Can progressive video be saved as DV without losing progressive advantages?

[boblin2]

I have many 30fps progressive video clips from a digicam. I resize them to 720x480, convert to 29.97fps (NTSC) for displaying on TV's (analogue and digital) and computer screens, and authoring DVDs.

Is the DV codec a good option for archiving the clips and assembled movies, and do I need to convert to 29.97fps?

Thanks.

[guns1inger]

The best format to archive in is the original format, as it has not been degraded by conversions.

As for DV avi and mpeg-2 for DVD, yes, you have to convert to a compliant resolution and framerate. I am assuming that your progressive footage is from a still camera with some digital video capabilities, or a dedicated digital video camera that records 640 x 480 @ 30 fps. If this is the case, you will lose very little in the way of quality (compared to the original) if you carefully convert to mpeg-2 for DVD. 29.97 fps being the closest to the original 30 fps, it would be the best choice, however it will be interlaced.

If your source is different to what I have assumed then you need to give more details regarding what it is and how it was acquired.

However at this stage, from what little detail you have given, I believe you are over estimating the quality of your source, and the quality drop from conversion to DVD in your case.

[boblin2]

The footage does come from a still camera with movie capabilities - The Cannon PowerShot S3.

My concern is that because of the processing I do on the video clips (resize, slow motion, color adjustments, and so on - in different programs), I am concerned about working in the MJPEG that the camera gives me, so I convert them to Huffyuv before processing. When I'm done processing and building the movie, what codec should I use to archive the clips and movie that a) is of a manageable size (like DV), and b) does not lose the progressive qualities of the video, which could be advantageous in the future?

[JohnnyMalaria]

The DV format is neutral w.r.t interlaced and progressive imaging. i.e., the encoded data representing each frame are encoded in the same way, irrespective of whether the video is interlaced or not. All there is to distinguish the two is a couple of flags in another section of the DV data stream. For playback/future use on a computer only, encoding progressive to interlaced DV makes no difference at all. The likely trouble comes when you pump that same DV stream out to a DV device (e.g., camcorder) and view the resulting analog signal on a standard TV/monitor. Even if the DV device isn't compliant with the DV specification and ignores the progressive flag, it will still end up interlaced since that's what the TV uses (assuming a standard definition TV).

There is a possibility that a codec or camcorder will baulk at a progressive flag in the DV data but you'll have to try it and see.

[GMaq]

boblin2,
Great question, I just got a Powershot S5, the MJPEG quality is really impressive, As far as working with the clips, MJPEG is very similar quality wise to DV and in most cases has a keyframe every frame like DV so I would suggest you drop the clips into the editor of your choice as is, most editing progs shouldn't mind MJPEG, if they do there are many good MJPEG codecs like PicVideo, MorganJPEG Etc. that will decode it so you can use it in an editor. Then do you editing/filtering and spit the finished product out in whatever format suits your end use, ie MPEG-2 for DVD

[boblin2]

Thanks, I will give the MJPEG approach a try.

I'm wondering though how progressive video from a true Video camera is stored, is it DV, MJPEG or something else?

[boblin2]

Progressive Video in DV
On reading more about progressive and interlaced video, and following up on JohnnyMalaria's feedback (thanks by the way), it is clear that my progressive video clips and movies can be archived as DV without significant loss in quality, while at the same time preserving the progressive qualities. Using DVPRO25 or DVPRO50 would be better still as it retains more color information, however the codecs are not as common as plain DV.

This web page was useful in understanding how progressive video is stored: http://adamwilt.com/24p/#24pRecording

Page 58 of this manual helped also:
ftp://ftp.panasonic.com/pub/Panasonic/Drivers/PBTS/manuals/OM_AG-DVX100.pdf

Compression Methods and Options
I tested working and saving my processed video clips in MJPEG, but the loss in quality, especially around moving objects, was very noticeable. It appears that because of the processing I want to do, I need to post-process in Huffyuv and save in DV.

This web page helped convince me of the codes to use (i.e. Huffyuv, DV, and DivX or XviD):
http://www.animemusicvideos.org/guides/avtech/video4.htm

My Video Processing and Archive Procedure
1. convert my progressive 640x480 30fps video clips to Huffyuv at 720x480 29.97fps, and archive the original clips to a DVD.

2. Post-process the Huffyuv video clips i.e filters, color adjustments, slow motion etc.

3. Convert the Huffyuv to DV, and discard the Huffyuv files (because they are so big).

4. Assemble my movie from the DV video clips.

5. Output the completed movie as DV for archiving, MPEG-2 for DVD, and DivX or XviD (not decided yet) for storing on my computer/network drive.

6. Archive the editor project file and DV video clips to DVD.

I might start to skip the Huffyuv step and go straight to DV. I will run some more tests, and then decide.

Footnote
Most digicams (still cameras) produce poor, jerky, mono video clips, however the Cannon PowerShot S3 and S5 produce video that is, visually anyway, approaching that of a standard DV camcorder, here's a link that you may want to follow (includes a video clip):
http://www.dpreview.com/reviews/canons3is/page7.asp

I would welcome any opinions on the process I intend to use.

[GMaq]

boblin2,
Thanks for all of your great info, To clarify I didn't realize that you were intending to archive your finished project in MJPEG, I have had success going right from the native MJPEG that the clips are in to H.264 to be viewed on my HTPC and portably on an iPod. There is very little quality loss this way (settings dependent) and H.264 is far better than DivX or XviD at comparable bitrates. Something to think about Codec wise. Thanks again for posting your findings