Sorry to be a dunce but I am quite confused on frame rate. Can anyone point me in the direction of a useful guide. I understand all the basic differences but have read conflicting reports as to the restrictions of each mode. Mainly regarding transfer to DVD/Bluray. I have always shot 50i as that is what my Z1 did but with the EA50 have many more capabilities. I read that 25p is not supported by Blu ray so does that make it useless if your project was shot and edited in 25p? Can 24p be output to Pal DVD? I understand it is fine for Blu ray. How about 720p compared to 1080p? What formats are people using when wanting to have final output on both DVD and Blu-ray? I want to shoot 24 or 25p but am afraid to shoot a wedding like that until I know the output will be safe.

Im not a tech head ... but I would say stick to 50p progressive. It's the absolute best quality your camera captures. Then edit in what ever format you want, but atleast you know the source file is the crem de la crem of frame rates.

I always shoot 60p. Not matter what. Then if I need to convert to 23.976 or 29.97 no problem. (Ntsc over here)

JC

So if I shoot in 50i or 50p I can just set up my timeline in fcp7 to 24 or 25p and render then export? Is it best to do the actual edit in the format shot in and then export then bring back the edited QuickTime file to final cut and place on a 25 or 24p timeline before exporting again. Thanks for all the advice, just want to make sure I have the best possible workflow.

Don't shoot interlaced. And expect to go to 24p or 25p nicely. ... stay in 50p or 60p. Then yes drop in ur timeline and export to the frame rate you want.... even if you want interlaced delivery; shoot 50p drop in 25i timeline .... at least for premiere cs6 this is fine...

25p is preserved in the form of PsF (Progressive Segmented Frame) in a 50i stream. Your encoder would split a full progressive frame into two interlaced frame thus your progressive content is preserved in BluRay output.

Blu ray supports HD1080i50. Most encoders will handle a 1080P25 conversion to 1080i50 with no problem. All LCD tvs are progressive by nature anyway, so it will end up being quite nice progressy anyway. The biggest issue with 50P is that you will end up using a shutter speed of 1/100 S resulting in half the usual motion blur. This might not be an issue for you.

And unless you state it explicitly to them no non-techies will notice the difference between 720P and 1080P. Believe me. The Danish cable broadcasters has been transmitting 720 P for the lest two years and nobody complained.

Why would you shoot 50P with 1/100s shutter? I shoot 60P with 1/60s shutter. 50P and 50i are the same exposure rate and 60i and 60P are the same exposure rate. In one case they record fields in the other full frames. Camera exposure parameters will be the same.

Ron Evans

I use a shutter of 1/50th as well with 50p, don't see any negative impact on the image because of that.

I always shoot 60p 1/60th.... no complaints here

I'm still confused, gonna hit the hay! Thanks for all the advice, seems that frame rates are a pretty cloudy issue, will just have to experiment until I find the look I like best.

It's not that confusing. You are limited to your geographical location and what frame rate options your camera provided. If you are in the US, 30p and 24p would be a popular choice.

If you shot 50i with your Z1 just use 50P and do what you did before in editing. You now just have the whole picture rather than half the vertical resolution ( field ) and nothing else has changed. If you need to take a still from the video file it will be full resolution.

Ron Evans

James,

If you shoot 1080p/50 you can put it on a timeline with 1080p/25 or 1080i/25 and render to 1080p/25 and 1080i/25 respectively. The process will either drop every other frame or interlace every frame as required. The only side issue as mentioned by Ron Evans is that 50fps cameras will normally use shutter speeds at least twice that of 25fps ones, so reducing the frame rate to 25fps may result in a gritty motion effect. Some editors can reduce this by applying motion blur that integrates adjacent frames to smooth the motion.

As far as 1080p/24 is concerned, unless you have a primary requirement to export to film, (i.e. the chemical stuff) or video to somebody in the 60Hz world, then don't bother. All broadcasters in Europe transmit movies created at 24fps as 25fps, (usually 1080psf/25). The 4% increase in speed is not considered an issue and if necessary the pitch of the soundtrack can be adjusted electronically.

The only side issue as mentioned by Ron Evans is that 50fps cameras will normally use shutter speeds at least twice that of 25fps ones

Why? I use 1/50th shutter all the time with 25p or 50p and don't see any disadvantages in doing so.

James,

..The only side issue as mentioned by Ron Evans is that 50fps cameras will normally use shutter speeds at least twice that of 25fps ones,.. ..

I didn't say that. I was questioning why one HAD to do that. With film that is the case as the shutter speed at 1/25 or 1/24 would potentially give a lot of motion blur since the judder at those low frame rates is bad enough. I always try to shoot at the same shutter speed as frame rate since I never shoot at the lower frame rates. Used to be 60i now mostly 60P for my cameras that can do that most of my shoots are in the theatre so shutter speed is 1/60 for a 60i or 60P camera. Only time the shutter speed is more is if I am outside with the little Sony's in auto where they will use shutter speed to compensate for the fact they do not have an ND. For my NX5U I use the ND's

Ron Evans

Ron,
The point that I was trying to make was that if rendering 50p source footage down to 25p for distribution, the source shutter speed will likely have a maximum duration of 20ms (i.e. a 360 degree shutter) whereas it will be 180 degrees when part of a 40ms frame period unless the NLE allows some motion blur that would emulate a slower shutter.
Strangely enough, rendering down to 1080i/25 would either produce a psf cadence or a halved shutter angle depending on whether the NLE recognised the temporal difference between the 50p frames or just grabbed every other one.

Steve, my point is that a 1/50sec shutter speed is the same whether the frame rate is 25 or 50. And will have the corresponding blur of a 1/50 exposure. I realize the mindset is different coming from a mechanical film camera where the shutter is keyed to the film pulldown. Not so for an electronic system. It just represents the time allowed for the sensor to charge before readout ( starts ). If that is 1/50 it doesn't matter what the frame rate is the motion blur will be for that time period identical for 25p or 50p. Taking every other frame of the 50p will result in the same judder as if shot at 25p with 1/50 sec shutter speed. The motion blur comes from the motion while the shutter is open and the judder from the motion differences occurring between exposures. There would be a difference if the shutter speed was 1/25 which would result in more motion blur of course. So with the same shutter speed above 1/50sec , 25p output from a 50p source will mainly introduce the judder of the slow frame rate.

Ron Evans

Ron,
I think that we are both coming from the same direction. I have recently bought a Sony CX730E which takes a good 50p. The native footage plays back with smooth cadence, i.e. limited judder and little motion blur as the image samples are frequent enough for each to cover little movement in the scene. When I put this footage on the same Vegas timeline as some 25p material with the intention of creating a 25p output, I apply some motion blur with a gaussian profile. This means that the original frames are combined with adjacent ones to create new blurred frames that effectively show as smooth movement that would otherwise be shown as judder where the shutter time was much shorter than the frame repeat rate.

Thanks for all the advice. With regard to 50p, do you all shoot at the 108050 / 60p PS Mode or does anyone shoot at 720 50 / 60p FX or FH. My Mac isn't that fast and I can't afford to upgrade at the moment and am getting a bit fed up of all the rendering time required even at 1080/50i FX at 24Mbps. I think 50p at 28Mbps would definitely be too much for my machine to handle and am curious about how 720p in FH at 17Mbps might look? Nothing is for broadcast as far as weddings are concerned so not bothered about that - I think that has to be 50Mbps now anyhow. My own documentary stuff, I might rather shoot at the top spec though. Look forward to hearing your thoughts.

James

Definitely shoot at 720p 50p/60p

If your mac is struggling with 50i, then record at a lower rate.

720p is still high definition and looks glorious on TV, especially if you deliver DVDs to your clients...

The only reason why I bother with 1080p is if I ever need to slightly zoom into my video, I can go down to 720p without any noticeable quality loss. Other than that I would of shot 720p all the time! luckily so far my PC seems to be able to handle it rendering 1080p 50p

Thanks James. So we have established that 720p is good, how about the recording mode FX(24 Mbps) or FH(17 Mbps)?

Well for starters you've downgraded from 1080p to 720p. That should give your PC a good enough boost in terms of performance.

Secondly, I would see how it goes with filming at 24mbps, because it is a higher quality 720p. Before trying the 17mbps (which again, will give you more of a boost in performance).

Take your camera to your garden, or somewhere with a lot of detail.

Record in 1080p PS, Record in 720p 24mbps and then 17mbps.

See how much detail you see missing in the 720p files.

This will give you an idea ...

The best is 1080p PS, but we all have to compromise ... your not in a position to go spend £1500 replacing your MAC, so 720p will have to do. Which isn't a significant difference if your providing clients with DVD's anyway.

In all honesty, i've seen 1080p PS look terrible if the lighting conditions are poor ...

720p is High Definition, where as 1080p is FULL HD.

The difference can not be seen by a un-trained eye. Just make sure everything else is perfect, you film in adequate lighting conditions etc and you'll be fine filming in 720p 17mbps.

Thanks James. Will do my next project in 720 and 17 and see how we go.

Following on from our discussions, I have been experimenting with 50p. It seems that the VG30 doesn't shoot 720P so have gone and shot some 108050p footage around the house. But having trouble converting the footage to Pros Res LT in FCP using log and transfer. Anyone help me on how they get their 50p footage into FCP 7?

Although I'm in 'PAL' land, I'm considering switching over to shoot 50i @ 50th or 100th shutter, rather than 50P. The reason for this is to reduce 'temporal' aliasing, ie: the slight jerkiness between 50p/60p frames. Although the absolute resolution of each 50i/60i frame may be slightly less than a 50p/60p frame, you may achieve a smoother pan and here's why: The best way to explain this technically, is to quote from an engineering friend of mine:

"This (ie: 50p/60p) is what gives it that tiny bit of jerkiness. It is tied up with shutter speeds and is apparent in all moderately priced electronic cameras. The higher end and thus more expensive ARRI Alexa and RED cameras apply an electronic shutter filter to the image. This has the effect of dissolving, if you will, between the original and the filtered image, resulting in a more smoother transition between the on/off shutter or exposure. This is done I believe around the 12Hz region.

One of the advantages of 50i/60i material is the fact that any movement of the frame through say panning is shared across 2 fields albeit half vertical resolution per field but the movement is smoother so I think you will get far better results using 50i/60i as your record format and less encoding artefacts during BD production. Temporal aliasing is not anywhere as noticeable using 50i/60i as well which is why broadcasters prefer it. Full resolution Progressive frames or Progressive Sequential Field recordings both exhibit the problem but interlacing results in a halving of the movement within a frame over 2 fields.

"...high frequency details (trees and leaves particularly) really pushes the ability of the sensor to charge and discharge at 50p/60p whereas halving this high frequency with 50i/60i recordings, minimises the aliasing requirements. 50P/60P recordings are wonderful, don't get me wrong but they really shine as static images rather than pans or where there is fast action contained within the frame. This is why the higher end cameras use shutter filtering circuits."

Just for interest too I shoot everything at 50i ...I know if I need to grab stills off the video the result will not be as good (then again I carry my Nikon outfit with me anyway) It's a matter of choice but I just find that 50i is so forgiving and with a lot of run 'n gun stuff including weddings that gives me the best overall result and doing non-repeatable stuff like weddings you can't have any screwups !

Just for interest I did shoot a wedding in 25P on my Panasonic HMC82's last year and for some totally unknown reason I found that , especially the cheek area of people's faces, tended to pixellate quite badly ..I tried a few static shots at home and also found the image centre showed some alarming pixellation ...I have no idea why that occurred but it did prompt me to go back to 50i and stay there.

To be honest I have not used either of my EA-50's in progressive mode (25P or 50P) and stick to 50i ...sort of the principle "if it works don't mess with it!"

Chris

.. Temporal aliasing is not anywhere as noticeable using 50i/60i as well which is why broadcasters prefer it..."

I think the only reason we have interlace is cost. Originally it cost too much for the technology of the time to make the hardware and it cost too much for the bandwidth to transmit the signals. Standards were then written around this fact and stay with us today. So camcorders were made interlace . The issue of cost is still with us but technology doesn't stand still. Processors get faster, smaller and lower cost so that complex encoders can be made. 16x9 TV are native 50/60P so that interlaced input has to be de interlaced. It is much easier to input a native frame rate and gives the consumer better quality so once the processors were fast enough camcorders became progressive and the consumer can connect and see wonderful home videos. The software that comes with these camcorders can then make much better stills from the video etc etc. Nothing to do with broadcast in my mind but all consumer driven, bigger numbers and the word progressive.

I think camcorder sensors have been full progressive for a long time its just that the video encoders were not fast enough to process the full output from the sensor so just processed fields. Technically 60i and 60p have exactly the same temporal motion. One records fields the other the full frames. The same shutter speed effects both the same way. Output from the sensor goes into a buffer memory at the same rate for both 60i and 60p so they should look the same one being half the vertical resolution of the other. However big difference can occur in how these signals are encoded. Do they get encoded to AVCHD 1.0 or 2.0 and whose encoder. Is the signal encoded to a 100Mbps external recorder ? Can the on board encoder create this output to the HDMI or HDSDi for the external recorder. I think there are likely big differences between a $400 stills camera shooting 60p and a $10000 camera shooting 60p !!!

Next we have to look at the display for 60i /60p. Unless the display is a full 1920x1080 display the full HD signal will have to be scaled say to a 720 display. So in this case the display has to not only de interlace but scale as well. Most of the time our impression of quality is really how good the de interlacing and scaling algorithms in the display we watch work. Moving to record at the same size and refresh rate as the display removes all these issues. On my Sony 240hz interpolating display I see no difference between video shot at 60i or 60p from my CX700, NX30U or my HX30V. Are any of them as good as an external recorder then I think not. They are however consistently better than most cable TV channels !!!! But the data rate difference between 24Mbps and 28Mbps is enough to encode the difference between 60i and 60p and to my eyes the same picture quality and I am sure that the engineers figured this out too. 60P at 28Mbps is a lot better than 60i at 9Mbps this difference is easy to see. Is AVCHD 2.0 as good as 50Mbps encoding or more in some format, probably not.

Ron Evans

Nevertheless, any thoughts on how to get the 108050P into final cut in the first place?

Nevertheless, any thoughts on how to get the 108050P into final cut in the first place?

No idea as I am PC based and Edius, Vegas and CS6 will all edit 60P native.

Ron Evans

Lightworks Pro 64bit will also edit native 50P/60P AVCHD but you will need a modern, fast PC with very fast Hard Drives or SSD media drives. (I prefer to work with 10 bit DNxHD transcoded files)

For more information, see Lightworks (http://www.lwks.com)

Lightworks Pro 64bit will also edit native 50P/60P AVCHD but you will need a modern, fast PC with very fast Hard Drives or SSD media drives.


Is that a lightworks requirement? Just asking because I still edit 1080p 50p on a previous I7 generation processor on 7200rpm single drives using edius with no issue, even when using 3 camera's in a multicamera sequence (all native formats)

No, not specifically a Lightworks issue. To edit any inter-frame acquisition format like AVCHD, you will need an optimised PC, especially the graphics board because of the Long GOP nature of the codec. Most laptops are unsuitable. Intra-frame codecs like DNxHD or ProRes are much less processor intensive so are a better proposition for really 'edit intensive' work. If you are just putting in the odd cut or dissolve, then you can edit native AVCHD.

Lightworks uses very refined, 'no frills' code so is a very fast editor - very intuitive. Out of all the PC based NLEs I have used: Avid, Vegas, etc Lightworks is the most satisfying. Perhaps it reminds me of cutting film the most. It is fast and fluent so one of the reasons it has been such a popular editor for cutting blockbuster Hollywood movies.

To edit any inter-frame acquisition format like AVCHD, you will need an optimised PC,

I'd rather say you need a optimized NLE, I have a simple GPU card (gtx460) and besides a cut or dissolve I can also colorcorrect in realtime. I don't have any experience with laptops where I suppose you need a recent higher end one but for desktops you can get a more basic one without any specific hardware requirements if you edit with Edius.

Like Noa I use Edius and I normally edit 4 tracks of AVCHD native multicam from a single 7200 rpm drive with no problems and I do not have a fast graphics card either as Edius does not use the GPU for editing only some of the plugins and filters use the GPU. My PC is a low cost i7 2600K CPU, 16G RAM running WIN7. I also have CS6 and Vegas so can also say that they will not edit native files as well as Edius, Vegas easier than CS6 on my system. You only need intermediate codecs if the system is incapable of editing realtime native and then I agree you will need fast drives because data rate has been used rather than processor power.

Ron Evans

I work with a low spec i3 laptop which is why I use timecoded DNxHD or timecoded MJPEG proxies then render from uncompressed intermediates to an uncompressed 10 bit AVI Master. One of the reasons I transcode my AVCHD to proxies and intermediates with AWPro is that it will generate and embed identical timecode into proxy and intermediate at the same time - also a great workflow for DaVinci Resolve.

I've not used Edius but it is highly regarded. Lightworks free is free and Lightworks Pro 64bit is only a $60 annual subscription - including all future upgrades.