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MEDIA FORMAT and MEDIA EMPTY operations with the HXR-NX5

April 12, 2010

Hi All

You need to reformat the NX5’s media in order to reuse it — this, in effect, erases previously recorded data (footage) so you can record over it.

There are two ways of reformatting (‘erasing’) media in the NX5:

1) MEDIA FORMAT, which, as I understand it, does not actually erase most of the data on the media, just the little bits of data that mark where actual image/audio data is situated on the media. This means that the camera or other device (such as a computer) cannot ‘see’ where the image/audio data is, so it is as if it does not exist, and can be recorded over with new data. (This is why one can actually often recover information on discs or memory cards that have been ‘erased’, because all that has been erased is the ‘in’ and ‘out’ points of files, not the actual files themselves.)

2) MEDIA EMPTY. This operation overwrites all the existing data on the media with a stream of randomly-generated ‘nonsense’ data, in other words it obliterates not only the information indicating where image/audio data is stored, but all the image/audio data itself, too. Once one has performed a MEDIA EMPTY operation on media, no footage can be recovered.

A MEDIA FORMAT operation is far quicker than a MEDIA EMPTY operation, because the former requires much less work — typically, on the NX5, a minute or two versus half an hour to an hour for a big SD card.

So, if a MEDIA FORMAT takes much less time than a MEDIA EMPTY operation, and achieves effectively the same results in terms of ‘erasing’ my media for re-use, why ever perform a MEDIA EMPTY operation? A couple of reasons come to mind:

i) You might want to irrecoverably obliterate all trace of certain footage.

ii) You might want to obliterate all corrupt data (perhaps the result of unplanned camera shutdowns during shooting, for example when the power gets cut in the middle of shooting a clip) that can potentially cause read/write problems or even camera malfunction. (One of the theories to explain the dreaded ‘buffer overflow’ problem with the NX5 is that it is caused by corruptions in the recording media). Therefore performing regular MEDIA EMPTY operations on one’s media can be seen as part of good media maintenance — especially after you have experienced unplanned shutdowns.

How to perform a MEDIA EMPTY operation (see page 65 & 66 of the camera manual):

1) Attach the camera to a mains power supply and turn it on.
2) Press one of the MODE buttons.
3) Choose MANAGE MEDIA > MEDIA FORMAT via the touchscreen or buttons/thumbwheel.
4) Choose the media to be formatted (card A or B or the FMU, if attached).
5) Press and hold the STOP button on the top control panel for at least 3 seconds – this will cause the MEDIA EMPTY screen to appear.
6) Follow the prompts YES > YES > OK.
7) The MEDIA EMPTY operation will then commence. This can take a long time (over an hour) with a full FMU128.

NOTE: You have to attach the camera to a mains power supply when performing a MEDIA EMPTY operation – the camera will simply not give you the option to do it when running on battery power. This is presumably because MEDIA EMPTY operations can take a long time, and if the power is cut during this time, the camera has to start the operation over at the beginning again, it can’t just pick up where it left off. Sony presumably thinks that users will often not have enough battery power to complete the operation, but for people like me who work a lot in Africa a fully charged battery can be a much more reliable power supply than the mains in many countries with poor infrastructure. I think this should be addressed in a firmware update — we don’t need to be prevented from doing MEDIA EMPTY operations on battery power, we just need a warning to use a fully charged battery.

I’ve noticed that MEDIA EMPTY operations on the Sony 16GB MemoryStick PRO HG Duo that I use go a lot faster than on similar-sized SDHC cards, even very fast SDHC cards. I’m not sure why this is, as they go so quickly that it seems impossible that all the data on the card is actually being overwritten, but I have been unable to recover any data from the MemoryStick after running a MEDIA EMPTY operation with SanDISK Recovery Pro so it seems that large chunks at least have been eliminated. (SanDISK Recovery Pro is a very useful piece of free software that comes with SanDISK SDHC cards and which will usually recover all files from a card that has been ‘erased’ with a MEDIA FORMAT operation.)

Cheers

Adam

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