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MillimeterJVC GZ-HD7: World’s First 1920x1080 MPEG-2 Camcorder, Part 2
Sep 10, 2007 12:00 PM, By Steve Mullen
Transcode to AIC
The green row displays data that represent the process of obtaining Apple AIC movies for use in FCP. The HD7’s MPEG-2 M2TS (Transport Stream) data is on-the-fly demuxed to video and audio Elementary Streams. The video stream is decoded and then recoded to I-frame MPEG-2. The MP2 audio stream is decoded to 48kHz PCM audio. This process is slow and results in a very large file.
Apple AIC movies can have a frame-size of either 1440x1080 or 1920x1080 pixels. However, only 1440x1080 movies can be edited in FCP using “Unlimited RT.” Therefore, if you shot FullHD, specify a Frame Size of “1440 x 1080 (4:3).”
Decode and Compress to DVCPRO-HD
The green row displays data that represent the process of obtaining Apple DVCPRO-HD movies for use by Xpress Pro 5.7 and Media Composer 2.7, as well as FCP. (While Avid can import DNxHD, the conversion from MPEG-2 is very inefficient.)
The HD7’s MPEG-2 M2TS (Transport Stream) data is on-the-fly demuxed to video and audio Elementary Streams. The inter-frame video stream is decoded and then compressed to intra-frame DVCPRO-HD. The MP2 audio stream is decoded to 48kHz PCM audio. The Frame Size can be either 1440x1080 (4:3) or 1920x1080 (16:9). The process is slow, and it results in a very large file.
Re-Mux to MPEG Program Stream
The yellow row displays data representing the process of obtaining HD MPEG-2 Program Stream files for use in Premiere Pro CS3. This process is very fast, and it results in no loss in quality.
The HD7’s MPEG-2 M2TS (Transport Stream) data is on-the-fly demuxed to video and audio Elementary Streams and then re-muxed into a Program Stream. Obviously, file size is not significantly changed in the process. Because re-muxing cannot rescale the frame-size, you must shoot only 1440CBR video.
Lessons
You may be wondering—What about timecode? There is no timecode on the video recorded to the HD7’s hard disk and memory card. When captured, each clip starts with a timecode of zero, and, therefore, no batch recapture is possible. However, if you clone HD7 video to HDV tape for a backup and archive, the tape’s timecode supports batch recapture from tape.
If batch recapture is not important to you, and if you edit with neither an Apple nor Avid NLE—JVC’s GZ-HD7 supports a straightforward workflow. Moreover, if you edit with either Vegas 7e or Edius 4.5, the workflow is exactly what you would hope it would be for a hard disk- and memory card-based camcorder.
(See www.mindspring.com/~d-v-c to learn about an available GZ-HD7 Guide.)
Continue the discussion on Crosstalk the Millimeter Forum.