Using Frame Controls in Compressor

Compressor has some very sophisticated technologies in the Frame Controls tab of the Inspector to enable it to perform high-quality resizing, retiming and deinterlacing of footage.

These are incredibly useful but it is very tempting to set everything to "best" when it is not at all necessary and causes a significant impact upon the processing time. So what this post aims to do is outline what each function does and when it should be used.

Firstly, if you are not resizing, retiming or deinterlacing footage, do not switch Frame Controls on at all.

Resizing controls
When an image is resized, new pixels need to be calculated. If you downsize an image, an area that was once 10 pixels could now be 2 pixels and vice versa if you are upsizing. Compressor goes through the resulting image and calculates what each pixel value should be based on the value at that point in the original image. These are not always integers. For example, a pixel at point (3,3) in the resulting image might correspond to point (2.8, 2.8) on the original. As there is no pixel at (2.8, 2.8), Compressor has to calculate a suitable value. The following options are different ways of calculating these pixel colors.

Fast (nearest pixel) - Compressor takes the value from the closest whole pixel in the original image. This is very fast but can result in significant visual artifacts and inaccuracies, particularly when resizing by a significant amount.

Suitable for: Minor size changes, situations where a fast encode is more important than a high quality one.

Better (linear filter) - This improves on the nearest pixel method by taking the values of four surrounding pixels and weighting them, increasing accuracy.

Suitable for: Most downconversions (e.g. 720p to NTSC).

Best (statistical prediction) - This uses more complex algorithms to maintain edge sharpness, at the expense of processing time.

Suitable for: Upconversions (e.g. NTSC to 1080p HD)

Anti-aliasing slider - This smooths rough edges but don't set it too high or you will visibly soften the image.

Suitable for: Smoothing jagged edges when upconverting footage (e.g. PAL to 720p HD)

Detail Level slider - This sharpens edges, increasing our perception of detail in the image. Use sparingly to avoid adding noticeable noise or jagged edges to the image.

Suitable for: Sharpening soft edges when upconverting footage.

Deinterlacing controls
To deinterlace, first select Progressive from the Output Fields drop-down menu. Use this instead of the Deinterlace filter in the Filters tab as it will provide greater output quality. Choose one of the following from the Deinterlace menu:

Fast (line averaging) - The two fields are blended into one frame. This, however, can result in strange motion artifacts because you are playing two fields at the same time that were originally offset in time.

Suitable for: Situations with very little motion.

Better (motion adaptive) - This method analyzes the fields and uses simple linear blends (equivalent to the Fast setting) on areas with no motion. For areas with motion it discards one of the fields and uses interpolation to build up a whole frame from the other field's data.

Suitable for: Most situations except those with extremes of motion. In most cases you will not get any benefits from choosing higher settings than this if you are working in Standard Definition (e.g. NTSC, PAL). The downside to this method is that you lose vertical resolution if there is a lot of motion in the image.

Best (motion-compensated) - This uses optical flow technologies to track the motion of objects and analyzes multiple frames at once. This data is then used to split the image into blocks (typical sizes are 4x4, 8x8 or 16x16) and then shift these blocks so as to align motion between the two fields. This is incredibly processor intensive and will take some time.

Suitable for: Situations with extremes of motion (e.g. sports).

Retiming controls

Fast (nearest frame) - If you slow down footage, Compressor will need to add extra frames. This option just duplicates the nearest existing frame. It is very speedy but it can result in very choppy / juddery motion. If you are speeding up footage however, the choppiness will probably not be noticeable.

Suitable for: Minor speed adjustments, fast motion

Good (frame blending) - This blends frames together to create "in-between" frames and is a lot smoother than the nearest frame method, at the cost of processing time. This is suitable for most applications unless you are performing extreme slow motion.

Suitable for: Most speed changes with the exception of extreme slow motion

Better (motion-compensated) - This uses complex algorithms to analyze a range of frames and interpolate (predict) what the in-between frames should look like based on their surrounding frames. It then creates these new frames from scratch. Obviously this is very processor-intensive.

Suitable for: Extreme speed changes or footage with large amounts of motion (sports for example)

Best (high quality motion-compensated) - Apple's documentation is a little unclear on what makes this particular option higher quality than the one below it. It could be that it analyzes more frames to produce the final result, it blends using a higher bit depth for greater accuracy, or it recreates every single frame instead of just the in-between ones for greater smoothness. Or maybe all of them.

Either way, this is incredibly processor intensive and should only be used if you cannot get good results with lower settings.

Suitable for: Extreme speed changes or significant frame rate increases (e.g. 23.98 to 59.94 fps)

Conclusion

So what does this tell us? It tells us that "Good" or "Better" should be adequate for most situations and it is not worth choosing "Best" unless your footage actually needs it. The best way of finding a happy medium is to start with everything on "Fast" and perform small test renders (10 seconds or so) for multiple areas of your movie. If you are not happy with the quality, go up to the next level and keep going until you reach a level of quality you are happy with.

Rough cuts

Shane Ross has a great post about "rough" rough cuts and how frustrating it is when producers cannot see past a lack of audio or sound effects, or a dodgy transition. What is worse is when the producer gets it into his or her head that you are trying to pass that off as the end product, despite your protestations to the contrary. That has happened to me and is a nasty situation for all involved.

I think the key is to make the producer comfortable with you. Normally these kind of problems go away on the second or third project as the producer realizes that you can do the job and are not a cowboy, and they get familiar with the way that you work. I also find that a comfortable producer will give you a lot more creative freedom (I prefer to see scripts as a guide rather than a rulebook for example) and in return you will take advantage of that freedom to return a better product, so it is mutually beneficial.

How to change default preferences for our online tools

I recently had a question about this. We have several useful online tools in the resources section of the site, many of which are used by people on a regular basis.

However, if you consistently work with a particular format (e.g. HDV) or work in meters instead of feet, it can be annoying to have to change the settings each time you want to use it. Here's how to get around that.

1. Delete your old bookmark for the page.
2. Go to the page and select the settings you would like to be the new defaults.
3. Click "Link to this calculation".
4. Bookmark the page.

For bonus points, you could create separate bookmarks for different settings - e.g. one for HD projects and one for SD for example.

8800GT performance improvements with 10.5.3

With the recent OS X Leopard 10.5.3 upgrade, several users are reporting performance improvements with the Nvidia 8800GT, which has received bad publicity over its poor ProApp performance.

As always, Barefeats have benchmarks comparing the card with and without 10.5.3 and against the stock Radeon graphics card. At Apple Discussions, users have also posted their comparisons.

Performance improved significantly with the update but unfortunately not by enough to warrant purchasing it over the stock card. In some cases it was still slightly behind the stock Radeon. But progress is a good thing I suppose.

One poster says:


It looks like that could be the case. I hope that if it comes to that, Apple will do the decent thing and offer an exchange program.

Update: Some users are reporting graphical anomalies and Adobe CS3 suite problems with this patch

Mac OS X 10.5.3 released

Apple just released Leopard 10.5.3 via Software Update.

Apple's change list page is quite sparse while other sites have posted a much larger list of fixes based on beta versions of the patch. What is unclear is whether or not these changes made it to the final patch release or not (although the answer is probably yes as the final patch is 536 MB).

As always, NEVER upgrade in the middle of the project and if your system ain't broke, don't fix it. However, if you are suffering from a major issue fixed by this patch, wait several days to see if there are any major problems with it (I have heard of Airport issues already) and then only install it after performing a full system clone.

If you are considering upgrading, you are advised to download the full combo updater rather than relying on Software Update:
Mac OS X 10.5.3 Combo Updater

"Codec overrun" error when installing our applications

A couple of people have emailed me to say that they are getting "codec overrun" errors when trying to mount disk images of our applications.

This error means that the file got corrupted during the download process. The most probable reason for this is that they are using download manager software such as Speed Download that breaks up the file into chunks and downloads each one separately before piecing them back together.

Some people have reported that they receive this error when sharing their internet connection via Airport (for some bizarre reason).

The solution to this problem is to either disable such software or download the zipped alternatives that I have now made available on every product page.

FCS Remover
Preference Manager

New tool: Power Load Calculator

We've just released a new online tool to the resources section of our site - Power Load Calculator.

Power Load Calculator allows you to calculate the load on a particular circuit when certain devices are plugged in. For example, you can calculate whether or not the circuit breakers in a location can handle the lights you want to use and if not, the size of the generator that needs to be hired. This sort of thing is better discovered during pre-production and not on the day of shooting, so this calculator is very useful in that regard.

You can also calculate the minimum circuit breaker size for a given power load which is very useful if you are upgrading a building's power supply in order to accommodate your needs.

As usual, there is also an iPhone edition available.

Check out our resources section for more tools.

"The filter failed to render" error fix

Just saw an interesting fix for the big red "The filter ____________ failed to render" message some people have been getting in Final Cut Pro.



I seem to get it randomly every now and again but this is a useful fix for those who were experiencing it on a permanent basis. Pity you need to lose a monitor though.

Activity Monitor 101: System memory

Activity Monitor (located in Applications/Utilities) is a great tool for monitoring system resource usage, and is a great way of locating rendering bottlenecks in your system.

In particular, the Memory tab shows you a great deal of information (note: this is from Leopard; Tiger's Activity Monitor looks a little different).



But what does this information mean? What exactly is wired memory? Here is a breakdown of what each item in the Memory tab refers to.

(For clarification, a swap file is a file on disk used to store currently inactive memory in order to make room in the system memory for active applications. For example, if you have Firefox running and you minimize it and then open iTunes, there is a good chance that a lot of Firefox's memory will be written to disk and the space freed will be assigned to iTunes. When you restore the Firefox window, it will copy the data from the disk back into memory again. Your hard disk is much slower than your memory chips so it is best to keep swap file usage to a minimum. This can be achieved by adding more memory to your system.)

Free: Unused memory that is available for any application to use.

Wired: Memory used by the operating system that cannot be touched by other applications. This memory cannot be written to a swap file.

Active: Memory currently used by applications. Note that this might not represent all of the memory used, as some may be stored in swap files.

Inactive: Memory stored from an application that is no longer running. OS X stores application data in a cache so that you can quickly relaunch applications a second time. If you start running out of free memory, the operating system will automatically start using inactive memory.

To clear inactive memory manually, go to Applications/Utilities/Terminal. When it launches, type purge and press enter. Note: it takes several seconds to process.

Used: Memory currently in use that cannot be immediately written to a swap file or allocated elsewhere.

VM size: The size of the swap file.

Page Ins / Page Outs: How often OS X is reading data from and writing to the swap file.

When deciding if you need an upgrade, consider the following:

• Are your page ins/outs approximately equal to one another? Are they increasing rapidly?
• Is the majority of your memory wired?
• Do you have 10% or less of your memory free?

If the answer to any of the above questions is yes, consider more memory.