"Black" Frames in EX1 MP4 Footage?

basspig

basspig

Veteran
I believe this may be an NLE issue, but in lieu of spending substantial money on two CODEC solutions that each bring their own problems to the table, I found that Premiere would accept the MP4 files directly off the camera without rewrapping. Just use FFmpeg to convert the audio to little endian and re-join in Premiere.

It all looks great and plays great on the timeline, but when I render that timeline to an output format, I noticed that the XDCam footage blinks every now and then. If I stop the playback and step a frame at a time, it appears to be one black frame every so often.

I also noticed that the thumbnail filmstrip in Premiere has black frames every few frames on the timeline. Other footage does not have these black frames.

Obviously, these black frames are going to be an issue when it comes to authoring the DVD.

Do we have any MPEG gurus here who may have an analysis of what may be causing the black frames and how to correct this so renders are 100% reliably free of black frames in XDCam footage?
 
I've noticed this same issue when importing raw files directly into After Effects for quick on-set green screen testing, either straight off the card or from a clone of the material laid off to a hard drive.

My theory is that the import code for AE (and apparently Premiere) simply isn't optimized or written for the exact flavor of file that comes from the EX1. This makes since, as the camera is much newer than any Adobe updates.

I don't think there is a possible fix for this... unless Adobe does an optimization for a new version of their code.
 
Arg.. that's what I was afraid of.

Looks like it will be necessary to rewrap to MXF and open in Vegas and then render back out to uncompressed to the RAID and replace all the instances in Premiere when I go to the final render.
 
XDCAM footage seems to play beautifully with FCP on the Mac, but with After Effects, the interframe compression seems to lead to nasty glitches and jumps. I am guessing this is similar to the problems you are having with Premiere. This is not a new problem (mpegs can play up similarly), as AE likes to work with discrete frames, so I tend to do a rough cut of all the footage I need in FCP, then export to an Intraframe QT codec (ProRes or PhotoJPG). It saves having to convert all the footage and filling my hard disc with multiple copies.
 
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Understood, and I can do that with Vegas, too, but it contravenes the purpose of buying this camera: to achieve maximum quality.
Multiple recompressions ruined the first minute of "Winter Thaw" (you folks were quick to spot that the opening scene had tons of banding) but I was unable to import the Cineform clip for that shot for some glitch occured in conversion, and had to bring the MXF into Vegas and render an uncompressed AVI. Apparently this "rendering" process lost a lot of dynamic range.
 
Just finished rendering the entire 93-minute concert edit to Blu-print for Blu-ray and the blink problem with the EX1 footage became severe. The fact is, you never get the same results twice with Premiere CS3's handling of EX1 footage.
At present, the only workaround is to run the footage through Vegas 8 and convert it all to uncompressed. That's going to use a huge amount of RAID storage, so my plan is to hold off to the last possible minute.

Comment about quality:

It becomes obvious that the EX1 footage is so much better than the V1U footage on this disc, it's really quite startling. For instance, the wood grain on the cello is not really visible in the V1U footage. It's smeared and looks like it was shot with cotton in front of the lens, compared to the EX1 footage, in which the wood grain of this reddish-colored finish is very clear. Skin tones are detailed on the EX1, but not overly so, whilst the V1U footage looks blurred in a rapid A-B comparison. The difference is stark. Color reproduction is much better too. And more punch, despite more dynamic range.
 
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