File sizes data rate and time left display

L

Lauri Showler

Member
I don't know if anybody else has noticed this (I did a quick search) but, although the data rate for the avchd for 1080 and 720p is 17mbs and a formatted 16gb card will tell you 2 hours remaining on the card....

I have jsut finished some 'time lapse' testing and locked the camera off and closed lcd, left it running for 45 - 50 mins, the resulting file size was about 1.4 gb, I also shot a bit more making an hour in total and about 2gb of data.

So after shooting this the display bottom right showed 1 hour and 50 mins remaining.

The scene I shot was fairly static and obviously no cmera movement. At first I thought htis might be battery remaining, but that makes no snse either. This implies to me that the data rate is dynamic or variable, depending on the amount of work the codec has to do.

I theory I think this is capable of getting 7 - 8 hours of static(ish) hd video onto a 16gb card.

Only one way to find out........ will test this tonight on mains power.
 
Yes, that's interesting as it supposed to be 29mins for pal clips too? irrespective of file size, is your gh1 pal.?
 
I think the codec uses VBR, if the scene is fairly static the bitrate will be low and therefore you can fit much more on a card. I am jealous as I am in PAL land and am restricted to 29.54 length clips

Andy
 
I'd love to get more GH-1 owner feedback on AVCHD real-world capacities on their SDHC cards.

I'm taking my GH-1 on a tour documenting a band and I'm trying to see how many/how big SDHC cards I need for the coverage I'm planning.

thanks for any feedback.
 
I just shot this stuff at AVCHD on a 8GB SDHC Class 4 card.

http://www.vimeo.com/5778826

I had no problems with it at all. I was worried the class 4 wouldn't be fast enough. As long as you don't do a ton of major movement you should be fine.

I haven't figured out the "time left" display, it doesn't seem to be terribly accurate, but I haven't had to fill up a card yet so I don't know how much I can fit on a full one.
 
Final Design Studios said:
I just shot this stuff at AVCHD on a 8GB SDHC Class 4 card.

http://www.vimeo.com/5778826

I had no problems with it at all. I was worried the class 4 wouldn't be fast enough. As long as you don't do a ton of major movement you should be fine.

I haven't figured out the "time left" display, it doesn't seem to be terribly accurate, but I haven't had to fill up a card yet so I don't know how much I can fit on a full one.
Click to expand...

your link is not viewable. scratch that...viewable now.
 
Well, I tried it on the battery, to test both, with the lcd closed and recording 720p it got to about 3 hours, the last time I looked. But.... I left it, and obviously the battery ran out, this ment the data could not be written to the card (not that I wanted 3 hours of me sitting about) so I lost it because battery ran out and the file could not be finalised, I guess. So, re-formatted and now running it of mains power, so will see how long it runs for.

Its japanese import, so no crazy 30 (or is it 15 now?) minute limit.

Ok, it ran for 2hours 40mins and I forgot I left about 20 mins of footage ont he card, so, in theroy, not using lcd screen and with a 16gb card, you might just get 3 hours out of the camera.

Out of interest, it splits the recording into 4gb chunks (i imagine the max for the card format). I need to check if there is a jump in sound next, (this happens on a sony HD camcorder I use, picture is fine but sound is lost over the join, not for long, but noticable).

I think now it's strangely the 'shutter speed' the time lapse was shot at I think at 3.2 (not the absolute slowest 2) on manual focus, this was shot at 60. So slow shutter speed = less data, fast shutter speed = more data?
 
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You have to think of how the codec is likely to interpret the scene. I guess at slower shutter speeds (at factors of the current frame rate) the is less change in between the frames, so more compression can be done.
 
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