Portability-HD Editing

There has been a lot of discussion recently on the reduser.net and dvinfo.net among other places, about portable HD editing systems.  Technically, almost any editing system is portable if you want to go to the trouble of taking it with you.  For the sake of this discussion, I am going to consider any collection of items that will comfortably fit within a regular backpack to be a legitimate “mobile” solution. 

Technology has come a long way in the last two years, especially in the CPU processing aspect of the equation.  A well equipt laptop can be purchased now that has more processing power than the highest-end Windows based workstations of two years ago, thanks to the Core2 Duo.  I bought a Xeon workstation in 2005, and one year later, bought a 12″ notebook for LESS money, that has MORE CPU power.  With the upcoming release of quad core mobile CPUs, we can remove processing power from the list of limitations that mobility imposes.

Next is RAM, and we are in a unique situation in that regard.  Most systems still use 32bit OSes, and are limited to 4GB of RAM.  This software limitation has allowed notebooks to catchup with desktops in this regard, as demand has not climbed as much past 4GB in the desktop sector, and notebooks were under no similar limit until they caught up.  4GB of notebook RAM can be had for under $200.  Obviously mobile solutions will not be limited by the maximum available RAM. (Any more than a desktop)

The first area where we encounter trouble is with storage, in both capacity and transfer rate.  While there are solutions that allow uncompressed HD speeds and capacities on a laptop (ExpressCard to CalDigit HDPro), that solution is not very portable.  The capacity issue can be solved via 1TB drives connected via firewire, or internal RAIDs or 2.5inch hard disks in large laptops, but there is currently no way to provide the required transfer rates for realtime uncompressed high-resolution editing, in a mobile solution.  This leads to a need for a different solution.  We can utilize the extra CPU now available by using a compressed video format to decrease the strorage requirements.  (As an aside, my FREE IDEA of the day is: A mobile array of 8x250GB 2.5 inch disks with an external PCIe interface for use with x1 PCIe or ExpressCards would offer 2TB at 250MB/s.  It would be an interesting solution, and if a company decided to create it, all the technology already exists.)

 Since there are no reasonable storage solutions for uncompressed, we must examine compression options.  The first standardized option is HDV.  The advantages are low-bitrate, wide support, and firewire I/O, which most laptops already have available.  The disadvantages are lower quality, 8bit 4:2:0 MPEG encoding, and a 1440 horizontal resolution limit.  The next option is a very recent one for Premiere Pro users, with DVCPro-HD, made possible by the release of the 3.1.0 update this week.  With datarates of 5-12Mb/s, this format is will within the 30MB/s capabilities of a single 2.5inch laptop drive.  The horizontal resolution is even more limited, to 1280 pixels wide, but it encodes 8bit 4:2:2 with DCT compression, and in general a higher bitrate should improve quality.  Since it doesn’t use MPEG compression, it should be less CPU intensive to playback and edit, leading to better performance.  The next step would probably be one of Cineform’s products.  AspectHD is limited to 1440 at 8bit, but it still the highest quality solution yet, usually at around 9-10MB/s, using Wavelet compression, which allows efficient low resolution playback as an added bonus. 

 Blackmagic Design released a MotionJPEG codec a while back that allows full 1920×1080 files at 8bit 4:2:2 to be used with a data rate of around 12MB/s.  The advantages are that it can be used for free, with out any limitations that I am aware of, but it is designed to be used with their I/O hardware for acquisition and preview.  The only disadvantage is not really a disadvantage comparedto the options below it, but image quality will not be as good as Cineform, and is limited to 8-bit.  Cineform’s higher-end product ProspectHD has few limitations, allowing 10bit 422 at full1920x1080 to be edited at around 15MB/s depending on settings.  This is easily sustainable on internal laptop disks, while an external firewire drive could increase performance and capacity.  Currently Cineform is the solution I would recommend if you need high end HD editing in a portable form factor.  The next question that Cinefrom prompts is, how high can I go, and currently 2K 444 RGB is possible at 30-40MB/s, meaning an internal RAID 0 would benefit playback on a laptop.  There is even talk of 4K realtime playback with the release of the RedOne, so it seems that the sky is the limit.

Other solutions that I am aware of, but don’t seem ideal are: Matrox MPEG I-Frame files from AXIO or RT.X2 at 12MB/s with the Matrox M.key in desktop mode, which I use, but the performance is not good for creative work without the hardware acceleration.  In the non-Adobe world, FCP offers DVCProHD, and now recently ProRES, a full frame 10bit 422 codec that runs about 15MB/s at 1080p I believe.  I have no familiarity with Avid, but XpressPro or Media Composer with DNxHD might be a portable HD option as well.

Laptops have done a lot of catching up recently, and the concept of “desktop-replacement” is a much more legitimate now than it was two years ago.  The most important aspect we have not yet examined is HD I/O for portable solutions, especially for portable acquisition, which I plan to go over next time.

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