HDV FAQ High Definition Video Information...

Q.Why Shoot HD?
A. There are NO disadvantages to recording in HDV today, other than the initial higher cost of the equipment. Recording HDV (High Definition Video on miniDV tapes) is as easy as the existing legacy low-resolution video, analog and digital. However, we realize that recording is just one part of using HDV. Editing is becoming easier every day as more software editors, accessories, and tools become available (and more affordable). With HD TV having turned the corner and being the display of choice for many buyers today, there are no obstacles to HDV other than there haven't been many HDV camcorders available. That is about to change dramatically with the introduction of Sony's consumer oriented HDR-FX1 HDV camcorder.

Q.Explanation of the HDV Specification
A. HD (High Definition) is more than simply "better quality than SD" or "wider than SD"! The current SD (Standard Definition) is quite standardized into interlaced frames at resolutions all manufacturers and users recognize: 720x480 pixel frames at 29.97 frames per second in NTSC video countries, and 720x576 pixels at 25fps in PAL countries. NTSC SD DV is shortened to "480i" meaning 480 scan lines with interlaced frames. To achieve a "wide screen" look, the resolution stays the same... and simply a "wide pixel" is used when in "16:9" mode. This allows rather easy implementation of a wide screen mode, but the full potential is not realized with SD DV (Digital Video) The current "SD" is used by MiniDV, Digital8, and MiniDVD recording camcorders, as well as DVD-video players and recorders. In some uses, the encoding or compression of video data is different, but the overall resolution is fixed and universal (down to the PAL and NTSC differences).

Q. Do I need a new computer to edit HDV?
A. Absolutely not. If you have a computer that can edit DV, you have a computer that can edit HDV. HDV in 1080i format is the same bitrate (25Mbps) as DV is. However, depending on the system, you may experience choking on the system, depending on whether you're editing Transport Streams or with an intermediary codec such as the Cineform Connect HD codec.

Q. How fast does the processor need to be to edit HDV?
A. If you have a processor of at least 2.6 Ghz or faster, you'll be plenty fast to edit HDV, particularly if you use an intermediary codec.

Q. What is an intermediary codec?
A. An intermediary codec is like a translator, or "in-between" codec, that assists the editing software. Connect HD (for Sony Vegas) Aspect HD (for Adobe Premiere) and Lumiere (for Final Cut Pro) are all intermediary codecs. You capture in either native MPEG from the HDV camera, and the video is converted to the intermediary either in real time after capture, or during capture. This assists in the editing process, as native MPEG transport streams are very heavy on the processor, and may be difficult to edit. Further, you don't want to be editing the raw MPEG transport stream because you'll endure a potentially significant loss of quality without the intermediary. When you render to print to tape, if you wish to print to your HDV camera, the intermediary will re-convert the intermediate stream to the MPEG format once again, providing you with a great image.

Q. Why don't I want to edit the transport streams?
A. The Transport Streams/TS files from the camera are MPEG data, containing I, B, and P frames. The nature of the long GOP (group of pictures) format causes generational loss during the encoding/decoding, not to mention that it's very hard on the processor and very slow.

Q. What does the intermediary codec do to the transport stream?
A. The Cineform Connect HD codec takes the 15 Long GOP and converts it to a proprietary 2 GOP, into a temporal wavelet format. This makes it scalable and a lot more efficient so that the NLE and CPU can process the information easier/more quickly. Read more at the Cineform technology page.

Q. What is a transport stream? (A ts file?)
A. A Transport/ts stream is the multiplexed packeted data that makes up the MPEG file. It is a muxed/blend of audio and video. It has a fixed length for structure. Demultiplexing is achieved by unique packet IDs (PIDs). .

Q. Is the Audio format of HDV any good?
A. The audio format of HDV is MPEG 1 Audio layer II. It has a bitrate of 384 Kbps, and can be very good. However, it's not suitable for heavy editing, so audio like video, is best sent to the intermediary. (and is automatically done so by the intermediary tools) Keep in mind that while this format is not quite up to CD standards, it is quite good. DV camcorders record audio in PCM format, so it's the same as a .wav file. The HDV audio spec is similar to very high bitrate MP3 audio. If you need high quality audio in a PCM format, we suggest you use a DAT or other uncompressed source that can do a true 16 bit/24 bit recording at 48k/96khz sample rate. Remember, when you use the Cineform intermediary audio is converted to a 48K/16 bit format, so you'll not need to worry about the audio quality in editing. .

Q. How do I capture HDV?
A. HDV is captured in exactly the same method as you capture DV. Using a capture application like the ones offered by Cineform, you'll capture media, and either conform it to the intermediary on the fly, or conform it to the intermediary later. Because HDV also has timecode embedded in the file, Batch Capturing and previewing scenes for capture should stay the same. .

Q. I heard that HDV has .5 second dropouts. Is this true?
A. It is true that if you experience a dropout in HDV that it will last for one-half second. This is due to the MPEG format of HDV, and how GOP Iframes determine the rest of the image and frame content. .

Q. Do I need a new monitor to preview HDV files?
A. Maybe. You can monitor HDV one of two ways. You can view it on a computer monitor that is at least 1900 x 1200, or you can use an external HD television monitor. If you want to use an external monitor, you'll need to use an HD card similar to the MyHD card from MIT systems, or something similar. Since HD will be viewed on plasma and LCD screens in the future, you'll want to view on a monitor similar to what the footage will be viewed on so that color correction, etc are accurate. You can view HDV in your NLE application on a lower resolution computer monitor, and likely be reasonably accurate, but for critical video, "reasonably accurate" just isn't good enough. .

Q. How does the camera connect to my computer?
A. The HDV camera connects to your computer via the same Firewire connection that you currently use to capture DV, connect hard drives, scanners, etc. Some proprietary hardware cards will also soon accept HDV information over Firewire. .

Q. Isn't HDV just too huge a data rate/stream to edit with?
A. HDV in 1080i format is the same bitrate (25Mbps) as DV is. However, depending on the system, you may experience slowdown on the system, depending on whether you're editing Transport Streams or with an intermediary codec such as the Cineform Connect HD codec. As mentioned above, HDV editing experiences can be just about the same as editing DV. A reasonably fast computer can manage the bitstream without any trouble. .

Q. How do I deliver HDV files to a broadcaster or client?
A. Eventually, HDV will be delivered via Blu-Ray discs in most scenarios. Blu-Ray is still just around the corner. Currently, your options are: Deliver on WMV-HD Downconvert to SD/Standard Definition, and deliver on DV, Beta, or DVD Upconvert to HDCam with an application like Sony Vegas. You will suffer some loss, but in seeing some footage upconverted to this format, it was pretty impressive. Deliver using NERO's Recode H264 format, playable on settop DVD players. .

Q. Can Vegas/Final Cut Pro/Premiere/AVID control my HDV camcorder?
A. Most applications can control the camera, but don't have the ability to ingest the data currently. As months go by, it's fairly safe to assume that all NLE systems will be able to accommodate the HDV stream .

Q. In Vegas, my HDV images look squeezed. Why?
A.The aspect ratio of HDV is 1.333. Vegas currently sees it as .909. Simply right click the file in the Media Pool, choose Properties, and convert the aspect ratio to 1.333. Vegas will then see/display the file correctly .

Q. Is HDV interlaced the same way as DV? Is it upper or lower field first?
A.HDV, unlike DV, is upper field first when working with interlaced modes. .

Q. I read that HDV has bad motion artifacts. What's the scoop?
A.If you attempt to do very fast pans with HDV, due to the way the frames are generated with MPEG and GOP, you may see motion artifacts. However, this is not nearly the issue as it's often painted to be. It's a good idea to rent, borrow, or download images from a website to see for yourself, how HDV works with fast motion. .

Q. Can I edit HDV in real time?
A.Of course you can. With the Cineform ConnectHD codec, you will have the 29.97 or 24p with 3:2 pulldown that you are already used to. It will edit quickly and easily. There is a lot of speculation about this, but the truth is, with an upper end processor and a fair amount of RAM, you should notice little difference between editing HDV and DV. And depending on the application you're using, you may not need the additional RAM. .

Q. What is "Super-HAD?" Sony makes a big deal about it in their advertising.
A.Super HAD or the Hole-Accumulation Diode, is a brilliant new technology that allows the HDV camcorder to process more color and light information by using all available area on the CCD, or Charge Couple Device, which is what receives the analog picture information and converts it to digital information. Sony has a great pictorial explanation here. .

Q. In Vegas, I'm not getting 29.97 or 25 fps playback with Cineform intermediary files. Why?
A.In Vegas, you'll need to set your RAM at a high level to view files at 29.97 (NTSC) or 25 (PAL) frames per second. Set your Preview Window to Preview/Auto or Preview/Full for best results. .

Q. I'm confused by HDV and it's colourspace. I'm told it's different than SD. Is this true?
A.Yes. HDV is compliant with the ITU BT.709 standard, while SD is compliant with the more strict ITU BT.601 standard. There are several sites on the web that very clearly explain the somewhat difficult concept of ITU BT.709 and how it differs from what you may currently be familiar with. The HDTV standard is ITU BT.709 regardless of where you live in the world. .