was inappropriate and change it so that YOUR post was clear. My facts were perfectly clear. The post was yours and yours alone. It was not written by the forum software but merely edited by it as a means to, hopefully, enhance what had been written. In this case it was wrong and you have failed continually to see that and correct its mistake which takes but a few clicks. Rather than do that you blame the software. You have still failed to explain how your second post clearly states that you were not referring to hybrid as a program especially when you give praise the the software for adding the link.

It is the rudeness of your third post that is the cause of all this to and fro. I had been nothing but polite in my first and second requests for clarification. Clarification which I feel justified in requesting as I try and understand what you are saying. Obviously two requests was one to many for you and you started to be rude saying that I should have realized what you were saying. Saying that it was obviously clear. Well it wasn't. If it had been I'd not have asked for clarification. You continually blame of the software for making the confusion but fail to see that you are in control of the software.

[hello_hello]

And you're not intelligent enough to edit your post and correct the forum software mistake. And now it is MY job to spend time and decipher what has been written by you rather than you write it properly.

I don't convert the word to a link. Is there a specific way I might be able to rephrase that statement so when you read it you'll understand I didn't convert the word to a link? Because from there it'd only require a few idle neurons and one or two nanoseconds of neural pathway time to realise if I didn't create the link, it's creation couldn't have been my mistake, and if you'd consumed a little caffeine to temporarily overclock those neurons, in the same couple of nanoseconds they could extrapolate those two conclusions into a realisation I did write the post properly, but the forum software changed it a little after I submitted it.

A bad workman always blames his tools. All I ever did was ask for clarification. The clarification was still unclear to me so I asked for further clarification. This has obviously got you riled as you've been nothing but rude ever since trying desperately to justify why I should have understood your confusing messages.

No, you made a statement. You asked nothing. I replied to your statement. If you wanted a more specific clarifaction you should have asked a specific question instead of expecting a reply to an implied question would suffice. We've been through this already.

As for the second part you have explained nothing. You have not answered the question. You are being evasive just as you were in your second post. It was "your use" of the link. The post was written by YOU. The forum software made an edit to YOUR post. The post still remained YOURS. You failed to notice that the edit was inappropriate and change it so that YOUR post was clear. My facts were perfectly clear. The post was yours and yours alone. It was not written by the forum software but merely edited by it as a means to, hopefully, enhance what had been written. In this case it was wrong and you have failed continually to see that and correct its mistake which takes but a few clicks. Rather than do that you blame the software. You have still failed to explain how your second post clearly states that you were not referring to hybrid as a program especially when you give praise the the software for adding the link.

I'll give you credit for one thing. It's been a while since I've read a paragraph the length of the one above, where the combination of words forming sentences resulted in 100% twaddle from start to finish. It'd probably be fairly high grade twaddle, if the irony contamination was a little lower.
I'm fairly sure I saw the forum had created an "inappropriate" link, although it's not the first time I've used the word hybrid in a post, and I'm fairly certain it won't be the last. Whether I'd perused the post in question or not has no direct relationship to a likelihood I'd have edited it to remove the link. Either way, likelihood's value remains unchanged and steady at "none".

It is the rudeness of your third post that is the cause of all this to and fro.

That's possibly because you're not aware there were four earlier drafts of that post, and therefore don't realised how much effort went into extensive re-writing to produce the final, family friendly post ready for submission.

I had been nothing but polite in my first and second requests for clarification. Clarification which I feel justified in requesting as I try and understand what you are saying. Obviously two requests was one to many for you and you started to be rude saying that I should have realized what you were saying. Saying that it was obviously clear. Well it wasn't. If it had been I'd not have asked for clarification. You continually blame of the software for making the confusion but fail to see that you are in control of the software.

You do realise it doesn't matter how many times you refer to having asked questions or requests for clarification, it's never going to make it true? You may eventually believe that's exactly what you did, I know a few people with an almost enviable ability to live in a slightly altered version of reality, but I still marvel when posters do it given the forum itself provides a record of what really took place. That sort of commitment to ignoring reality is almost admirable.

Your first post:
"Your use of "hybrid" here refers to a program (or so the links takes us) rather than a mix of two frame rates so I don't see its relevance here. "

Number two:
"So your "hybrid" refers to the program and not a mix of frame rates and therefore still irrelevant."

Both simply statements. Both corrected in my reply to each. Not a question in sight. No direct requests for clarification to be found. If you're not happy my replies weren't statements of the obvious based on a foundation of having said everything which goes without saying, then make your requests for clarification as specific as the clarification you require. And it's just a thought, but maybe you might find the answers to your questions will be more to your satisfaction once you've err.... asked them. In my experience the asking and answering process tends to produce far more satisfactory results if kept in that order.

[Interpolator]

This is an old thread, but I wanted to chime in, because:

1. I can, and that's what threads are for.
2. The topic comes up repeatedly, and there are reasonable arguments for using both, if one understands the advantages and disadvantages.

Want a simple answer? Use a constant frame rate (CFR). Why? For most types of video and bitrates variable frame rate (VFR) rarely offers more than a trivial compression advantage and greatly increases the risk of playback and editing problems.

Want a more complex answer? Variable frame rate is a pain to deal with in most editing and transcoding tools, easily introduces audio-sync problems, and offers essentially no compression advantage at all but the lowest bitrates for modern codecs with most types of video. The very nature of video compression deals well with frames which change little or none from one frame to the next. If slightly additional compression is the goal, you're almost always better off to either use slower, more aggressive encoder settings, a slightly slower bitrate (or slightly higher quantization or constant-rate-factor setting), or some other strategy such as a better noise filter.

You can illustrate for yourself how little frame rate makes on compression easily, and it doesn't even require using variable framerate: Take almost any constant frame rate (CFR) test video (30fps, for example) and transcode it, then do the same at half the frame rate (15fps in this example), and compare file sizes. With most types of video and codecs, you'll find a difference, but it will probably surprise you at how little it is with such an extreme frame rate drop (twofold).

So when does VFR have an advantage, and how advantageous is it? At very low bitrates, particularly for realtime videoconferencing (i.e. webcams, smartphones, etc.), for some types of animation such as cartoons (including "anime") as well as things like presentations, where a significant amount of the video is a slide-show shown at full screen (such a lecture, where the presenter may be shown only a fraction of the total time).

The other times there may be a noticeable advantage is with some uncommon codecs or codec settings, particularly when there may be long static scenes (such as slide presentations).

Even these presentations and transcoding of low-bitrate conference video will likely surprise you at how minimal the VFR advantage is, because the analysis-phase of the transcoding is "smart" enough to detect duplicate frames.

So when should you use VFR for transcoding? Rarely. Almost never, and ideally only after first making a CFR transcoding to compare the difference with. If it's important enough for you to even consider using VFR, you should make a CFR version first anyways. It's probably not even worth considering except at very low bitrates that will be streamed realtime to a large audience.

If it's not for live streaming, it's arguably inconsiderate to go with VFR unless you're positive no one will edit or transcode the video later on, and positive no one will have a problem with audio-sync in their player. In other words, if you're going to share the video, it's probably a bad idea to use VFR unless you've seen a major compression advantage for your particular video when compared to the CFR version.

There can be advantages to using VFR, but it's very seldom worth it, hence the numerous passionate arguments you hear against its use. For all but a very few applications, there's almost always better ways to attain your compression goal.

[EDIT: The topics of de-interlacing, telecine, and more occasionally come up... these are separate issues, and still usually deal with CFR sources. In these cases, it's probably wisest to de-interlace separately and go with the highest CFR frame rate if you're splicing together a mish-mash of sources of varying frame-rates. There's surely exceptions here and there, but it's still seldom wise to use VFR for CFR film or television sources.

Also, some will choose to go with VFR based on some bizarre philosophical view of what moving pictures actually are... a collection of still frames that approximate varying rates of motion. This is completely true, but absolutely irrelevant, and frankly a bit silly (believe it or not, one thread commenter even used the word "zen" and suggested meditating on the matter). In these cases of a VFR source, it's probably wisest to go with either the maximum frame rate, or a close modern standard such as 24fps, 30fps or possibly even 60fps if the clip contains high-action scenes. Again, there's always exceptions for certain types of source material and end-product use; high-action video shot at 300fps for slow-mo might have a special playback purpose in mind. The key is to be damn sure your VFR advantage is worth the risk of future playback and editing problems.

Not 100% sure? Then encode two versions - CFR and VFR or don't use it. If you must, please don't share the VFR version without the CFR version.]