View Full Version : GH1 720p30 mode


Steve Mullen
March 5th, 2009, 10:26 PM
Although the GH1 can record using AVCHD, it can also record to Photo-JPEG which is very EZ to edit. One potential issue -- recording is at the non-video rate of 30.00fps rather than 29.97fps.

I've got video samples, but no way to host.

Bill Koehler
March 5th, 2009, 10:35 PM
Steve,

If you would confirm for me, the video bitrate for the JPEG video is 30.8 Mbps?
I'm just not used to seeing numbers that high in a consumer product.

On the other hand, the audio numbers, especially the 16 KHz sampling rate, confirms that anyone half way serious about shooting with this will be recording double system audio.

16KHz might be OK for dialog, but not for any kind of musical performance.

Paulo Teixeira
March 5th, 2009, 10:38 PM
If it’s a bandwidth issue, you can either upload it to a file sharing site, Vimeo, or I’m sure Chris Hurd wouldn’t mind hosting them.

Liza Witz
March 5th, 2009, 11:04 PM
Can you upload them to Vimeo? IF you do so, you can set it so that others can download the original files (if they have a free Vimeo membership.)

I'm keen to see and play with any examples from the GH1.

Steve Mullen
March 5th, 2009, 11:16 PM
Steve,

If you would confirm for me, the video bitrate for the JPEG video is 30.8 Mbps?
I'm just not used to seeing numbers that high in a consumer product.

On the other hand, the audio numbers, especially the 16 KHz sampling rate, confirms that anyone half way serious about shooting with this will be recording double system audio.

16KHz might be OK for dialog, but not for any kind of musical performance.

Remember this is, contrary to what I thought I'd read, Photo-JPEG not Motion-JPEG. So the data rate seems right.

Bill Koehler
March 6th, 2009, 12:43 AM
Steve, Thanks. Just trying to make sure what little I know, I know.

Adrian Frearson
March 6th, 2009, 02:36 AM
Steve

Thanks for posting this info. I'm really look forward to seeing some clips from this camera, other than the tiny ones on the Panasonic website. There must be a few typos in the Panasonic specs for the camera DMC-GH1 | PRODUCTS | LUMIX | Digital Camera | Panasonic Global (http://panasonic.net/avc/lumix/systemcamera/gms/gh1/specifications.html)

It does say Motion Jpeg, Photo Jpeg is unusual I think as a camera codec, but I'd welcome it as it's great to work with even if it would fill up memory cards pretty quickly!

Adrian

Henry Olonga
March 6th, 2009, 04:29 AM
Hi Steve,I too look forward to some samples of the video.I second Vimeo.Easy sign up and we can download the original.Or Exposureroom as well.Take care
H

Steve Mullen
March 6th, 2009, 03:19 PM
Hi Steve,I too look forward to some samples of the video.I second Vimeo.Easy sign up and we can download the original.Or Exposureroom as well.Take care
H

Give me a few days I'll do ExposureRoom.

Jose A. Garcia
March 8th, 2009, 10:37 AM
Do you have 1080p24 samples too?

Steve Mullen
March 8th, 2009, 08:35 PM
Do you have 1080p24 samples too?

Yes. But AVCHD can't be uploaded.

Ivan Pin
March 9th, 2009, 09:47 PM
Steve, you can upload raw samples here: RapidShare: Easy Filehosting (http://www.rapidshare.com/)

It's free.

Steve Mullen
March 10th, 2009, 01:21 AM
OK -- here is the link to ExposureRoom:

Steve Mullen On ExposureRoom - Videos

Remember these are 3rd generation videos. Anyway, I was checking for motion judder because I could see noise in the prototype which meant it was not a unit I was going to use for pix quality checks. You can also see the AF and AE at work.

The zoom ring was so stiff there was no way I was going to try zooming while shooting. Big negative for run & gun.

The other negative -- I have small hands and the grip was WAY too tiny to feel good and to feel solid. Pana skimped it a crucial area.

The switches and manual controls were wonderful. The symbols made no sense to me or to the rep.

Enjoy!

Kevin Shaw
March 25th, 2009, 01:12 PM
One potential issue -- recording is at the non-video rate of 30.00fps rather than 29.97fps.

What would be the visual consequences of shooting and editing 30.0 fps and then rendering out to standard HD video at 29.97 fps?

Anna Uio
June 17th, 2009, 04:35 PM
What would be the visual consequences of shooting and editing 30.0 fps and then rendering out to standard HD video at 29.97 fps?

I believe it is simply that every 1000th frame is dropped. Also audio will build up a lag with video by 1 frame, i.e. 1/30th of a second, over a period of 1000 frames (33.33 seconds), and then instantly catch up when the frame is dropped.

Some software will blend frames instead of just dropping, but that looks terrible, and causes a weird periodic blur that comes and goes every 33 seconds.

Cheers,
Anna

Brett Sherman
June 19th, 2009, 09:11 AM
You could also "Conform" the footage to 29.97p in Apple's Cinema Tools. That would change the audio sample rate and require FCP to convert the sample rate in the timeline. To me it's better to manipulate the audio rather than the video.

You could also process the audio separately from the video by making AIFFs from the original video file and just remember to remove an audio frame every 30 seconds to keep it in sync. A dropped frame in video is usually obvious, not so with audio if it is chosen carefully.

Steve Mullen
June 19th, 2009, 09:38 PM
I believe it is simply that every 1000th frame is dropped. Also audio will build up a lag with video by 1 frame, i.e. 1/30th of a second, over a period of 1000 frames (33.33 seconds), and then instantly catch up when the frame is dropped.


Given shots are typically 20- to 30-seconds long -- this should not be a major issue. These shots are then trimmed to 5- to 10-seconds.