Choosing a Camera for OnLine Streaming

9255421High-quality video starts at the source, and today's camcorders offer more options than ever to help you capture a first-class image. But with choices comes confusion; here are five questions to ask that can help you pick the camcorder that's right for you.

If you bought a camcorder 10 years ago, chances are it was DV or DVCAM, and it stored its video on DV or DVCAM tape. If you bought one 3 years ago, it was likely HDV and DV tape. Today, it could be any one of five or six HD formats (AVCHD, HDV, DVCPRO HD, XDCAM HD, or AVC-Intra) stored on four or five different storage mechanisms (tape, SD or SDHC card, P2, SxS, hard disk, or optical disc).stream_com

Are you concerned about navigating through this maze of options? Well, if so, you’ve come to the right place. Over the next 3,000 words or so, I’ll detail these options and others, and I’ll tell you which questions to ask before buying your next HD camcorder. I’ll even detail the top four camcorders to consider in 2009.

To make my word count and to maintain my sanity, I’ll focus on 3CCD camcorders that cost between $3,500 and $5,000, which I think is the real sweet spot for high quality and value. If you’re a bargain-basement shopper, an indie filmmaker, or a wannabe, you might learn some valuable information, but you’ll probably want to buy a different class of camcorder. With so much to get through, let’s jump right in.

Question One: Parlez-Vous Progressive?

At this point, it’s generally accepted that progressive-scan source video produces higher-quality frames for streaming than interlaced source material, so if you’re purchasing for streaming production, be sure to purchase a camcorder that shoots in progressive mode.

Unfortunately, there’s lots of debate as to which camcorders actually shoot in “true” progressive. To explain, Panasonic and JVC have traditionally been credited with true progressive recording, while other vendors have used a variety of techniques to simulate progressive. Sony’s CineFrame mode, as implemented by Sony in the HDR-FX1/HVR-Z1U class of camcorders, produced noticeably lower-resolution video than the interlaced mode, which translated to slightly fuzzy detail. For this reason, in most instances, shooting in interlaced mode and deinterlacing in your editor or encoding tool would produce better results than shooting and producing in CineFrame mode. Interestingly, Sony’s HVR-Z5U, which will replace the Z1U in 2009, records in true progressive mode, making it a good choice for streaming production. 
 
Panasonic’s HVX200 is credited with “true” progressive video, which provides source video suitable for streaming.

Conversely, though Canon never claimed “true” progressive for the Frame mode used in its XH A1 line of camcorders, I found the quality identical to side-by-side progressive shots from the Panasonic HVX200, which is credited with true progressive. For this reason, I use Frame mode when shooting for streaming, and I wouldn’t hesitate to buy or to recommend the XH A1S for those users buying a camcorder for streaming applications.

Though Canon never claimed “true” progressive for the Frame mode used in its XH A1 line of camcorders, I found the quality identical to side-by-side progressive shots from the Panasonic HVX200.

Fortunately for us, true progressive-scan capture is supported in most newer camcorders, though more for indie filmmakers trying to achieve the filmic look than for streaming producers seeking top quality. If you’re looking at older models, however, you may need to scratch beneath the surface to figure out if the progressive is true or faux.

Question Two: What Format, Dude?

The next question to ask is which storage format is used by the camcorder. Table 1 contains the most relevant formats, though I won’t extensively discuss Sony camcorders in the XDCAM HD class since they’re too expensive for our price filter.

Storage formats used by the camcorders discussed in this article.

Starting at the top, the display aspect ratio is the way the video is displayed during full resolution (think TV), and as you can see, all HD formats have a display aspect ratio of 16:9 with a maximum display resolution of 1920x1080. In contrast, the maximum storage resolution represents the pixels actually stored in the format’s digital file. For example, you probably knew that HDV files are stored at 1440x1080 resolution, which is zoomed to 1920x1080 during display, hence the pixel aspect ratio of 1.33 (1440x1.33=1920). Why is that significant?

Not all camcorders work this way, but some, such as the Sony HVR-HD1000U, do, so roll with me on this. Specifically, the camcorder captures each frame at a full resolution of 1920x1080, but then it stores the frame at the HDV maximum resolution of 1440x1080. During this process, the camcorder essentially discards every third pixel. Then, during display, the camcorder or other player zooms the video out to 1920 and essentially recreates the pixel by interpolating from the surrounding pixels.


How much does this matter? In my resolution chart tests, formats such as HDV and DVCPRO HD proved incredibly adept at recreating the information that was thrown away during the storage process—the difference in resolution is almost imperceptible. Still, all other things being equal, you’d prefer a format that stores the video data at the same resolution that it’s displayed.

For example, most early AVCHD camcorders stored the captured video at 1440x1080 resolution rather than the maximum of 1920x1080. Though the difference is modest, if buying for professional use, you should opt for a full-resolution AVCHD camcorder (look for the “FullHD” logo) over one that stores at 1440x1080.

It’s also instructive to understand the compression technology used by each format and the associated data rates, which affect quality, editability, and storage requirements. Historically, DV uses an I-frame-only encoding scheme, which retains very high quality and is relatively easy to edit. Interestingly, DVPRO HD uses the same basic scheme, but the data rate is four times higher, which neatly corresponds with the 4X increase in stored pixel resolution (345,600 compared to 1,382,400). For this reason, DVD PRO HD also offers very high-quality video and is easy to compress, though the 4X DV data requires capacious storage. HDV uses long-GOP MPEG-2 to encode HD video down to the same 25Mbps data rate as DV. long-GOP means a mix of I, B, and P-frames, or a compressed structure that’s harder to decode and edit than I-frame-only DV; this is because the majority of frames need to refer to other frames in order to construct an entire frame of image data. In the Core 2 Duo and beyond era, this really isn’t a problem, and editing is very efficient. Ditto for XDCAM HD, which uses the same basic technology at up to twice the data rate.

However, AVCHD uses long-GOP H.264 for compression, with a maximum data rate of 24Mbps, which results in a higher-quality file than the long-in-the-tooth MPEG-2 but may be much harder to edit depending upon your program and platform. For example, Final Cut Pro converts AVHCD to ProRes during ingest, which costs you some conversion time but makes editing much more responsive. Adobe Premiere Pro CS4, by contrast, edits AVCHD natively, which is very memory-intensive. On a 32-bit Windows system, which can only address 4GB of memory, you may experience some editing delays with even moderately complicated projects, and rendering is very slow. However, on the Mac and on 64-bit Windows systems, which can address much more memory, performance is reasonable.

Now that you know all this, when do you care? At a high level, all the formats have been tested and have proven worthy. They’re all very good. In extensive comparison tests, which unfortunately didn’t include XD CAM HD, I saw very little quality difference unless the clips included extraordinary (above and beyond the call) levels of motion. If I had to rank them, I would choose DVCPRO HD first, AVCHD second, and HDV third. Still, the difference is so exceedingly minor that I wouldn’t use this factor to choose between the camcorders.

However, when comparing AVHCD camcorders, be sure to identify both the maximum storage resolution and the maximum storage data rate. The Panasonic HMC150, which is the only AVCHD camcorder I feel comfortable recommending for professional use, was the first to record at 1920x1080 at a 21Mbps data rate. All early versions of AVCHD camcorders recorded at 1440x1080 resolution or lower, with a maximum data rate of 14Mbps.
 
The Panasonic HMC150, which is the only AVCHD camcorder I feel comfortable recommending for professional use, was the first to record at 1920x1080 at a 21Mbps data rate.

In addition, when comparing camcorders within a class, such as HDV camcorders, knowing the storage resolution will help you evaluate the quality of the CCDs or CMOS sensors used by the camcorder, as we’ll see in the next section. Finally, formats are inextricably tied to storage medium, which can be a crucial decision factor.

Question Three: How Many Pixels in That CCD Thing?
 
The next question to ask is how many distinct pixels the camcorder’s sensing devices actually capture. Why is this important? Many early HDV camcorders had sensors with fewer than the 1,555,200 pixels necessary to capture the stored 1440x1080 image, pixel for pixel. For example, the HVR-Z1U camcorders that the Z5U will replace only had about 1 million effective pixels. This means that the Z1U captured 1 million pixels and interpolated upward to the required 1,555,200.

Quality was good, but it was never as sharp as camcorders such as the Canon XH A1, which were built with 1.6 million-pixel CCDs and could capture the image without interpolation. Canon was the first to step up with full-resolution CCDs; Sony appears to be following with the HVR-Z5U. Specifically, the product’s press release states, “The CMOS sensors capture full HD 1920x1080 resolution, resulting in better picture quality when recorded onto miniDV tape in the HDV format (1440 pixels x 1080 lines).” I haven’t compared HDV systems that captured at 1920x1080 (such as the new Sony) with those that captured at 1440x1080 (such as the Canon), so I don’t have an opinion regarding which approach is superior. I do know that with all other factors being equal, higher pixel counts in the image sensors improves sharpness.

The new Sony HVR-Z5U is reportedly the first Sony HDV camera with sensors equipped to capture full 1920x1080 HD resolution.

Panasonic is the only vendor not drinking the pixel-count Kool-Aid. The DVCPRO HD-based HPX-170 stores at 1280x1080 resolution, but its three 1/3" CCDs have 960x540 active pixels and use a technology called “pixel-shifting” to produce the necessary additional pixels. In my tests, the results were slightly softer than the XH A1, which means less detail. Similarly, while Panasonic hasn’t released the CCD pixel resolution for the HMC150 camcorder, it has stated that the effective pixels are fewer than the 2,073,600 necessary for full-resolution capture, again, using pixel-shifting to fill in the difference.

With both camcorders, the difference was only noticeable in resolution chart testing, with real-world images very sharp and clear. Still, if I were comparing AVCHD camcorders, I would expect models with higher pixel counts to produce sharper video than those with lower pixel counts—not dispositive, but it’s definitely a good data point to identify.

Question 4: What’s the Storage Mechanism?

Next, consider how the camcorder stores the video: both the primary media as well as any ancillary options. For example, most HDV camcorders store video on tape and include FireWire output for simultaneous or alternative capture to a hard disk recorder, such as the HVR-DR60 60GB hard drive that Sony offers as an option to the HVR-Z5U. However, most AVCHD camcorders only have a single SD card slot with no FireWire option for ancillary storage—a bummer if you’ve already purchased an HDD option and want to supplement your supply of SD cards. This section discusses some considerations for the most common media options.  

Most HDV camcorders store include FireWire output for simultaneous or alternative capture
to a hard disk recorder, such as the HVR-DR60 60GB hard drive that Sony offers as an option to the HVR-Z5U.

Tape is tried and true for HDV, and it represents a cheap archive system for the source footage. On the other hand, capture from tape occurs in real time, which is slow, and tape mechanisms are fragile devices and usually the first subsystem to fail on a camcorder. Recording to tape means occasional dropouts, or short sections of lost data, and finding scenes on tape for playback is cumbersome.

Hard drive and solid-state storage options such as SD, SDHC, and P2 cards offer multiple advantages over tape, including more reliable operation, faster capture, and easier scene identification in an interactive shoot. Few shooters who have ever worked with either hard disk or solid-state memory ever want to return to tape—it’s that much of an improvement. Still, with all these forms of media, you’ll need an alternative mechanism for archiving your raw footage.

SD storage is one of the best features of AVCHD, and prices for this type of storage are dropping rapidly, with 16GB cards that are capable of holding more than an hour of video now costing less than $200. On the other hand, when you consider the storage requirements of DVCPRO HD (about 1GB per minute) and the cost of P2 cards ($2,495 for 64GB), you have an untenable cost structure for many shooters.

I personally think that this is likely the last generation of HDV camcorders, since it’s a kind of bastard format designed more for DV tape compatibility than any other reason. Several higher-end Sony camcorders offer recording 50Mbps long-GOP MPEG-2 to Blu-ray Disc. This seems to be a wonderful option to me since discs are cheaper than SD media and can provide both acquisition and long-term storage. For the time being, however, HDV stored on DV tape remains a very solid option for many producers, especially those continuing to shoot in DV.

Question Five: What Other Features Should I Consider?

These are the biggies; now, let’s look at some other features you should consider when purchasing a new HD camcorder.

Focus Assist
One of the biggest challenges of HD recording is trying to achieve a sharp manual focus using only the camera’s CCD or tiny viewfinder. Some HD camcorders can zoom the preview image to 2X to assist focus, but this view is usually only available during preview, not while recording, which is like a GPS device that works when you’re stationary and turns off once you start driving.

In contrast, the Panasonic HPX170 offers four Focus Assist features (in addition to a peaking display) that stay visible while you’re recording. To start, when you enable Focus Assist, the camcorder displays a zoomed preview in the middle of the viewfinder, a histogram in the upper-right corner, and a moving bar below the zoomed image. The histogram has black pixels on the right and white pixels on the left; as you focus in, the white pixels shift to the right, receding if you dial the focus ring too far.

I found the moving bar more helpful. Essentially, as you focus on your subject, the bar extends to the right. If you go too far, it starts backing down to the left; so you focus until the bar is at maximum length. However, both indicators remain onscreen while you’re actually recording, so if your subject does something radical, such as move, you can maintain your focus.

The HPX170 also debuted a feature called Manual Focus Assist. In this mode, you manually focus with the focus ring as you normally would, and once you get close enough for the camera to discern your target, it takes over, automatically making the last fine adjustments, which you can track by watching small movements of the focus bar. The result is absolutely striking and quite comforting, as the image in the CCD and viewfinder (and, ultimately, the recording) was absolutely sharp the whole time. Note that if you want your image to be slightly out of focus or if you want to shoot a rack-focus shot, you can disable this feature and go all manual.

The HCM150 offers the zoomed preview and a histogram but not the bar or Manual Focus Assist. At the very least, unless you plan on having a large-screen preview monitor with you at all times, you should make sure that the zoomed preview stays active while you’re actually recording.

Internal Waveform
Another cool feature of the new Panasonic camcorders is an internal waveform monitor on the LCD panel, which is a much more accurate gauge of lighting than the internal zebra stripes also available on these and most other camcorders. Both camcorders also display the luminance value of the pixel in the center of the frame, so if it’s not 95-plus when you’re white balancing, you know that you’ve got potential exposure issues.

Getting exposure right is 90% of the battle, and these types of tools really make your job simpler.

Optical Zoom
This sounds like a consumer-oriented feature, but if you shoot events or other structured presentations where you can’t control camera location, a 20X zoom lens can be heaven. I’ve shot 12X and 20X camcorders side by side, and I vastly prefer the 20X zoom.

Audio Connectivity
Probably the most significant difference between pro and consumer camcorders is XLR connectivity, which is necessary for connecting microphones and soundboards to your camcorder.

The first two 3CCD HDV camcorders on the market, the “consumer” Sony HDR-FX1 and the “professional” HVR-Z1U, were virtually identical except for the XLR connectivity, which was justification enough for Sony to give it the professional designation and to price it about 30% higher than the FX1.

Hot Prospects for 2009
I haven’t looked at all of these camcorders (some weren’t available at the time of this writing) but if I had to compile a short list of camcorders most likely to succeed in 2009 and beyond, it would be the following:

Sony HVR-Z5U (MSRP $4,995)9255421
This successor to the Z1U resembles its predecessor in that it records HDV to tape, but it also uses three 1920x1080 CMOS sensors to get there and records in true progressive. A 20X optical zoom and histogram (but no waveform) complement the CMOS, and there are multiple alternative storage mechanisms, including hard disk and compact flash. Sony has a well-deserved reputation for low-light sensitivity, ease of use, and very high-quality video that I expect this unit will continue to reinforce.

Canon XH A1S ($3,999)
CanonMy Canon XH A1 (HDV) has produced the sharpest images that I’ve ever recorded, and a new 20X lens should only improve things. The update also offers more manual adjustments for those who like to craft their image.

Panasonic HPX170 ($5,695)
This DVCPRO HD camcorder succeeds the HVX200, whichimAGHPX170psaghpx170 was exceptionally popular with the indie and documentary filmmaker crowd. It’s completely tapeless, and comes with a 5-year warranty. Its manual controls are legendary, and DVCPRO HD offers exceptional quality, albeit at a data rate more than four times that of any camcorder recommended here. With the focus assists and waveform monitor, you’ll be able to travel light, and you can flip the display to work with 35mm adapters that don’t offer flip mechanisms. P2 costs and a 13X zoom are the big negatives.

Panasonic HMC150 ($3,995)
imAGHMC150psaghmc150With full-resolution AVCHD at up to 21Mbps, three CCDs, and a strong feature set, this is the first truly professional AVCHD camcorder. It highlights most of the format’s advantages, such as 3 hours of full resolution HD video on an SD card scarcely larger than your thumbnail. While not quite as robust as the focus assist on the HPX170, the HMC150’s focus aids are still much better than those offered by most competing camcorders, and the waveform is very similar to the higher priced HPX170.

Jan Ozer () is a frequent contributor to industry magazines and websites on digital video-related topics and is the author and producer of the Critical Skills for Streaming Producers family of tutorials.

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