Sony's Middle Way: XDCAM 422 50mbps
When it comes to digital production formats it would be a mistake to think that Quality is everything...
A statement like that is bound to the purist cat among the pigeons but the overriding truth prevailing a holistic sense of production is the workflow and set of balances being more significant than image quality on its own.
If this wasn't the case then there would be no production other than 444 12bit Uncompressed production. A notion ludicrously un-viable in any practical sense for anything but the biggest budgets.
So instead we have 'workflow' and a host of choices to be made to form a balanced production suitable to the project. Purity of image quality is but one of those choices. 422, 420, Intra and GOP, lossy and lossless, spatial and temporal compression, constant and variable bitrates; all point towards the process of manipulating the visual data as much as the qualitative properties of the data itself.
It seams that Sony have now added to the choices available by striking a new middle ground in acquisition HD formats. Until now the debate concerning HD has centered on extremities - intra-frame, highbitrate, high bandwidth HD such as DVCProHD and AVC-Intra on one side. Long GOP, lower bitrate formats such as HDV and XDCAM on the other.
HDV and XDCAM, as 420 long GOP formats, are lauded for their enormous efficiency and derided for their lack of color space and perceived motion image issues. Conversely DVCProHD and AVC-Intra are celebrated for their 422 colour space and frame accuracy and derided or their gross inefficiency and perceived minimal benefit for their massive data rates and file sizes.
Both formats are perfectly valid in context of a production needs but it now seems Sony have sought a middle way that retains the acquisition efficiency of Long GOP Mpeg-based XDCAM at modest bitrates whilst attaining the visually lossless colour space of YUV 422.
The new flavour of XDCAM moves the format from its traditional 420 35mbps to lossless 422 50mbps. The move is highly significant and strategic for Sony as it effectively eliminates most of the criticism that has been leveled at XDCAM in the past. In particular XDCAM is moved to a more viable format for greenscreen and effects production whilst retaining its high efficiency.
Completing the equation for XDCAM is the doubling of capacity of the blu-ray-based ProDisc recording media. With all the non-linear attributes of solid state memory but circumventing the major shortcoming of solid state by also serving as shelfable cost effective source master. With 50gb capacity for US$60, recording 95min of 50mbps 1080p HD, there really isn't anything not to like about the new edition of XDCAM.
Studio Daily has more info here.
Posted at 12:00AM Mar 04, 2008
by Mike Jones in video |
