HMC150 - Terrible problems with strobe lights!

2,930,688 bytes for a 2-second video (MPC-HC does not show video duration in milliseconds or frames) yields about 11.7 Mbit/s, including audio. MPC-HC shows average video bitrate of 8 Mbit/s in the Properties pane.

Yeah, seems like a user error. AVCHD reputation is safe ;-)
 
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These results are extremely abnormal. There is likely an error somewhere, either user error, or file copy error, or a faulty card, or something. PH mode should easily be able to handle stuff like this.
 
PH mode can and does. The last wedding I did there was lots of strobe stuff I shot from the dance floor and its perfect,,, there's nothing I can fault from my footage. This is definately an error somewhere.
 
I have had the same thing happen twice. I end up filming shows and events a few times a month and there is always strobes. I think it has to do with OIS. Here is an example of mine from Friday. My settings for this one where 720/24 the first time is happened was 1080/24



http://kumpfilms.com/strobe.png

Its cropped weird because I just did a quick frame frag from qt.
 
Looking at Justyn's footage I noticed one frame like this, it is a darkish one so not noticeable when played. Personally I haven't had any problems with multiple camera flashes at weddings, but maybe strobes push it a bit too far. May not actually be noticeable to the viewer most of the time if it's just the odd frame. Alternatively, get a HPX-170.

I think the original poster had it in a low bitrate mode which would obviously make the problem much worse.

As for the comparison with HDV, I wouldn't expect this to be any better than PH mode personally. You would need to test 2 cameras side by side to find out of course.
 
Again I will say, it was PH mode - using a program suggested here on the ORIGINAL file, not the tsmuxer cut I get :

avsee.jpg


I can upload the full 400+ mb file if people want to have a look at it all in the flesh
 
Barry_Green said:
These results are extremely abnormal. There is likely an error somewhere, either user error, or file copy error, or a faulty card, or something. PH mode should easily be able to handle stuff like this.
Click to expand...

No user error on my part, since purchase its been set to PH mode, file copied fine no errors there and no corruption on the card since or after, it never glitches like this unless there is high speed strobing which is a bit crap since I use it primarily for music events.
 
It can be that the encoder's bitrate calculator could not keep up with flashes and did not raise bitrate when needed. Gotta appreciate CBR codecs, sometimes they come handy.

Still, pretty weird, as the encoder should allocate bitrate when needed, judging by amount of change in a scene.
 
Try resetting the camera and see if you get footage like that again.

I recently had a simular issue, but with low light footage. It seems to have disappered after a reset. I forget where in the menu it is, but it is the one that resets the menus and the scene files to factory.

I swear my footage was encoded wrong. It was in PH mode and the file properties (and file sizes) say the same but the images look like a much lower quality setting.
 
I export out a fully contained master, throw it on Compressor for a medium quality 264 codec and size accordingly. Done a lot of online video work so its part of the process now...
 
Cranky said:
It can be that the encoder's bitrate calculator could not keep up with flashes and did not raise bitrate when needed. Gotta appreciate CBR codecs, sometimes they come handy.

Still, pretty weird, as the encoder should allocate bitrate when needed, judging by amount of change in a scene.
Click to expand...

Yes, that's what is going on here.

For some reason the longer strobing sequences are triggering the hardware encoder to allocate less bitrate - it should be doing the exact opposite.

You can see the bitrate "dips" down to ~5Mb/s correlate exactly with the artifact sequences. Even if it stayed at relatively constant ~18-21Mb/s you should have no problems with AVCHD and fixed GOP length (12 for PAL spec, 15 for NTSC spec). It's not that the codec "can't keep up", it's more likely a problem with bitrate allocation due to the hardware implementation.

In theory, the AVCCAM version of AVCHD should stand up to "strobing" more than other AVCHD implementations, because it uses 4 reference frames instead of 2 like that of Sony's or Canon's consumer model AVCHD cameras

Maybe some more testing is needed to confirm to see if this is a replicable event, and not limited to 1 specific unit or card combo
 
The 13 Mbit/s mode is CBR, at least it is CBR on my SD1 and I don't think that Panasonic changed it for the HMC150. So... instead of using the high-quality PH mode that can drop as low as 5 Mbit/s one might try using 13 Mbit/s CBR mode.

If Panasonic cannot make its bitrate calculator bulletproof, it should allow shooting CBR in all quality modes. This would be a much appreciated firmware update. This would be akin turning stability control off when you want to go into powerslide.

Does XDCAM use CBR recording?
 
Ill find out the make of strobes used. They are super fast though, unlike most night club strobes I have seen before.

Who do I contact at Panasonic to send them my file - and will they care?
 
The person to send it to is probably Jan Crittenden Livingston, who is a member here; you can send her a PM and coordinate it.
 
Thanks Barry, Ive dropped her a PM and asked her if she could have a look at this thread and the MTS file I uploaded.
 
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