A BRIEF INTRODUCTION TO DVCPro HD
Panasonic produce a competing tape-based format to HDCAM called DVCPro 100 or DVCPro HD. There are 2 x discrete formats which use the same DVCPro tapes: the first is Varicam (720p) and the second is a 1080p version which is used by the HDX-900 Camcorder. The tapes and VTRs are common but the similarity ends there.
DVCPro HD has received a lot of popularity recently as the easy post-production capability to edit to edit native HD in Final Cut Pro (FCP) and AVID, makes this a very practical acquisition and post format.
The BBC Starwinder project produced a report a few years ago which estimated that compared with shooting on Digi Beta, editing on AVID and conforming onto Digi Beta for a standard delivery project, money could actually be saved by shooting onto DVCPro HD using the HDX-900 and post-producing using FCP in HD and then delivering to HD afterwards! The dynamic range is also better than the ubiquitous DVW-790p Digi Beta Camcorder, stock is approximately the same cost and the filmic qualities are also excellent, which explain why series like Robin Hood and others now shoot using the HDX-900 Camcorder onto DVCPro HD. There is a later variant which shoots the same image size and format but shoots instead onto solid-state memory cards called P2 – however, if you are happier shooting onto tape, then this is a serious camera and format to consider.
Panasonic HDX-900 1080p DVCPro HD Camcorder
Due to the difficulties of editing Varicam pictures, Panasonic brought out an equivalent camcorder to compete with the Sony HDCAM camcorders, which they called the HDX-900.
This stunning camcorder also shoots onto DVCPro tapes but shoots 1920x1080 images in 25p or 50i, the same as the Sony HDW-790P. The same highly regarded image processing as the Varicam has been introduced into this camcorder and it copes with a very large contrast latitude, same as the Varicam. It shoots extremely beautiful ‘film look’ images and in common with all of the camcorders already mentioned, is compatible with all HD zoom and prime lenses.
However, one major advantage of this camera and its format is that there is a total support for firewire post-production in 1080 mode. This means that for off-line and on-line, the same low-cost non-linear edit suites can be used using a single HD firewire cable alone. More on this later.
Compatible with 24p
In common with the HDW-F900R, The HDX-900 is a ‘world camera’ which means that it shoots in all world HD TV formats of interlaced and progressive in the European and US frame rates (25p, 29.97p, 50i & 50.94i) in 1920x1080 resolution. However, unlike the HDW-790, this camcorder can also shoot at the 23.98 and 24p frame rates in 720 mode for cinema release.
Varicam – 720p DVCPro HD Camcorder
Similarly so, the Varicam is also a ‘world camera’ shooting on all standard world HD frame rates including 23.98p and 25p. However, the Varicam system is an enigma of HD tape acquisition, as you will see.
It records smaller frame sizes (1280x720) than other HD formats but don’t be put off by this. It can shoot at continuously variable frame rates between 4 and 60/second including 24p and 25p. The image processing and clever compression ensures that you can blow up for the very large screen with spectacular results (Both Varicam and HDCAM look equally stunning when viewed on a 60ft screen). The wide range of contrast latitude (measured at 13 stops by ex-BBC engineer, Alan Roberts) and cine gamma always ensures beautifully filmic results.
Varicam always records 60 frames per second irrespective of the frame rate mode and the clever frame flagging system permits multiple frame rates for acquisition and slow and fast frame speeds for special ramping shots (compared with HDCAM which shoots at fixed frame rates with a maximum of 30 fps).
Despite shooting in 720p mode, the VTRs will automatically uprez to 1080 so there is full compatibility with other HD formats in post-production and thus is compatible with all 1080 delivery requirements for Discovery HD etc. It is also compatible with all AVIDs and Final Cut Pro for off-line and for on-line with 3 main considerations.
The first is that the majority of your acquisition material must be at a standard frame rate (24p or 25p etc) for easy post.
Should you shoot at any other frame rates including faster than real-time images (i.e. not 24P, 25P or any of the 7 prearranged production speeds, then you MUST record the ‘off-speed’ images onto a separate tape, as these images will need a special treatment. These images will need to undergo a post-production stage called frame-rate conversion in order to digitally slow down the images and uprez them to 1080. Without this stage, the footage is useless as it is incompatible with pretty much every post-production technology and the conversion can be costly, so ensure that you have budgeted adequately for this. This stage can be very effectively done using Apple Final Cut Pro – see the FCP/DVCPro section below.
Whilst Varicam has complete firewire support with Final Cut Pro, it is not for the feint hearted. It edits in the native 720P environment and additional HD-SDI cards are needed if mastering onto HDCAM or other 1080 line formats. To read a success story of a Varicam program being edited on Final Cut Pro, please read the testimonial on http://www.kenstone.net/fcp_homepage/dvcpro_hd_workflow_balis.html
Editing Varicam using the HD firewire port needs very specific settings, which are not intuitively obvious – in fact it only works if you work in 60 fps mode, irrespective of the project frame rate for example and the editor needs to be very clear about how Varicam and Final Cut Pro interact.
An alternative solution is to use edit suites with an HD-SDI capture card (e.g. AVID Adrenaline, FCP black magic ard etc), in the same way as editing from HDCAM.
Irrespective of the post-production route, variable ‘off-speed’ footage will need to undergo a frame -rate conversion stage prior to off-line or on-line editing, whether this is done externally or within a PC or Mac environment using appropriate software plug-ins. A caveat here - be aware that various versions exist and ensure exactly what frame rates are compatible with your plug-in version prior to shooting – it used to be that only 59.94p was compatible with the FCP frame rate converter plug-in but this is no longer the case.
The Panasonic Varicam received world acclaim on it’s debut in 2005 and the popular AJ-HDC-27F was replaced with the superior HDC-27H a couple of years ago which is the unit to use if you are considering shooting on Varicam.
The new Varicam 2 and Varicam 3 (P2 Versions)
Panasonic released two new P2-based Varicam camcorders in late 2008, the HPX-2700 and HPX-3700.
The Panasonic HPX-2700 is the same as the HDC-27H with a 1280x720 pixel sensor (same as Varicam) which records to P2 instead of tape, so other than non-linear record. If you are using the slow-motion ramping facility, this is a positive advantage as it can cut-out the frame-rate conversion stage but if you shoot mainly at regular speed offers little advantage to the present Varicam, though this camera is becoming known as the Varicam 2.
The Panasonic HPX-3700 is a 1080 version of the Varicam with slow motion capability also recording to P2 cards instead of tape – however, the slow motion capability is limited to just 30p, due to the lack of availability of a Panasonic-manufactured 1080/60 CCD block . This camera model is becoming known as the Varicam 3.
DVCPRO HD POST PRODUCTION
The real benefit to shooting on the Panasonic DVCPro HD format equipment, is that the post production can be carried out using low-cost edit systems (such as AVID and FCP) in full HD and avoid the cost and complication of the conform – this is because the edit systems work in the same compression scheme as the cameras, so the compressed signal in full HD can be ‘ingested’ (transferred) into the edit computer using a single firewire cable.
This is much more useful that using firewire with HDCAM, in that with HDCAM the firewire cable is only capable of transferring standard-definition firewire to the edit suite but using DVCPro, you can transfer either standard-definition or alternatively High Definition signals instead.
If you decide to use HD firewire, then the signal transferred to the off-line edit is a digital clone of the camera material, so the off-line edit will be at uncompromised HD quality, yet the media files will still be very small (1GB per minute or only 4 times the size of DV! Compare this with HDCAM which takes more than 400GB for one hour of full HD). It also means that HD editing is fast and you will not need to invest in an HD-SDI input card for your Edit system.
DVCPro HD and Slow Motion
One of the real benefits of shooting on DVCPro HD is its slow motion ramping capability.
Varicam is designed to perform up to 60fps effortlessly but requires special post-production treatment in order to be able to edit this material.
This requires a special process, whereby the slow-motion sequences are played into a frame-rate computer called a Panasonic Frame Rate Converter (illustrated right) and then when the material is ingested, the computer plays back the media at the slowed down or speeded up rate and the output is recorded onto a new tape.
This process is not required if you use FCP, since Panasonic produce a frame-rate converter plug-in http://www.panasonic.com/business/provideo/support/fcphd.asp which allows you to do this in post and avoid this process.
One lesser known fact is that the HDX-900 is capable of shooting slow motion sequences in just the same way as Varicam. If you shoot in 720 mode, then you can shoot in either 50 or 60 modes, which allows you to shoot in either 60p (actually called 59.94p) if you are shooting in 60 mode for 24p or US HD programmes, or alternatively 50p if you are shooting 25p or European frame rates.
As such, assuming that you are shooting for the UK, you would shoot your main programme in 25p and then your slow motion sequences in 50p. The 50p sequence will need to be frame rate converted prior to edit
One good practise is that you should only shoot sequences in slow motion that you want to frame-rate convert afterwards and shoot any slow motion sequences on a separate tape – this will make the conversion much more simple and keep both the complication and cost down!
DVCPro HD VTRs for edit and down-conversion
Panasonic make two commonly available VTRs – they both look the same only the AJ-HD1200 is dark grey and the AJ-1HD-1400 is light grey!
All DVCPro HD VTRs permit standard definition output of HD material in real-time. This is of course frame-rate dependent, since if you are shooting at an unusual frame rate, such as 24 fps, there is no equivalent SD format at this speed.
They both have real-time HD and SD firewire outputs, though be aware that sometimes the outputs are muted depending on the menu setups, which can be quite tricky.
The major difference between them is that the earlier AJ-HD1200 worked in all 1080 formats but only 720/25p and 720/60 modes, which makes it completely compatible with the Varicam and the HDX-900 working in all 1080 modes. So, if you are shooting in these modes, then you can use the cheaper HD1200 VTR, rather than the later and more expensive HD1400 model.
However, when the HDX-900 was released, Panasonic also released a 720 format which worked over 50 frames and called this 720/50. If you shoot in 720/50 with the HDX-900, then you will have to use the later AJ-HD1400 VTR, as this format is not compatible with the earlier HD1200 VTRs – easy!
That complication over, once you have chosen the right machine for playback, the menus are set up for your image size, frame rate and output, then you have a simple case of plug and play and can easily ingest and edit native HD material directly into your FCP or AVID.
When you have finished your edit, simply take your media drives to your post house for grade and HD play out. Even if you shoot and edit in a native 720 format (like Varicam), don’t worry about this, as the play-out will always be in 1080 HD. Play-out for delivery is invariably made to HDCAM SR, due to its excellent multi-generation quality and 12 audio tracks.
Managing Director, VMI December 2008