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SLT-A57 in Movie Mode - Help please!

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springy69
Explorer

SLT-A57 in Movie Mode - Help please!

I have an application where I want to use my SLT-A57 camera in Movie Mode.

The application is a golf swing analysis package from V1.

The application recommends a frame per second rate of 30f/s.  The specification as I read and understand it, quotes 25f/s for MP4.  Nothing is mentioned for AVCHD.

I am currently discussing with V1 the possibilities of using the AVCHD format.  The software is a few years old but still works with my computer operating system (W7).  It would seem that AVCHD is not listed with the formats that can be used although on initial discussions it may be possible to download/install the necessary codecs, (whatever they are!), for AVCHD to work.

So can anyone explain what the frame rate is in AVCHD?

3 REPLIES 3
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alphaholic
Contributor

Hi springy69

You can choose the fps in AVCHD or MP4. These fps are possible:

Movie recording mode - AVCHD 1920 x 1080 (50p recording, 28 Mbps, 50i 24 Mbps, 50i 17 Mbps, 25p 24 Mbps, 25p 17 Mbps, 25p 12 Mbps) (50p = 50fps, 25p = 25fps)

Movie recording mode - MP4 1440 x 1080(Approx.25fps, 12Mbps(Average bit-rate)

Hope this helps 🙂

Cheers from switzerland!

alphaholic

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springy69
Explorer

Hi,

Thanks for the response.

I have been looking into the matter further and I have had a reply from V1, (the people responsible for the golf swing analysis software).

The technician (Dean) says that he can open the short sample file that I have sent them.  This was an AVCHD file.  I don't yet understand how he has managed to open the file as I couldn't see it.  I can only assume he has the latest codecs which have enabled him to do this.

Apart from that, his comments are as follows:

I can open and play your sample file.

It is huge in picture size and doesn't play very smoothly in slow motion. As you know, this is a MTS file which is mpeg2. This type of file is fine for playing back on your TV in standard motion and the video looks great.   But, for your motion study, you need to shoot 640x480 with as many frames per second as possible.

Looking at the manual, I'm not sure I could readily figure out how to make a DSLR work well as a video camera for the use of motion study. I think you should talk with a Sony technician about what settings you should use to get 640x480, high frame rate. From what I can see of the specs, I can't tell that this camera can do that.  

The sensor is huge and will give you stunning snapshots. That is what this camera was designed for. But for motion study you need high  frame rate and a shutter speed of about 1/2000. I can't tell if the shutter is global or rolling. I would have to experiment with it. If you can manually set the shutter speed to 1/2000 and work outside in the bright sunshine, that will help.  In order to have that shutter speed you need to have great light.

This is as much info as I can give you. I hope that it helps.

Dean 

So what do you make of that then?

I have established that is a "rolling shutter".  I haven't got a clue how I acheive the settings he is describing, I only know that the shop where I bought it from assured me that it would do the job.

profile.country.de_DE.title
cmosse
Contributor

Hi

Th Sony SLT A57 offers the features you need for your purpose


go to the movie menu:

set the File Format to VGA


Turn the mode dial to Movie mode.

Turn the camera to manual focus

Press the Fn button and select the movie mode icon (top left)

Switch to S-mode


Set the shutter speed to 1/2000s as suggested


Use AUTO ISO.


Tell us if you succedd with the golf shot software


Best Regards

Michael