Visible flicker: PAL vs. NTSC

[hollowman]

FYI: I'm watching on 60hz North-American gear (TV, DVD/VCR or computer).

Looking at some 1970-80s BBC PAL video -- orig. videographed on 25fps (??) 2" broadcast studio machines, I assume -- I notice NO flicker, even in fast-moving scenes. It looks like smooth 30fps NTSC from the same time period.

Some of these programs are classic BBC Dr. Who episodes which switch between video tape and film sources (sometimes scene to scene). And the flicker diff. between the film and videotape segments is very apparent.

I have NEVER watched PAL programs on PAL equipment. So I don't know, e.g., what viewers in the UK would see on their native gear.

Bottom line: why is orig. PAL-shot video as smooth as 30fps NTSC? Is it careful interpolation (conversion) during transfer (e.g. for use in N. America or Japan)? I see NO conversion/transfer artifacts. Might some "PAL" captures/recordings --regardless of where captured, such as in PAL countries -- been ORIGINALLY captured at higher fps like 30 and then converted to PAL for PAL broadcasts and not converted for NTSC. IOW, was the BBC actually capturing/recording at 30fps?

[manono]

Do you have any samples you'd like to upload? I have yet to see any BBC programs from that era on NTSC DVD that didn't look like crap.

[hollowman]

Do you have any samples you'd like to upload? I have yet to see any BBC programs from that era on NTSC DVD that didn't look like crap.

Why UPLOAD? Online streaming is good 'nough -- n'est pas?
Here's a 1975 Dr. Who on Daily Motion. Pretty good quality, too:
http://www.dailymotion.com/video/xsmdtc_revenge-of-the-cybermen-part1_shortfilms
(You can download in MP4 format using JDownloader or similar and play on VLC)
As far as "looking like crap" from that era? WHAT looks like "crap"? Remember the orig. query is about visible flicker of PAL vs. NTSC. And I claim I can't tell the diff. for material photographed/recorded onto videotape.

[manono]

Right, like Dailymotion is a good substitute for untouched DVD. I've seen a lot of BBC TV series from that era (but no Dr. Who episodes) And they all exhibited PAL to NTSC fieldblending and looked horrible.

If that's the only source you have then someone else can try and help. And no, none were shot using interlaced 29.97fps video cameras so they'd look good for the NTSC market. On the face of it that makes no sense at all.

[hollowman]

Right, like Dailymotion is a good substitute for untouched DVD. I've seen a lot of BBC TV series from that era (but no Dr. Who episodes) And they all exhibited PAL to NTSC fieldblending and looked horrible.

WOW! That's quite a statistic, sir! Okay, your time to provide "any samples". YouTube or DailyMotion is good 'nough.

If that's the only source you have then someone else can try and help. And no, none were shot using interlaced 29.97fps video cameras so they'd look good for the NTSC market. On the face of it that makes no sense at all.

I have this episode on a 2009 commercial DVD (USA release on BBC video) and also self-recorded onto Beta tape 25 years ago (from a PBS broadcast). As far as the DailyMotjon version: Whomever uploaded it used a decent source. And for the sake of this query, it's MORE than good enough.

Manono -- still not convinced? You can use Amazon or iTunes and buy a v. good-quality download version; $2.00 for this experiment is WORTH it. Or try your local Public Libr.: most have some classic BBC on DVD (since we all know you're religious about that holy ... uh ... "untouched" ... format).

[hello_hello]

I should begin by pointing out that writing Doctor Who as Dr. Who can potentially get you lynched in some countries.....

I live in PAL-Land but I've seen quite a few old Doctor Who episodes (mainly Tom Baker episodes as obviously he's still the best Doctor Who) encoded from NTSC DVDs and yes there's field blending for days. And some of them seem to be "remastered" (ie made to look like over-processed digital crap) and I won't mention the colors.... but there's also DVDs with CGI effects which replace the wobbly BBC models/effects of the day, which improve the overall viewing experience in much the same way the new CGI added to the re-release of the original Star wars didn't, but anyway.....

I assume you're playing NTSC DVDs of Doctor Who and not PAL DVDs on NTSC equipment capable of playing PAL video or anything like that? I can't explain the flicker in some scenes but not others, unless some was shot interlaced and some progressive and the conversion to NTSC somehow made a mess of it, but I'd agree it's an impossible question to answer without a sample of the DVD you're viewing.

"Flicker" to me is kind of like "CRT flicker" or "florescent light flicker". Is it flicker or is it more a jerkiness in playback in some scenes?

[manono]

Okay, your time to provide "any samples".

I said I had seen, not that I owned. You're the one claiming that the NTSC versions of these old series are nice looking. I've seen Faulty Towers, Jeeves And Wooster and other Wodehouse series DVDs, Black Adder, and others I can't remember. Yes, that Dr. Who episode looks good. I can't download it and have no interest in doing so but I don't understand why you act surprised that a 25fps show (which is what I presume it is) looks good. My claim is only that when converted to NTSC they look very bad.

Your first post said:

Bottom line: why is orig. PAL-shot video as smooth as 30fps NTSC? Is it careful interpolation (conversion) during transfer (e.g. for use in N. America or Japan)? I see NO conversion/transfer artifacts. Might some "PAL" captures/recordings --regardless of where captured, such as in PAL countries -- been ORIGINALLY captured at higher fps like 30 and then converted to PAL for PAL broadcasts and not converted for NTSC. IOW, was the BBC actually capturing/recording at 30fps?

And I replied that when converted to NTSC it doesn't look smooth, is loaded with artifacts, and isn't what you claim at all. And as evidence you show me something which I presume is 25fps. But since I've never seen the Dr. Who episodes, I can't prove they're PAL, but maybe you can if you have that episode on your hard drive. And if it is 29.97fps, maybe they're using better conversion techniques now (interpolation, as you guessed).

Edit: Oh, one isn't supposed to write it as Dr. Who?

[hello_hello]

Edit: Oh, one isn't supposed to write it as Dr. Who?

Sacrilege!

Then again, it could be easily argued the new serious is guilty of it too, only for different reasons.... well these days it's generally because it's complete crap.

[jagabo]

Watch the video in this post on a 60 Hz monitor. You'll see the obvious difference between 24p, 30p, and 60p on a 60 Hz display:

https://forum.videohelp.com/threads/307004-Best-framerate-conversion-%28eg-23-97-to-30-...=1#post1888926

24p or 25p is inherently jerky/flickery. It's especially noticeable on high contrast smooth panning shots. It's easily visible on TV and movie theaters.

That type of flicker is different than the flicker you get with interlaced CRT. CRT flicker is caused by the fact that only one field is visible at a time. That lends a one scanline vertical bounce to the picture that is visible on sharp horizontal edges, even with static shots.

I downloaded the "high quality" MP4 file from the Dailymotion site. It is interlaced video (25i), incorrectly resized and encoded as progressive (25p). It shows the same type of jerk/flicker as any 24p or 25p source.

[hollowman]

Dr. Who was/is quite popular, so I'm sure a lot of resources went into clean conversion when it was not distributed in its orig.-source PAL
I saw that the Daily Motion file was in 25fps. Hmm...yet I still PERCEIVE it as NTSC 30fps -- or at least smoother than 24fps film. Could that one extra fps -- 25 instead of 24 -- make THAT much differece? We do know that the orig. 24fps was selected based partly on the science of human eye/brain sens. to "flicker". But since film was not cheap, there was a trade off between quality and quantity.

Some other possibiltes may include:

-- personal (genetic) sensitivity to frame-rate based motion "flicker" or "jerkiness". Possib. genetic attribute, like some can detect 180-degree phase diff in audio, or that PCT (phenylthiocarbamide) bitter/bland test from HS bio class!
-- brain burn in of NTSC video. Video-tape -- regardless of fps or region format -- has that "videoy" look (possibly due to chrominance/luminance) which is quite diff. than film. So the "smoothness" one may PERCEIVE is unrelated to fps.

I have seen PAL videotape based progs. in which the lower (25) fps is quite apparent. E.g. (also BBC ca. 1975, like the Dr. Who epi. noted earlier) Survivors season 1. But I just found this YT version of this series' pilot epi. which looks smooth (at least to me):
http://www.youtube.com/watch?v=Ak1SrFGXgA4

[manono]

I saw that the Daily Motion file was in 25fps. Hmm...yet I still PERCEIVE it as NTSC 30fps -- or at least smoother than 24fps film. Could that one extra fps -- 25 instead of 24 -- make THAT much differece?

What are you comparing it to? A 24 (or 23.976)fps file on Daily Motion or YouTube? Or an NTSC DVD from a 24fps movie? If to a 24fps video on DailyMotion then I don't believe you that the 25fps video is obviously smoother playing. If to a DVD then the answer is obvious - 3:2 pulldown.

[jagabo]

Dr. Who was/is quite popular, so I'm sure a lot of resources went into clean conversion when it was not distributed in its orig.-source PAL

The old episodes I've seen went through the usual PAL to NTSC field blending hardware.

I saw that the Daily Motion file was in 25fps. Hmm...yet I still PERCEIVE it as NTSC 30fps -- or at least smoother than 24fps film. Could that one extra fps -- 25 instead of 24 -- make THAT much differece?

No. I think it looks smoother to you because the video wasn't deinterlaced so remaining comb artifacts are creating some thing of a motion blur.

[manono]

But I just found this YT version of this series' pilot epi. which looks smooth (at least to me):
http://www.youtube.com/watch?v=Ak1SrFGXgA4

That one I can download. It was converted from 25 to 30fps by adding duplicate frames. Every sixth frame is a duplicate of the one before. It doesn't play smoothly at all.

[jagabo]

But I just found this YT version of this series' pilot epi. which looks smooth (at least to me):
http://www.youtube.com/watch?v=Ak1SrFGXgA4

That one I can download. It was converted from 25 to 30fps by adding duplicate frames. Every sixth frame is a duplicate of the one before. It doesn't play smoothly at all.

Yes, five little jerks every second.

I have the first season of Survivors on PAL DVD. It's a mix of 25p and 25i. On-location scenes were shot on film, studio scenes on video tape.

[hollowman]

But I just found this YT version of this series' pilot epi. which looks smooth (at least to me):
http://www.youtube.com/watch?v=Ak1SrFGXgA4

That one I can download. It was converted from 25 to 30fps by adding duplicate frames. Every sixth frame is a duplicate of the one before. It doesn't play smoothly at all.

Yes, five little jerks every second.

I have the first season of Survivors on PAL DVD. It's a mix of 25p and 25i. On-location scenes were shot on film, studio scenes on video tape.

Lotsa videotaped outdoor scenes, too -- so not just "studio." Many of you are noticing frame-related jerkiness. But I don't see much.
BTW: For this series, I'm viewing only on PC, laptop or tablet.
BTW2: By "jerkiness" or "flicker", it is assumed we are all referring to the strobe-like effect inherent in ANY frame-based capture/playback/display. This can include anything from the real jerky 19th century stuff, 1960s NASA space footage, all the way up to modern 60fps and even ShowScan:
http://en.wikipedia.org/wiki/Showscan

[hollowman]

I saw that the Daily Motion file was in 25fps. Hmm...yet I still PERCEIVE it as NTSC 30fps -- or at least smoother than 24fps film. Could that one extra fps -- 25 instead of 24 -- make THAT much differece?

What are you comparing it to? A 24 (or 23.976)fps file on Daily Motion or YouTube? Or an NTSC DVD from a 24fps movie? If to a 24fps video on DailyMotion then I don't believe you that the 25fps video is obviously smoother playing. If to a DVD then the answer is obvious - 3:2 pulldown.

For the sake of this argument ... let's forget about dedicated DVD plyrs, TV and other/traditional living-room equipment. ALL my video watching is via some PC/computer device -- even for DVD optical discs.
With DM or YT stuff -- whether streamed and played in Adobe Flash browser plug-in, or downloaded and played using VLC -- the software on my end does a pretty good job. E.g., VLC has several good built-in processors, such as Yadiff, that IMO go beyond older stuff like 3:2. Also, YT, DM, BBC News, or other major Flash-video sources do some pre-processing (on their end) to clean and smooth things out before "sending you the goods".

[manono]

With DM or YT stuff -- whether streamed and played in Adobe Flash browser plug-in, or downloaded and played using VLC -- the software on my end does a pretty good job. E.g., VLC has several good built-in processors, such as Yadiff, that IMO go beyond older stuff like 3:2. Also, YT, DM, BBC News, or other major Flash-video sources do some pre-processing (on their end) to clean and smooth things out before "sending you the goods".

Sure, if the video was prepared properly (jagabo said the DailyMotion one you help up as an example of a good-looking video had been resized without being deinterlaced first) and was still 25fps, then it should look OK. My point from the beginning, though, is that all (or all I've seen) BBC sourced stuff from earlier times (and even the more recent stuff I've seen) looks bad once converted to NTSC. You haven't shown anything yet to contradict that.

VLC has several good built-in processors, such as Yadiff, that IMO go beyond older stuff like 3:2.

Then you don't understand 3:2 pulldown if you think deinterlacing it makes it good again. For soft-telecine nothing should be needed. But a flag-reading player such as VLC can't perform on-the-fly IVTCs of hard-telecine and will rely on a deinterlacer such as Yadif and, once again, you'll get repeated duplicate frames and stuttery playback. And it can't fix field-blended PAL to NTSC conversions on DVD.

[hollowman]

OK. My point from the beginning, though, is that all (or all I've seen) BBC sourced stuff from earlier times (and even the more recent stuff I've seen) looks bad once converted to NTSC. You haven't shown anything yet to contradict that.

And you haven't noted any specific examples as to what looks COMPARATIVELY "good" (in your opinion). E.g., an American 70s era studio-taped sitcom, released on DVD. Yes, I have some of these, and they don't consistently look better or worse than 70s era Dr. Who.

Also, we have no idea what you are viewing your video software on. Since my first post in fall 2007, I updated my VH profile page with my gear list, in most of its gory detail.

Sorry ... but to me, your baseless (= exampleless) feedback follows the old adage: a lotta talk, but not much said.

[manono]

Cute. I watch DVDs in a DVD player sent out to a TV set. I have no interest at all in watching in front of a computer monitor as I sit in front of one enough without getting my entertainment through one. I and others have already mentioned that the BBC series have been converted to NTSC in a sub-optimal way, none of which means much to you anyway, apparently. If I come across any examples I'll post. Until then feel free to have the last word.

[hello_hello]

For the sake of this argument ... let's forget about dedicated DVD plyrs, TV and other/traditional living-room equipment. ALL my video watching is via some PC/computer device -- even for DVD optical discs.
With DM or YT stuff -- whether streamed and played in Adobe Flash browser plug-in, or downloaded and played using VLC -- the software on my end does a pretty good job. E.g., VLC has several good built-in processors, such as Yadiff, that IMO go beyond older stuff like 3:2. Also, YT, DM, BBC News, or other major Flash-video sources do some pre-processing (on their end) to clean and smooth things out before "sending you the goods".

Well for the sake of argument, lets not forget that the same rules still apply. If you're watching video on a TV or on a PC monitor it's still refreshing at a fixed rate which may or may not be an exact multiple of the frame rate.
If the video is interlaced it's still got to be de-interlaced whether by the player, the video card or the monitor/TV.... assuming the TV/monitor is progressive. A video card might have setting to apply inverse telecine where applicable. Mine does. How well it works I have no idea as I live in PAL-land.

Nothing really works any differently just because a PC is being used for playback, although if you're using a smallish/lower resolution computer monitor to view video rather than connect the PC to a large TV, the monitor itself may be effectively hiding a lot of the nasty stuff you'd otherwise see.

Why not upload a sample of the video in question instead of asking about it and then refusing to accept anything anyone offers in reply?

Here's an example of frame blending from a Doctor Who episode converted to an NTSC DVD. Taken from an old, xvid/AVI encode admittedly, but it's still there. At normal speed though you probably don't see it, but maybe the blurriness it adds to motion is what you're interpreting as less "flicker". Maybe try opening one of the videos in question and stepping through it frame by frame. If VLC doesn't have the ability, MPC-HC does.

[hello_hello]

Same section of video, two consecutive frames, taken from a PAL DVD encode. Or maybe a PAL TV capture. I can't remember.

[Island_Dweller]

I disagree with the premise that youtube or dailymotion is good quality for interlaced material. Most interlaced material gets deinterlaced to half the temporal resolution, i.e 50i to 25p OR 59.94i to 29.97p and that is no longer going to be smooth. I've tested this with a bunch of truly interlaced materials (PAL, NTSC, SD, HD) and to get truly smooth results on a PC requires full framerate deinterlacing (i.e, 50i to 50p).

Furthermore, as was already pointed out, watching 25p or 24p on 60Hz PC monitor will invariably involve judder, which some people might mistake for smoothness. My PC monitor can do 47.952Hz, 48Hz, 50Hz, 59.94 Hz and 60Hz refresh rates when using an HDMI connection. Thanks to madVR, MPC-HC automatically switches the refresh rate appropriately. As an example, watching Top Gear @ 1080i50 is smooth with full frame rate deinterlacing. But if it is deinterlaced to 25p, it is no longer as smooth.

[hello_hello]

I disagree with the premise that youtube or dailymotion is good quality for interlaced material. Most interlaced material gets deinterlaced to half the temporal resolution, i.e 50i to 25p OR 59.94i to 29.97p and that is no longer going to be smooth. I've tested this with a bunch of truly interlaced materials (PAL, NTSC, SD, HD) and to get truly smooth results on a PC requires full framerate deinterlacing (i.e, 50i to 50p).

I wouldn't argue with that. Myself...... not that I work with interlaced video much these days, but when I have I've always done it the traditional way when encoding, ie de-interlaced it to 25fps or 29.970fps etc. It's only recently I've experimented with de-interlacing to 50fps or 59.94fps etc and the difference is night and day.

I'd not even really compared the original video being displayed on my TV to the encoded version until recently. At least not in terms of smoothness of motion. I've done lots of comparing in terms of compression/de-interlacing artefacts etc but never really paid attention to how smoothly the video plays. I guess you get used to the "jitter" at low framerates and become somewhat oblivious to it, but once you compare the two......
I can only assume the video card/TV de-interlaces to 50fps/59.970fps as interlaced video looks very smooth on playback, even when using MPC-HC to display it on the TV (although MPC-HC's own de-interlacing seems to be complete crap so I don't let it decode interlaced video). The only way to duplicate the way the original video displays when de-interlacing/encoding is to de-interlace it to the full frame rate.

Which does make me wonder why it's always been "traditional" to de-interlace video before re-encoding it. I assume it's because it makes it much easier to compress.
Recently I re-encoded a bunch of old interlaced DVDs while de-interlacing to 50fps and it surprised me a bit how little it increased the file size compared to de-interlacing it to 25fps (same de-interlacer and x264 settings both times). In fact once I started using QTGMC to de-interlace at 50fps the output file sizes were consistently smaller then the old encodes using Yadif to de-interlace at 25fps. I guess a lot of that comes down to how well QTGMC de-noises etc though.

Anyway, I think you're completely correct. A 25fps/29.970fps encode of interlaced video can look perfectly good, until you compare it to the same video de-interlaced at the full frame rate. I can't imagine I'll ever de-interlace to half frame rate when encoding again.

[jagabo]

Which does make me wonder why it's always been "traditional" to de-interlace video before re-encoding it.

Until recently most computers and devices couldn't play 50 fps or 60 fps video smoothly.

[Island_Dweller]

Which does make me wonder why it's always been "traditional" to de-interlace video before re-encoding it. I assume it's because it makes it much easier to compress.
Recently I re-encoded a bunch of old interlaced DVDs while de-interlacing to 50fps and it surprised me a bit how little it increased the file size compared to de-interlacing it to 25fps (same de-interlacer and x264 settings both times). In fact once I started using QTGMC to de-interlace at 50fps the output file sizes were consistently smaller then the old encodes using Yadif to de-interlace at 25fps. I guess a lot of that comes down to how well QTGMC de-noises etc though.

Anyway, I think you're completely correct. A 25fps/29.970fps encode of interlaced video can look perfectly good, until you compare it to the same video de-interlaced at the full frame rate. I can't imagine I'll ever de-interlace to half frame rate when encoding again.

Well, for truly interlaced material, there's always the option of encoding as interlaced h264 and letting the media player deinterlace during playback. To be honest, I'm unsure how this will affect file size or encoding time, but it's worth experimenting with.

[hello_hello]

To be honest, given QTGMC seems so good at cleaning up the video while de-interlacing it, I think I'd prefer to de-interlace to full frame rate anyway. Pity it's so slow, but I guess it's motivation for me to mess around with a multi-threaded version of AviSynth. Although admittedly... simply running two encodes at a time keeps the CPU pretty busy anyway.

[hollowman]

hello_hello, in #20 and 21, is that Genesis of the Daleks? If so , I have that on USA NTSC DVD orig, BBC video release ... and I will search for that for the holy upload you endoparasite hosts have been begging for. But frankly ...y'all are into all this far more anal-retentively than I. I watch videos on my iPad while on the throne. Good 'nough for guvment work So, just mock me, as a joe public. At least I have no problems defecating, and no messy wipe-ups. Now if you'll 'scuse me ... this joe has to visit the john ... with a 25p on the 'Pad ... and lovin' the dump LOL!!!

This message sent from my bathroom iPad.

[hello_hello]

hello_hello, in #20 and 21, is that Genesis of the Daleks?

Yes. Episode 1.
It's nothing to do with being anally retentive and more with not being able to offer the magic answer you apparently think is out there.

[jagabo]

But frankly ...y'all are into all this far more anal-retentively than I.

No. You claimed that 25 fps PAL doesn't flicker. That's simply not true.

[smrpix]

It seems hollowman prefers frame blending to what he perceives as flicker on a better quality transfer.

As for watching frame-blended video on the throne -- that's just a fine definition of garbage in, garbage out.