Improving Video Export Quality

[ This article was first published in the December, 2008, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe. ]

IMPROVING EXPORT QUALITY

Paolo Raho sent in a question I’ve been getting a lot recently:

I’m very familiar with all of your tutorials, and I know for the highest quality it is always recommended to export the sequence under the settings in which the footage was shot and captured. I was reading a couple of forums lately and they were discussing the idea of exporting a DV sequence as 8 or 10 bit uncompressed; a process that would yield a higher quality image, specifically for text and graphics. I wanted to get your opinion on this, whether there was any truth to it.

 

And one other question along the same lines, let’s say I have shot and captured in DVCPRO HD, and exported a sequence under the same settings, has my exported movie suffered any quality loss, or has it remained identical to the captured footage? That is to say, does exporting, even under the correct settings, result in an quality loss?

Larry replies: Paolo, Damon Jamal echoes your questions with his own:

Can you explain:

 

1) why when exporting using animation or prores the resulting quicktime movie looks better and

 

2) why that doesn’t matter?

 

Also you wrote to export as quicktime using current settings but if your sequence is set to prores (for example) then wouldn’t that result in what I wrote above in #1?

 

I’m just a little confused, so I would appreciate it if you can shed some light on this…

Larry continues: Here’s the basic problem. As Martin Baker describes in the Update below, on many systems DV is SAVED at high-quality, but not DISPLAYED at high-quality.

Here is an example. The image on the top is a portion of an exported DV clip displayed in QuickTime, the image on the bottom is the same portion using the Animation codec. Clearly, at this level, the Animation codec is FAR superior.

But, let’s run both of these through Compressor and check the compressed images. Now, the two variations look very, very similar. (Both of these sets of images were further compressed into JPEG from Photoshop using the Maximum quality setting. – so some additional quality loss has occured.)

Again, the difference is that DV requires a hardware chip for high-quality display in real-time. Compressor contains all the necessary algorithms to properly compress the image, but it can’t do so in real-time. For this reason, be sure to make your quality decisions after a file goes thru compression, and not before.

So, to answer your questions more specifically:

1. Is it better to export as 8 or 10 bit uncompressed? My feeling is that if you are shooting DV, no. If you are working with 8-bit or 10-bit source material – yes. The problem is that DV does not display at high quality on a Mac monitor. For this reason, people assume that the video is poor quality. This is a display issue, not a video quality issue.

 

I’ve done a test where I export DV footage using the Animation codec – the highest quality SD codec on the Mac – and the DV codec. I compressed both and compared them. To the eye, the compressed versions were identical. The intermediate versions looked significantly different – DV looked far poorer than the Animation codec. But after compression they looked the same.

 

2. Does DVCPRO HD change? Well, that depends. If you are adding effects, transitions, or something requiring rendering, then, yes, the video is being altered from its original state. On the other hand, that’s why you applied the filter in the first place. As to whether that’s a quality “loss” that depends on the filter you added – I would suggest that a color correction filter, properly applied, will make the clip look better.

If you are simply putting the video to the timeline and not adding effects what you get out is the same as what went in.

UPDATE – Dec. 18

Martin Baker, from Digital Heaven, wanted to clarify this a bit more, so he wrote:

It’s not a lack of hardware that causes the softness, it’s historical reasons. When DV was the new kid on the block and Macs were way less powerful than they are today, QuickTime Player decoded DV at half res to reduce the amount of processing required. Apple did this by adding a “High Quality” playback flag to the DV video track and disabling it by default when exporting a movie from FCP.

• High Quality disabled = half res
• High Quality enabled = full res

Most people freaked out when they saw their videos looking soft but weren’t aware this is purely a playback issue inside QuickTime Player and isn’t connected with the quality of the export. The DV file is full res, which explains why recompressing it to another format gives the same results as Animation codec.

 

 

The old “fix” was to enable the flag manually by opening Window > Movie Properties, or typing Command+J,selecting the Video Track, and checking the “High Quality” checkbox inside Visual Settings tab.

 

When Apple released QuickTime Player 7, they added a preference (QuickTime Player > Preferences > General > “Use high-quality video setting when available”). If this is enabled, then QuickTime Player will override the flag in the movie and always play DV movies at full res.

Larry continues: Thanks, Martin, for the update. The only point I want to add is that in most systems I see, this High-Quality default is turned off — which probably adds to the confusion. And thinking of preferences, Ben Balser wrote in with another that we need to pay attention to.

UPDATE – Dec. 20

Ben Balser, from the South Louisiana Final Cut Pro User Groups, added this:

To add to the discussion about QT Player’s video quality settings for playing back video, there’s also this preference folks should look for. I’ve found many of my User Group members complain about color shifts between the QT version and the FCP versions. Here’s how to fix it. By the way, I’m running QT Pro 7.5.5.

 

 

In QuickTime Player go to the “QuickTime Player” menu, to Preferences, in the General settings, at the very bottom of this window, make sure the last setting, “Enable Final Cut Studio color compatibility” is also checked off, as QT Player uses a different gama than FCP does.

Larry replies: Thanks, Ben and Martin, for these updates.

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