Dance Class Highlights (Looking For Feedback)

[Cary Knoop]

Originally Posted by Lewis Raymond

Hi Cary,

Do you mean give you a minute from the raw file or do you mean before it's colour-corrected etc? Because the raw file for one minute is around 400MB.

I've never used ffmpeg before. So this just takes my MXF file and produces the raw, cut copy?

I always use Premiere Pro H.264 (usually around 10 mbps CBR for a full HD video) then Encore to do the processing. If anyone knows a program which gives better encoding then I'm all ears.

Can you dropbox about 20 seconds of the out of camera file?

The ffmpeg will cut 20 seconds from the MXF without reencoding (make sure the destination extension stays MXF).

I think something must have gone wrong in the workflow, if you provide some unaltered out of camera original we can determine that. 10Mb/s for an intermediate file is rather low.
Just trying to help.

[Greg Clark]

There is only one solution. Teach the Dance School how to light a stage. Even parents would dislike the lighting.

[Lewis Raymond]

Hi Cary,

Took a few hours to set it up, but finally think I managed to get 20 seconds of raw file downloaded.

It can be downloaded from here on the original format: https://www.dropbox.com/s/2fn6z3b4or...utput.MXF?dl=0

It's a 117MB XMF file.

Let me know what you think. You may have noticed how red it looks as raw. I've tried to remove this however I doubt I'm using the best tools to do so, as I only use the three way colour corrector. I also end up losing some of the green on their dresses.

[Cary Knoop]

I first deinterlaced the footage to 50p, adjusted the overall gain, then I adjusted the red color cast by lowering the red gain and red gamma (in linear light). Then I added some contrast to add some more black definition. I noticed your camera has some pixel errors popping up once in awhile. I would make sure your intermediate files use a high bitrate and especially for dancing or other action I would deinterlace to 50p.

Here is an unpublished link:

dance01 on Vimeo

[Lewis Raymond]

Hi Cary,

The XF300 uses 50i, and I always shoot on the maximum of 50mbps. As far as I'm aware you can't deinterlace 50i footage to 50p, it has to be 25p.

[Ron Evans]

Deinterlacing will always replace the missing field by interpolation so it doesn't matter whether its to 25P ( drop every other field and interpolate the missing one in the remaining 25) or interpolate the missing field for all 50 fields to get 50P. 50i isn't 25p with the frames split into 2 fields. The timing of the fields is exactly like 50P with identical temporal motion. Going the other way if you shoot at 50P you can get 50i for DVD or Bluray by the NLE just extracting a field from the full frame. That is what I do as I have a mix of interlace cameras ( NX5U ) and 60P cameras. I edit on an interlace timeline and the NLE ( EDIUS in my case ) just takes a field from the progressive file to make a DVD or Bluray. You can go either way but you get more detail by shooting in progressive and the progressive interpolation from interlace is very dependent of course on how good the interpolation method is for the particular subject matter.

[Cary Knoop]

Originally Posted by Lewis Raymond

Hi Cary,

The XF300 uses 50i, and I always shoot on the maximum of 50mbps. As far as I'm aware you can't deinterlace 50i footage to 50p, it has to be 25p.

Well, the video is there as proof, you are wrong it is possible! Download the video and verify for yourself that each frame is unique.

A camera at 50i records 50 unique half vertical resolution events per second, by interpolation and motion compensation you can deinterlace that into 50 full resolution events. If you deinterlace 50i to 25p you throw away temporal resoution which is detrimental for sports and action scenes.

[Cary Knoop]

Originally Posted by Ron Evans

50i isn't 25p with the frames split into 2 fields. The timing of the fields is exactly like 50P with identical temporal motion.

That is exactly the reason why you should frame double, by converting the footage to 25p you destroy temporal resolution.

[Ron Evans]

Originally Posted by Cary Knoop

That is exactly the reason why you should frame double, by converting the footage to 25p you destroy temporal resolution.

Isn't that what I said. To me it isn't frame doubling either. I shoot everything at 60P or 60i they both have the identical temporal motion . It is unfortunate that 60i in the standard is 29.97 fps and this is not the same as 29.97P fps. People get very confused. NTSC interlace has a sample rate of 59.94 images a second. In interlace the recording is of course just a field. 60P may cause a problem of course with equipment that expects the video to have a 29.97fps timecode to sync with for the same time period. Yes in this case it does look like a doubling. History causes all sorts of problems !!!! The timecode coincided with the sync pulse for interlace ( every two fields, that told downstream equipment which field was being received ) I assume it was easier to sync the timecode to this pulse. Although 2 fields make a frame the two consecutive fields in an interlace video do not come from the same full frame they are about 1/60 sec apart in time of course.

OF course most TV's do exactly what we are talking about when they play interlace TV. They fill in the missing fields. Depending on the TV this can be quite elaborate in using many fields to interpolate from and make the progressive image as good as possible.

[Cary Knoop]

Originally Posted by Ron Evans

Isn't that what I said.

To me it is very simple: if you have a 50i or 60i source and you want to put it on YouTube or Vimeo you turn it into 50p and 60p unless the 60i source is telecined, in that case you turn it into 24p (or 23.976p).

So if that's what you say as well we seem to agree. :)

[Ron Evans]

Yes, but my response was to the "frame double" comment really. Agree with everything else you said.