HDV: What is it?
HDV (not to be confused with HD) is High Definition Video recorded on the same digital videotapes that miniDV is recorded on today.
During image capture the signal is compressed inside the body of the camera before being recorded to tape. As a result HDV recorded material contains a lot less picture data than true HD, so the resultant image is of comparably lower quality. However, as a result of compression, HDV data becomes as manageable and portable as Standard Definition (SD) DV, despite providing a vastly superior image.
HDV formatted video possesses 4.5 times the resolution of Standard DV.
Who's behind it?
Sony, Canon, Sharp and JVC are the pioneers of the HDV format, and cameras and decks are spilling on to the market.
JVC produce HDV cameras which operate at '720p' (a resolution of 1280x720 pixels with a progressive signal). Sony on the other hand produce the HDR-FX1 and HVR-Z1 cameras which operate at '1080i' (a resolution of 1920x1080 pixels using an interlaced signal).
The JVC's 720p HDV format captures in 8-bit 4:2:2 and is compressed using MPEG-2 resulting in datarates of around 2.4MB/s. The Sony 1080i format captures in 8-bit 4:2:0 and is compressed using MPEG-2 resulting in datarates of approximately 3.1MB/s.
Hands on with the HVR-Z1
Why produce in HDV?
The HDV format essentially provides HD resolution on a budget, and given the relatively low costs involved, the results are superb.
The question is not so much, 'why would I want to work in HDV?' as,'why wouldn't I?', given the vastly superior picture quality and relatively small cost increase over producing in DVCAM/miniDV.
When comparing similar footage shot in DVCAM and in HDV, on a SD monitor and a HD monitor respectively, there is simply no comparison in terms of clarity and colour range. Almost 5 times the amount of pixel information is captured in HDV. The video has a completely different look and feel.
Probably the greatest argument for shooting HDV is that you are futureproofing your content; content which may ultimately be destined for HD broadcast or HD-DVD/Blu Ray media, or indeed for other HD resolution platforms which don't even exist yet!
HDV also offers compatibility with anamorphic DV in that downconverting HDV formatted material is a fairly straightforward process.
When not to produce in HDV
HDV's disadvantage is that compared to true HD formats it is 'brittle', and so for heavy effects work during post production it is less than ideal. During acquisition, image are compressed and recorded as an MPEG2 transport stream on to tape. MPEG2, like many compression schemes, involves throwing away data from within consecutive frames, based on how little that data changes from one frame to the next (temporal compression).
Manipulating image which have been compressed in this way can result in unwanted artefacts within the image, and so any show which is likely to be effects heavy or coloured/graded is not a prime candidate for this format.
Some documentary work and news features, together with corporate and institutional films including training and events are, however, ideal for this format. HDV is truly a high-quality low-cost acquisition format in this regard.
HDV Editing
HDV cameras capture at (or near) HD resolution, but actually encode that captured data to an MPEG2 transport stream before recording to tape.
MPEG2 is not compressed one frame at a time, but in groups of pictures. This is problematic for NLEs (Non-Linear Editing software) because to display a particular frame of video they must fetch and decompress multiple frames, before displaying the desired frame. This is often called Long-GOP editing.
The solution to this problem is arriving in the form of updated NLE's from the likes of Apple and AVID which support 'native' HDV editing.
What does HDV look like?
We can't show you HDV material at 1920 x 1080 on an HD resolution monitor; we can't even show you uncompressed HDV on your computer screen due to the limitations of bandwidth.
We can show you this though, shot at night in Paris, to test the qualities of our Sony HDR-FX1E.
Obviously this resultant video is hugely compressed, but it may demonstrate some of the qualities of 1080i HDV. Along with obviously the 16:9 aspect ratio, you should be able to see more details in the blacks and a clarity and sharpness that wouldn't be there if the same clip was shot in DV and compressed in the same way.
This video travelled the following route: Shot Sony HDR-FX1E, captured with Lumiere HD, demultiplexed, Offline edit in FCP, Onlined using original MPEG2 files, rendered out 10bit 4:2:2 1920 x 1080 QT movie, then Compressed as Quickime Progressive Download movie using Media Cleaner.
Curious about HDV? You'll find more in our Resources section.