How do I get TRUE 24p playback?

[slaman]

I am trying to get perfectly smooth 24p playback using a remux of the amazing Planet Earth HD DVD into an MKV container.

Motivation:
- I use Media Player Classic - HomeCinema integrated into my HTPC front-end
- I own a Toshiba Regza capable of receiving 24Hz input, and through the Clearframe 120Hz, 5:5 Pulldown functionality, and the Film Stabilization feature, can properly display 24FPS from a 24p input
- There are a few scenes where there is a slight jitter from Planet Earth - I assume this is caused by the fact that the video is not outputting 24FPS to the TV. Particularly Episode 2, from 24:35 - 24:45 - the rocks along the bottom "flicker"

Disc Details (from the Properties screen of MPC-HC):
Video: WVC1 1920x1080 29.97fps [Video]
Audio: Dolby AC3 48000Hz 6ch [Audio]

Disc Details (from HighDefDigest and DVDTalk):
Video: 1080p/VC-1 - DVDTalk indicates that it is shot at 24FPS
Audio: English Dolby Digital 5.1 Surround (448kpbs)
Reference (HighDefDigest): http://hddvd.highdefdigest.com/669/planetearth.html
Reference (DVDTalk): http://www.dvdtalk.com/reviews/28590/planet-earth-the-complete-bbc-series/

Remuxing Technique:
- I used EAC3To demux the video to MKV
- I used MKVMerge to merge the AC3 file to the demuxed MKV
- The resulting MKV correctly show 23.976FPS under Properties

Playback:
- In every version of MPC-HC, the flicker exists (currently 1.2.958.0)
- I have nothing selected for External Filters - the only things selected under Internal Filters are Matroska (under Source Filters), and H264/AVC (DXVA) and VC1(DXVA) under Transform ilters

http://slaman.homeip.net/images/options.JPG

- I use the EVR Custom Pres.
http://slaman.homeip.net/images/output.jpg

Possible Issues:
- Source has the flicker in it - don't think this is the case because it turns jerky instead of flickery when I set my computer's resolution to 60Hz
- The MKV should playback at 24FPS not 23.976FPS - tried using ReClock, doesn't fix it
- The resolution should be set at 23.976Hz instead of 24Hz (tried using Powerstrip - doesn't fix it)
- TV can't play 24p smoothly

Questions:
- Any ideas on how to get this working?
- Has anyone else gotten perfectly smooth playback of Planet Earth - particularly 24:35 - 24:45 of Episode 2?

[Adub]

I think you are getting things confused. It is often common practice to refer to 23.976 as 24p. As far as I know, I don't think anything is actually shot in 24 fps. It's always 23.976.

However, you say that you have the HD DVD version? So do I. I can take a look if mine replicates the same issues as yours and report back.

[slaman]

I think you are getting things confused. It is often common practice to refer to 23.976 as 24p. As far as I know, I don't think anything is actually shot in 24 fps. It's always 23.976.

However, you say that you have the HD DVD version? So do I. I can take a look if mine replicates the same issues as yours and report back.

I would love it if you could do that... I've had a couple people take a look, and they all see the same flicker... but I think that's more because they can't get true 24p playback.

And I understand that 24p = 23.976... The only thing is that when I set my ATI CCC's resolution, it only says 24Hz - and I'm not sure if it's rounding or not...

[TinTime]

I've just checked mine (it's the UK release) and I think I see what you mean at the 24:35 - 24:45 bit you mention. I think it's just the patterns in the rock though that make it flicker. Possibly they just messed up the filming slightly here and it should be a bit more blurry - a longer exposure per frame or however they deal with these things.

That said you said you can't notice it at 60HZ, whilst I still can. Possibly our TVs are just different here. I'm using a plasma and I think the Toshiba is an LCD. Maybe your TV does some kind of interpolation at 60HZ that it doesn't at 24?

I'm happy that the image is not stuttering though (and doesn't anywhere else in the series). I do have to use Reclock to get smooth playback. My refresh rate as reported by Reclock is actually 23.949 so I will get a dropped frame every now and then if I don't use it.

One final thought - this episode is split evenly into two evos, I would think at the layer change of the HDDVD. I just checked the length of each evo with eac3to and the join is at 24:21. Maybe there was some kind of ripping error around the layer change.

[slaman]

I've just checked mine (it's the UK release) and I think I see what you mean at the 24:35 - 24:45 bit you mention. I think it's just the patterns in the rock though that make it flicker. Possibly they just messed up the filming slightly here and it should be a bit more blurry - a longer exposure per frame or however they deal with these things.

This really could be the case - unfortunately, I haven't been able to find similar scenes in any of my other movies. I notice that it happens with a fast-moving vertical pan that has a lot of horizontal detail. There are a number of scenes in Planet Earth that have this "flicker" phenomenon, or maybe I'm just really hunting for it now.

If you can think of any others movies that have a fast-moving vertical pan, it would be great if you could test to see if the same issue persists!

That said you said you can't notice it at 60HZ, whilst I still can. Possibly our TVs are just different here. I'm using a plasma and I think the Toshiba is an LCD. Maybe your TV does some kind of interpolation at 60HZ that it doesn't at 24?

I think it may be a technology difference between plasmas and LCDs - in my case, which is an LCD, the flicker is replaced by a very noticeable judder. These terms seem nonsensical without being able to show you visually ;)

I'm happy that the image is not stuttering though (and doesn't anywhere else in the series). I do have to use Reclock to get smooth playback. My refresh rate as reported by Reclock is actually 23.949 so I will get a dropped frame every now and then if I don't use it.

One final thought - this episode is split evenly into two evos, I would think at the layer change of the HDDVD. I just checked the length of each evo with eac3to and the join is at 24:21. Maybe there was some kind of ripping error around the layer change.

Interesting - when you saying ripping error, are you suggesting that it might be when I merged the EVOs and converted to MKVs? I just used the appropriate option to create the joined MKV in EAC3To.

[MfA]

Even if the TV did the 5:5 pull-down correctly "smooth 24p" is a contradiction in terms ... the film look is a non smooth look. You are always going to be trading off flicker (noticeable black intervals between frames) against judder (smaller black intervals will force your eyes to focus on the still image of each frame, making it look like stop motion).

The only way you are ever going to get smooth out of a 24 Hz source is by motion compensated conversion. I know you purists hate it, but it's still the plain truth ... smoothness or "pure" 24 Hz, you can have one or the other.

PS. just curious, how well does the smooth setting on your display work with planet earth? ("standard" is 5:5 pulldown, "smooth" is MC conversion).

[slaman]

Even if the TV did the 5:5 pull-down correctly "smooth 24p" is a contradiction in terms ... the film look is a non smooth look. You are always going to be trading off flicker (noticeable black intervals between frames) against judder (smaller black intervals will force your eyes to focus on the still image of each frame, making it look like stop motion).

The only way you are ever going to get smooth out of a 24 Hz source is by motion compensated conversion. I know you purists hate it, but it's still the plain truth ... smoothness or "pure" 24 Hz, you can have one or the other.

PS. just curious, how well does the smooth setting on your display work with planet earth? ("standard" is 5:5 pulldown, "smooth" is MC conversion).

The black intervals between frames you reference - why would that occur in 24p? I thought the human eye couldn't see this?

I'm not too sure the difference between the standard and smooth options on my TV, but the "smooth" option is significantly better.

I wouldn't say that I'm a purist - I just want super-smooth playback - any advice on how to convert the video to compensate for motion? Would love to see the effects...

[TinTime]

Interesting - when you saying ripping error, are you suggesting that it might be when I merged the EVOs and converted to MKVs?

I meant the actual read from the disk. It was just an idle thought really. I suspect if there really had been a read error it would be very noticeable.

As MfA says it's probably that 24fps isn't enough for fast moving detail like this. In feature films I guess they would avoid this kind of shot altogether. I don't know where you're located but I've heard it said that people who grew up with PAL (like me) are used to flicker but sensitive to judder, whereas those who grew up with NTSC are the opposite. If this is the case then we're into the realms of visual psychology and I probably can't help :)

Another idea - you could turn down the sharpness control on your TV and / or PC. Perhaps if the image is softer it will appear less flickery. This is pure guesswork though.

You're right though. Without being able to see what you're seeing it's hard to say what the issue might be.

[MfA]

The black intervals between frames you reference - why would that occur in 24p?
The black intervals don't have to occur ... the motion just looks better if they do occur. As I said, it's a trade off between flicker and judder ... if you have 0 black interval between frames you have maximum judder.
I'm not too sure the difference between the standard and smooth options on my TV, but the "smooth" option is significantly better.
The smooth option does motion compensated conversion, so you don't get true 24 Hz anymore ... motion compensated conversion does have the tendency to fail now and then, so maybe that is the flicker you are seeing.
I wouldn't say that I'm a purist - I just want super-smooth playback - any advice on how to convert the video to compensate for motion? Would love to see the effects...
The TV does that for itself, that's what it is doing when you turn on the smooth setting. If you would want to do it with say Avisynth, MVTools and some of the scripts based on it can do motion compensated framerate conversion too.

[TinTime]

You are always going to be trading off flicker (noticeable black intervals between frames) against judder (smaller black intervals will force your eyes to focus on the still image of each frame, making it look like stop motion).

I didn't think you got black intervals between frames on plasmas / lcds / dlps. Only at the cinema when running film through a projector. Flickering or strobing comes from short exposure times for each frame as done deliberately in Saving Private Ryan and Band of Brothers.

[MfA]

I didn't think you got black intervals between frames on plasmas / lcds / dlps.
True, they tend to go for maximal judder ... I'm just saying that it's a mixed blessing. As long as you are stuck at 24 Hz it will suck one way or the other.
Only at the cinema when running film through a projector. Flickering or strobing comes from short exposure times for each frame as done deliberately in Saving Private Ryan and Band of Brothers.
Traditional film projectors will obviously have black intervals, have to find some time to move the film forward.

[2Bdecided]

As long as you are stuck at 24 Hz it will suck one way or the other.There are forums where I could put that as my signature and get hate mail! ;) It's true though.

Cheers,
David.

[slaman]

True, they tend to go for maximal judder ... I'm just saying that it's a mixed blessing. As long as you are stuck at 24 Hz it will suck one way or the other.

Traditional film projectors will obviously have black intervals, have to find some time to move the film forward.

So are you suggesting that 24p material cannot be played smoothly without either judder or flicker given today's technology?

[MfA]

That's a rather negative way to put it, the smooth setting on your Regza seems to be getting it right most of the time already ... it's only going to get better.

5:5 pulldown (the standard setting) could still be improved a bit with blackframe insertion to get closer to the true film look ... although I'd rather see better motion compensated framerate conversion myself, I see no intrinsic value in the film look.

[slaman]

That's a rather negative way to put it, the smooth setting on your Regza seems to be getting it right most of the time already ... it's only going to get better.

5:5 pulldown (the standard setting) could still be improved a bit with blackframe insertion to get closer to the true film look ... although I'd rather see better motion compensated framerate conversion myself, I see no intrinsic value in the film look.

It is a negative way to put it, but unless there is a firmware update for my Toshiba that improves the motion-compensated smooth setting, this is about as good as it gets eh?

Well, thanks for explaining the situation to me so clearly... without it, I know I would have wasted another 100+ hrs trying to get the perfect playback!

[TinTime]

An update to this story.

It occurred to me that the audio on this HDDVD sounds a little dodgy - it contains the kind of artefacts you get when changing the speed of the audio and then correcting the pitch. So I rented out the PAL DVD version. The DVD audio sounds correct.

From this, and the fact that it it's a BBC production, I reckon that it should be played back at 25fps rather than ~24fps. It would make it a little less flickery.

The two extra episodes of Natural World on the last disk are definitely 25fps material that's been changed to 60i.

I guess it was slowed down for the NTSC market. Do HDTVs in NTSC areas not do 50Hz I wonder? I've got the first series of Torchwood (also BBC) on HDDVD as well and that has also been changed from 25p or 50i to 60i.

[2Bdecided]

It's a disgrace that the BBC releases 50i content in 60i the world over, but they've either decided that it's cheaper than doing two separate versions, or that 50i isn't/wasn't well supported even in the UK, and so have taken the "easy" (and poor quality!) way out. EDIT: or, being charitable, maybe they think lots of UK users have imported US BluRay players (e.g. US PS3s) which won't play 50i.

I think it's most likely they want to make one disc for a worldwide market, and since many US players (inc US PS3s) won't do 50i at all, it has to be 60i. Shame :(

Cheers,
David.

[Ryokurin]

What video card are you using? It's my understanding that ATI cards have trouble with 24fps playback resulting in stuttering like you are having.