MOV, Motion jpeg ( mjpeg ) , real world experiences please,

[theewizard]

I'm considering this camera http://www.walmart.com/catalog/product.do?product_id=5634173

Pentax 7.1 MP Optio M30 Digital Camera w/ Image Stabilization, SDHC Compatibility

and would like some opinions from others who have used the mjpeg video format , in regards to converting to DVD and or other video formats

thanks

[Soopafresh]

Mjpeg clips on left side of screen


http://www.archive.org/details/SecretGardenParty

[edDV]

What are your expectations?

The way MJPEG is implemented in these digital cameras, best setting 640 x 480 - 30 fps is being compressed 3-6 times more than typical DVD MPeg2. Since MJPEG is a sequence of JPEG frames without motion compression, the intraframe (in frame) compression is considerably higher than MPeg2.

MJPEG can be used to make high quality video comparable to DV format at ~35Mb/s. Digital camera MJPEG runs closer to 1Mb/s. DVD MPeg2 runs ~4-7Mb/s with motion compression over frames.

[JohnnyMalaria]

Until I switched to DV in the late 1990's, M-JPEG was the format I used for capturing analog video (starting with an Orchid Videola on Windows 3.1 in 1994 and ending up with a FAST AV Master - now gathering dust....)

As edDV states, M-JPEG is simply a sequence of JPEG images. The JPEG compression scheme is actually very similar to DV. However, DV has a fixed, defined bitrate. M-JPEG can be tailored to suit the source. e.g., a lower bitrate for VHS and a higher bitrate for Hi8/S-VHS etc.

However, the compression level in a still imaging camera with video capability will be quite high and the results may be unattractive.

[edDV]

I used hardware generated MJPEG with the Miro (later Pinnacle) DC-30plus* for years for Adobe Premiere editing. My experience then was MJPEG needed 6-8 MB/s (48-64Mb/s) for quality recording. That was because the Miro device worked in 4:2:2 and had a mid-90's hardware codec..

When DV came along (1998) it was better in most every way at 3.8MB/s (~30Mb/s with audio) than MJPEG at double the bitrate. DV uses a more efficient DCT algorithm and uses 4:1:1. Back then you needed a SCSI RAID for MJPEG. DV could use a single ATA-66 drive. What a breakthrough in cost per minute!

Since then MJPEG encoders have improved narrowing the gap in performance.


* later the DC-1000/2000

[theewizard]

thank you soopfresh , i'm downloading some now for a look see

edDV & everybody thanks for the info keep it comming

I downloaded the brochure and the manual in PDF format

the specs in the brochure say the video movie file is MOV quicktime mjpeg at 30/15 fps with sound

the manual says three quality settings best better good, and the file size is bigger for each higher setting, but not what the specs or bitrates are..

I may have to try this out just to see what it is like on the BEST setting, luckily walmart has a good if limited time return policy

[Soopafresh]

Too bad the max res is something like 640x480. So close to 704x480...

[edDV]

It will be nothing like camcorder quality.

A similar Pentax Optio W20 is reviewed at Steve's Digital Cameras.
http://www.steves-digicams.com/2007_reviews/optio_w20_pg2.html

Best 640x480 30fps compression setting consumes about 64MB per minute (~1MB/frame).

64MB = 512Mb
512Mb/60sec = 8.53Mb/s at highest quality. (About a third DV format rate)

A 1GB SD card could record 8 minutes at that rate or about 13 minutes at 320x240.
Those transfer rates require that a more expensive Ultra II SDHC class card be used.
http://www.sandisk.com/Compatibility/Device(8345)-Pentax-Optio_M20.aspx
http://www.sandisk.com/Products/ProductInfo.aspx?ID=1164
http://www.sdcard.org/sdhc/index.html#caution

Authoring to DVD would require upconversion from 640x480p/30 to 704x480i/29.97 or upsize+framerate conversion to 704x480p/23.976 (for a progressive DVD).

[theewizard]

well it did look interesting, maybe i'll just stick to my hi8mm camcorder, its analog not digital, an oldie but a goodie

[bebs1408]

I have a Pentax w20, I am not able to copy my MOV on DVDs.
Any suggestions please?

[theewizard]

try using quick time pro 7, to export the MOV as an avi, then use convertXtodvd or one of the other programs to convert to dvd compliant files and author the DVD

[bebs1408]

thanks, I tried that, but quality was VERY poor.