The FPS Question?

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gswhite
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Joined: Fri Mar 23, 2007 3:46 pm

The FPS Question?

Post by gswhite »

Been searching the forums but not found exactly the answer I ened, and was wondering if anyone could help here?

I am using the latest beta of Handbrake 0.8.5b1 and am encoding using the Preset 'AppleTV' for my videos.

However I have noticed on a couple of the latest encodes that Video content from a DVD that was sourced from a PAL 25FPS DVD has severe stutter when being played back.

It's unwatchable when streaming, and when you sync to the internal HD, it improves but not by much.

There is no mention of 25FPS on Apple's tech information on the AppleTV website, can it actually play PAL 25 FPS and is this maybe the problem?

any help much appreciated.

thanks
G

jbrjake
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Post by jbrjake »

...well, wouldn't the easy way to find out be to encode a chapter at 25fps and see how it plays?

gswhite
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Post by gswhite »

jbrjake wrote:...well, wouldn't the easy way to find out be to encode a chapter at 25fps and see how it plays?
It was encoded at 25 fps :) It was set manually using Handbrake after I checked in Mplayer and FFMpegX

It plays Awful and there is so much stutter it will not play on the AppleTV at all.

I tried another rip of the 1st 4 chapters of the source DVD and the same happens when setting Handbrake to use 'Same as Source'

If there is anymore information I can give you please let me know?

Cheers
G

jbrjake
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Post by jbrjake »

What exactly does this mean?
Video content from a DVD that was sourced from a PAL 25FPS DVD
Are you saying that you have a DVD that's a transfer from a PAL DVD? In that case, are you sure that a pal->ntsc conversion wasn't applied then? What happens when you directly specify 23.976 fps, or 29.976fps?

gswhite
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Joined: Fri Mar 23, 2007 3:46 pm

Post by gswhite »

jbrjake wrote:What exactly does this mean?
Video content from a DVD that was sourced from a PAL 25FPS DVD
Are you saying that you have a DVD that's a transfer from a PAL DVD? In that case, are you sure that a pal->ntsc conversion wasn't applied then? What happens when you directly specify 23.976 fps, or 29.976fps?
It's a PAL DVD that runs as 25 fps. No conversion has taken place, It is a region 2 PAL DVD ripped with MTR and then run through Handbrake, setting the fps to 25.

The Video file plays fine on any one of my Mac's but not on the AppleTV system either via streaming or syncing.

Thanks Again
G

deckeda
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Re: The FPS Question?

Post by deckeda »

gswhite wrote: ... and when you sync to the internal HD, it improves but not by much.
So try knocking down the bitrate a little, or at the very least letting us know the particulars of your conversion.

gswhite
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Re: The FPS Question?

Post by gswhite »

deckeda wrote:
gswhite wrote: ... and when you sync to the internal HD, it improves but not by much.
So try knocking down the bitrate a little, or at the very least letting us know the particulars of your conversion.
Ok here is conversion spec -

3000kbps
44 Khz 160kbps audio
Anamorphic setting - ON

It produced a file roughly 2.6GB in size. I have ripped with this configuration many times, but only experienced this problem since going to 0.8.5b1

Hope this information is helpful?

thanks
G

cvk_b
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Post by cvk_b »

Try 48 Khz Audio, Anamorphic off.

jbrjake
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Post by jbrjake »

I don't think changing the audio samplerate will really change anything, unfortunately.

Lowering the bitrate to 2500 might help.

But if it plays fine on your computer but not the AppleTV...then, yeah, maybe it can't handle 25fps. Which is odd, as the device is sold in PAL countries...I figured the tech specs were just North America oriented.

You might try just lowering the fps to 24 or 23.976, and see what happens. That output might stutter on the computer like it does on the aTV, indicating it is definitely the appletv dropping frames from 25fps.

voxsola
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Post by voxsola »

FWIW... I don't have an AppleTV however I did rip a PAL DVD with MacTheRipper and used Handbrake to convert videos for my iPod. I set the FPS to 29.97 and they play fine on the computer, with QT, in iTunes and on my iPod.

gswhite
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Joined: Fri Mar 23, 2007 3:46 pm

Post by gswhite »

Well I am more confused then ever, lol.

I have tried to encode the movie in question 3 times now, each time with the same result, even if I drop the FPS.

So I thought I would try another PAL DVD source. My Wife recently purchased 'Miss Potter' which is a PAL DVD standard 25 fps.

So I encoded that video and it's perfect! Plays fine, no stuttering at all.

So it's certainly not the case that AppleTV can not play PAL 25 fps.

I tried some other encoding software on the problematic source material and that encoded fine as well, although with only stereo sound.

G

rdaulton
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stuttering video

Post by rdaulton »

I have noticed this problem too, and it took some time to figure it out. What's going on is a framerate difference between "normal" framerates, and DVD output. :? Let me explain:

***Numbers are for NTSC standards.... please adjust number for PAL accordingly***

Normal Framerates:
Film - 24fps
TV/Video - 29.97fps

Now, you would assume that the framerate used on a DVD would be the same frame rate as the ORIGINAL source--DVD's made from movies captured on film would be 24fps, and movies made from video would be 29.97fps.

When converting using HB, naturally I would set the Framerate setting to "Same as source". For some reason, I kept getting videos that would stutter, or seem jerky... almost to the point that it was too hard to watch.

But the problem seemed familiar... it showed the same characteristics of a bad video capture when I do editing. I captured DV-NTSC video using FCP, but instead of using the native framerate (29.97), I captured at 24fps. :shock:

The final video I ended up with came out jerky... exactly the same problem that I'm having now... :idea:

I looked at the fps reported by Quicktime for each video I had converted with HB, and noticed that all were converted using 24fps--which was fine for some. I have no idea why, but some DVDs are encoded at 29.97fps! Even ones that were originally filmed with celluloid, and not DV.

Forcing HB to use 29.97fps instead of "Same as source" fixed this problem for each video that had the stutter problem.

My suggestion is to convert a couple of chapters using different framerates and see which works best for each film. I know this has worked for me, and I hope it works for you.

Good Luck!

gswhite
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Joined: Fri Mar 23, 2007 3:46 pm

Re: stuttering video

Post by gswhite »

rdaulton wrote:I have noticed this problem too, and it took some time to figure it out. What's going on is a framerate difference between "normal" framerates, and DVD output. :? Let me explain:

***Numbers are for NTSC standards.... please adjust number for PAL accordingly***

Normal Framerates:
Film - 24fps
TV/Video - 29.97fps

Now, you would assume that the framerate used on a DVD would be the same frame rate as the ORIGINAL source--DVD's made from movies captured on film would be 24fps, and movies made from video would be 29.97fps.

When converting using HB, naturally I would set the Framerate setting to "Same as source". For some reason, I kept getting videos that would stutter, or seem jerky... almost to the point that it was too hard to watch.

But the problem seemed familiar... it showed the same characteristics of a bad video capture when I do editing. I captured DV-NTSC video using FCP, but instead of using the native framerate (29.97), I captured at 24fps. :shock:

The final video I ended up with came out jerky... exactly the same problem that I'm having now... :idea:

I looked at the fps reported by Quicktime for each video I had converted with HB, and noticed that all were converted using 24fps--which was fine for some. I have no idea why, but some DVDs are encoded at 29.97fps! Even ones that were originally filmed with celluloid, and not DV.

Forcing HB to use 29.97fps instead of "Same as source" fixed this problem for each video that had the stutter problem.

My suggestion is to convert a couple of chapters using different framerates and see which works best for each film. I know this has worked for me, and I hope it works for you.

Good Luck!
Thanks for all the excellent information and I will keep that in mind. I have tried one more time to encode the video.

This time I left the Frames to be set 'Same as Source' but used Constant quality of 70% using CRF.

And Voila! Perfect! No problems at all, no Stutter, nothing! Very strange and very weird.

SO short term my problem is solved, but woud like to get this down as an exact science so I know what to encode and how the bext way to encode video is...

G

deckeda
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Re: stuttering video

Post by deckeda »

rdaulton wrote:Forcing HB to use 29.97fps instead of "Same as source" fixed this problem for each video that had the stutter problem.
That would be because I think it was rhester who clarified that "same as source" is simply mislabled. That setting is actually always 23.97fps (i.e. film) --- HB doesn't really sense the source's fps. And so using a framerate that's too slow can give you the st-st-stutters.

deckeda
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Joined: Thu Feb 22, 2007 8:38 am

Post by deckeda »

^^ Clarification, from this thread: http://handbrake.m0k.org/forum/viewtopi ... =7212#7212
jbrjake wrote:To explain a bit, in case you've been using it, the "Same as Source" drop-down in the Mac GUI is misleading to the point it's a bug. It only deals with PAL versus NTSC, not with whether the DVD is at film or video speed. It needs to be renamed and should have been before this beta...sorry.
clee wrote: ... Well, [Handbrake does] detect the proper *initial* framerate. The problem is that DVDs contain video content that can actually change framerate in the middle of the video stream. That's harder to fix, because as far as I know that's not something we can do mid-stream with our existing output libraries.

hawkman
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Post by hawkman »

As hinted at there, frame rte worries are generally irrelevant on PAL DVDs - it's 25fps, although there's no telling how it was decimated to reach that of course...

Sounds like in this case, there was some combination of settings that the ATV was struggling to decode... a high number of pixels, plus a high bitrate, plus a high framerate. As I've said before, the ATV is a computer: there's only so much it can do at once. Lower the load in one area (say, bitrate) and you'll be able to push it a little further in other areas (like framerate). That's why the suggestion to lower the bitrate was raised a couple of times.

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