Final Cut Pro X - Import AVCHD?

Hi billcode,

I think you're better of posting this issue in a new thread

Hi Billcode

Blurring on movement is an intrinsic issue with interlaced video that is viewed on devices other than TV's. I now shoot only in progressive (720p) because I get 60 (non-interlaced) frames per second, with very smooth movement, and mostly I'm just shooting my family and friends or sports with the intent of playing it back on a computer.

The basic issue with interlaced video is that successive fields (half frames) are different where movement occurs. When a whole frame (two fields) is frozen on a computer, the computer has to decide what to do with the two fields, each of which can be quite different from the other. It may show both fields at once, or it may show just one field. Settings in the viewing application will determine what it does.

If only a single field is displayed, you won't see any of the ugly movement artefact, but the vertical resolution is halved.

If both fields are displayed at once, the visual result on your screen depends onthe zoom level and the settings for displaying interlaced video. At 100% zoom or more easily 200% zoom of interlaced video that shows both fields, you'll see comb-like artefacts in areas of subject movement between fields. At lower levels of zoom, most computers blur all the fields together. Where the fields differ markedly, eg on movement, the result is an unnatural kind of 'shadow' that no-one wants to see. This does not mean that there is anything wrong with the underlying interlaced video, which may look great on a TV.

When exporting interlaced video to a non-interlaced format, eg for playback on a computer, there are ways to eliminate these artefacts. When shooting 1080i setting the project properties to 960x540 and exporting at that size removes all artefacts. Multiple deinterlacing options are available in Compressor, but I find the project properties the best, because a lot of the deinterlacing algorithms result in the artefacts I don't like. There are dedicated and sophisticated deinterlacing applications to retain full 1080 resolution however all result in some kind of artefact.

The good thing is that If your output is intended for broadcast TV then keeping it interlaced is what you should do, because TV transmissions are interlaced, and TV's display interlaced material really well. Even if it looks sort of crap with the movement artefacts that you see on your computer, it should be fine when output to a TV over HDMI or when broadcast.

Verifying that your ProRes output is still interlaced can be done by importing it into FCP and by examining the video at at say 100% or 200% zoom; you should see the same combing interlacing artefact in areas of movement that you have in the original.

The video element of an AVCHD file typically ends in MTS but the actual data format is H.264. If in FCPX import preferences you do not select create optimized or proxy media, then the imported events become plain h264 mov files. I can't remember if this was the original way FCPX did things, but the video data is not altered from the original in any way by doing this, and it isn't something to worry about.

I'm happy to be corrected on these statements if they are wrong - broadcast video issues are honestly outside my area of expertise.

I think that a lot of people who are creating video for broadcast use one or more external TV monitors. There are interesting thunderbolt to HDMI adapters that facilitate this kind of thing. I have no idea how the new Retina MacBook display will deal with interlaced video.

Cheers

Chris.

Billcode - If the clip viewer is set to view at 100% and the option under the little switch is set to 'display both fields' then you see the jaggies due to sideways subject movement quite easily.

Possibly a lesson to shoot in progressive from now on...love my NX5 but AVCHD does have some issues. thanks for your reply ctszsnoose and others...good tips for future. in the end some creative compressor work dealth with the 'shadows' and jaggies.

If the question regarding AVCHD transcoded in FCPX to Pro Res appearing as H264 in another thread it would be helpful to post the link to that I thread I think

Tom,

You're the guru here…can you please tell me why all of a sudden, when I use ClipWrap to convert my .mts files (Sony a65) to ProResLT, the frame rate is now changing from 59.94 to 29.97?

thanks!

K Lohse

You'll have to ask ClipWrap that.

Does it matter so much..both technically NTSC. must be converting to 29.97 with 2 fields and maybe dosnt understand if you've shot 60P?

Just a thought.

It matters if you want to use 59.94 and conform it in the project to 29.97 for slomo.

Precisely sir! Which is why I'm bothered by this sudden change. I DID contact ClipWrap and have sent them an .mts file which ClipWrap was "auto conforming".

Funny thing IS…tried the SAME thing with SourceForge's Media Converter and it RETAINS the 59.94 frame rate?!?!

But I'd RATHER use ClipWrap, because of its batch processing…or obviously not having checked myself…does anyone know if you can drag and drop multiple files to Media Converter?

You're doing this because you want ProRes LT rather than ProRes files, is that right?

presumably streamclip does not work for this...sorry if I am not being helpful.

correct. trying to keep the files as svelte as possible!😉

NOW…ClipWrap writes and says my .mts file is 60i which ClipWrap conforms "correctly" to 29.97. Do I need to go in and change my camera's settings to 60p 28M? I don't remember EVER fiddling with the frame rate setting - that's what so confounding about all this.

Streamclip can do it. It's a little tricky with the current OS because you have to do it with drag and drop, and Streamclip gives an error message, but it does seem to work.