Today’s sophisticated sensors demand a recording system that is capable of carrying a much higher-level quality image. For this reason, Panasonic has announced AVC-Ultra. AVC-Ultra is backward compatible with AVC-Intra. That means that an AVC-Ultra decoder can decompress all of Panasonic’s P2 codecs. AVC-Ultra offers several quality levels. (See Table 3.)
The Panasonic AVC-Ultra family defines three new encoding parameters from the MPEG-4 Part 10 standard. Unlike the Intra codecs, Ultra codecs can utilize the AVC/H.264 4:4:4 Predictive Profile.
AVC-Intra Class 50 and 100 are extended to Class 200 and Class 4:4:4. The Class 200 mode extends the bit rate to 226Mb/s for 1080/23.97p, while Class 4:4:4 extends the possible resolution from 720p to 4K with value depths of 10 and 12 bits. It’s possible Class 4:4:4 at 10 or 12 bits with a 4K frame size will be employed in the 4K camera Panasonic showcased at NAB2012. The Class 4:4:4 bit rate varies between 200Mb/s and 440Mb/s depending on resolution, frame rate and bit depth.
There is also a new 8-bit AVC-Proxy mode that enables offline edits of 720p and 1080p video at bit rates varying between 800kb/s and 3.5Mb/s.
Both the Class 200 and the Class 4:4:4 are intra-frame codecs. Although Panasonic has always promoted intra-frame encoding, its new AVC-LongG is an inter-frame codec. AVC-LongG enables compression of video resolutions up to 1920 x 1080 at 23.97p, 25p and 29.97p. Amazingly, 4:2:2 color sampling with 10-bit pixel depth can be recorded at data rates as low as 25Mb/s.
—Steve Mullen is the owner of DVC. He can be reached via his website at http://home.mindspring.com/~d-v-c.