Learning about the Canon XL-H1

This camera caught me by surprise as many of the camera vendors now contact CineForm before they announce their HDV camera (even many non-HDV vendors discussion CineForm implementations.) However this is a very nice surprise, and we all expect Canon to have a high quality solution. As the XL-H1 is a 1080i HDV camera it will be closely compared with the Sony HVR-Z1; neither camera offers a progressive imaging sensor, yet both have a pseudo 24 frames implementation -- speculation on this is great as the Sony method under-whelmed the market, Canon may/should take a different approach (see my speculation below). The good news is this new camera should operate flawlessly with all CineForm products as it complies with existing HDV and HDSDI (bonus) standards.

The clear difference between this unit and other HDV cameras is the addition of HDSDI. We already have several customers using live HDSDI feeds into Prospect HD workstations for onset capture, bypassing the camera compression of HDCAM/DVCPRO-HD etc, so the same work-flow will apply for the Canon XL-H1. So just like the high end HD solutions, the HDSDI feed is pre-compression, the raw data from this HDV camera is the highest quality feed, perfect for Prospect HD's 10-bit CineForm Intermediate compression (the HDV tape acts as a backup only.) There has been speculation whether the HDSDI feed is 8-bit or 10-bit YUV 4:2:2. I believe it is more likely to be 10-bit, counter to a few opinions, as there is no technical reason not to output 10-bit. The RGB CCDs capture light in a linear manner with 12 to 14 bits of precision (depending on the sensor), after in camera processing the resulting RGB linear data is converted to YUV 4:2:2 in a 709 colorspace. The RGB precision is plenty to support a 10bit YUV gamma corrected output. The top 8-bits would then be sent on to the MPEG compressor (where it is further down sampled to 4:2:0.) If the processed linear RGB data is converted directly to 8-bit YUV, that would have been an error on the part of Canon engineering (so I don't think they would have done this), particular as HDSDI is inherently 10-bit (8-bit data is sent as 10bit with the two least significant pixels set to zero.) So as soon as cameras are available it is straight forward to determine the bit-depth of the HDSDI feed.

As we will get an uncompressed 1920x1080 out from HDSDI (higher than HDV's 1440x1080) the sensor resolution is significant. Canon has increased the resolution over the Sony Z1's three CCDs of 960x1080 (which use a horizontal pixel shift of the green sensor to increase the effective resolution to approach that of 1440.) Instead the XL H1 has gone with 3 16x9 CCDs of 1.67M pixels each, suggesting a sensor resolution of around 1720x970 (assuming square pixels.) I just read that the effective sensor area for HD is 15.6M pixels, which would indicate of non-square pixel sensor of 1440x1080 (which makes better sense.) If the lens allows, this should resolve a sharper (or detailed) image. The down size of so many picture elements on a 1/3" CCD, is a reduced light sensitivity. Sony the 960x1080 CCD, with their extra elongated pixels, have a larger area to collect light, and therefore potentially slightly more sensitive.

The most anticipated element of the XL H1 will be how it achieves 24 frame acquisition using a interlaced sensor. Canon has been up front with the 24 mode not being acquired in a true progressive sense, but in one statement it seems it will not have the motion jutter of Sony's CineFrame 24, which suggests the sensor may be run at 48Hz rather then 60Hz for the 24F mode. This will be an excellent first step. However if all data is interpolated from a top or bottom field, the vertical resolution can't exceed 540. I don't give much weight to an intelligent de-interlacing process, as that will potentially introduce motion artifacts as the good algorithms would take too long for the camera to compute. Canon could generate a good resolution pseudo progressive image if they ran the green CCD with reversed field dominance (output a bottom field when red and blue CCD output a top field) this way the same pixel shifting technology that makes Sony's 960 res CCD output near 1440, could help the three 540 fields (red-blue and pixel shifted green) could achieve a progressive vertical resolution approaching 810 (which is about the maximum a normal interlace picture can achieve any way.)

One last note on the 24F mode. The "Advance" 2:3:3:2 pull-down of 24p DV is unnecessary in HDV as there in no frame compression used in the 1440x1080 mode (spec HD2.) As only field compression is used, the standard 2:3:2:3 pull-down will work perfectly well. A true progressive frame signal can be exacted with ease.

P.S. 10/12/05 -- Now that we have a camera I have posted some real world data.

So many new HD cameras to choose from, so much misinformation.

There is much heated discussion on the various HD and HDV forums regarding sensor resolution, compressed types and bit-rates of the new crop of prosumer HD cameras. So much is focused on these elements, yet the numeric data is often less significant than the quality of the lens and the physical size (not resolution) of the CCD/CMOS. This is encouraged as so much of the marketing of these cameras is rooted in the numbers -- three CCDs is assumed to better than one, chroma sampling 4:2:2 better then 4:2:0, and 100Mb/s is better than 25Mb/s, all seems so true, yet in most cases the impact of image quality is far more complex than that, with the numbers often hiding more significant characteristics.

What is the true resolution of a camera? Put a resolution chart in front of its lens and you have better information than any of the marketing data. However the ability to resolve detail will be impacted by the sensor resolution, physical pixel size, compression resolution and chroma sampling. I in the next few post I intended to go into interesting technical details on a range of these new cameras, pointing out where I think the marketing information based on the numbers are either misleading or significant to the final out image quality.

Here are the range of the sub-$20k HD cameras that are annouced or currently available.

Canon XL-H1
Grass Valley Infinity
JVC GY-HD100U
Panasonic HVX-200
Sony HVR-A1
Sony HVR-Z1
Sony XDCAM-HD

I intend to discuss a little on each. Please point out if I have missed any interesting new cameras.

Extending the Prospect 2K work-flow on Lbs

Our next major film project Lbs will be using the upcoming Prospect 2K editing engine. Prospect 2K is a work in progress and we aren't currently marketting or selling it. I will occassional discuss the product's updates as will learn from the post-production of this film.

One of the post-production requirements is to monitor the timeline via HDSDI even though the scanned frame resolution is 2048 x 1276 , larger frame size than HDSDI generally supports (at full frame rate.) As the feed is primarily used for color correction we will window the 2K source so that most of the image (80%) can be seen across HDSDI. For this project will are sending out the center 1920x1080 image. This HDSDI feed will pass though a BlackMagic HDLink box to enable the mapping of log density image for accurate viewing on an HP 24" DVI LCD panel.

All of this has been working perfectly well. The trick now is to come up with the necessary curves between the log images and the 2.2 gamma LCD such that color correction performed, with this simple workstation setup, will match the final film out. This will involve correcting for the errors / distortions in the film final out -- we will be performing film out tests and using that data to help generate the curves. This is the next big stage of this project, and no small feat. It should be a lot of fun.

Sorry it has been such a long time since posting. This is due to large number of things happening rather than the lack of events. Just in the last weeks:

• The scans for the Lbs project where completed and the conform within Prospect 2K is basically done. The source for the whole movie, ten 20 minute reels of cut negative, scanned at 3028x1276 (10-bit log) fits on a single 300GB drive. If that doesn't change filmmaking...
• The recut of the 3D-IMAX movie Santa vs the Snowman from O Entertainment was completed (and looks awesome.) I will be showing some of this at SIGGRAPH with the AMD booth.
• Aspect HD 3.2 was released, rolling in many quality enhancement from Prospect HD.
• Connect HD 1.8 was released (yesterday.)
• And personally, I directed a short for the 48 Hout Film Project (San Diego division) last weekend and had a complete blast. This was an HDV project shot with two Sony Z1s in CineFrame 25 and edited in 24p using Aspect HD 3.2. The screening is tomorrow night a Landmark La Jolla Village, 7pm. The film is called the The Disc. Today I just re-mastered the film at 1280x720p24 using Window Media 9, looks very cool for writing, shooting and editing within 48 hours.
  

Deep AVIs within After Effects Pro.

The professional version of After Effects has the very import feature of 16-bit processing. This is something CineForm loves and we made extensive use of this on the production of Dust to Glory. To allow greater than 8-bit AVI support within After Effects, CineForm has created its own I/O module to offer importing and exporting of deep AVIs. Cool huh? Yet this comes with some resistance from Adobe themselves as we had to override their existing After Effects importer. The concern is fair, just as AE doesn't support deep AVIs (annoying to our customers), the CineForm importer doesn't support DV (annoying to many of their customers.) Unfortunately the two importers can't play well together, as After Effect is missing the mechanism that Premiere has which enables multiple importers to co-exist. Sigh.

To overcome Adobe's concern and the After Effects limitation, the new release of Prospect HD (v1.1 is due out any day now) will allow you to select which importer you will use on the launch of After Effects. You can permanently select deep AVIs, or stay with 8-bit processing, or dynamically select which you are using in each AE session. The beauty of this approach is it actually overcomes the AE limitation for all AVI types (with a little user work-around.) It turns out the AE limitation only applies to the action of importing, not to using multiple AVI types loaded in previous sessions (weird I know.) If you're working with deep AVIs but you still need to mix in some DV clips, here is how you can do it (in PHD v1.1.) Starting with a project with deep AVIs, to add DV elements:
1) save your project and close AE.
2) re-open AE (while holding SHIFT+CTRL) which will open the CineForm importer control panel.
3) Select 8-bit AVI mode from the CineForm pop-up.
4) reload you project and import all the new DV elements.
You are done. Now all the media types work together while gaining the benefits of deep pixel processing. If you need more deep AVI elements, simply repeat the steps and switch back into deep AVI mode. This shows AE is so close to working as we all would prefer, yet this work-around allows the highest quality output without compromissing your source flexibility.

Putting the team back together for the 48 Hour Film Project.

The 48 Hour Film Project is a touring guerrilla film making competition. Last year was the first time in San Diego for this competition, so CineForm put together a team. This was a team of software engineers (camera, lighting & sound), technical support staff (editing), the wife (writer & acting), even the company's insurance agent (boom operator) all lent a hand. With actors from Criag's list we had a total blast and made a fun, but not yet a winning film. This year we are back to try again.

Like last year, we will be shooting HD, totally overkill for this type of project (SD only projection.) We do it because can -- it was also a plus to shoot a little wide for very fast setups, then crop in within post (HD giving us the extra definition for the crop.) The whole film was written, shot, edited, and mastered out in 48 hours so HD actually helped us save time. We where the only team last year with HDV cameras, this year I expect to be competing with other HDV teams (some may competing using our software.) Last year was shot with two JVC HD10U cameras, this year it will be either a couple of Sony Z1s or any upcoming prototypes I can get my hands on. What every we shoot with, we will be using the latest Aspect HD (hopeful a beta of the next release as nothing finds bugs faster than a competition like this.) I hope we can shoot something worth while to post online.

Scripting the rendered world.

It seems that there is an increasing number of customers using primarily computer generated sources. Customers are showing up with large number of Targa (TGA) or TIFF sequences and trying to work out the real-time editing work-flow. Although Premiere and After Effect happily import TGA sequences it becomes a very labor intensive task to convert tens or hundreds of sequences into separate AVIs. So I have been working on a simple shell tool to help batch convert image sequences CineForm Intermediate AVIs. This was is an off shoot of the work required by Pixel Havest (Lbs project); a version of this tool now runs on the film scanner. This is in an alpha version today, but I will make it available to Prospect HD customers upon request. Feedback is welcome.