DV Info Net - GH2 24p Cadence "judder"...

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- Panasonic LUMIX S / G / GF / GH / GX Series (https://www.dvinfo.net/forum/panasonic-lumix-s-g-gf-gh-gx-series/)

- - GH2 24p Cadence "judder"... (https://www.dvinfo.net/forum/panasonic-lumix-s-g-gf-gh-gx-series/505504-gh2-24p-cadence-judder.html)

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Steven Bills (Post 1716775)

https://vimeo.com/37309808

PS: That's as smooth a pan as I have ever done, and it still looks choppy!

The Vimeo file is 30p. The judder is either because you edited 24p on a 30p timeline or because Vimeo converted it to 30p after uploading. This is an example of how 24p looks when played back at 30p using duplicate frames.

Re: GH2 24p Cadence "judder"...

@Eric: I made sure that I was editing the video at 23.976 fps. Could this actually be my problem?? Should I be editing at an even 24p rather than 23.976?

Also, is vimeo converting my 24p stuff to 30p?!?

And I am not sure I like the look of the 1/30 SS stuff...

SB

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Don Litten (Post 1720052)

David, is that a hack or stock?

Hacked but the only thing I did was boost the bit rate from 22000000 to 42000000

Re: GH2 24p Cadence "judder"...

It's doubtful that any hack would help much with judder. Generally the hacks are dealing with bit rate increases that don't change the limitations of capturing movement with a limited number of frames per second.

1/30 shutter speed certainly would reduce judder as the image smear connects the frames better. It certainly makes the pan shots posted earlier smoother. However we start to enter a realm of issues caused by slow shutter speeds which start to translate to slower frame rates. Essentially frame rates slower than 18 frames impart a dreamlike quality to movement. 1/30 shutter speed works with modest subject motion but fast motion starts to look odd.

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Steven Bills (Post 1720060)

Using 23.976 fps is correct, but there is something wrong with your workflow. The streaming video file on Vimeo is 30p and has the exact 4:5 cadence that you get by duplicating one frame out of every 4 to fit 24p into 30p. Here is the output from mediainfo for your Vimeo file:

Code:

General

Complete name                    : 37309808-hd.flv

Format                           : MPEG-4

Format profile                   : Base Media

Codec ID                         : isom

File size                        : 2.31 MiB

Duration                         : 7s 367ms

Overall bit rate                 : 2 634 Kbps

Encoded date                     : UTC 2012-02-22 14:08:24

Tagged date                      : UTC 2012-02-23 14:08:24



Video

ID                               : 1

Format                           : AVC

Format/Info                      : Advanced Video Codec

Format profile                   : High@L3.1

Format settings, CABAC           : Yes

Format settings, ReFrames        : 4 frames

Codec ID                         : avc1

Codec ID/Info                    : Advanced Video Coding

Duration                         : 7s 367ms

Bit rate mode                    : Variable

Bit rate                         : 2 477 Kbps

Maximum bit rate                 : 3 890 Kbps

Width                            : 1 280 pixels

Height                           : 720 pixels

Display aspect ratio             : 16:9

Frame rate mode                  : Constant

Frame rate                       : 30.000 fps

Color space                      : YUV

Chroma subsampling               : 4:2:0

Bit depth                        : 8 bits

Scan type                        : Progressive

Bits/(Pixel*Frame)               : 0.090

Stream size                      : 2.18 MiB (94%)

Writing library                  : Vimeo Encoder

Encoded date                     : UTC 2012-02-22 14:08:24

Tagged date                      : UTC 2012-02-22 14:08:24



Audio

ID                               : 2

Format                           : AAC

Format/Info                      : Advanced Audio Codec

Format profile                   : LC

Codec ID                         : 40

Duration                         : 7s 82ms

Bit rate mode                    : Variable

Bit rate                         : 157 Kbps

Maximum bit rate                 : 180 Kbps

Channel(s)                       : 2 channels

Channel positions                : Front: L R

Sampling rate                    : 44.1 KHz

Compression mode                 : Lossy

Stream size                      : 136 KiB (6%)

Encoded date                     : UTC 2012-02-22 14:08:24

Tagged date                      : UTC 2012-02-22 14:08:24

I would recommend checking the original file you uploaded with mediainfo.

http://mediainfo.sourceforge.net/en

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Eric Olson (Post 1720077)

Using 23.976 fps is correct, but there is something wrong with your workflow.

Definitely something wrong with his workflow.

Re: GH2 24p Cadence "judder"...

Workflow aside. Just thought I would chime in and give you guys a link that shows some really good motion characteristics using 1/40 and a Orion hack for the gh2 that is optimized for the motion.

https://vimeo.com/35999739

The guy is really helpful and is a font of information. I think the motion looks as smooth as most of the high end cameras Ive seen.

Maybe the hack can help some?

Re: GH2 24p Cadence "judder"...

Steve, I'll have to look into that hack and those settings some...

But since the last few posts have talked about workflow, I thought I'd chime in again with another video. This was shot at 24p at 1/50, edited at 23.976, and rendered at 23.976.

https://vimeo.com/38299244

Let me know what you think, and if you still see some judder.

SB

Re: GH2 24p Cadence "judder"...

Yes, I see the judder your talking about. I would look into the hack I mentioned for the smoother motion and see if that helps some. I usually try to avoid panning as much as possible or I do it really slow.

I remember when I used to export 1280x720 h.264 and upload to vimeo I would get color and motion issues. Someone told me to start using 1280x720 Windows Media Video file output 10k bitrate and I havent
noticed anything weird going on anymore with colors either. I don't know if its due to the way vimeo handles re-compression or what but its worth looking into. Its all I use now and Ive been very happy.

P.S. I am definitely no expert, just my experiences and talking to various people.

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Steven Bills (Post 1720607)

Let me know what you think, and if you still see some judder.

Vimeo has converted your 23.976 fps .wmv file to a 30 fps .flv file. The original file does not have judder, but the streaming video has the same judder as before. I don't know why Vimeo is messing with the frame rate. Try uploading a .mp4 file instead.

Re: GH2 24p Cadence "judder"...

I converted your .wmf file to .mp4 with ffmpeg

http://ffmpeg.org/

using the command

Code:

ffmpeg -sameq -i 88459348.wmv -y 88459348.mp4

and then uploaded it. Vimeo had no trouble creating a proper 23.976 fps .flv file for streaming.

Re: GH2 24p Cadence "judder"...

Quote:

Originally Posted by Eric Olson (Post 1720622)

Vimeo had no trouble creating a proper 23.976 fps .flv file for streaming.

Now your talking! That looks as it should. Problem solved!:)

Re: GH2 24p Cadence "judder"...

woops. I missed that you already were using a .wmv file. Anyway I am glad it worked out for you. I use TMPGENC, so I don't know how much is/if any difference with the various encoders.

Cheers!

Re: GH2 24p Cadence "judder"...

So I hacked my GH2 last night after reading the post above. I will do some tests and post again! Except this time I will upload an mp4 instead of a wmv.

Does anyone know if anybody else has had this 24p --> 30p problem with vimeoo??

SB

Re: GH2 24p Cadence "judder"...

Okay so here is a test with the Quantum v9b hack (the hack which was mentioned above).

Settings are the same as before, except I uploaded an mp4 file to vimeo instead of a wmv, thus (hopefully) preventing the 24p --> 30p conversion.

Let me know what you think.