Bridging H-DV with Miranda
Apr 1, 2005 12:00 PM, BY GILBERT BESNARD
 Miranda’s HD-Bridge uncompresses the H-DV signal in such a way as to assure a first-generation, full-quality image. The image can be edited as HD-SDI without any need to recompress the material, thereby allowing lossless editing. Click here to see an enlarged diagram. |
H-DV is now generating a lot of excitement. It offers amazingly good quality at a low price point. It should enable HD to move beyond networks and high-end content producers, as well as penetrate parts of the market that would have otherwise taken five years to move to HD.
However, until now, there has been an obvious area of concern: the connection of H-DV devices to higher-end editing systems and infrastructure. After all, without a solution for interfacing H-DV to existing plants, the format will never realize its full potential. This situation with H-DV has many parallels with earlier format introductions. For instance, in the 1980s, the Betacam camera and editing systems made quality video affordable for a wider range of stations.
In 1995, DV further “democratized” digital acquisition and editing for SD. DV offered much lower price points and was even nicknamed “Dispose-a-cam” by some. All this contributed to widespread adoption of DV for news and independent production.
With DV, the arrival of broadcast-quality DV interfacing, which allowed full interfacing with the station's SD infrastructures, was a key factor in driving the adoption of the format. For instance, the DV-Bridge from Miranda offered key features such as timecode conversion and machine control for effective operation with DV editing systems.
H-DV, which has a price point starting at $3500 for cameras and an excellent quality/cost trade-off, seems set to follow the DV model. The new format is ideally positioned for rapid adoption as it uses the same cassettes as DV, the same 25Mb/s bit rate and the same IEEE-1394 transport (Firewire). H-DV also uses the same MPEG-2 long GOP format used for HDTV broadcast. In fact, major editing systems such as Avid, Apple, Sony and multiple smaller systems already support H-DV.
There are several key H-DV interfacing tasks to be addressed for successful adoption. Perhaps the most critical is broadcast distribution and playout, which requires edited and stored H-DV material to be transformed into an HD-SDI signal for direct on-air broadcasting. Post-production monitoring in the editing suite also will demand conversion of H-DV to various analog video, SD, HD and audio formats.
Another core requirement is converting H-DV captured on-set into HD-SDI so that it can be edited with HD-SDI systems for lossless content creation. Although it is anticipated that H-DV will be used mostly for local broadcast news and simpler documentaries, there are projects that will demand lossless, multi-generation editing. Here, converting H-DV to HD-SDI ahead of editing can significantly improve the final quality. At this stage, a tool that allows all these interfacing tasks to be performed is Miranda's HD-Bridge.
This compact, desktop H-DV to HD-SDI decoder provides high-quality conversion and was developed in collaboration with Sony. Critically, the HD-Bridge uncompresses the H-DV signal in such a way as to assure a first-generation, full-quality image, which can be edited as HD-SDI without any need to recompress the material, thereby allowing lossless editing.
When paired with the new breed of H-DV cameras, this new type of interface effectively creates a new HD-SDI workflow paradigm, which just requires the H-DV camera and the H-DV to HD-SDI decoder to output full quality uncompressed HD format. This compact set-up comes at less than one-tenth of the cost of HD cameras or film cameras.
These H-DV to SD-HDI decoders represent the catalyst that will allow many budget-conscious operations to consider implementing high-quality, low-cost HD content creation. Key areas expected to migrate to H-DV are news, specialty and cable programming, and corporate video production. These are the content producers with exacting standards of image quality but typically without the budget for HD until now.
However, H-DV is not just of interest to smaller broadcasters and low-cost producers. At the other end of the production spectrum, there will be real interest from the big names in news, especially for generating HD content from places too unpredictable or dangerous to risk sending an expensive film or HD camera.
Looking ahead, it is obvious that the HD “chain reaction” is progressing fast. By making HD's bottom line more attractive, the combination of the new H-DV cameras and H-DV decoders will further stimulate the adoption of HDTV playout around the world.
Gilbert Besnard is director product development for Miranda Technologies.
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