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[jmone]

There a many myths floating around on the net on how to "tweak" you system to get smooth video playback especially for Film derived material (eg Blu-ray).  Even though I've done it my self I'm amazed at the lengths and time we go to tweak various settings based on these myths (which inevitably results in frustration that it all "should just work").  

There have been a couple of questions recently about this topic on in the forum so I've update the following Wiki page with an extract of the Reclock Manual that explains it far better than I ever could.  Have a read --> http://wiki.jrmediacenter.com/index.php/Video_Playback_Customization

Thanks
Nathan

[gappie]

interesting wiki, nathan... thanks. ill have a play with it soon.

 
gab

[glynor]

Thanks for doing this, Nathan.  I did note one little possible error in your post, so I threw up a comment on the Discussion tab.  Might want to check it out.

FWIW... The philosophical reason that Microsoft originally chose to use the audio clock in the computer, is that audio quality is more important than video quality.  This is a well known "fact" in the industry.  Audiences will accept poor image quality (especially when done for effect, like handheld shots or DV cam footage for the "home video" look) but they will not accept poor quality audio or sync issues.  There have been a ton of studies on this very subject.

That's actually one of the reasons I don't use ReClock myself.  It messes with the audio, and I'd rather see the very occasional bout of jitter, than worry about the audio quality fluctuating all the time.  Of course, I'm in NTSC land, and the jitter problem with 24p video isn't very bad here (and if it bothers you, just upgrade to a 120hz or 240hz display and the problem will completely vanish).

The real problem in PAL land isn't 24p video (which as you mentioned, is just sped up and played at 25p), but is actually with playing NTSC video.  The pulldown pattern for displaying 29.97 progressive video (or 59.94 fields per second if interlaced) isn't a good one.

[Daydream]

Of course, I'm in NTSC land, and the jitter problem with 24p video isn't very bad here (and if it bothers you, just upgrade to a 120hz or 240hz display and the problem will completely vanish).

Correct me if I'm wrong but TV sets in Europe (say UK) have 100 / 200 / 400 MHz specs, not 120 / 240 like in US. So then what gives? I'm curious as to what happens when you play a BR there, since also the same TVs are advertised as having a 24p input.

The pulldown pattern for displaying 29.97 progressive video (or 59.94 fields per second if interlaced) isn't a good one.

This is kind of on the side but I'd like to know for sure: the abracadabra frame rates in US are (more or less) a direct consequence of the properties of the power grid used here, correct?

[gvanbrunt]

The frame rates of both NTSC and PAL are based on the frequency of the power in those areas, which are 60Hz and 50Hz repsectivly. When televisions were first invented, syncronizing frames for display was a huge problem. The simple and cheap "fix" was to use the power system itself as a clock/timer. So you are correct, that is where they come from.

[jmone]

Thanks for doing this, Nathan.  I did note one little possible error in your post, so I threw up a comment on the Discussion tab.  Might want to check it out.

Seems logical to me so I've asked the Q on the reclock forum so I'll update with what comes back.

Also, for what it's worth, there is very little video out there of any source (unless poorly encoded) that is actually 24p, 30p, or 60i. When they say that, they actually mean 23.976, 29.97, and 59.94. The only modern examples would be very old archive NTSC video from before there was color broadcast, like some of that on Archive.org and the Library of Congress site.

You are correct on the origins of 23.976, but I don't think the statement on source material is complete as there is a difference to how material is recorded vs transmitted and the techniques used, eg I'd suggest:
1) FILM based material is shot in 24p.  It may be then either
   a - slowed down to 23.976p and telecined to 29.97/59.94i for NTSC Transmission compatibility,
   b - speed up to 25p for PAL Transmission compatibility, or
   c - while it can be stored as 24p on blu-ray discs it is usually slowed down to 23.976p (for better NTSC compatibility)
2) TV based material is usually shot in 59.94i (called 60i) or 50i (eg News, TV Docos, Sport etc) and can also be stored on Blu-ray in these formats

FWIW... The philosophical reason that Microsoft originally chose to use the audio clock in the computer, is that audio quality is more important than video quality.  This is a well known "fact" in the industry.  Audiences will accept poor image quality (especially when done for effect, like handheld shots or DV cam footage for the "home video" look) but they will not accept poor quality audio or sync issues.  There have been a ton of studies on this very subject.

I love the unattributed "men in white coats" proved....."insert fact here".  Given the very specific nature of this post, let me know the actual studies that shows users preference of perceived quality in playback between:
1) Dropping / Adding Video frames to keep sycn with the Audio track (how it is done by a PC)
2) Resample Audio stream to keep sycn with the Video track (how it is done using Reclock on the PC) [/quote]

That's actually one of the reasons I don't use ReClock myself.  It messes with the audio, and I'd rather see the very occasional bout of jitter, than worry about the audio quality fluctuating all the time.

Ahhh but it does not "mess" with the Audio, it just resamples it (just like happens with the JR plugins, the mixer on your PC, your Receiver).  The two things I hate about Blu-ray has been the fight on the PC platform to get smooth jitter free video and lipsync, which lead me to this obsession!  The Video streams on these discs have 24 frames per second so 1 extra or less frame is pretty easy to see.  The sample rate for Audio on most Blu-ray disks is usually 48,000 times per second so if it is resampled at 48,040 or 47,060hz to keep pace with video do you think I'll hear the difference (reclock will even do a slight Pitch Correction)?  Note, Unlike the Video Option I'm not adding or dropping any Audio Frames - just resampling.  One thing that does get me laughing is all the effort some people appear to go to then output these HD audio over SPDIF, now how is that for "messing" with the Lossless Audio streams that are available....

Of course, I'm in NTSC land, and the jitter problem with 24p video isn't very bad here (and if it bothers you, just upgrade to a 120hz or 240hz display and the problem will completely vanish).

The ideal option is a refresh rate divisible by 24 (film), 25 (pal), and 30 (ntsc), so while 120hz is a good single refresh rate for NTSC folk, it not so good for us in PAL land and given the ability of monitors to take any frequency, you may as well switch to the one you need for the media being played.

The real problem in PAL land isn't 24p video (which as you mentioned, is just sped up and played at 25p), but is actually with playing NTSC video.  The pulldown pattern for displaying 29.97 progressive video (or 59.94 fields per second if interlaced) isn't a good one.

I think you are probably right on this, and suspect it is just what we get used to.  The original use of reclock was to play PAL encoded 25p material back to the slower original film 24p to fix the 5% audio pitch problem.  However, being brought up in a PAL contry it just sounds normal to me so hence it is not annoying.  Likewise I suspect that telecine judder is something NTSC viewers are used to and hence just don't notice, yet as a PAL'er it is noticeable to me (but your right native 60i material is not a great look at 50hz).  I'll also grant that 24p material looks much better at 60hz than 50 so noticeable judder is more pronounced for us in PAL land.

Anyway - all gets back to - if you can adjust your Monitor's frequency to that (or a multiple) of the frame rate of the media you are playing back then that is a good start.  The next bit is on what method is used (if you care) on keeping the Audio and Video in sync.

Thanks
Nathan

[glynor]

You are correct on the origins of 23.976, but I don't think the statement on source material is complete as there is a difference to how material is recorded vs transmitted and the techniques used, eg I'd suggest:
1) FILM based material is shot in 24p.  It may be then either
   a - slowed down to 23.976p and telecined to 29.97/59.94i for NTSC Transmission compatibility,
   b - speed up to 25p for PAL Transmission compatibility, or
   c - while it can be stored as 24p on blu-ray discs it is usually slowed down to 23.976p (for better NTSC compatibility)
2) TV based material is usually shot in 59.94i (called 60i) or 50i (eg News, TV Docos, Sport etc) and can also be stored on Blu-ray in these formats

I'm not done reading yet, but this is old information.

1) Most production Film cameras now shoot 23.976 native (they usually have the option to shoot either "true" 24 fps or 23.976 fps via a hardware switch).  This has been true for quite some time.  Besides, using real film is becoming rarer and rarer, and all digital cinema cameras shoot 23.976 (like the RED or ARRI's new digital cameras, for example), unless they're in a varicam type of mode for effect.  The difference between "true" 24 fps and 23.976 fps is not visible to the human eye or brain, I've watched the side-by-sides on half-million dollar digital cinema setups myself.  We're talking less than 1/100th of a second of difference.

However... It really doesn't matter, because even if it IS shot at 24fps on a film camera, it gets changed to 23.976 in the cutting room (or actually, usually on the film scanner).  It is IRRELEVANT what specific frame rate the raw footage is actually shot at, all that matters is the Post workflow, and that means 23.976.  Nothing comes out of AVID or Final Cut in "true" 24p, unless you REALLY go out of your way to do so, and that is pretty rare because it does not matter and all of the software applications are set up where 24p = 23.976 fps.

I suspect the main times when they are actually retiming 24fps to 23.976fps after the fact is when someone is actually cutting together a film with tape and film spools like the old days.  Outside of art-house stuff, this is incredibly rare anymore.

2) The vast majority of HDTV shows are now shot at 24p or 30p (29.97), except for sports (and occasionally news programs).  Almost all dramas are shot at 24p on either film, high end digital camcorders (RED/ARRI), or cameras like the Canon 5D Mark 2.  Most "reality TV" shows are shot at 30p (29.97) if destined for stateside broadcast, though even many of those are shot at 24p (Survivor is shot at 24p on Panasonic P2 Varicams).  A LOT of TV news used to be shot at 60i, but they almost always switch over to either 24p or 30p workflows when they switch to HDTV broadcast (and they use, by and large Panasonic P2 Varicams like the HVX200b or it's bigger cousins).  About the only exceptions are when things need to be captured that move VERY quickly, and you don't want to have motion blur for a film-look (usually news).

I'm just telling you... In the industry, 30p means 29.97 fps and  24p means 23.976 fps.  10-15 years ago you often had to "qualify" those statements, but over the past 5 years or so, as the digital and HD "revolution" has completed, they've become synonymous.

[glynor]

I love the unattributed "men in white coats" proved....."insert fact here".  Given the very specific nature of this post, let me know the actual studies that shows users preference of perceived quality in playback between:
1) Dropping / Adding Video frames to keep sycn with the Audio track (how it is done by a PC)
2) Resample Audio stream to keep sycn with the Video track (how it is done using Reclock on the PC)

No studies like that exist that I know of.  I'm just telling you that the "rule" in the industry is that audiences will forgive a lot of image quality sins, but they will not forgive audio issues at all.  I don't have the studies to prove that right at my fingertips (though they do exist, I've taken notes on them in class), but if you don't believe me, go to film school.  You'll learn that from literally every professor on the first day.

That would explain why Microsoft would have chosen the audio timeclock as the "authoritative" clock.  I'm not saying that decision necessarily applies anymore (the clocks in PCs are VASTLY improved from the days when the audio/visual pipeline was first designed by Microsoft), but that is probably the historical reason they made that choice.  Someone consulted with them that had worked on a film or TV set, and told the engineers that audio was more important than image quality.

Ahhh but it does not "mess" with the Audio, it just resamples it (just like happens with the JR plugins, the mixer on your PC, your Receiver).  The two things I hate about Blu-ray has been the fight on the PC platform to get smooth jitter free video and lipsync, which lead me to this obsession!  The Video streams on these discs have 24 frames per second so 1 extra or less frame is pretty easy to see.  The sample rate for Audio on most Blu-ray disks is usually 48,000 times per second so if it is resampled at 48,040 or 47,060hz to keep pace with video do you think I'll hear the difference (reclock will even do a slight Pitch Correction)?  Note, Unlike the Video Option I'm not adding or dropping any Audio Frames - just resampling.  One thing that does get me laughing is all the effort some people appear to go to then output these HD audio over SPDIF, now how is that for "messing" with the Lossless Audio streams that are available....

I understand that.  I would disagree, in principle, that it is "just resampling it".  It is doing a time-based resampling of the audio, done continuously and on the fly, in order to match it perfectly to the video time clock.  That's more complex of an adjustment than a simple bitrate resampling done by your average DSP, so equating the two operations is disingenuous.

However, I completely agree that the tiny differences introduced are not audible in the vast majority of cases.  My point is, that the tiny amount of jitter introduced once in a great while does not bother me enough to install and maintain a separate filter (especially one that was well-renowned for having issues in the past).  If it did, my solution would be to upgrade my 60Hz TV to a 120 or 240Hz TV, not to add a new filter to the chain.  (And, you must admit, that there are likely wacko edge-cases where using ReClock MIGHT mess with the audio in an audible way.  If something can be contrived to mess up the LAME encoder's algorithms, then you can almost certainly confuse the ReClock algorithms, unless they guy who designed it is the greatest engineering genius of all time.)  If I lived in PAL land, I would be singing a completely different story.  In that case (or for watching PAL sources in NTSC-land), then ReClock is the usually the best bet.

What makes me laugh is the ends that people will go to to see "perfect" video on their consumer class HDTVs.  Let me tell you a secret...  You aren't seeing anything even remotely CLOSE to the "perfect" video quality you'd see in the cutting room unless you are on a production monitor.  If you really want to see what it looks like in the cutting room, you need a very high end production-class monitor from TVLogic, Panasonic, JVC, or Sony (or actually a Barco or Christie 4k, because that's often what they use for screening anymore) with an all HD-SDI dual-link path.  The auto-sharpening and color-correction logic in the DSP in your TV is going to introduce all sorts of errors, tearing, and color shift all on it's own, and you can't turn most of that crap off, even on the best high-end consumer TVs.

Now, do I sit at home watching my latest episode of LOST on a TV Logic LUM-560W or even a $8.5k Sony LMD4250W monitor?  Heck no.  That'd be awesome, but I don't have that kind of cash for no reason (though I have been known to watch TV on my little Marshall field monitor, which is awesome).

[jmone]

Thanks Glynor -
1) I've certainly hit the edge of my understanding on the modern  production process of how film and TV is produced so will happly bow out of the discussion on this (as I said the Net is full of "facts" and I'm no different and happy to be simply wrong).  FYI for us in the PAL world "The vast majority of HDTV shows are now shot at 24p or 30p (29.97)" is actual shot in 1080/50i or 720/50p...
2) I also see the evidence that many (most?) are ambivalent on Audio quality in general (just look at iPods full of compressed music in $2 headphones, Blu-ray audio output over SPDIF etc) but I'll not guess why MS did anything in their builds much less the choice of clock.  Also regardless of the industry "rule" says Video > Audio or compromises taken in the past does not mean I don't want to maximise the best of both.
3) Resampling - If your interested the geeks over at Reclock have an ongoing thread on which of the three resamplers in Reclock you can use, their limits, audible difference, impact on CPU cycles etc etc.  I just stick to the defaults on this one, but if you want to know more that is the place.
4) The maintenance and development of reclock was taken over by Slysoft only a couple of years ago after lying dormant for some time.  If you have not used it for a while you might be surprised.  But then again if you don't have any perceived stutter issue then it's simply not for you.
5) I know what you are saying on the quality of the display with Commercial grade equipment.  I did purchased a $10K set (60" Pio Kuro Prof) and had a professional ISF qualified tech come with all his fancy gear and calibrate the set and all the input devices (including turning off all the "picture enhancement crap") and I still see issues in various feeds (judder in some sports broadcasting, poor compression from sat feeds etc).  Also it is what output frequency the video card is capable of sending and the equipment is receiving that is important (not the internal processing frequency of the TV/Monitor).  My equipment (and I still think this is true of most if not all CE TV equipment) can accept scan rates of 24/50/60hz only.
6) I'm also happy with the 24 is 24 is 23.976 and that any tiny difference is irrelevant in the quest for smooth playback.

Anyway the apple has rolled a long way from the original tree, so I'll modify my original statement by qualifying it as follows:

If you perceive and wish to remove video judder then there are many myths floating around on the net on how to "tweak" you system to get smooth video playback especially for Film derived material (eg Blu-ray).  Even though I've done it my self I'm amazed at the lengths and time we go to tweak various settings based on these myths (which inevitably results in frustration that it all "should just work").  

There have been a couple of questions recently about this topic on in the forum so I've update the following Wiki page with an extract of the Reclock Manual that explains it far better than I ever could.  Have a read --> http://wiki.jrmediacenter.com/index.php/Video_Playback_Customization

If you are happy with the your current video playback then this guide is not for you.

Thanks
Nathan

Thanks
Nathan

[jmone]

I've also updated the Wiki to better delineate between the two separate issues of:
- Telicline Judder --> fixed just by selecting appropriate refresh rates (can use either MC internal options or Reclock)
- Audio/Video sync induced Judder -> fixed by Reclock

Thanks
Nathan

[Daydream]

So, when is the industry starting shooting everything at fixed 100FPS (or multiples) and do away with decades-old practices that need ultra-convoluted explanations? Ahh, that would be a cool day!

[JustinChase]

Probably the same day the US adopts the metric system 

[glynor]

So, when is the industry starting shooting everything at fixed 100FPS (or multiples) and do away with decades-old practices that need ultra-convoluted explanations? Ahh, that would be a cool day!

Never, but that's not entirely a bad thing.  A film is not a video game.  Higher is not always better, just like a photo isn't always better than a painting.  Then again, sometimes it is, of course.  I'd prefer to see NLEs and display devices evolve to be able to use variable framerates, actually.  So you can film dramatic parts of your movie in nice slow 24p for beautiful slow pans with motion blur, and action sequences in 60 or 100p for perfectly fluid motion.

The 24/30/60p problem really can be entirely solved at 120Hz+.  Not for those of you in PAL land, but frankly, Edison invented the Kinetoscope here.  Don't invent your own standards (even if ours are ridiculous and based on antiquated stuff) and then complain that you can't watch our stuff "perfectly".    

I would really like one of those Samsung B8500's though...

[Daydream]

Never, but that's not entirely a bad thing.  A film is not a video game.  Higher is not always better, just like a photo isn't always better than a painting.  Then again, sometimes it is, of course.  I'd prefer to see NLEs and display devices evolve to be able to use variable framerates, actually.  So you can film dramatic parts of your movie in nice slow 24p for beautiful slow pans with motion blur, and action sequences in 60 or 100p for perfectly fluid motion.

That idea with the film not being a video game it's a very true idea, worth studying. Jokingly, there should be a new standard - constant visual fluidity, and it'll imply custom visual sync with your eyes, taking into consideration color and brightness, peripheral and direct vision, etc.

The 24/30/60p problem really can be entirely solved at 120Hz+.  Not for those of you in PAL land, but frankly, Edison invented the Kinetoscope here.  Don't invent your own standards (even if ours are ridiculous and based on antiquated stuff) and then complain that you can't watch our stuff "perfectly".    

I resist with all my might to get on an argument about that . I lived a couple of decades in Europe and also a few years now in US. I am a user torn apart; don't really like much either... aren't there like 279 PAL standards? - B/G/D/K/I/M/N/L  However I'll just say the 220-230V power grid is better, and if we agree on that it might just wipe every 23.#%@$#(*(@^^(3) FPS argument clean.

But above all, I'd be for a united standard, which should be none of the existing ones. I admit that's wishful thinking but in hindsight it's 2010, I find it infuriating to deal with legacy specs dating so far back, just because the industry is unwilling to move. Maybe before they come up with the next format war, they'll put their energy to something that's worthy and universally better?

P.S. Metric system - off topic. I've always been curious how the kids study physics in school, in countries that use the imperial system. All constants are metric in physics, so... how does one wrap his head around that?

[jmone]

I resist with all my might to get on an argument about that .

I almost bit (nice bait Glynor)! 

The 24/30/60p problem really can be entirely solved at 120Hz+.

The 24/25/30/50/60 problem is already solved, just setup your system to automatically change its refresh rate.

[rpalmer68]

All constants are metric in physics, so... how does one wrap his head around that?

Very carefully I would say! 

[glynor]

P.S. Metric system - off topic. I've always been curious how the kids study physics in school, in countries that use the imperial system. All constants are metric in physics, so... how does one wrap his head around that?

We learn the Metric system and then we all go "Wow, this is so much better.  Why aren't we using this everywhere again?"  Teachers mumble something about winning WW2 and not having to listen to anyone else, even if they make sense and we don't.

I almost bit (nice bait Glynor)! 

Liked that?    

[flac.rules]

Never, but that's not entirely a bad thing.  A film is not a video game.  Higher is not always better, just like a photo isn't always better than a painting.  Then again, sometimes it is, of course.  I'd prefer to see NLEs and display devices evolve to be able to use variable framerates, actually.  So you can film dramatic parts of your movie in nice slow 24p for beautiful slow pans with motion blur, and action sequences in 60 or 100p for perfectly fluid motion.

The 24/30/60p problem really can be entirely solved at 120Hz+.  Not for those of you in PAL land, but frankly, Edison invented the Kinetoscope here.  Don't invent your own standards (even if ours are ridiculous and based on antiquated stuff) and then complain that you can't watch our stuff "perfectly".    

I would really like one of those Samsung B8500's though...

Yeah, everything should be recorded at 120 Fps (or more) compability is good, and you can alway repeat frames to get the nice unsmooth 24fps-feel if one likes that. Although i don't see the problem concerning PAL?

[flac.rules]

Correct me if I'm wrong but TV sets in Europe (say UK) have 100 / 200 / 400 MHz specs, not 120 / 240 like in US. So then what gives? I'm curious as to what happens when you play a BR there, since also the same TVs are advertised as having a 24p input.

This is kind of on the side but I'd like to know for sure: the abracadabra frame rates in US are (more or less) a direct consequence of the properties of the power grid used here, correct?

AFAIK its the exact same TVs with the same capabilities, they are just labeled differently because old CRTs was 100 Hz, a "100 hz" TV in europe can do 5:5 pulldown on 24p, and takes 60 Hz input just fine. I would guess a 120 Hz tv can handle pal signals just fine too.

[glynor]

Yeah, everything should be recorded at 120 Fps (or more) compability is good, and you can alway repeat frames to get the nice unsmooth 24fps-feel if one likes that. Although i don't see the problem concerning PAL?

Fantasy land stuff.

Number one, that isn't necessary.  Your eyes (and more importantly, your brain) really can't tell the difference between a frame that lasts 1/60th of a second and one that lasts 1/120th of a second.  Anything above 40-50fps is "smooth motion" capable.  Higher refresh rates help you with long-term viewing (your eyes do perceive the line-draw flicker, even if your brain processes it out of the "image" that you see), but that applies to screen refresh, not the framerate of the video.  These do not need to match, they just need to be an even multiple to look perfect.  A 60fps video played on a 120Hz monitor will look identical to a 120fps video played on the same monitor.  Our brains just aren't designed to process visual information that fast.  That's how film works!  The issue is when you try to play a 24fps monitor on a 60Hz monitor (or 30fps content on a 50Hz monitor).

More importantly... As we move forward, ALL video will be delivered via a digital network (we're pretty much already there).  Bandwidth isn't unlimited.  Internet delivery of 120fps material would be nearly impossible with the current infrastructure.  It takes roughly 1.5-2mbps to get an acceptable quality live-compressed 720p stream in h264 at 30fps (and that's basically just "acceptable", no one who knows compression would call it "good").  At 120fps you'd need 6-8mbps.  I don't want to pay that bandwidth bill to Akamai when 300 people decide to watch the video on my website!  (Not to mention that almost no-one would have the 6mbps+ guaranteed bandwidth needed to actually watch the video.)  ATSC also doesn't have unlimited bandwidth.  Would you be willing to cut your broadcast resolution in 1/2 to achieve these absurd and unnecessary frame rates?

Lastly, the number of movie theaters that still receive film reels is also steadily dropping, and those digital movies they're using to replace them?  Guess how they come in?  Though the Internet (via a highly secured VPN, but it is still over the Internet in many cases).  Why would the movie houses accept quadrupling their download times for no reason?

Maybe 30 years from now that will be technically feasible, but hoping for it now is a pipe dream.

[glynor]

The 24/25/30/50/60 problem is already solved, just setup your system to automatically change its refresh rate.

Or, buy a 120/240Hz TV and set it to 120Hz and leave it there and don't watch any ridiculous PAL content.   

Seriously, though... I completely agree.  Assuming you have a monitor that can do it.  Unfortunately, I don't.  I have one of those crappy 60Hz-only HDTVs at home.  It is wonderful that MC has the features built-in to do this for us for when I eventually get one.

[flac.rules]

Fantasy land stuff.

Number one, that isn't necessary.  Your eyes (and more importantly, your brain) really can't tell the difference between a frame that lasts 1/60th of a second and one that lasts 1/120th of a second.  Anything above 40-50fps is "smooth motion" capable.  Higher refresh rates help you with long-term viewing (your eyes do perceive the line-draw flicker, even if your brain processes it out of the "image" that you see), but that applies to screen refresh, not the framerate of the video.  These do not need to match, they just need to be an even multiple to look perfect.  A 60fps video played on a 120Hz monitor will look identical to a 120fps video played on the same monitor.  Our brains just aren't designed to process visual information that fast.  That's how film works!  The issue is when you try to play a 24fps monitor on a 60Hz monitor (or 30fps content on a 50Hz monitor).

More importantly... As we move forward, ALL video will be delivered via a digital network (we're pretty much already there).  Bandwidth isn't unlimited.  Internet delivery of 120fps material would be nearly impossible with the current infrastructure.  It takes roughly 1.5-2mbps to get an acceptable quality live-compressed 720p stream in h264 at 30fps (and that's basically just "acceptable", no one who knows compression would call it "good").  At 120fps you'd need 6-8mbps.  I don't want to pay that bandwidth bill to Akamai when 300 people decide to watch the video on my website!  (Not to mention that almost no-one would have the 6mbps+ guaranteed bandwidth needed to actually watch the video.)  ATSC also doesn't have unlimited bandwidth.  Would you be willing to cut your broadcast resolution in 1/2 to achieve these absurd and unnecessary frame rates?

Lastly, the number of movie theaters that still receive film reels is also steadily dropping, and those digital movies they're using to replace them?  Guess how they come in?  Though the Internet (via a highly secured VPN, but it is still over the Internet in many cases).  Why would the movie houses accept quadrupling their download times for no reason?

Maybe 30 years from now that will be technically feasible, but hoping for it now is a pipe dream.

That is not true, we can percive information from pictures just beeing displayed in 1/200th second, probably even less (but i have not seen research about it), of coursethere will be less and less additional benifit asthe framerate goes up, but there is a benifit, and there will be visible differences in the right circumstances, also above 40-50 fps. It might be a pipe dream, i men they still kling to darn 24 fps, which is very low. But the framerate should have been higher, at least the double, on movies. But here is quite a lot of "should have been" and bad solutions because of tradition/older technology that is not relevant any more in the TV and film-standards, so i Expect no better in this regard. I can tell you that I much rather see an increased framerate than all the 3D-stuff they implement.

[rick.ca]

but there is a benifit, and there will be visible differences in the right circumstances, also above 40-50 fps.

I don't understand the technical issues, but I've seen nothing here to support the apparent assumption a faster frame rate is better. I'm interested only in what I perceive, and not in any subliminal processing my brain may be doing. I find this a much more plausible explanation...

Never, but that's not entirely a bad thing.  A film is not a video game.  Higher is not always better, just like a photo isn't always better than a painting.  Then again, sometimes it is, of course.  I'd prefer to see NLEs and display devices evolve to be able to use variable framerates, actually.  So you can film dramatic parts of your movie in nice slow 24p for beautiful slow pans with motion blur, and action sequences in 60 or 100p for perfectly fluid motion.

I'm generally not happy about technology destroying art. So I'm prepared to wait for this fantasy.

[flac.rules]

I don't understand the technical issues, but I've seen nothing here to support the apparent assumption a faster frame rate is better. I'm interested only in what I perceive, and not in any subliminal processing my brain may be doing. I find this a much more plausible explanation...

I'm generally not happy about technology destroying art. So I'm prepared to wait for this fantasy.

Teh only way technology can destroy art is by limiting it, lower framerate is more limiting, because you have to use low framerates, but if you have 120 og 48 you can use lower framerates, or you can use higher, its the artists choice, just as you can have low detail on a bluray.

As i said, people can percive information down to 1/200 of a second, probably less. I have not argued on any subliminal basis.

[jmone]

I personally loved the jump in quality as we went from compressed sound (MP3, DD etc) to uncompressed (FLAC, PCM, WAV, WMA Lossless, etc) on the PC.  One thing that enabled this was the steady increase in bandwith/storeage coupled with a drop in it's price.  So as the "price" came down the cost/benefit of moving to lossless got better and better.  It no longer matters if a file that was 7MB (MP3) is now 70MB (Lossless) or that it is rate was 128kbps and is not 1,000kbps.  On Blu-ray discs the sound tracks have gone from Lossy DD at say 384kbps for all 5.1 channels to up to 5,000kbps (PCM Lossless) and would on their own would fill a DVD.  

Likewise we have seen the Bitrate of the Video tracks also increase inline with technology.  We now transmit HD TV using 10mbit+ streams and it is up to 40mbit on a blu-ray disk.  Unfortunately, the goal of full rate, uncompressed Video is at any frame rate is going to be a long way away.  Uncompressed Video consumes something like 3gigabits for a 1080/24p stream and I can not see that Governments are going to allocate that much bandwidth for Terristial TV and we are going to need an order of magnitude increase in the Net and Physical Media to accomplish that.  So we are back to the techies making compromises of what info they are going to sacrifice to fit it into the constraints that they have.  They will, use interlacing, limit resolutions, colour depth, frame rates and use lossy inter and intra-frame compression algorithms to get a "spec" that will fit and hopefully not be too bad on the quality front.   Come on Moores law, keep giving me more and cheaper bandwith/storage ..  Imagine the jump in Video Quality when they sort all of that out!

Thanks
Nathan

[glynor]

As i said, people can percive information down to 1/200 of a second, probably less. I have not argued on any subliminal basis.

Perceiving information in 1/200th of a second on a single still image flashed before your eyes (and that would be the subconscious mind processing it, not the conscious mind) is very different from being able to perceive the difference between multiple frames flying at 60-100 per second.

It doesn't matter anyway because it isn't going to happen.  You might as well wish for the tooth fairy to be real.  I'd much rather see native 4k screens than any of that other speed hogwash, or silly 3D-for-the-home.

[glynor]

There's absolutely no reason to broadcast uncompressed HD for consumer use.  Are you planning on keying out greenscreen on commercially produced content at home?

The increases in transmission and storage quality have followed the bandwidth advances, not the other way around.

EDIT: A MUCH better use of any increases in available bandwidth, over either increasing frame rates or decreasing temporal compression would be: a) increasing chroma subsampling rates (you CAN tell the difference between 4:4:4 and 4:2:2) and increasing frame size (you can also tell the difference, on a sufficiently large display, between 2k and 4k).

[jmone]

There's absolutely no reason to broadcast uncompressed HD for consumer use.  Are you planning on keying out greenscreen on commercially produced content at home?

 Who made either of these statements?  That said I'm sure there is no reason for you to listen to uncompressed music either then....

The increases in transmission and storage quality have followed the bandwidth advances, not the other way around.

 They go hand in hand.

EDIT: A MUCH better use of any increases in available bandwidth, over either increasing frame rates or decreasing temporal compression would be: a) increasing color subsampling rates (you CAN tell the difference between 4:4:4 and 4:2:2) and increasing frame size (you can also tell the difference, on a sufficiently large display, between 2k and 4k).

I agree with use bandwidth increases for going to full colour sampling.  However, the obsession with increasing Resolution for most is farcical as their screens are either too small and/or they sit to far way to perceive any futher increases in resolution.  I'd rather see the removal of interlacing and an increase in Frame Rates.  

[flac.rules]

Perceiving information in 1/200th of a second on a single still image flashed before your eyes (and that would be the subconscious mind processing it, not the conscious mind) is very different from being able to perceive the difference between multiple frames flying at 60-100 per second.

It doesn't matter anyway because it isn't going to happen.  You might as well wish for the tooth fairy to be real.  I'd much rather see native 4k screens than any of that other speed hogwash, or silly 3D-for-the-home.

That depends entirely on the material, what if the artists makes a movie with 199 dark frames and a single frame with some information after those frames? That is only possible with 200 frames if you want the duration to be a second, and that visual stimuli and perception cannot be reproduced by lower framerates. Of course you can rgue that its a pretty far-fetched and seldom occurrence in a movie to have a lot of dark frames, and a sudden very short duration of some other image. But in that case, there will be perceivable difference.  AS i said earlier, there will of course be less and less benefit as framerates goes up, as there will be fewer and fewer situations where one can sense a difference, but situations where you can see a difference will exist, also above 50 fps.

[Daydream]

Jmone, that graph troubles me to no end (because it's true). On a 60" TV at 20ft (6m and some change) still 1080p looks just as good as any lower resolution. This shows how 1080p is far from being crazy cool as advertised. On the PC monitor side of the story is much more evident; the monitors grew in size 15-17-19-21-24", etc. and you can tell right away the increase in resolution. Pixel density rules supreme! In TV land, here we have 1080p and we're gonna blow it up on 55",65", screens... but you have to almost press you nose against the screen to actually enjoy it!

I wanna see crazy cool details on a 65" screen from 20ft away... but wait I need a SuperHiVision setup for that. Damn, there is something wrong with this business.

[gappie]

it is an interesting thread.. 
and when it was about sound i would be on elvis his side. with video it just makes me uneasy. when its a good movie i would not even notice when there is a stripper for the screen, undependend of the framerate.
in the cinema its more about people crunching too loudly then anything..

 
gab

[glynor]

Who made either of these statements?

Me.

Video compression is not the same as audio compression.  Delivering uncompressed video to consumers is just ridiculous.  That doesn't mean we can't use better, smarter compression, but pining for an "uncompressed" standard would just hold us back in many other ways.  It is as silly as arguing that a WAV sounds better than a FLAC file.

There is absolutely no way you can see any difference between Apple ProRes 4:4:4 and Uncompressed 10-bit 4:4:4 on any screen or display technology that has ever been invented.  Heck, without very contrived example footage, there's no way to tell the difference between Apple ProRes 4:2:2 and Uncompressed 10-bit 4:4:4, and that's assuming you're viewing it on a $120k Barco or Christie 4k, or other "pro" class display technology.  Take it down to a consumer display device, and there's no way.  And that's not even mentioning other compression systems like REDCODE or DNxHD.  Uncompressed footage is useful for things like keying, forensic analysis, coloring, and for playback performance (assuming you have the disk throughput to handle it), but it is a pain to cut with, much less deliver to the end-user.  AVC High Profile is VERY good at high bitrates.  If we switched to a 4:4:4 chroma sampling scheme (or just went RGB, which would be simpler), it would solve even the minor problems with AVC High Profile.  But it isn't like AVC and MPEG-2 are the only options out there, or the last generation of compression that we'll ever see.

I know all about the screen size/viewing distance/resolution relationship (though I disagree that the relationship is as linear as that oft-cited graph makes it seem).  But that's beside the point... My point wasn't that the benefit for 4k is large for most people.  It clearly is not.  My point was that it was larger than the benefit of going to absurdly high frame rates (or uncompressed video).  But it isn't hard to beat no benefit at all.  

[Daydream]

iwhen its a good movie i would not even notice when there is a stripper for the screen, undependend of the framerate.

Problem is, even in theaters I can tell that for certain scenes the framerate is too low. Just that the judder is not caused by all the problems related to home equipment, but by the shutter of the camera used, that operates at parameters defined in 1926. Go Hollywood!

[gappie]

Problem is, even in theaters I can tell that for certain scenes the framerate is too low. Just that the judder is not caused by all the problems related to home equipment, but by the shutter of the camera used, that operates at parameters defined in 1926. Go Hollywood!

yes.. exactly my point.   i notice things like that with sound, but not with visual things (or i dont care as long as it is good). still i think the thread is really an very interesting read. just a reminder that maybe one wants to understand but not see..

[glynor]

Problem is, even in theaters I can tell that for certain scenes the framerate is too low.

Absolutely.  Most judder that people see is from the camera shutter.  However, the assumption by some seems to be that smooth motion is always a good thing.  But that's a false assumption.  Motion in a film is not always meant to be perfectly smooth.  Sometimes a little "stuttery motion" with some motion blur adds something to the composition.

I agree that for action sequences (especially those with fast horizontal pans), a higher frame rate would be helpful.  That's why the ability to vary the frame rate over the course of a film would be the best solution (to use the high rates when you need it, and save the bandwidth and the "art effect" of the motion blur when you don't).

That would take a complete redesign of both our editing systems and our distribution systems, though, so it is also a pipe dream.

[jmone]

I know all about the screen size/viewing distance/resolution relationship (though I disagree that the relationship is as linear as that oft-cited graph makes it seem).  But that's beside the point... My point wasn't that the benefit for 4k is large for most people.  It clearly is not.  My point was that it was larger than the benefit of going to absurdly high frame rates (or uncompressed video).  But it isn't hard to beat no benefit at all.    

FYI - The same source (http://carltonbale.com/1080p-does-matter) quotes the following (emphasis is mine):

"In conclusion: If you are a videophile with a properly setup viewing room, you should definitely be able to notice the resolution enhancement that 1080p brings. However, if you are an average consumer with a plasma on the far wall of your family room, you are not likely to be sitting close enough to notice any advantage. Check the chart above and use that to make your decision. Also, the Imaging Science Foundation (ISF) states the the most important aspects of picture quality are (in order): 1) contrast ratio, 2) color saturation, 3) color accuracy, 4) resolution. Resolution is 4th on the list and plasma is generally superior to LCD in all of the other areas (but much more prone to reflections/glare.) So pick your display size, then measure your seating distance, and then use the charts above to figure out if you would benefit from the larger screen size."

...and if so, we as consumers would be better served with technology that delivers enhancements these others aspects before resolution.  Don't get me wrong I'd love to pair 4k with a wall sized display device that can deliver 1, 2 and 3....but I recon I've a long wait for that.  I'm not pining for "uncompressed" (I should clarify as "lossy compressed") video but clearly as tech advances are made we continue to wind back the compromises made to the original video stream.  My Canon DV20 has more compromises than I care to consider (especially dinkly little consumer grade zens, image sensor size etc) but it is fascinating seeing the jump in quality from footage compressed and stored as HDV (Anamorphic 1440x1080@25p or 50i with 4:2:0 chroma) VS the same Camera with a direct HDMI feed (1920x1080/50p in 4:4:4) bypassing the HDV codec to the same 1080p display.  It was not resolution that made the difference.  We have arguable reached the stage already with Audio that you don't have to accept any compromises to faithfully recreate the original recording.  We are still a long way from that with Video.  Going out on a limb and given the domestic equipment it's a shame we did not adopt a common 1080/50 or 60p in 4:4:4 or equivalent.

Thanks
Nathan

[glynor]

Oh, we agree on all of that, Nathan.  I was only saying that 4K > Frame Rate.  (Frankly, we agree on pretty much everything, it is just entertaining to discuss.)

If you didn't actually mean uncompressed, then sure, I'll agree.  HDV is a horrific compression scheme.  It samples to 4:2:0 but often uses chips originally designed for 4:1:1 on MiniDV?  And they did all of this because they wanted to use the same processing chips that were used on older-generation DV camcorders and allow the new HDV camcorders able to output to MiniDV tapes that no one uses anymore (adding on only commodity MPEG-2 chips for compression)?  It was a hack, plain and simple.  That's why I bought a Panasonic P2 DVCProHD camcorder instead of a Canon HDV camcorders, when they were roughly the same price in the market.  Canon had the better sensor and glass, but paired it with an awful compression scheme and recording mechanism.

But just because HDV is crap, and most consumer-oriented AVCHD camcorders tear horribly, doesn't mean that compression is bad.  Compression is GOOD.  It lets us do things like have higher resolution and higher framerates in the same bandwidth (or storage) space.  Bad compression is bad.

Going out on a limb and given the domestic equipment it's a shame we did not adopt a common 1080/50 or 60p in 4:4:4 or equivalent.

Sure, that'd be wonderful.  Not possible, but wonderful.  Had we settled on a 4:4:4 compression scheme, we'd have had to cut our resolution or frame rate to 1/3-1/2 what we eventually decided upon, because the available bandwidth (broadcast, storage, cable, Internet, etc) would not have allowed us any other choice.  Mr. Bale didn't explicitly explain it, but putting resolution last on his list (but not including a ton of other relevant factors like compression ratios, frame rates, and transmission mechanisms) assumed a minimum of usable resolution.  His argument was that once you got to a certain level of resolution quality (based on your viewing distance), that those other factors mattered more.

However, watching a 52" image at 8 feet at 640x360 @ 60p is going to look like crap even if it is 4:4:4 and has an awesome contrast ratio.

[jmone]

I like lossless compression (its like getting something for nothing!).  It's the lossy compression that introduces the compromises we currently have to live with.  In the audio world I'll take FLAC/WMA Lossless over PCM/WAV over MP3/WMA Files.  Given the impracticalities of dealing and transmitting lossless Video the powers to be have a bunch of compromises to choose between (res, colour space, frame rates, interframe compression, intraframe compression, interlacing) each time a new standard comes out.  While I "like" none of these compromises I will certainly live with them 'cause its what we have at the moment in consumer land.  The only "power" I have is to determine how to consume the content I want, for example I stopped buying DVD's years ago in prep for Blu-ray and now have a couple of hundred of these discs.  I don't buy MP3, only CD's and rip to lossless.  I tune the HD channel not the SD one...Also the list of "importance" is not Bale's it is from the ISF.

Now the camcorder purchase was an easy one for me at the time....the DV cam just died, I wanted backwards compatible with DV tape, and the HV20 had just won camcoder of they year (http://www.camcorderinfo.com/content/Canon-HV20-Camcorder-Review.htm).  It is a good example of making the best compromise of features/benefits/issues at the time.  To further the point on resolution not being the be all and end all.....about the same time we had a TV crew shot a promotional video for MS and they gave us a copy on DVD.  Lets look at the "specs" on the output from these two processes, both use the same compression (MPEG), both use the same format/colour space (PAL), the Camcorder is HD (anamorphic 1440x1080i), the DVD from the TV shoot is SD (720x576i), the Camcorder data rate is 25mbps, the DVD rate is 8mbps.....and the camcorder footage looks very very ordinary compared to the DVD.

We do agree on most, but if I was offered one thing to upgrade from the current blu-ray spec (the best we consumers currently have) say from from 1920x1080/24p/50i/60i 4:2:2 x264I'd take extra frames (or fields) --> eg 1920x1080/50p over bumping the resolution...

Thanks
Nathan

[jmone]

Probably the same day the US adopts the metric system 

Nahhh this new fangled system will never take off.....woops looks like the final holdouts are the USA, Burma, and Liberia (http://en.wikipedia.org/wiki/International_System_of_Units).  The funny thing is the US is already metric....but talks in imperial  "In 1893, Thomas C. Mendenhall, then Superintendent of Weights and Measures in the Treasury Department, concluded that the metric standards, the official meter and kilogram bars supplied by BIPM, should become the standards for all measurement in the U.S. With the approval of the Secretary of the Treasury, this decision was made and published; it has since been called the Mendenhall Order. The order didn't mean that metric units had to be used, but since that time the customary units have been defined officially in terms of metric standards. Currently, the foot is legally defined to be exactly 0.3048 meter and the pound is legally defined to equal exactly 453.59237 grams. ( http://www.unc.edu/~rowlett/units/usmetric.html )

[jmone]

Jmone, that graph troubles me to no end (because it's true). On a 60" TV at 20ft (6m and some change) still 1080p looks just as good as any lower resolution. This shows how 1080p is far from being crazy cool as advertised. On the PC monitor side of the story is much more evident; the monitors grew in size 15-17-19-21-24", etc. and you can tell right away the increase in resolution. Pixel density rules supreme! In TV land, here we have 1080p and we're gonna blow it up on 55",65", screens... but you have to almost press you nose against the screen to actually enjoy it!

I wanna see crazy cool details on a 65" screen from 20ft away... but wait I need a SuperHiVision setup for that. **, there is something wrong with this business.

It's been a good marketing tool ... more is better.  That said back when they use to market both 1920x1080 ("full hd") and 1280x720 ("hd") screens I'd still recomend buying the 1920x1080 screen regardless of size as some of the internal scaling employed to push 1080i DTV onto those cheap 720p sets looked terrible.  That said, the same cheap scalers made a mess of upscaling 576i to the 1080p as well...you get what you pay for...

[flac.rules]

Nahhh this new fangled system will never take off.....woops looks like the final holdouts are the USA, Burma, and Liberia

Its the same as a lot of movie standards i guess, clearly inferior systems beeing used becuase fo tradition/compability with older things.

[jmone]

Its the same as a lot of movie standards i guess, clearly inferior systems beeing used becuase fo tradition/compability with older things.

Look at the spec for ATSC, it supports 23.976, 24, 25, 29.97, 30, 50, 59.94, and 60 frames/fields at various resolutions but 29.97 and 59.94 are just antique hold overs...

[glynor]

The HV20 was a very nice camcorder in it's time for a little > $1k toy.  The HDMI out is quite nice on it.  I actually have two of them at work, hooked up to a Blackmagic Design Intensity card for some live recording.

At the time I bought my primary cameras, I was comparing the Canon XL H1 (around $8-10k) to the Panasonic HVX200 (same price).  Like I said, the Canon had better glass and a nicer sensor, but the rest of the "guts" of the camera were effectively the same as the older standard-def XL2 with a MPEG-2 encoder chip tossed in (same as the HV20).  The compression ruined it all.  Sure, you could get the HD-SDI out the back of the camera if you wanted it, but you couldn't record that feed at all with anything easily portable at the time.  DVCProHD (the Panasonic P2 format) is 100mbps, so you can imagine that it would do a far superior job to HDV at 25mbps (which was kept at 25 because that's what the DV chips were designed for).

Of course now, there's the XF305, which makes some much better compromises for a little guy.  Record to regular compact flash cards at 50mbps in MPEG-2 long?  Sounds good.  Full-quality HDMI-port out the back fed to an AJA Ki-Pro for when you need the quality?  Sounds awesome!

If only I was in the market for a new camera...  

[jmone]

XF305 a little guy!    For me that's the big compromise....size (I'm like Ipod users, I want a simple cheap Pocket sized cam and pretend it will somehow put out studio quality footage....)  I also followed for awhile the posts at www.hv20.com of they guy doing a "portable" bat operated HV20/BlackMagic/PC in one setup...that wasn't you by any chance?

[maid]

Hi Jmone,

I have installed reclock on two machines.

My office shows reclock in action.

My HTPC I cant see the icon in the taskbar, how do I know if its working?

I have uninstalled re installed and told it to ask when loading, it did ask but still no icon??

[jmone]

By default, Reclock should just load when DirectShow Audio playback starts and to see what it is up to you can click on the tray icon which will display all sorts of info on what is being played.

It it is not loading check the following (see pics below):
1) in MC's Options --> Video make sure the "Playback Device" is either Default or Reclock
2) in Reclock's Options make sure that:
  - Do not show icon in tray is unchecked
  - that Media Center 15 is set to Always Load
  - I also recommend the JRWorker is set to Never Load (it is what makes the thumbnails)

[maid]

Fab thanks.

Now why does it say that I have to change my frame rate to match.

I thought that it was all automatic.

[jmone]

The aim of relcock is to fine tune the matching of the frame rate playback to the refresh rate of the HW when they are close.  You have 3 options to set the refresh rate:
1) Manually (PITA)
2) MC - you can set your playback options in MC and it will change the refresh rate
3) Reclock - you can enable reclock to kick off a script to change the refresh rate automajically (see pic) and from the Reclock Read Me:

“Enable events notifications”: if enabled, ReClock will launch the file named “RunEvent.vbs” in the ReClock install directory, each time a media file is about to be played or stopped, when playback condition have changed, or when quitting the player. You can customize this script to do whatever you want, for example to change the monitor refresh rate when it does not correspond to the one of the played media file. For convenience, the distribution of ReClock provides a sample called “RunEvent.sample.vbs”. For more explanations have a look inside this sample, and don’t forget to modify it properly and to rename it to “RunEvent.vbs” before to use this feature.

Remember, you can only change to a refresh rate your HW supports!

[jmone]

Have a look at the "RunEvent.SetDisplayFrequency.sample.vbs" file and rename it "runevent.vbs" if you are happy with the contents (or edit away).

[maid]

Sorry to be a newb but what is HW?

I am also not understanding the refresh rates

Can you possibly offer a bit more help regarding the settings in my pc eg refresh rate?