Using proxies involves using low-resolution files to speed up the production process. The resolution of the cameras are constantly increasing, thus the recording codecs require more power and space from workstations. The use of proxies is therefore becoming more essential.
The use of proxies is far from new when it comes to large-scale productions and newsgathering. Native files are of course extremely demanding due to file sizes, so the use of proxies makes it easier to edit in low definition first, before conforming to HD, 4K and DCP at a later stage. This technique is now easier to use thanks to being automated directly within most editing softwares.
Proxies transcode the video clips in low definition. When these clips are exported, they are replaced with the native footage and applied into the content for full quality. Better still, a lot of Panasonic cameras, from the UX180 to the VariCam series, are capable of recording both the native full resolution file and its proxy version simultaneously. This allows images to be either transmitted during shooting via a wired or wireless network , and for an edit to be made before the master version is available.
The problem with Proxies
Everything sounds great with proxies, right? No matter how much you build up the processing power of your work station, there is always a reduction in power when working with large file sizes. When in post production, the more effects you add, the longer you wait for render. The faults lie with the following causes:
- The increase in quality of image is traded off with the more efficient codecs that occupy less space for the same quality, as is the case for H264 and now H265 (HEVC). As a result, if a camera takes care of encoding the images during shooting in a linear way, it is much more delicate when it comes to decoding the images, to apply effects to them, or to multiply the flows as found with multicam shoots. When in the edit, the computer must decode the image, or in the case of LongGOP codecs, decode what is before and after. Despite this, these codecs allow us to capture 4K in 4:2:2 10-bit at 100 Mbps, which would have been unthinkable before.
- Despite the increase in computing power, it is not always possible or necessary to update your workstation every six month, therefore the likelihood is that you will get a gradual lag as you work on more projects
- Even when shooting with a codec that requires less processing power, we then have to deal with files that require significant playback rates during editing, especially if we stack several clips. There is no longer a power problem, but a storage capacity problem that makes it difficult to ‘spit out’ data at the right rate.
- Transmitting images in full definition is still far too heavy on 4G networks for newsgathering operations, and so they must be compressed. Hopefully with 5G this will no longer be an issue.
- The first alternative to a proxy has been to use an intermediate codec for assembly. The idea is simple – all of the shooting deliverables are converted into the same editing format i.e. ProRes on Mac, DNXHD/HR or Cineform on PC for example. This leads to much greater fluidity. This codec can then be used for mastering. The issue with this is that the files are uncompressed and therefore take up far more space. For a 64GB card shot on an EVA1, you can find yourself with around 300-400GB of data once converted. This conversion can therefore take time, particularly when you have hours of rushes.
- Another alternative is the use of an external recorder during shooting, where an intermediate codec is captured on a SSD. There’s no need to offload cards – instead, you insert the disc into a rack after your shoot. The issue with this is that a lot of SSDs have to be available, whilst use of recorders can make a set-up bulkier, particularly when powering them. An additional issue is that most cameras do not allow you to record both in-camera and externally onto an external recorder simultaneously.
- The use of proxies is the final method, and with this the usual workflow is almost unchanged. All rushes are imported onto your work station, and the editing software can then create proxy copies. A simple switch on your timeline allows you to switch from the master version to a lighter version, and the same effects will be applied to both versions. Unlike the intermediate codec, the conversion is ultra-fast and its file size is light. As found in the case of cameras that generate proxies themselves, it is straightforward enough to attach both versions together, with no conversion required. You can switch between both versions with a single click, meaning you can work on both the master and the proxy version quickly. We have also found this method to extend the life of an ageing machine, with the major processing power coming out of the final export
Proxies – the limitation
The use of proxies requires organisation by storing the proxies next to your master rushes, otherwise you risk mixing between both media.
The use of proxies also requires careful management of metadata to be included within the master file, particulary timecode. You must also be careful with time manipulations – for example, if you are generating proxies and have formatted a rush from 25p to 24p, make sure that the proxy will also be in 24p or risk generating shifts on the timeline. Some users can also use the wrong codec, and find themselves with heavier proxies than the originals – again, be careful of this trap!
Proxies in editing software
With Premiere Pro:
As always with Premiere, it could have been simple, but unfortunately it is complicated when proxies are used fo the first time. By default, the software has only a few presets to generate proxies and they are not necessarily adapted. You have to create your own preset as follows:
- Launch Media Encoder and in the Presets pane, click on + to create an Export Preconfiguration, because you can’t directly customise a preset ‘ingest’
- Name the preset, then choose a Format (Quicktime for example), customise the Codec (for example, Proxy Pro-Res or 10-bit Cineform YUV Gopro).
- Customise the quality (by lowering it to the minimum) and the resolution. We find that 960 x 540 pixels is a good compromise.
- Leave the rest of the settings at ‘depending on the source’ and finally, uncheck ‘return to maximum quality’. You can save the preset by naming it as precisely as possible (Proxy 960 – Pro-Res – export)
- Create an Ingest preset. Choose the same format (Quicktime in our example). And give the same naming convention as before, but this time add ‘Ingest’ for differentiation.
- Choose the ‘media conversion’ option (and enter an unimportant destination). And that’s where you’ll be able to choose the preset you created for export. Save it all while validating.
- In the list of presets, select the preconfiguration you have just created and use the command ‘display file’ to find out where it has been saved.
- In Premiere Pro, import your dailies, select them all, and with a right-click/proxy, choose “Create”. In the dialog box displayed, you will now import your ingest preset using the path to where it was saved.
It’s finally over and you’ll only have to do this once, as the preset now permanently installed.
We recommend that you create a set of presets right at the start so you don’t have to go through this painful process again as you only have to do this once. Once the preset is now permanently installed, you can now click on the ‘Proxy’ button in the Program Monitor to switch from one version to the other. It is this kind of defect that we mentioned in our Premiere Pro CC 2019 test. The one advantage that we can take from this is that at least everything is customisable to meet your own needs, and Premiere is then able to attach the proxy without generating them itself, something not found within all softwares.
With FCPX it’s exactly the opposite – you won’t have any choice, but you won’t have anything to do either! All you have to do is to select the media, and generate one-click right click/transcoder/media/proxy proxies.
In the Program Monitor Overview menu, as in Premiere Pro, you simply switch between original media and Proxy. All media will have to be transcoded into Pro-Res Proxy.
Here again, simply choose in the general preferences the type of Proxy to generate (in Resolve, they are called “Optimized Media”).
Then, as in Premiere, we select the media to be transcoded. Finally, in the Playback menu, select “Use Optimized Media if available”. It’s as simple as that.
Are proxies worth it?
As we have seen, proxies offer many advantages, but you must always ask yourself if it will benefit your working experience. If for example you have a simple edit with few effects, and a less powerful workstation, it may not be worthwhile transcoding in order to save time, space and the performance of your machine.
If however, you are planning to capture a sizeable amount of content with hours of rushes, then you will have to integrate the use of proxies in order to maintain fluidity within your post-production process.