I just wonder why Sony decided to implement a 1080/30p in 60i container? As far as I know it is much easier to remove interlacing in NLE than to interlace the footage that was shot progressive.

Also a question - is there a separate 1080/25p /50i version for EU or is the camera switchable?

The Euro version is 25p (50i) but its not 50i at all - each "field" is the same - the NLE and Blu-ray just thinks its 50i which it's not - your material will always feel like 25P - so keep those pans under control!

The Euro version is 25p (50i) but its not 50i at all - each "field" is the same - the NLE and Blu-ray just thinks its 50i which it's not - your material will always feel like 25P - so keep those pans under control!

Thank you Paul for the reply. Now it starts to be even more confusing... So when I edit the footage (in Sony Vegas for example) and my NLE gets cheated so sees the 30p or 25p as an 60i or 50i - shall I force the NLE to see the truth..? I mean: shall I force it to treat this footage as a progressive? In other words: what timeline should I declare and use - the one for progressive or interlaced?

I know that AVCHD requires an interlaced format, but even so - what the heck was the purpose to cheat the AVCHD and Blue-rays etc. instead of just leaving the camera to record interlaced? Isn't it better in almost all cases to have native, interlaced material and de-interlace it only when you really need it? The biggest advantages, like the smooth panning etc., are lost when you shoot progressive! And de-interlacing is so easy, while interlacing the progressive material simply does not work. So what was the reason to put progressive recording into an interlaced container, instead leaving it just interlaced? Is it because the consumers market demands for the "film look", so progressive scanning became the 'golden rule'..? I don't get it, sorry.

A progressive frame in an interlaced signal is split by alternate lines of resolution into each field. Odds and evens. A progressive frame has arguably more resolution than an interlaced frame especially during motion as an interlaced frame is essentially two half resolution frames in sequence but displayed together due to image latency on the display device. So yes, motion is smoother in 60i because it's actually 60 frames per second although it's counted as a 30 frame signal.

"1080/30p in 60i container" is more properly known as psf - progressive, segmented frame. See Progressive segmented frame - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Progressive_segmented_Frame)

In essence it contains exactly the same information as a progressive image, and has the same characteristics. The only difference between the two is the order in which the lines are presented, 1,3,5,7..... then 2,4,6,8 for psf, rather than 1,2,3,4,5,6 etc for progressive. Otherwise the lines are identical. All the lines in each frame are captured at the same moment in time. Hence translating from psf to p and back is a totally lossless process, simply a matter of line reordering.

In the case of interlace, the even lines are captured at a different moment in time to odd lines. De-interlacing, to form progressive frames from interlace, is NOT a lossless process, and not reversible.

The reason for psf is to carry a progressive signal on systems designed for interlace, such as broadcast transmission networks, So in the UK, the system is 1080i/25, but since most production is 1080p/25 most of the time it's actually 1080psf/25 that is being transmitted.. To a receiver, 1080i/25 and 1080psf/25 are identical signals technically - even if they may look different to the viewer in terms of motion..

Well, now it is clear, at least technically, thank you guys. But from the point of view of the videographer - the smoothness of the fast movements is better when the footage was shot interlaced or progressive? When for example there is a leaf or a flag trembling on a wind or a bird flapping wings - I can always see kind of a flickering on a footage that has been recorded using progressive-scan. So I rather don't like progressive, just because of the flickering effect, but maybe I should change my mind..?

Shutter speed is important. A leaf falling in 30p or 25p will look odd if the shutter is set too fast. Generally the shutter is set for twice the speed of the frame rate. 1/48th for 24p, 1/50th for 25p, 1/60th for 30p, 1/100th for 60i.

...... the smoothness of the fast movements is better when the footage was shot interlaced or progressive?
No simple yes or no to that. The reason (using 50Hz country rates) is that interlace ALWAYS implies 25 frames per second, 50 fields per second, and the appearance of movement "looks" like the field rate - 50fps.

With progressive, you can have 25 or 50 complete frames per second (25p or 50p) and 50p gives the same appearance to motion as interlace. Whereas 25p will give a more jerky effect - or "film-look".

So it follows that in general, 1080 is better than 720, progressive is better than interlace, and 50 fps is better than 25 fps. Hence, the best system obviously becomes 1080p/50? Unfortunately, even now, that's still too difficult to implement in most equipment (without cutting corners, which some consumer cameras are starting to do), so you have to choose which two of the three factors are most important, so it becomes a practical choice between 720p/50 and 1080i/25 if "smooth motion is important. If it's not, and some directors actually prefer the "film-look" of 25p, then the best system is unarguably 1080p/25 - which can be carried as psf25 over an interlaced system.

No simple yes or no to that
[...]

I do agree with everything what you say. And shutter speed should be just right, but generally speaking - the fps is more important, as the higher the frame rate, the better the smoothness. 25p gives 25 complete frames per second. 50i is NOT 50 frames per second, but FIELDS per second, so since the complete frame is built of two fields - it is also 25 frames per second. In todays world, most of the display devices require stream of deinterlaced images, so my main question is:
- is it better to shoot progressive
or
- shoot interlaced and then deinterlace it in NLE. In other words: what will bring better results as the smoothness of fast moving objects is the priority?

In other words: what will bring better results as the smoothness of fast moving objects is the priority?
In answer to that question alone, 50p will look the same as interlace. They will both look better than 25p in terms of smoothness of motion. Yes, 1080i/25 is 25 frames per second, 50 fields per second, but because the fields correspond to different moments in time, the eye is presented with 50 different images (motion wise) per second. If both fields of a frame correspond to the same moment in time, (as with the VG10) that's 1080psf/25.

I'm confused by what you say about "shoot interlaced and then deinterlace it in NLE". That will get you a derived 25p - with less smooth motion - and why not then just shoot in 25p in the first place? In terms of the display, best to just feed it interlace, and let it do it's own de-interlacing to drive the screen. Or feed it 50p - but that then means you must work in 720p/50.

I'm confused by what you say about "shoot interlaced and then deinterlace it in NLE"

When interlaced footage is played (on a computer screen for example) the odd/even lines looks ugly. Therefore it has to be de-interlaced first in some non linear editing comp. program. That is what I meant. And I was not talking about VG10 but in regards of general rule.

Well, thank you David for your kind explanations. And for confirming that 50 fields per second brings better results, because the impression of a watcher is of better smoothness. However, the 50i/60i in a technical specification of the Nex-VG10 might be very confusing to buyers and I was very much confused with it.

My understanding is that Sony Vegas is the only NLE that sees VG10 footage as 50i, hence the fact that you're finding the need to deinterlace. Other NLE's eg FCP ignore the interlaced wrapper and see it as 25p. Indeed FCP will convert the footage to Proroes 25p footage when logging and transferring automatically. As far as I'm aware this process does not involve deinterlacing, just discarding the redundant wrapper. This being the case, maybe you could use a program like mpeg streamclip to get rid of the wrapper prior to bringing it into your NLE.

As for why SONY did this in the first place, my understanding is that it was so you could burn BLU-RAY discs in the source format, as they only work with 50i footage...

When interlaced footage is played (on a computer screen for example) the odd/even lines looks ugly. Therefore it has to be de-interlaced first in some non linear editing comp. program..

1) the deinterlacing in an HDTV is usually far better than the one you would use on your computer -- unless you are willing to wait a very long time.

2) what you see on your NLE has no relevance to what your video will look like.

3) when you pause in an NLE you never see both fields, so you wont see interlacing.

4) when you play video in an NLE you should not see interlacing either. You might see them IF you create a progressive sequence and drop interlace video into it. That is your error.

5) if you need progressive, deinterlace only on export.

6) when you play interlace on your computer it is always deinterlaced so it should look fine.

Bottom-line, I'm not sure why you think you can see combing on your computer!

Now about the VG10. Every NLE I've tried sees the video as INTERLACED. As long as you edit in an interlaced Sequence, you will be fine AS LONG AS YOU EXPORT TO INTERLACED MEDIA. If you want progressive output, you must be sure you or you streaming service does NOT deinterlace the video.

Therefore, it is better to edit as progressive -- which is what the video really is -- as long as you can ret-tag the clips in a Bin or in a Sequence as PROGRESSIVE. You can export as either progressive or interlaced (PsF) video.

If your NLE can't do this, it may auto-deinterlace (BAD) if you use any FX that scale video.

PS: iMovie will automatically deinterlace unless you use my iMakeFullHD software that batch re-tags clips as progressive.

Steve, I hate to disagree but my version of FCP (studio 2) converts to prores 422 on log and transfer and sees the footage as 25p by default. Would FCP be auto deinterlacing on log and transfer?

Sony Vegas is the only NLE that sees VG10 footage as 50i

And both products come from Sony...

And the VG10 image sensor captures it's video images in either 30p or 25p (according to Sony specs) so it is unable to capture an image in 60i or 50i. If you are looking to get 50 frames (either progressive or interlaced), a regular video camera will be a better option.

One extra note, for recording subjects where the viewer wants motion detail, sports for example, a higher frame rate is preferred. For recording subjects where you want to impart the impression of speed to the viewer, a lower frame rate is preferred. A car speeding down the road looks faster at 24f than at 60f due to motion blur.

A car speeding down the road looks faster at 24f than at 60f due to motion blur.

That is very logical, but it is hard to find it just by yourself, unless you are not well experienced. Many thanks for such a great tip!

Steve, I hate to disagree but my version of FCP (studio 2) converts to prores 422 on log and transfer and sees the footage as 25p by default. Would FCP be auto deinterlacing on log and transfer?

My ProRes and AIC clips come in as 30p.

I doubt it is auto deinterlacing.

But, I have an idea.

AVCHD has the ability to mark a video FILE as interlace (50i/60i) or progressive (23.976, 24. 25. 29.97, or 30). I'll bet there is no PsF option, so the stream is set to interlace. Which is the virtue of PsF, it simply passes through.

In the NTSC world 60i can be 60i, 60i/23.976p, or 60i/29.97PsF.

Now if there is another flag in the data itself it could also be set to interlace or progressive. So were this flag set to progressive, there would be confusion over which progressive: 60i/23.976p, or 60i/29.97PsF. So the flag is never set to progressive. Therefore the video header simply says 60i and leaves it to the editor to decide how to process the clip.

In the PAL world 50i is 50i. Or, is is 50i/25sF. If the data flag were set progressive, it must be 25PsF. So region 50 camcorders do not operate like region 60 camcorders.

Smart software would know that 50i files should be checked for the second flag. Dumb software would not.

MY MEMORY IS HAZY ON THIS: This could explain why some Canon camcorders don't work with iMovie. Owners set the frame rate to 25p but iM sees the video as interlaced just as it would had they set the frame rate to 50i. Canon blamed Apple and eventually this camcorder was removed from the list of valid camcorders for iMovie.

It also might explain why I read a post somewhere that Sony Vegas recognized the clips as progressive. Somehow I think I remember he was in Region 50. In the USA it comes in as interlaced!

The default sequence settings place the file within a progressive 25p stream but for some weird reason field dominance is set to "odd". I'm assuming that treating the footage as 25p means that field dominance should be set to "none" and this is what I've done to date. I haven't needed to deinterlace the footage on export and don't seem to have lost any res. at any stage in the process.

Are the Canon cam's you refer to the ones that shot 25f? It was a sort of fudged almost, but not quite progressive used by the HV20 and the XH-A1. That was dealt with simply by logging and capturing the footage as 25p. You could though, if you chose, capture the footage as 50i.

The ODD indicates that FCP is seeing it as 25fps interlaced. So you need to batch change all clips to NONE. Now FCP will treat the video as what it really is.

Sounds right to me. Thanks, Steve.

Sometimes I feel so stupid. I've always wondered why there is AVCHD Lite when the AVCHD spec supports 720p.

Of course it does, but Bluray only supports 720p50 and 720p60. And, since the idea is to be able make camcorder to BD copies -- the camera MUST record 720p50 and 720p60. And, since the sensor of these cameras can only do 25p/30p -- each frame either must be recorded twice or a REPEAT FRAME flag used.

And, since BD does not support 1080p25 or 1080p30 nor 1080p50 or 1080p60 the ONLY thing Sony could do is make the captures look like 1080i50 or 1080i60. That's why the spec from Japan HQ said INTERLACE.

In Japan BD is the norm so camcorders must be BD compatible!

Frankly, I can't see why everyone doesn't toss DVD. I just bought 2 BD players. The last for $90 and it includes all the streaming services.

And, since my VAIO has a BD burner I use the Sony PMB application to burn copies of SDHC cards. One 8GB plus one 16MB card. Or, one 32GB plus one 16GB card.

I too finally broke down and picked up a couple BD players, with wireless, and streaming, also well under $100 for a "top of the line" Sony wtith 3D even! Sure they were prolly customer returns, but for the price, it was a no-brainer, and definitely looks way better even on aging 720p HDTV's (which look almost new again).

A burner is probably next, with them available right around $100, and disks under a buck...

HD will likely finally become a "standard", with BD adoption making inroads with the lower price point. And 1080 is going to become the standard, with 720 fading out, IMO.

I've been rendering/burning BD compatible to DVD for a while, until burners came down, but I'm running out of excuses!

In my experience, once you start putting your HD projects out on BD and viewing them on 1080 HDTV, you'll never go back.
It's breathtaking :)