Vegas v7.0d Support for Sony''s 24p HVR-V1

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With NAB having come and gone, this seems like a perfect time to look at how Sony Vegas supports 24p. To make things more interesting, I also ran a few simple performance checks.

Version 7, unlike Vegas Version 6, allows you to place the single Preview monitor at the top of the screen with the timeline below. This nicely allows one to make Vegas look more familiar.

Nevertheless, in my opinion, the GUI wastes a good amount of screen space—area that could be used for a much-needed set of Toolbar buttons. Vegas lacks not only buttons for most editing tasks, it also lacks a complete set of “transport” buttons for the Preview monitor. To make the Trimmer behave more like a Source monitor, I added a set of shortcut keys. Now I was ready to capture, edit, and export.

The Sony HVR-V1 records 24p using two modes: a general mode and a more specialized mode for videographers who want a 24fps look, but who either “edit in camera” or do not plan to edit using a 24p timeline.

The first mode, 24A, forces every clip to begin with an “A” frame. Due to the forced “A” frame, when playing 24A from a camcorder or VTR, brief when you plan to edit using an NLE that supports 24p editing. I used 24A for my tests.

The specialized mode (“24”) will playback without pauses between clips. Therefore, a production can be played from tape with no editing, or it can be edited in a 60i timeline. (Judder frames are red.)

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Before capture, I issued Options > Preferences, chose the Video tab, and unchecked "Use external video capture application." Next, I used the File > Capture Video function to capture native HDV. Although you can neither log (or import a capture EDL) and then batch-capture HDV clips, Vegas does have a "scene detect" function. While the lack of EDL import is a serious omission for those who log offline, I found the scene detection a valuable Version 7 enhancement.

With Vegas, there is no need to specify any capture “presets.” I captured 1080i60, 1080i60/30p, and 1080i60/24p from a V1 camcorder. After capture, I checked clip Properties and they were all correct: 29.970fps interlaced; 29.970fps progressive; and 23.976fps progressive.

After my clips were captured, I created three HDV Projects: 1080i60, 1080p24, and 1080p30. I created the last using the 1080i60 HDV preset and changing Field Order to “None (progressive scan).”

Once my projects were ready, I imported my HDV clips (called "events" by Sony). I placed a pair of 30-second clips of the same format as the project, into each project''s timeline. I slid the second clip over the first to create a 3-second “transition overlap.” Now I dragged a “hard edge” Clock Wipe transition into the overlap.

All test results were obtained using a 3.2GHz Pentium 4 (with an 800MHz front side bus), 1GB PC3200 (DDR400) RAM, plus a 60GB, 7200rpm Hitachi hard drive. This configuration is faster than the recommended system for Vegas editing HDV.

Best (Auto)

• A 1080i60 Timeline played at about 18fps.
• A 1080p30 Timeline played at about 17fps.
• A 1080p24 Timeline played at about 17fps.

Clearly, the “Best Quality" Vegas playback option is not a good choice with my single-processor PC.

Good (Auto)

• A 1080i60 Timeline played at about 29.9fps.
• A 1080p30 Timeline played at about 29fps.
• A 1080p24 Timeline played at about 23fps.

The "Good Quality" playback option delivers reliable full-speed playback for 24p and near full-speed playback for both 60i and 30p.

When, however, I ran a dual-stream test, my PC struggled even using the “Preview Quality" option.

Preview (Auto)

• A 3-second Clock Wipe caused 1080i60 playback to dip to 14fps.
• A 3-second Clock Wipe caused 1080p30 playback to dip to 13fps.
• A 3-second Clock Wipe caused 1080p24 playback to dip to 20fps.

Draft (Auto)

• A 3-second Clock Wipe caused 1080i60 playback to dip to 23fps.
• A 3-second Clock Wipe caused 1080p30 playback to dip to 23fps.
• A 3-second Clock Wipe caused 1080p24 playback to dip to 23fps.

With my PC, the "Draft Quality" playback option was obviously the best choice for realtime playback. This confirms what I found with Vegas 6 when editing 720p30. Unfortunately, “Draft” video quality is poor, which led me to choose Preview quality for the next tests. (Preview quality is very acceptable.)

• A 1080p24 timeline with color-corrected clips played at 23.976fps.
• A 3-second Clock Wipe placed between color-corrected clips caused 1080p24 playback to dip to 12fps.

Replacing the Clock Wipe with a Dissolve caused playback to dip only to 16fps. Conversely, replacing the Dissolve with a Page Peel caused playback to drop all the way down to 10fps.

For the export test, I removed the second clip''s color correction filter. This better simulates a timeline where half the clips are color-corrected.

To export an HDV file from Vegas 7, issue Tools > Print Video to HDV Tape. Click Next, and select “HDV 1080-60i.” Now click Next and then select “Crash Recording” followed by Finish. After the conform, the file was exported using i.LINK.

• The export time for 1080i60 HDV has a 4.5:1 time ratio.
• The export time for 1080p30 HDV has a 4:5 time ratio.
• The export time for 1080p24 HDV has a 7.5:1 time ratio.

During export of p24, Vegas adds 2:3 pulldown as shown below.

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It''s important to remember that you can only record 1080i60 to a V1. Despite this limitation, after exporting a 30p timeline as 1080i60, there should be no problem recapturing video and using it in a 30p timeline.

However, even with 2:3 pulldown applied during the export of a 24p timeline, the output from Vegas does not match the 1080i60/24p format recorded by the V1. According to Sony, it doesn't create the necessary MPEG-2 flags, which, to remedy, would require an enhancement to the MPEG-2 encoder. (This is an enhancement that may or may not make it into the next version of Vegas, according to Sony.) Next month I''ll report what I learn at NAB from Sony. And, when you read this, hopefully, we will all know which NLEs support 24p from an HVR-V1.

Steve Mullen owns Digital Video Consulting, which offers eBooks on HD production. DVC now offers a new eBook: the Sony HVR-V1 and HDR-FX7 Handbook at: www.knowledge-download.com/V1-FX7.