@balazer I'm not sure what your point is. Regardless of whether it's "proper", the 7.5 IRE pedestal shift needs to be corrected before you can do a good color grade. For gamma adjustments to work properly, you need black to be at 0 IRE.

Also, the QP quantizer setting is only half of the quantization story. The other half is the contents of the Scaling Tables, which in Flow Motion v1.11 are customized to produce P and B-frames of comparable quality to I-frames.

The pedestal correction you're talking about has everything to do with the fact that the software you're using doesn't comply to the rec.709 standard, and nothing to do with any fault or difference in the GH2. Other cameras produce rec.709 video just like the GH2 does, and would require the same correction using your software. Other software is compliant, and requires no special correction.

And pleeeease stop talking about IRE. IRE is a scale of voltages in analog video, completely meaningless for digital video.

Thats not really true, most pro software can and does apply a correction, but it can also be turned off. In most cases software shifts (as in expands) the footage into sRGB (or linear space, or whatever it normally works in) or even 709 extended (as opposed to legal) for preview and for internal processing. Edit : Although the preview/internal processing will be different conversions I mean, the conversion for internal processing will probably be putting the information into something much wider than the sRGB preview. When you write out your processed footage, then you select what you're delivering to and let the software do the conversion on the whole. But of course, you can with good software force this to be done, delivered, in a specific way. There are differences software to software of course, for example Nuke assumes when it reads 709 footage that its 709 extended and not 709 legal, so you read it in set to 'raw' and then a grade node is needed to set the blackpoint/whitepoint (to 64/1023 and 940/1023).

The proper solution is to expand into the full RGB colourspace, which adjusting the pedestal isn't doing I believe. Thats just a clamp I think.

@Stray - "...for example Nuke assumes when it reads 709 footage that its 709 extended and not 709 legal..."

And exactly how is the NLE supposed to know that it is in fact reading "709 footage"? After all, there is no universal metadata tag that brands a video stream as "Rec. 709". Is each NLE then expected to maintain a complete database of codec file formats (including camera manufacturer-specific variants) and automatically and unerringly select the appropriate color-space correction for each video it imports?

@Stray - The reason I recommend doing a pedestal adjustment first is because it corrects the 7.5 IRE black-point offset of Rec. 709 without affecting any other aspect of the video's color balance. Shifting the entire waveform down to set black to 0 IRE simplifies all of the mathematical interactions of the various grading adjustments, and gives you a bit more headroom on top as well. After the pedestal correction, my next step is usually to adjust the gamma and/or gain, and these adjustments will not produce the intended effects if black is set to a dark shade of gray instead of at zero.

@LPowell regarding the recording time with different settings, since there are coarser quantizers on 24L, am I better off selecting settings that give me the amount of recording time on 24H that I need? I was hoping to have the length I need on 24L, with the ability to shoot 24H when recording time wasn't a factor.

Also, what is the best way to make a pedestal adjustment using Vegas Pro 10?

Strange I loaded the last patch v1.11. Is it really 75mb in L mode cause when I open Ptool the modified bitrate is under the original one: 12500000 instead of 1600000 A I wrong? And my remaining time on my SD card seems so high in L mode: 2h34 (16gb sd card) How can I change this: One hour in L mode would be enough.

@LPowell Thanks for this discussion about pedestal. I have a question - maybe you can help. I open a raw GH2 MTS file in Premiere CS5.5, and display it on the waveform monitor. There are no blacks below 7.5 IRE, but that's because there's a little box that says 7.5 IRE and it's checked. If I uncheck the box, the blacks now reach down to zero. So my question is, which is correct? What is actually on the file?

@royadkins @bricolo - I designed 24L mode (as well as FH and L) to serve two main uses: ETC zoom mode and 4GB file-spanning on Class 10 SD cards (95MB/sec UHS-1 cards will span in all modes). To support file-spanning at over 50Mbps, I used the GH2's "Trick Mode", which drives the file transport stream at a lower bitrate than the video stream. A minor side-effect of Trick Mode is that it confuses the camera's recording-time estimate and the time-duration listed for the file on the Window's desktop. NLE's however, detect the correct duration of the video stream and have no difficulty handling it correctly.

At 100Mbps, 24H mode will record for at least 5 minutes without needing to span files. If you need a longer single take than this, I recommend using either a 95MB/sec UHS-1 SD card in 24H mode, or a Class 10 SD card in 24L mode.

@bricolo - the numbers displayed in PTool patches should not always be interpreted as actual bitrates. They are interdependent parameters that work in combination to produce the overall behavior of the encoder in various modes. In Flow Motion v1.11, 24L, FH, and L record at a max bitrate of around 50-60Mbps, but in dimly-lit situations bitrate can drop lower than this. At 50Mbps, you would get at least 40 minutes of recording time on a 16GB SD card.

@towi "The GH2 video is 16-235 (Y')"

Yes, but my question concerns the 7.5 IRE checkbox in Premiere's waveform monitor. Do I assume this is just how the picture is going to be mapped in the waveform monitor, and has no bearing on the underlying data? If this is so, why does LPowell feel it's necessary to do a correction for 7.5 pedestal?

For those of us using Premiere, is setting the black input level in Color Corrector to 16 the same as a Pedestal adjustment, or should I set the pedestal in Luma or RGB corrector? (trying to use fewer filters) and what is the equivalent in Pedestal in the Luma/RGB setting (obviously not 16)? Or, simply, what are the ideal numbers to plug in using Premiere?