Distibuted Production

High Quality Video Distribution Workflow

One problem I've had in working with video productions in a distributed way is getting high quality source material from where it's shot to where it's edited. Often people remixing videoblogs, for example, will just grab the hightly compressed QuickTime videos posted on various sites. This is done because it's, one, convienent, and two, uploading and storing DV quality files at 220MB/minute just isn't practical in most cases.

I developed this workflow for situations where you want to shoot in one city (or country) and edit in another with high quality video that will yeild results as close as possible to working with the original video while remaining practical to transfer over the Internet. Specifically this was developed for Alive In Baghdad where video is being shot in Iraq and edited in the United States. In this particular project, because of the unreliablilty of electricity and Internet access, the Iraqi correspondents mail their original tapes to Brian in Massachusets. Brian does some preliminary editing, culling usefull footage into a single file. That video is then compressed using the 3ivx mpeg4 codec from 220MB/minute to about 16MB/minute while retaining an amazing amount of the original video quality. That compressed video is then dropped into our SpinXpress group where it starts transferring directly to my computer. Once I've received the video I trans-code the video back to the DV format for editing. The resulting video is approximatly the quality of a good digital cable broadcast, ie. HBO.

The key to making this work are the 3ivx compression settings. These settings were designed with a number of considerations:

1. I wanted the final video to look as close to the original as possible.

2. I wanted 30 minutes of video to be less than 500MB when compressed so that it could transfer in a reasonable amount of time - approximately 3 – 5 hours.

3. I wanted compression time to be as short as possible.

In order to achieve this I chose the 3ivx codec over H.264 because H.264 encoding time is prohibitive for the amount of video we’ll be using. Additionally, although at lower bit rates dual pass H.264 yeids better quality that 3ivx dual pass, I found single pass 3ivx quality to be better than H.264 single pass at our target bit rate. I also picked 3ivx over Apple’s mpeg4 because it offers better quality and only slightly longer encoding times. And I choose to go with single-pass encoding vs. dual-pass encoding because at the bit rate were using, dual-pass doesn’t increase the quality much at all while adding complexity and twice the encoding time to the process.

Using this process, 30 minutes of DV video can be compressed to approximately 500MB in about 1.5 - 2 hours, transferred via SpinXpress in about 3 – 5 hours and transcoded back to DV in about an hour. This makes it possible to transfer this video between any two locations on the planet via the Internet in under 8 hours. Take that FedEx!

Setup SpinXpress

Screencast for setting up a Spin group

Video

Here are the 3ivx settings:

Note: The 3ivx software will not run on the new Intel Macs. If they are to be used for this part of the process they will have to use QuickTime Pro for Windows via Paralles Desktop (recommended) or BootCamp. Since this isn't always practical, here's a screencast showing how to export using single-pass h.264. This takes about 6X the length of the video on a Dual 2GHz MacBook Pro.

1. From Final Cut Pro, FILE > EXPORT > USING QUCIKTIME CONVERSION…

From iMovie, FILE > EXPORT > QUICKTIME > EXPERT SETTINGS > SHARE

From QuickTime Pro (Mac & PC), FILE > EXPORT…

2. FCP – Format: QuickTime Movie, then click Options…

iMovie & QuickTime Pro – Export: Movie to QuickTime Move, then click Options…

3. FCP, iMovie & QT Pro are the same from here on out. Click the Video Settings… button.

4. Select 3ivx D4 4.5.1 from the Compression Type drop down menu.

5. Compression Settings dialog:

Frame Rate: Current fps

Data Rate: Restrict to 2000 kbits/sec

Compressor Quality Best

Then click the Options… button

6. In the 3ivx panel configure the Basic Options:

Encoder Mode: Single Pass – Average Bitrate

Maximum Quality: QP 2 = 100%

Minimum Quality: QP 7 = 75%

7. In the 3ivx panel configure the Advanced Options:

Force keyframes after 300 delta frames

Check – Half Pixel Motion

Check – Four Vector Motion

UNcheck – MPEG Quantizer (ASP) LEAVING THIS CHECKED SEEMS TO MAKE THE VIDEO INCOMPATIBLE WITH INTEL MACS

Check – Adaptive Quantization

Uncheck – Output Pure MP4 Video (Mac Only)

Check – Use VopN Coding (Mac Only)

Pixel Aspect Ratio – Square Pixels (PC Only)

Click OK, then OK again.

8. Click the Video Size button

Dimensions: 640 X 480 VGA

UNcheck – Preserve aspect ratio using:

Check – Deinterlace Source Video

Click OK

9. Click on the Sound Settings button

Format: AAC

Channels: Stereo (L R)

Rate: 48.000 kHz

UNcheck – Show Advanced Settings

Render Settings:

Quality: Normal

AAC Encoder Settings:

Target Bit Rate: 160 kbps

Click OK, then OK again

10. Give your file a name and choose a location to save it to, then click SAVE.

The video will start compressing now. It will take approximatly 3X the length of the video, ie a 30 minute sequence will take about 90 minutes to compress.

Once the video is compressed, add it to the SpinXpress group so that it can begin transferring. Once the video has been received it has to be trans-coded back to DV for editing.

Transcode to DV:

In Final Cut Pro: FILE > IMPORT > FILES… then select the compressed video. Then drag the video to a standard DV sequence and then go to SEQUENCE > RENDER > BOTH.

In iMovie simply drag the video to the clip bin. iMovie will convert the video to DV as it imports.

Future Possibilities:

One immediate where the process can be improved is if SpinXpress picked up the compressed file when it appeared in a watched folder. This way you woundn't have to wait for the compression to complete just so that you can drag the file to your SpinXpress group. This alone could potentially save many hours. For example, et's say QuickTime finished compressing at 2am and I didn't get up until 7 and only then added the file to my group. I would have wasted 5 hours - which is probably enough time to have transferred the file.

Or, let's say I leave the office at 5 with QuickTime compressing. The way it is now I don't get to add the compressed file to SpinXpress until the next morning. If SpinXpress watched the folder where the compressed file was going to be saved I could probably compress and transfer an hour of high quality video over an 8 hour period.

That alone is a power feature. If we could also work out a way for compression and transfer to happen at the same time, that would be a killer feature. Then, as long as the compression process is slower than my upload speed the entire process could happen in the time it takes to transfer the compressed file – about 3 – 5 hours.

Another usefull feature would be to preview files that were downloading (similar to how Limewire works). Let's say a large video was about half way downloaded, maybe I could get started on my work with just the first half of the video. I could click the save as button and it would save a file that consisted of what has downloaded up to this point. Later when the file was complete, clicking save as would save you a copy of the entire file.

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