All posts by interceptor121

Sony RX100 – Tips for UW Video Part 1- File Formats

When the new SONY DSC-RX100 was released early June many people were really excited as this camera featured a 1″ sensor at its heart.

Scott at Underwater Photography guide posted a raving review from which I was left salivating

Later on backscatter selected the RX100 as the best advanced camera of the year read more here however one statement left me concerned in the Pro and Cons section: No way to execute custom white balance in movie mode, must jump to photo mode

This sounded quite uneventful considering that we are almost used to one push custom white balance on most mid level compacts.

Maybe those guys looked at the Sony entirely from a still perspective and did not make much of the features or lack of thereof that this Sony has, anyway I have now bought the camera itself and I am facing a few issues and dilemmas.

Let’s take a close look at those one by one and start this issue with…


SONY has decided to adopt the new high specs AVCHD formats for this camera, I will from now on refer to 50p or 50i to indicate 50 progressive or 50 interlaced frames as this is the PAL standard. This would be 60p or 60i for NTSC US and Japanese users.

The AVCHD format had initially a 1080/50i and a 1080/24p format and a bunch of lower resolution formats, later on a 1080/50p format has been added with an increased bit-rate of 28 Mbps instead of the original 24.

Now you would normally assume that Sony would have chosen to support all those formats and instead has decided just for the 1080/50i and 1080/50p. The universal 1080/24p format that is compatible with both PAL and NTSC is not supported on the RX100. Why has Sony made this decision is a mystery.

The make things worse today interlaced display do not exist anymore and most of the non linear video editor convert interlaced footage in progressive otherwise you can’t actually edit the clips. Not only that very few software programs actually accept the new 1080/50p format, with the notable exception of Sony software that even at low level supports those formats. Adobe premier is another one, but the whole set of Apple software including iMovie and Final Cut Pro don’t know what to do with those files. Let alone the fact that no devices except powerful computers can actually play those files well.

The RX100 offers an MP4 format at 1440×1080 rectangular pixels with a 16:9 aspect ratio as a reminiscence of HDV. This format is however easily digestible by the majority of NLE on the market. So we would feel rather tempted to use it.

The question is how do we set our RX100 to capture underwater video?

The answer is actually at the highest possible setting that is 1080/50p. There are several reasons for this.

  1. The human eye is very sensitive to resolution. So the MP4 1440×1080 format goes out of the window
  2. We can still change the frame rate in editing phase to make the file a more normal 1080/25p
  3. There is not a huge difference in memory card use between the 24 Mbps of the highest interlaced mode and the 1080/50p
  4. It is easier to edit progressive frames without conversion
  5. Progressive footage does not introduce artifacts asĀ  interlaced does

On a negative note the fact that we are saving AVCHD streams means goodbye back ups on our tablets or mobiles so plenty of memory cards with us during our trips.

The next challenge will be to import the AVCHD streams into our movie editor. As mentioned earlier the 1080/50p format is not recognized by many entry level programs so some will not even see those files.

Other programs will try and convert it, this option has to be disabled and the files imported as they are without any changes to preserve quality.

So what do we do if our software refuses to process the 1080/50p files in our AVCHD streams?

A number of help tools come handy unfortunately the freeware one are mostly on windows and I have not managed to produce anything that works yet with Wine for Mac. On Mac there are two tools iVI that costs $9.99 and ClipWrap more expensive both functional and will produce an M4V or MOV that can be processed with iMovie or other tools that would have previously rejected the file you go figure!!!