[Tom Brooks]

Charles,
Thanks for the input. You confirm what I thought in general. Yeah, I don’t know what’s up with the iPod encoding of the 24P. It looks like the result you get when deinterlacing is done by simply throwing away one field. The 60i version was much smoother and higher res, using the default settings of the iPod setting, which does create progressive output. As you suggest, the MPEG-2 looks somewhat better in 24P and doesn’t lose resolution like the iPod setting does. There also may be issues with the camera doing things behind the scenes. Looks like the 24P setting could stand more detail, for example. Again, thanks.
-Tom

[Tom Brooks]

Is the format that Compressor makes used for broadcast purposes?

Final Cut Studio, FCP 5.1.2, After Effects 6.5 Pro, Quicktime 7.1.3, G5 Quad 2.5, Kona-LHe V3, 4.5GB RAM, Nvidia GeForce 7800-GT, G-RAID 2x1TB FW800.

[Tom Brooks]

Is this example good?
https://www.jjgifford.com/expressions/basics/example_wheel.html

[Tom Brooks]

Is this example good?
https://www.jjgifford.com/expressions/basics/example_wheel.html

[Tom Brooks]

What’s an MPEG – ts file?
Are you referring to the VIDEO_TS and AUDIO_TS folders that are found on a DVD? If so, what you want is a program to make a DVD from a .mov file. Use Apple’s DVD Studio Pro or Adobe’s Encore DVD or even one of the Roxio programs like Easy Media Creator. They’ll all do it in different ways and with different amounts of complexity.

[Tom Brooks]

I have tested a short sequence of same content (a still object on a studio background)C in 24PA and 60i. Compressed to iPod video and m2v.
Settings for iPod video were the standard setup in Compressor 2.3 (Frame controls automatic, output fields same as source, avg data rate 600kbps).
Setting for m2v is the standard 90 Min. Best Quality 4:3.

Comparing the two iPod versions, the 60i has better resolution, seen as less jaggies on diagonal and curved smooth edges. The 60i version has some dark edges that look like a higher detail setting in the camera and seems to have darker blacks overall. The 24PA version is smoother, less of the dark detail edges, more open in terms of rendering values. Judging which is better, I’d have to say it’s almost a draw. Each has its advantages, but the difference in the resolution is disturbing and a drawback of the 24PA. Items like the edges of glasses are going to be noticeably more jaggy in the 24PA version. The data rates were reported by Quicktime player as 600kbps for the 60i version and 360kbps for the 24PA version (both were encoded using the setting which specifies 600kbps). I may try again and attempt to get the same total file size for both versions and see how the 24PA holds up in that comparison. I can’t be sure where the difference in the black levels (call it gamma) is coming from, although I assume it’s in the camera rather than the encoding process.

Comparing the two m2v versions, the same applies to the rendition of blacks or the overall gamma curve. The 60i version has darker blacks, more contrast, but there’s a dark edge that just doesn’t show up in the 24PA version. There is no major difference in resolution! Again, the 24PA version looks smoother in terms of rendering values (call it the gamma curve if you will). The data rate is the same for both versions–around 6mbps. Apparently, the encoder for MPEG does a different compensation to get the same total data rate even with a difference in frame rate per second. Which is better in this case? There is no clear winner in terms of judging the quality of the image between the two. If I were to lean one what it would be toward the smoother, more film-like look of the 24PA. That’s strictly looking at the image quality and not factoring in issues of motion quality due to the 24fps. My mind tells me that the 24PA should look somewhat better because it is using the same amount of data to produce fewer frames–thus, each frame should contain more data and should look better. To my eye however, the difference is very slight.

If anyone has any commment on this analysis, I’d like to hear it.

[Tom Brooks]

Will do.

[Tom Brooks]

My shot in question is plain old mini-DV shot on an HVX-200. Very much a run & gun type of shot. On the waveform outside of FCP, the light sources is hitting right at 110 IRE and it is just starting to clip at that point. If I color correct the highlights down, the problem gets better. If I go the other way and make it worse, what I see on the scope as the white clips, is sort of a phantom baseline below the 0 IRE line. When this happens the video starts really jumping. I guess the initial learning here is that the LHe is not very forgiving of clipped levels above 100 IRE. If you throw that kind of garbage into it, it throws something else back out at you. Thanks for your thoughts.

[Tom Brooks]

[Bob Zelin] “Are you seeing this flicker only in FCP.”

I captured straight FW into FCP, so I didn’t really analyze the video prior to that, but would have to answer, yes, it’s only coming out of FCP. It doesn’t jump in the Canvas either, only on the output from the Kona.

I tried a couple monitors (Sony PVM type) with identical results, so I can rule out a flaky monitor.

And, color correcting the highlights down OR using the Kona’s “limit to legal video levels” switch fixed the jumping. I think the hot spot from the light is actally spiking chroma down into the vertical sync area. I’ve just never seen this coming out of an NLE system before–they usually clip things to the point where this can’t happen. The levels might be illegal, but not to the point of causing sync problems.

Final Cut Studio, FCP 5.1.2, After Effects 6.5 Pro, Quicktime 7.1.3, G5 Quad 2.5, Kona-LHe V3, 4.5GB RAM, Nvidia GeForce 7800-GT, G-RAID 2x1TB FW800.

[Tom Brooks]

I don’t mean a mere flicker of an element within the frame, but rather vertical instability of the whole frame. It jumps up and down about 10 lines worth.

Final Cut Studio, FCP 5.1.2, After Effects 6.5 Pro, Quicktime 7.1.3, G5 Quad 2.5, Kona-LHe V3, 4.5GB RAM, Nvidia GeForce 7800-GT, G-RAID 2x1TB FW800.