unsmooth camera pans

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sdm
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unsmooth camera pans

Post by sdm »

First off, nice work on this so far.

I've encoded my dvd Lord of the Rings - Felllowship of ... This movie has a lot of camera pans and many cases they don't play smoothly.
The framerate is ntsc film. The files are .AVI(h264+AC3)

I'm concerned that MediaFork may be dropping frames.

When I play the dvd on my mac the motion seems smooth.

Anyone have any thoughts on this?

BTW - I haven't seen this problem on my other encodes.

Thanks,
--sdm.
jbrjake
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Re: unsmooth camera pans

Post by jbrjake »

sdm wrote:This movie has a lot of camera pans and many cases they don't play smoothly.
When you encode, are you setting the FPS to 23.976 or are you leaving it as "same as source"? Sometimes when left to its own devices, MediaFork/HandBrake gets confused and uses 29.97 fps instead, which will produce jerky pans.
sdm
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Post by sdm »

jbrjake wrote: Sometimes when left to its own devices, MediaFork/HandBrake gets confused and uses 29.97 fps instead, which will produce jerky pans.
Hi Jbrjake
Yes, I ran it that problem in the past with Handbrake.
But the answer is no, I didn't manually set the framerate. But MediaFork got it right. VLC and QT both report 23.976 fps.

I just encoded LOR-Return of the King (the third movie). I ***think*** it doesn't have the same issue.

Can you help? I can send you a portion showing the problem.

thanks,
--sdm.
hawkman
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Post by hawkman »

What kind of resolution are you encoding to? Losing pixels will increase jerkiness. Note that unless you're using the anamorphic encoding, even at 720x??? you're losing a lot of vertical pixels...
sdm
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Post by sdm »

720x480 anamorphic cropped to 720x368 anamorphic = 853x368 square pixels.

I think I'm not losing any lines of resolution. i.e. if I hadn't cropped, the frame would still be 480 lines tall.

Maybe as a test, I should re-encode without cropping? What do you think?

-- sdm.
golias
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Post by golias »

sdm wrote:720x480 anamorphic cropped to 720x368 anamorphic = 853x368 square pixels.

I think I'm not losing any lines of resolution. i.e. if I hadn't cropped, the frame would still be 480 lines tall.

Maybe as a test, I should re-encode without cropping? What do you think?

-- sdm.
You haven't mentioned what you are using for playback, and what you might be running in the background.

h.264 is an impressive-looking format, and it requires a fairly narrow stream for high-quality images, but it does require a little more CPU horsepower to decode than simpler formats.

Both Quicktime and VLC will drop frames to cope with a computer that is not keeping up with the stream for some reason.

Another possibility is that you accidentally left the "de-interlace" box checked when you did your rip, and so the jerkiness is the result of frame-doubling.

Just spit-balling a few things which could be the problem.
sdm
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Post by sdm »

Hi Golias,

Thanks for the ideas. I'm running OSX 10.4.8 on both a dual 1.8GHz G5 PowerMac and an Intel 1.6 GHz Core Dou Mac mini. I've tried on both macs in both VLC and QT. The problem seems to be consistant, no matter what I try.

Its definitely not a de-interlace problem.

I think I'll encode as xvid tonight and see if I notice any difference. After that, I'll try mpeg streamclip. That may help pinpoint if its MF or something else.

I'll report back if I find a solution.
sdm
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Gonna Give up

Post by sdm »

I've reluctantly decided that I must be over-sensitive to this (possibly non-) issue - like I'm looking so hard for it, that I'm seeing it everywhere. Now I see it when watching TV too. If I focus on the subject instead of the moving background, its okay.

I said I would report though.
I encoded to MF's AVI(divx+ac3) and AVI(divx+ac3) and streamclip's AVI(divx+ac3). Seems like the same thing, but maybe the scenes are just so complex that, as Golias said, the computer is not displaying properly.
(for the record QT reports 'Playing FPS' fluctuating between 23.5 and 24.5 fps. VLC reports no dropped frames).

Yes, I think thats it! The encoded move doesn't have dropped frames, rather QT (or VLC) decodes a little slow for a fraction of a second, then speeds up to catch up.
This is causing the 'unsmooth motion'. Does this seem likely to anyone?

Opinions?
-sdm.
hawkman
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Post by hawkman »

Entirely possible - on my old PowerBook the fps fluttering like that was usually a sign QuickTime was working as hard as it could.
Spazgadget
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Post by Spazgadget »

SDM, there's good news and bad news.

The good news is you're not going crazy. I've had the exact same problem with everything I've ripped on a dual 2.0 Ghz G5 running 10.4.9. Video quality is great with the exception of barely-noticeable jerky motion, as though it's missing one out of 20 frames or something.

The bad news is I've never found a solution for this (but would love to) - I've tried varying framerates and bit rates, to no avail. I wondered if the QT issue was the problem, but the files seem to play exactly the same on my AppleTV...

Not a dealbreaker, and it's something only I seem to notice, but it's definitely a little distracting to me, especially (as you mention) in pans or motion shots. Everything is just a little jerky.

Anyone figuring out a solution will be rewarded with my undying devotion, and possibly a nice mix cd for your troubles :)
Seifer
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Post by Seifer »

I had this exact problem but it was fixed by setting framerate manually, or by using ffmpeg.

If you still have the problem after setting the framerate, perhaps run the same file with similar settings through ffmpeg to see if its still choppy. That would tell us if it was a problem with handbrake or not.
golias
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Post by golias »

Spazgadget wrote:SDM, there's good news and bad news.

The good news is you're not going crazy. I've had the exact same problem with everything I've ripped on a dual 2.0 Ghz G5 running 10.4.9. Video quality is great with the exception of barely-noticeable jerky motion, as though it's missing one out of 20 frames or something.

The bad news is I've never found a solution for this (but would love to) - I've tried varying framerates and bit rates, to no avail. I wondered if the QT issue was the problem, but the files seem to play exactly the same on my AppleTV...

Not a dealbreaker, and it's something only I seem to notice, but it's definitely a little distracting to me, especially (as you mention) in pans or motion shots. Everything is just a little jerky.

Anyone figuring out a solution will be rewarded with my undying devotion, and possibly a nice mix cd for your troubles :)
Is it possible that you guys have a video refresh rate which is badly out of synch with the frame rate of the videos you are watching?

Or possibly a video card set for an interlaced output going to a progressive-scan display?

Again, without actually seeing it for myself, all I can do is throw out wild guesses based on some of the things which <i>can</i> cause jerky pans.

Oh. Here's a question. Does the jerkiness happen on both vertical & horizontal pans, or just the horizontal ones?
hawkman
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Re: unsmooth camera pans

Post by hawkman »

jbrjake wrote:When you encode, are you setting the FPS to 23.976 or are you leaving it as "same as source"? Sometimes when left to its own devices, MediaFork/HandBrake gets confused and uses 29.97 fps instead, which will produce jerky pans.
Is this useful advice for PAL regions too? I know it depends partly what's been done with the video to convert it, but for instance if it's been speeded up so it runs at 25fps - will HB detect that it's 25 or get confused? Anyone know? :)
Spazgadget
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Post by Spazgadget »

Golias - I've run the video on everything from a Powerbook to an iMac, to AppleTV, to a dualie G5. I've manually set framerate to the exact framerate specified in the dvd player menu. Haven't tried ffmpeg but will try that next.

It doesn't seem to be about vertical or horizontal pans per se, the whole video just has a slight "strobe" effect. Again, it looks like it's just stopping one frame, every 20 frames or so. Logically it seems like it's just an incorrect framerate setting, but nothing I try (see above) has any effect on it.

At this point I'm just learning to live with it, but am always open to ideas!
depeche818
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Post by depeche818 »

Spazgadget wrote:Golias - I've run the video on everything from a Powerbook to an iMac, to AppleTV, to a dualie G5. I've manually set framerate to the exact framerate specified in the dvd player menu. Haven't tried ffmpeg but will try that next.

It doesn't seem to be about vertical or horizontal pans per se, the whole video just has a slight "strobe" effect. Again, it looks like it's just stopping one frame, every 20 frames or so. Logically it seems like it's just an incorrect framerate setting, but nothing I try (see above) has any effect on it.

At this point I'm just learning to live with it, but am always open to ideas!
I am having similar issues, and I have noticed that it only seems to happen when I start at the beginning of a DVD, if I start at chapter 2, everything is smooth. Another thing that I have noticed is that it doesn't do this when I don't use the deinterlacer... so maybe it has something to do with that. The DVD in question ( and the first I have tried to use MediaFork with ) is the Sarah Silverman Jesus is Magic DVD.

Anyone else know what may be the cause of this?

Thanks
rhester
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Post by rhester »

I saw a report today on IRC that the "strobe" effect is Apple TV-specific and may be related to a too-high bitrate on your encode.

Rodney
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Post by depeche818 »

rhester wrote:I saw a report today on IRC that the "strobe" effect is Apple TV-specific and may be related to a too-high bitrate on your encode.

Rodney

I am having this issue on my Mac Mini whilst playing the file through QuickTime or FrontRow
rhester
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Post by rhester »

You're seeing strobing or skipping? Strobing is a problem specific to Apple TV with high bitrates, jerkiness is a mismatch between the source DVD framerate and the ripped framerate.

Rodney
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Post by depeche818 »

rhester wrote:You're seeing strobing or skipping? Strobing is a problem specific to Apple TV with high bitrates, jerkiness is a mismatch between the source DVD framerate and the ripped framerate.

Rodney
It looks like skipping, though the framerate is the same as one that doesn't skip...It's very odd, as it only seems to happen if I start at the first chapter. If I start at chapter 2, the entire DVD rip is fine, but if I start at chapter 1, it skips ... It's subtle, but it's definitely noticeable. I wonder if there's something about the DVD Format that makes this happen, or if it's something with Handbrake / Mediafork....
rhester
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Post by rhester »

It's actually quite likely that you have a title where the first chapter is at a different framerate from the second chapter. This is most common in NTSC TV episodes where chapter 1 is the intro (often at 29.97) and chapter 2+ are the show itself (at 23.976). If that's the case, it's a hard call - ripping at 29.97 will solve the intro problem but introduce subtle smoothness problems during the show itself, where ripping at 23.976 will make the intro look awful but the show look good. There are advanced frame decimation and blurring filters for some ripping tools (not HandBrake) that partially mitigate this problem, but in general, mixed-rate content is a bear to work with.

Rodney
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Post by depeche818 »

Thanks for the tip...I'll check it out and see if that is indeed the problem. The odd thing is, that it doesn't seem to do this if I process the file through, say, MPEG StreamClip. MPEG StreamClip's quality doesn't look as good as MediaFork though, so I wanted to avoid it. It also doesn't seem to happen in MediaFork if I don't use the deinterlacer, or maybe it's just less apparent.

I'll check it out and report my findings. Thanks again for your help
Deleted User 803

Post by Deleted User 803 »

rhester wrote:I saw a report today on IRC that the "strobe" effect is Apple TV-specific and may be related to a too-high bitrate on your encode.

Rodney
And what would be "too high"? I average my videos at 1.5mb/s MP4, and I'm very happy with the quality, but on my AppleTV, it does give me the feel like once every second or so, it's skipping a frame. Not sure if anyone else sees this, but I don't notice these problems when playing back on my macbook. Also, it might be that some of the dvds in question are ripped to the hard drive with MTR, and then backed up with DTOX. Maybe DTOX is causing all my problems? Anybody else doing this procedure? It seems like I'm mostly having issues with TV Show DVDs, like 4400 especially. With 4400, I had one episode that was repeating a frame even at 30fps, every 5th frame, while other episodes on the same disc were fine at 24fps. That episode at 24fps repeated every 4th frame, and was awful.
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