Friday, December 23, 2005
Tuesday, December 20, 2005
Mobile direct-to-disk captures.
One interesting note is the Wafian HR-1 is A/C powered, so to gain mobility they run this unit of a UPS system, given them 15+ mintues of capture time while moving. I understand there is a wireless device used to start and stop the captures remotely.
Thursday, December 08, 2005
New Compression Controls
This is taking a while to write all this up. :) The last, but not least, is the new Custom compression options. Previous versions of Aspect HD and Prospect HD only had Small, Medium and Large compression options. Large begin the best quality mode of real-time compression of demanding footage at 720p60 or 1080i60 on a Dual Opteron workstation (using up to 90% of the CPU bandwidth.) As we now have the pulldown extraction options to encode 24p vs 60p or 60i, we have saved some compute time that we can apply to even higher quality (note: the faster Opterons like the 254s and 280s have the same effect.) As CineForm is already visually lossless why do we need higher quality? In 99% of cases we are already higher quality than most application needs, yet for difficult keying and effects work we have now added four new higher quality modes (and one lower quality mode.)
From lowest to highest quality:
Off line - This was added for very large documentary style projects which may need to keep more hours of source material that can be inexpensively fit on an average system. For a 24p 1080 project, 30 hours of source (using Large mode) results in around 2 TB, which these days is simple and inexpensive to add to a PC (around a $1500 cost in SATA drives.) So for the average independent narrative feature, everything can fit in $1500 worth of disk -- NO OFFLINE REQUIRED. For 720p24 productions, you get twice the storage time (or need to spend half as much on drives.) Yet a project with 100+ hours of source material gets a bit tricky as the biggest drives are 500GB. Whereas four drives fit easily, 8-16 drives is a big issue within a desktop and pricy (for those that can afford it a SAN is an excellent option.) So for these very large projects an off-line mode still makes sense. Using this format a 1920x1080 image is encoded to around 4MBytes/s (720p24 to around 2MB/s), they will increase the storage capacity around 4 times. The beauty of this mode is it is still a full resolution file with the same 709 colorspace, much better than switching to a format like DV, switch has different size, pixel aspect ratio and a SD 601 colorspace. Your off-line in CineForm Intermediate will be a lot closer to you final result than a traditional off-line.
Optimized Large -The is the same quality tables as the original Large, yet all data-rate caps are turned off. Standard Large capture typically lets the data rate be variable up to around 160Mbit/s, then it is limiting the data rate from get too much higher (peaking at around 200Mbit/s.) However for effects work turning these limiters off will potentially help. This is not to be used or needed for every day shooting.
Chroma Key - This is a new designed modes for chroma key applications. How it works will remain a secret. For creating the best key use this mode for chroma key shooting only. We are still tweaking this one so feedback is welcome.
Optimized FilmScan 1 & Optimized FilmScan 2 - These mode have come from Prospect 2K, and are mainly used for encoding scanned film (not telecine.) There is little point in there usage of real-time HD captures, (so we may remove them), just something to play with.
New Pulldown Extraction Modes Explained
The base-band acquisition from these cameras is a different story. The first downside is there are no MPEG flags indicating active or repeated fields, the upside of course is there is no MPEG, DVCPRO-HD or any other heavy compression interfering with the image. So the extraction of pulldown requires on the fly image analysis to determine the pulldown cadence of the incoming uncompressed HD signal (which I have touched on here.) This feature is controlled by the new capture panel, which tell Prospect HD which pulldown type to look for.
The most common mode will be the "2:3 (extract 24p)" mode. As we are not performing any predictive deinterlacing, the camera must be in the appropriate mode. On the Canon that is the 24F (or F2) setting and on the JVC HD100 it is the 24 frame mode. Note: this 2:3 pulldown extraction should also work on the HVX200 and Sony Z1U (there are some limitations of CineFrame 24) -- not tested yet. Even when you are capturing the a 24p stream, the incoming video format must match that of the camera's output : for the 100U use "1280 x 720 p 59.94" and for Canon use "1920 x 1080 i 29.97" (some call this 60i.)
The next two extraction types only apply to 720p sources. The "2:2 (extract 30p/25p)" is simply to half the frame when 30p is sent over 60p or 25p is sent over 50p. European users of the HD101E in 25p mode will use this pull-down type to capture a pure 25p signal. The final "1:1:1:2 (extract 48p)" is a bonus to JVC HD100 users, this allows for a perfect 48p signal for those who would like a 2X slow motion over 24p.
New Slowmotion Capture explained.
With the new capture interface you have an easier option. Using the Slow-Motion Output Rate field you can set the frame rate the output file will be flagged to play back as. All 60 frames per second will be captured, yet the resulting file will be immediately ready for slow-motion playback. Setting the output rate to "Default" results in the same 60p data you had in the previous release.
Other differences to notice. When you previously captured 60p as 60Hz, the file reported an average data rate of 18+MBytes/s. Now when you record 60p for 24Hz playback the file will a much lower data rate more like 8MBytes/s (data rate will depend greatly on your source.) The low number doesn't mean the quality is lower (it in fact could be higher) instead the data rate is now the new playback rate, during record 18+MBytes/s is sent to disk.
Wednesday, December 07, 2005
Many new capture tools for Prospect HD (and soon Wafian HR-1)
In my next post I will explain the key features in more detail, plus where items can be enhanced with your feedback.