Need Advice on Upgrading from HDV
 

Hi

I produce and direct amateur fiction films but am hoping, someday, to be able to get something on the telly or even show films in a cinema.

I've shot a film in DV and 2 films in HDV. But now I've reached the point where I really want to upgrade from HDV to a better format. By better I mean full 1080 HD (not 1440 x 1080 upscaled) or higher resolution, 4:2:2 color sampling or better, progressive capture and intraframe compression.

I currently own a Canon XH A1. And I could really use a camera with better features now, especially a better viewfinder to make focusing easier, more switches (you can never have too many switches) and interchangeable lenses. The problem is, what do I upgrade to?

I'm thinking of spending up to $9000 (£6000) at most, including a lens or lenses and rails and stuff if needed. But if there's a far better camera for a little more I'll just have to save up for longer...

I've considered the Panasonic HPX300 or the RED Scarlet so far (when it comes out - still need to save up so no rush). Does anyone have any other suggestions?

Another option I considered was a DVC Pro HD , HD CAM, HD CAM SR type tape format, but the big ENG type cameras that run these tapes might be out of my price range, unless I can get a second hand one. I'm not sure which of these formats are intraframe compression though and intraframe is a must.

I do own some very good Canon EF-S lenses (10-22mm and 17-55mm) that I use with my digital SLR, but I'm guessing these are not going to be compatible with any upgrade camera I get?

I guess another thing to consider is using a 35mm adaptor, since I am looking for a more cinematic feel to my productions. But the price would have to be included in the total listed above so it might be out of my range.

I'm a bit overwhelmed and out of my depth so any help would be much appreciated

Thanks for listening

Stuart

Um... to jump up to HDCam/HDCamSR you would need to increase your budget by more than a factor of ten.

At that budget figure, you may want to stick to dSLR shooting with a ton of support gear (and good glass) IF you are looking to do mostly dramatics. For more verité stuff, the EX1r with support gear might serve you well.

Hi Stuart if you need to check out a HPX301 you are welcome to come and see mine I am in Durham about 60 miles away.

Surely at that price point, the EX3 must be the obvious choice? Don't forget all the extras you may need to get with more expensive cameras apart from matte boxes etc - I'm thinking of pro batteries and memory if it's a solid state camera. (An HPX371 is about £7,250 plus VAT in the UK - batteries, charger, and enough memory for 2 hours recording will easily push that up to well over £9,000 plus VAT.)

It also gives you the chance to start using it now within your price range, whilst still saving for a nanoFlash to give a fully approved broadcast codec.
Can I ask why? You may get motion artifacting with lower bitrate interframe codecs (such as HDV) but above a certain bitrate level that effectively goes away. For editing, it's obviously possible to transcode anyway.

Both HDCAM and DVCProHD (not HDCAM-SR) are sub-sampled, and rely on older technology - personally I'd prefer XDCAM-HD over them, in spite of it's being interframe.

David: Thanks for the camera recommendation. I wanted to avoid intraframe codecs because of the unpleasant tearing artefacts we've seen when panning (even slow panning) to follow the action or do reveals in my films. What do you think is the minimum bit rate to go for to avoid these artefacts with long GOP compression? The EX3 looks good, I'll add it to my list. Do you have an EX3?

Shaun: Good thinking. I've thought about going down the dSLR route (I have a 550d), but for the ambitious pull focus shots, dolly shots and stuff I tryto do I'm not sure it'll work (I really need someone to control focus remotely with a Lanc controller or suchlike, like we do with my XH A1).. Plus I'd have to invest in an audio recorder as well as there's no XLR in on an SLR. And I think I'd miss zebra stripes and easy white balancing and so on. I think the compression on these SLR cameras is going to give artefacts where there's too much movement as well? I'm shooting complete fiction, no Cinema Verite or documentary stuff.

Gary: Thanks very much, I'll send you an E-mail and pop over on the train one weekend...

Does anyone think the RED Scarlet might be the camera I'm looking for?

XF series
 

Hey Stuart.....
If you're on a budget, but want those specs, i would suggest looking into the Canon XF series camcorders.
It shoots 1920x1080 square pixel and 4:2:2 at CBR 50mbps.

Although it won't give you the same look as film, 35mm adapters are being sold at a fever's pace nowadays. I'm not sure what's needed to screw onto the larger thread of the XF lens.

If this is over your budget, i'd suggest sticking with HDV, and using a Redrock Micro...

Good luck!!!

The Canon XF range look like really nice cameras Peter! Good recommendation, thank you!

50 Mbps is pretty good, isn't that double the HDV bitrate?

Do you think at this bitrate I'll completely avoid the compression artefacts that have plagued my productions in the past?

And the XF cameras takes standard CF memory cards which will save quite a bit of dough.

I notice these cameras have HD-SDI out. I guess that could be potentially useful in the long term if I decide to go even higher quality in the future and record to an expensive disk system.

Do the XF series cameras have a fixed lens? I'm assuming so but it doesn't seem tell you on the Canon website.

I think the key features for my next camera are:

* Avoiding compression artefacts with camera movement and fast action.
* Having 4:2:2 color sampling or better.
* Full HD resolution.
* A better viewfinder and better focus controls than on my XH A1... I could always invest in a 35mm adaptor in the future, I can do without one for now.

Any other suggestions anyone?

I assume a misprint and you mean interframe....? There's interframe and interframe - and a lot is down to bitrate. Reduce the bitrate too much and it's true you'll get artifacts, above a certain level they'll be small enough to neglect. Also bear in mind that intraframe will show a different type of artifacting, it may handle motion better but can show problems on detail - and even on static shots.
The EBU did a series of codec trials a year or two back, and their recommendation with MPEG2 is 50Mbs - they give that unqualified approval for broadcast acquisition. For intra-frame the recommendation is AVC-Intra at 100Mbs. They describe either of those as effectively "transparent" in normal usage.

Personally, most people will struggle to see much difference between XDCAM at 35Mbs and 50Mbs in normal viewing. Raw numbers don't really mean very much, a lot may depend on the standard of individual equipment, and overall quality may depend far more on the quality of the camera front end than codec.

You can add a nanoFlash to an EX to get the 50Mbs rate (and many people do), but the point of the previous post was that a basic EX is easily within your price rating now - you can always add a nanoFlash as and when you can afford it.
I would suggest you price it up, I think it may be out of your price range. I believe the post workflow is more complicated than most.

The Canon XF300/305 seems to be comparable to the EX. In it's favour are the 50Mbs codec natively, and there are good reports about the lens performing better than expected for a 1/3" chip camera, on the other hand, it's a fixed lens and the chips are 1/3" v 1/2" of the EX. It's the only 1/3" camera to get BBC approval for HD use, which must give it an edge over the HPX300. (The EX1/3 gets approval only if used with a nanoFlash.)

Oops, well spotted David, I did mean interframe.

Thanks for all the info David, that's clarified a lot of issues for me :)

The Nanoflash is certainly expensive but looks amazing. I guess in the long run the XF300/305 would be a bit cheaper for me as it's already 50Mbps. Then again if I wanted to go even higher quality then the nanoflash would allow that. Or there's the HD-SDI out on the XF300/305 which I could feed into a nanoflash too I suppose?

I notice the EX3 can have remote controllers plugged into it which would be really useful for the dolly shots and stuff we tend to do.

I've got plenty of options to mull over. I'll have to look at the heated XF300/305 versus EX1/3 debates now...

Just out of curiosity, would you go for an EX or an XF David?

Then, given the extra expense is it worth getting an XF305 rather than an XF 300; or an EX3 rather than an EX1 do you reckon?

The EX3 has interchangeable lenses. The EX1R and XF300/305 do not.

I'm looking to upgrade same as you but I think it's flawed to buy based on a spec that doesn't consider sensor size. But you can read up on the discussions and make your own conclusion.

I've concluded the EX line (at 4:2:0/35MB) has image advantages due to the larger chip size. My sense is that the EX 1/2" sensor/4:2:0/35MB may solve the HDV artifact problem for you. And as you noted, it has an SDI out for later when you want to shoot 4:2:2/50 or 4:2:2/100.

On the EX series, you'll be getting your 4:2:2 off of 1/2" chips vs 1/3" chips from the XF305 (the XF300 does not have SDI out). BTW, the EX1R is a fixed lens like the XF but also has the 1/2" chips like the EX3 and it also has SDI out. It's cheaper than the XF as well.

In the should you save up and wait, I think people expect Canon to rev it's XL line in sept (I am only repeating others) and that line has interchangeable lenses so..... nonetheless, consider the sensor size.

Sony showed a 35mm-ish sized sensor camera with interchangeable lenses designed for documentary filmmakers at NAB:

Thanks for the insights and other camera options Les.

I'm really glad I asked in the forum after getting all this help. What did we do before the internet and forums? I'd have bought something totally inappropriate I guess!

The EX3 might be more future proof for me with its interchangable lenses, but with nanoflash it's going to make it a bit too expensive. These are the prices I've come up with on Google Products:

EX1R = £4500
EX3 = £5600

Nanoflash upgrade = £2600

XF300 = £4900
XF305 = £5600

I guess I'd have to factor in accessories as well, especially the memory cards. It looks like the SxS cards the Sony EX cameras use are very expensive. So perhaps the XF300/305 are better value as they use lower cost CF cards and come with 50MBs bit rate as standard.

I'll keep an eye out for the new Canon XL, the upcoming Sony 35mmish and the RED Scarlet while I'm saving up...

Probably still the EX, but whereas up until now it's been a one horse race around that price point, now it's far more difficult. To me, the main draw of the Canon is the fully approved 50Mbs codec, against that the EX is 1/2" chips and you can always add an external recorder later. I don't think there's a simple answer.
I'd probably go for the EX3, mainly for better connectivity and being able to genlock and slave timecodes if desired. It also has interchangeable lenses, and is better ergonomically than either the EX1 or the Canons when handheld. (Though it's far from perfect.) It's also more suited to having "extras" bolted to it, and with an adaptor you can make use of pro type batteries, which also help with weight and balance.

Maybe out of your price range (about £9,400 plus VAT), but take a look also at the PMW320 which is similar to an EX, but in a full pro style shoulder mount.

And what sort of timescale are you working to? If not in a desperate hurry it may be worth waiting to see what happens at IBC, and Les also brings up the subject of the camera Sony announced at NAB, though that's likely to be a little way off.
Ah, a pleasant surprise for you! Do a search on the EX forum and you'll find a lot said about using SDHC cards in the EX with an adaptor. At first, it was a bit hit and miss - not all adaptors and not all cards worked - but now it's much less of a worry. Tested adaptors are sold exactly for the purpose, and Sony have now given the idea seal of approval to the extent that they market their own adaptor to allow both SDHC and Memory Stick to be used.

You do have to follow a few golden rules. ONLY use approved adaptors and memory cards - and the approval list can change. ALWAYS test the SDHC cards before proper use - occasionally you may find a card which is below spec, good enough for still camera use, but not for sustained video. DON'T rely on them for overcranking. (You can always record overcrank to a true SxS card, then copy the clip to SDHC in camera.)

Thanks again David, I'm becoming more enlightened by the hour :)

And you're selling me on the EX3! Even though I've always been a Canon man up to now.

I didn't realise SDHC cards can be used in the EX1/EX3 with an adaptor, that's fanastic news! And really useful to know for pricing things up.

What do you mean by overcranking David?

There's no rush to buy, I won't be able to afford a new camera until next year, so I'll definitely wait and see what comes up at the IBC in September... and see if the new Sony 35mmish thingy is revealed... and maybe, just maybe, the RED Scarlet might come on the market...

Look, you probably want 100MB for a feature film anyway. The Canon XF305 is the same price as the EX 3 yet doesn't have interchangeable lenses which I thought was a requirement for what you want to do.

Do apples to apples. If you compromise on the lens mount, then price the SDI enabled XF305 against a fixed lens EX1R which has the SDI output. For interchangeable lenses, compare the upcoming SDI enabled XL model (probably 1/3" like the XF) against the 1/2" EX3.

Also, isn't image quality as important as specs? Depending who you believe, the XF image at 50MB isn't better than the EX at 35MB and the EX also has a minimum 1 stop or more (depending on who you listen to) lowlight capability. It follows that 100MB off the 1/2" EX will be better than 100mb of the 1/3" XF.
You may have seen this comparison: XDCAM-USER.com Canon XF305 Review with Sample XF/EX clips

A colleague of mine just sold his EX1 and bought 3 EX3s. He uses the Hoodman Raw SxS adapter and their SDHC cards. A 16GB is $1340 and 32GB is $240. He says he's had zero failures with them:
RAW SxSxSDHC Memory Adapter-Hoodman Corporation

I empathize with you on Canon but things have changed and their products, ergonomics and market strategy may not serve your needs. They don't mine.

Not to stir the pot but you should double check there's an adapter for whatever camera you choose that will let you use the lenses you have. And, there's also this Panny coming out soon targeted at your space:
Panasonic Introduces AG-AF100 4/3-Inch Professional High-Definition Camcorder | Studio Daily

But for all of these APS-C based cameras, you are buying into the 1.0 versions (bleeding edge). Also, you may find they've moved onto a new CODEC like AVC which is also new.

Then there's the DSLR route....YMMV

The official Sony adaptor is listed at Sony : MEAD-SD01 (MEADSD01) : Features : United Kingdom and as for what Sony have to say about it:

The MEAD-SD01 has been specifically developed by Sony to operate with XDCAM EX hardware and, as long as users follow the usage guidelines with recommended Class 10 SDHC products, they can be confident of the correct operation of their XDCAM EX hardware.

Note the caveats - equivalent to my "golden rules"!

Also be aware there are other, cheaper, third party adaptors on sale.
Filming at a higher frame rate than the film will eventually be shown. The origin of the term goes back to hand cranked cameras - it meant turning the handle on the side faster than normal! It means that a slow motion efect will be seen on playback.

As far as the EX goes, then in a 50Hz country, you may wish final playback to be at 720p/25 standard. With the EX, that will be natively recorded with a 35Mbs data rate. It is possible to shoot at 50fps, at double the data rate, so that normal 25fps will still be a 35Mbs standard XDCAM-EX file.

Now whilst the adaptor/SDHC card may be reliable for normal data rate recording, there is no guarantee that it will record higher bitrates, and indeed, Sony recommend against it. But seeing how far you can push it can give a very good idea of how much safety margin there exists, Certainly people are reporting being able to overcrank far more than ever used to be the case.

Oh yeah, forgot to mention that when I assessed these cameras myself, I noticed something. When you price out your SDI enabled fixed lens choices (XF305 vs EX1R), you have to normalize the pricing to include 16GB of recording media because unlike the EX3, the EX1R DOES come with media: a Sony Pro 16GB SxS (good stuff). According to B&H, XF305 is on Preorder but based on the XF300 packaging, the XF does not include media. B&H shows a 16GB Sandisk Pro CF on sale for $175US and non-Pro for $125US. YMMV

Thanks Les, that's a really good insight. I'll compare apples with apples and oranges with oranges when the Canon XL comes out...

Good point, so I might still need a nanoflash for an XF305 anyway in the long run so should not take the extra cost into consideration when comparing with the EX models. I also thought the EX3 would work out considerably more expensive at first because of the SxS cards, then David enlightened me about SDHC adaptors. That's why I was thinking of letting the interchangeable lens thing go, but it would be great to have interchangeable lenses.

The AG-AF100 certainly looks interesting, but it would need a Nanoflash too since it's maximum is 24Mbps, wonder how much the camera will cost when it's released...

I'm definitely leaning heavily towards the EX3 at the moment.

Les: Do you think a better version of the APS-C sensors might come out soon?

What's bleeding edge?

David: Thanks for the extra info on SxS - SDHC adaptors.

Afraid you've lost me there David. Are you saying the EX1/EX3 cameras can record at bit rates higher than 35 Mbs to memory cards if you overcrank and film at 50FPS rather than 25FPS?

Yes, the SDHC based SxS cards give you the reliability of SxS and are much closer in cost to the expensive CF cards you need for these hi data rate (35mb and 50mb) applications. The XF is the first in this class of codec to use CF BTW so the reliability is undetermined. I've seen demos where an SxS card is yanked while recording and not a single bit of video was lost. I did that on my CF HDV camera and lost the whole 2GB segment. I don't know if Canon has done anything to make the CF cards as reliable as SxS.

When I said APS-C I meant the new family of large sensor camcorders like the Sony and Panny I mentioned. Canon may have one too but their strategy has been to be the last ones in the market segment. I think the APS-C sensor cameras are single chip FWIW.

Bleeding Edge is a pun on Leading Edge aka buying into the first generation large sensors. While you get to be first on the block, it's joked that you pay for that in blood (problems, glitches, top dollar pricing etc).

With all due respect Stuart, it is a common misconception among amateur filmmakers, that by spending a bunch of money on a camera that has, as you put it... "More switches" "interchangeable lenses" or uses a different codec, will push you to a professional level. When in fact most of the time the camera has absolutely nothing to due with that. It is still the same film, only shot with a different camera.

There is nothing wrong with the camera you own, and there have been many professional productions shot with the XH-A1. If you need a better viewfinder to make focusing easier, then purchase a proper monitor which can be used with any camera you might choose to use.

Bottom line, there are so many other places to spend your hard earned cash which will have a more significant impact on your productions that buying a new camera. And in most cases, rentals make the most sense when you get to that level.

All the Best!

I want to go on record to agree wrt to the need for storytelling, lighting etc skills and that getting a next level camera in and of itself isn't going to take a filmmaker to the next level. I assumed Stuart assessed he had what it takes.

However, I do empathize with wanting to move to something with better low light sensitivity, DOF, file based workflow, and get some ergonomic improvements like hi-res LCD/VF, full stop rings and a few others.

Hey guys

Hopefully I've got what it takes... I'm currently engrossed in several books on cinematography and directing and scriptwriting... find it hard to have time to keep up with the latest cameras and stuff in between editing, planning, full-time job, etc, etc... If I haven't got what it takes, it's not that important to me - as long as I can keep making films.

I put so much work into my films I just find the compression artefacts a real shame. Every time I watch the films I've made I see the artefacts, not to mention the dodgy HDV color, and think I wish I'd recorded in a better format. There's also the issue of how difficult it is to execute focus pulls while dollying, getting smooth zooms, etc, etc... The lower bitrate HDV format also means I can't do the shots I want because if the camera pans or moves on the dolly any faster than really really really slow to follow action I get nasty tearing in the image. But no action is really that slow and it's really limiting.

One other advantage to upgrading my camera is that at least my films might reach a wider audience on a satellite channel or suchlike and I can try to get back some money for future films.

David: Good thinking, I've never really looked into rental before, I have no idea how expensive rental is for cameras like the EX3. At the moment my filming is all done at weekends (usually 7-8 weekends in a row) so it's a bit awkward to pick up and drop off equipment each weekend. The nearest rental place is about 30 miles away as well. But I'll look into getting some rental prices.

Les: maybe it's best for both of us to wait until the big APS-C sensor bleeding edge cameras have been replaced with cameras with a slightly blunted edge and then invest... or invest in chainmail gloves... hmm...

Most rental houses have special weekend rates that will save you money.
Use the money you save renting vs purchase to hire a pro audio person and grip truck w/gaffer.
The key is really surrounding yourself with the best team you can assemble.

Good Luck!

Stuart, I am really beginning to wonder whether you may not have got some other problem which you're blaming on HDV and compression. HDV is not a broadcast codec, but it's not THAT bad - most of the time you are hard put to see any problems. To put it in perspective, it's arguably better than the standard used for broadcast HD TV transmission - when BBC HD was MPEG2 I believe it was around 19Mbs, subsampled to 1440, 4:2:0 colour sampling. (It's now an even lower bitrate, but using H264.) You may have been able to see the odd artifact - but "....the artefacts, not to mention the dodgy HDV color...." and ".....if the camera pans or moves on the dolly any faster than really really really slow to follow action I get nasty tearing in the image....." ?

Excuse me? That sounds worse than the cheapest consumer camera at very low bitrate AVC-HD. It sounds vastly worse than any HDV camera should be, and certainly an XH-A1 - I think your problem may be something other than HDV. In what way do you consider HDV colour "dodgy"?

Stuart, further to David Heath's comments, maybe you could post s short clip of what you've done. That may help to determine if what you are seeing is a result of the HDV Codec or some other factors.

I use to shoot with an XL H1a and XH A1 and did some independent shorts with them. Given the correct setup both cameras could produce very good pictures. Whip pans were a no no but you could pan at a reasonable rate an not see the effects you are mentioning. With the footage from those two cameras the first thing I would do is to transcode into CinForm intermediate prior to doing any post work. If you do use heavy color correction on HDV files they will exhibit some pretty nasty artifacts.

I currently shoot with an EX3 and nanoFlash. This combination, especially shooting at I-Frame only 180Mbps or higher yields some truly stunning results.

This is my personal set up and if a producer were to want anything higher I would rent as the cost of investing in a higher end rig is not justified for most independent shooters. I've had some of the projects I've worked on shown in local theaters as well as broadcast over local cable and with the EX even using native files (not from the nanoFlash), the final product is pretty impressive.

A word of caution though. You did hit it onto an aspect most people going into these cameras don't anticipate. That is the higher cost of accessories. Batteries, for example, are much more expensive, You'll need a good tripod also. As for your critical focus, nothing beats a good HD monitor. I can focus decently through the EX3's VF when I'm handheld but if I'm on sticks I always have my monitor going to aide in focusing.

Garrett

One of the things I absolutely love about my Sony V1U is that it has a HDMI port with the video signal at full HD resolution direct off the sensor block. Industry people have dropped their jaws when they see the quality of the image that comes out of that connection. Much better than HDV.

All I need is a unit that records from a HDMI input and I've essentially got myself a codec upgrade without having to purchase a new camera.

Andrew

Limiting factor being the 1/4-inch CMOS Sensor.

True, true.

But just think of that beautiful 20x optical zoom you get. :-)

Andrew

Good afternoon,

there are a number of cameras out there that can out put full resolution via an hdmi port!!

An hdmi recording device other than a lap top would make them outstanding choices!!!

Thanks for all the help and replies guys!

Great suggestion Dale.
Would you need a Nanoflash to record to or do you mean the sort of HDMI recorders you get for recording hi-def television?
Do you do this yourself and what camera do you use for it?

Hi Andrew. Didn't realise the V1U has HDMI out. What do you record to? Does the recorder compress your footage? And in what format?

Hi Garret. I'll try to post some footage or stills of the tearing effect. I've seen the effect in other people's footage online so I don't think my camera's faulty. I always see it when watching back footage where panning or other camera moves are too fast. I did some tests a while back and found I had to pan at a speed where an object passed from one side of the frame to the other in no less than twenty seconds to prevent the tearing problem. 5 seconds or less looked terrible. 10 seconds wasn't great. It looked like compression artefacts to me and I hunted around forums and Google to see if anyone else had similar problems to no avail.

That's a good idea to get a decent monitor to aid focusing.

Thanks for the insights there David. I might have been a bit hasty with my wording there. Just having more colour to work with in colour correction would be nice. And I'm going to be doing some chroma key and compositing work in the future so 4:2:2 colour sampling might help give better results. My main concern is the tearing artefact, as I call it. I'll try to post some images and video of the tearing artefact today or tomorrow.

Thanks David. You're right, I really could do with getting a pro crew together and better equipment, I've used volunteers so far. I'll try and figure out rental costs and how much it'd be to hire a crew for a film.

Hi Stuart,

I'm still recording to tape. But at least I have this option available in the future, should tape become rare.

Andrew

Hi Stuart

I believe the V1U is CMOS based and CMOS technology is famous (or infamous) for so called rolling shutter aka jellocam, etc

The sensor cells in a CCD camera all store their values in an associated holding cell at the same instant when the shutter "closes" and then the camera scans down the holding cells in some amount of time. But since all the holding cells were filled at the same time, the image is just the same as if the cells had all been scanned instantaneously.

CMOS on the other hand doesn't need/have holding cells so the camera scans the actual sensor cells sequentially at the end of the frame's exposure. This means that the cells at the bottom of the frame are scanned later than the cells at the top of the frame and upright objects can look like they're "leaning" a bit as a result.Slow pans look OK, faster pans can look tear-y or jello-y. Effect is worse in some cams than others

Just guessing and this may not be what you're referring to, but hope this is relevant

If by tearing you mean the effect you see in really old still pictures of a racing car where the wheels look like the top is ahead of the bottom then this is probably it.

Andrew: Thanks for getting back to me.

Jim: Hi. Luckily my XH A1 is a 3CCD sensor so shouldn't have the jello effect.

I had a quick look at the problematic footage in Avid last night.

Bizarrely the video looks fine paused but as soon as you play it you see the effects regardless of if it's the original HDV footage or if it's transcoded to DNxHD. Hmm, I wonder what it means?

I wonder if there's a way of fixing it?

Will post some video of the tearing problem later today...

Sounds like a field reversal or something of the sort.

I captured progressive footage and edited the footage in a progressive Avid project. So it shouldnt be a field reversal problem should it?

It's only seen when there's camera movement that's too fast. When it happens the screen almost looks as if it's splitting into 3 or 4 sections along horizontal lines.

Has anyone used the V1 + Nano combination? I am really interested in how well this works.

I've attached a clip that shows the tearing artefacts worst of all. This clip was recorded in HDV and exported from Avid as a Quicktime movie. It also displayed the tearing artefact when viewed in Avid, but not when paused.

I was going to use a different clip, but when I exported it as a Quicktime Reference file then reformatted it to an MP4 (AVC) file it looked fine. Boy, did I feel like a plonker!

But the attached clip is definitely looking awful on my system.

Has anyone else experienced problems like this?

Is it an Avid or Quicktime format problem?

Or is it a graphics card or graphics driver problem?

Maybe even the bitrate is too low?

Thanks!

I'm wondering if is something where it's easier to notice that your computer isn't keeping up with displaying the content to the screen.

Best thing would be to either put it on to a blu-ray disc or play back to a monitor from a HDV deck as these playback options are pretty much guaranteed to not have this sort of issue. This way you can tell for sure if it is your footage at fault or not.

Andrew

I think the latter comment gives it away - if you are seeing a "tearing artifact" on playback (which you earlier described as "the screen almost looks as if it's splitting into 3 or 4 sections along horizontal lines") but not when paused - I'd be fairly certain it's a function of the computer you're playing it on. And absolutely nothing at all to do with HDV, rolling shutter or anything else to do with the camera. If it was, you'd see it on the still frame.

The only way to be absolutely certain is (as Andrew says above) to replay the original HDV tape (either in the camera or a separate deck) and look at the output on an ordinary TV. (Look at the SD downconvert if you haven't got access to an HD set.) I'd be prepared to put a sizeable bet that the problem will have gone away. And conclusively prove that the problem is nothing to do with the camera or the codec it's recording to.

I've looked at the clip you posted and can't see the effect you describe ("....splitting into 3 or 4 sections along horizontal lines.....") at all, which leads me even further to thinking the issue lies with your computer system. I'm assuming you've further compressed the material down from HDV? (11MB for an 11 second clip seems far too small for raw HDV.) I can see static compression artifacting, but that's more visible on stills than the moving image and I'd assume that's down to this further compression.
Hmm, sounds so simple, doesn't it? I'll agree that 4:2:2 is preferable to 4:2:0....... IF (and only if) all else is equal. Unfortunately that's rarely the case.....

Firstly those numbers are ratios - not absolute numbers. The former is fundamentely saying there are as many colour samples as luminance in the signal, the latter is saying only half as many colour as luminance. So the former must be better, mustn't it? Well - if I offered you all the money in my left pocket, or half the money in my right pocket, which would you choose? The left pocket sounds the best deal? But what if you found out I had £1 in the left pocket, £4 in the right? Now, it's better to have half of £4 than all of £1, isn't it!?!

And you can get similar situations with video. For full raster 1080, we have 1920x1080 luminance samples, and with 4:2:0 chroma 2x960x540 chrominance samples. (1,036,800) For subsampled 1080 (such as DVCProHD) you have 1280x1080 luminance samples, so with 4:2:2 chroma sampling 2x640x1080 chrominance samples. (1,382,400) It's more - but nowhere near the twice as many you may have expected. And since the results of the chromakey will depend on the luminance signal as well as the chrominance, the far greater number of luminance samples of the first example MAY prove more significant than the extra chrominance samples of the latter!!

In practice, it gets vastly more complicated, and heavier compression can adversely affect chroma key and compositing work far more than the 4:2:2/4:2:0 issue, for example. And all sorts of things to do with the front end of the camera - is that inherently noisy? It doesn't matter what the recording spec is if the image sensor etc is giving poor quality to it.

Andrew: Good thinking. I'll dig out the tape and try playing through the camera and into the the telly at home.

David: I feel a bit embarressed I didn't work this out before... but I think your're right. Maybe my graphics card isn't up to spec or there's a driver issue or something like that. Your computer is obviously superior to mine! That clip looks terrible on my computer, I did compress it and it came out smaller than I thought.

Will dig the tape out this evening and check it on the old telly...

I see what you mean, it is very comlicated!

I didn't realise DVCProHD was subsampled David.

Is HDV subsampled at 1440x1080 luminance samples?

So HDV has 1440x1080 luminance samples and 720x540 chroma samples... but it is compressed more heavily than DVCProHD so although the resolution may be higher for HDV the end image is worse? Does that make sense?

If HDV is 4:2:0, how bad is that zero at the end compared to the 2 in 4:2:2?

I was under the impression it mutes the colours quite a lot?

Would you say CMOS sensors are generally worth avoiding in a video camera because of the artefacts they can give?

Yes, but it would be wrong to think of it (and the same with the subsampling of DVCProHD) as necessarily a terrible thing. It's just one factor of a very complicated picture - same with 4:2:2/4:2:0.
The more you go into it, the more complicated it gets! Yes, HDV is compressed more heavily than DVCProHD if you look at it purely in terms of number of bits in, versus numbers of bits out. But it also takes advantage of more "tricks" than DVCProHD does - looks for similarities frame by frame, not just within each frame. Hence the end result isn't as cut and dried as simple bitrate numbers might suggest.

But the differences are much deeper than simple "quality". The more "tricks" a codec uses, the lower the bitrate it can use for a given quality. The drawback is that the "tricks" add complexity, and can mean much higher computing power necessary. The positive side is that a high quality can be achieved with a fairly small bitrate compared to a less complicated codec - that can make a big difference if (for example) it means cheap memory such as SDHC can be used, P2 or SxS being necessary for the higher bitrate codec.
It doesn't "mute" the colours, just means that the vertical chroma resolution is half that of the vertical luminance resolution. In each case, the horiz chroma res is half that of the luminance, in the case of 4:2:0, that means there is now symmetry vertically and horizontally. (There is a difference between an interlace system and a progressive one, but I'm not going to start on that.)

As for how bad is it, what do you think when you watch any Blu-Ray disc, or BBC-HD, say? Do the colours look "muted"? Because nearly all delivery systems are 4:2:0.

Viewing is one thing, when we think about chromakey etc otherwise invisible differences can start to make a difference. Yes, colour space is one such factor, but arguably factors such as general compression, luminance subsampling etc can be even more important - and that's before we even get on to the front end of the camera, and things like noise levels. It's wrong to obsess over any one factor, and 4:2:0 certainly shouldn't be seen as "muting" colours - that just sounds like the sort of terminology a salesman with a vested interest in 4:2:2 products may come out with...... ;-).

If you want to read more, start with Chroma subsampling - Wikipedia, the free encyclopedia . To put things in perspective, analogue PAL savages the chrominance information far, far more than 4:2:0 does!