AVCHD video is darker on Mac than on Windows or camera itself

[Snowwalker]

I have Panasonic Lumix DMC-TZ7. I record video in AVCHD format, and have made a few nice outdoor videos using iMovie on MacBook Pro (from 2006 with 2.16 GHz Intel Core Duo).

Now I recorded a video under water in a bit dark condition. The video looks ok on Windows PC and on TV when playing the video directly from the camera.

But the video is very dark on Mac both in iMovie and in VLC.

This makes me wonder if there is something wrong with my MacBook Pro.

Would anyone have idea why the video is dark only on Mac and not on other divices?

 

[spinnerlys]

It has to do with your colour profile (System Preferences > Display > Color) and the Gamma setting Mac OS X 10.4 and 10.5 uses. Mac OS X 10.6 has a Gamma setting like Windows, thus it should look the same in Snow Leopard as it does on the camera or Windows.

 

[KeithPratt]

This issue here is gamma; and that's a complicated issue. Because so many things play a part in how gamma is assigned and interpreted, there are so many possible causes for any given gamma issue.

So first things first: how does the video file you're viewing in VLC or iMovie look on Windows.

Mac OS X 10.6 has a Gamma setting like Windows, thus it should look the same in Snow Leopard as it does on the camera or Windows.

People were hoping Snow Leopard would signal an end to all gamma issues, but from what I've seen it hasn't.

 

[kev6677]

Ganmma is not the problem it has to do with the higher contrast (black levels) ratio's of the LED display.Led and plasma tv's usually have higher black or contrast levels naturally.

 

[LethalWolfe]

Gamma would be my first guess as well.


Lethal

 

[Snowwalker]

It has to do with your colour profile (System Preferences > Display > Color) and the Gamma setting Mac OS X 10.4 and 10.5 uses. Mac OS X 10.6 has a Gamma setting like Windows, thus it should look the same in Snow Leopard as it does on the camera or Windows.

I should have mentioned earlier that I have Snow Leopard on my Mac.
Changing gamma from native 2.4 to e.g. 1.8 does not change the darkness of the video, but moving gamma to 1.0 makes video's darkness to lighter (better), but changing gamma that much affects coloring that much that the result is not as good as it should be.

When I looked at the video with my iPhone, the video was not that dark than on my MacBook Pro, which again makes me feel that MacBook Pro (this rather old model) is the problem.

 

[Snowwalker]

This issue here is gamma; and that's a complicated issue. Because so many things play a part in how gamma is assigned and interpreted, there are so many possible causes for any given gamma issue.

So first things first: how does the video file you're viewing in VLC or iMovie look on Windows.

Windows shows the video as it is shown on the Lumix camera itself. Same goes with viewing the video on Panasonic plasma display TV. In iPhone, the video's lightness/darkness is not as good as in Windows, but better than in MacBook Pro.

People were hoping Snow Leopard would signal an end to all gamma issues, but from what I've seen it hasn't.

I have the same bad feeling.

 

[KeithPratt]

Windows shows the video as it is shown on the Lumix camera itself.

That's the video iMovie has converted (upon import), right, not the original files?

 

[Snowwalker]

That's the video iMovie has converted (upon import), right, not the original files?

I uploaded the original video via Windows to Youtube, and there the video is much darker when watched on MacBook Pro or on iPad. On Windows the video in youtube looks ok - there is some loss in colours, but much less than when watching the video on Mac.

And if I play with Mac's gamma values, then other videos will look too bright, which is not good either.

Thus what's wrong with Mac and dark scenes in videos?

 

[KeithPratt]

I uploaded the original video via Windows to Youtube, and there the video is much darker when watched on MacBook Pro or on iPad. On Windows the video in youtube looks ok - there is some loss in colours, but much less than when watching the video on Mac.

I didn't actually mean the H.264 video iMovie outputs to upload to YouTube or the YouTube video itself, but rather the Apple Intermediate Codec video iMovie converts your AVCHD footage into on import. Reason I asked is because gamma is not just part of display calibration, but also a value tagged within videos and photos. I was trying to find out at what point the issue first occurs.

This article gives some background on gamma — which you may or may not care to read — and towards the bottom there is an Automator workflow that may work some magic.

 

[Snowwalker]

I didn't actually mean the H.264 video iMovie outputs to upload to YouTube or the YouTube video itself, but rather the Apple Intermediate Codec video iMovie converts your AVCHD footage into on import. Reason I asked is because gamma is not just part of display calibration, but also a value tagged within videos and photos. I was trying to find out at what point the issue first occurs.

This article gives some background on gamma — which you may or may not care to read — and towards the bottom there is an Automator workflow that may work some magic.

Thanks for additional information related to this subject. I tried Automator and its three different profiles (SD, PAL and HS) for video, but none of them made the image better.

For the time being I will just record video in better lightning conditions.