1080p 60fps on GH2 with hack?

[mpgxsvcd]

As svecher pointed out, shooting in your target distribution format is only an advantage when you intend to limit post-processing to simple edits and transitions. If you have any need to do color grading, resampling, or effects processing, you really need to start with source material captured with higher bitrate and broader latitude than what you plan to deliver. Every time you render or transcode the original source video, it suffers an irreversible loss in resolution. While it can be artificially sharpened up in the final render, it's far better to start with material that can withstand some degradation and remain intact.

For the purposes of interim file distribution during post, 24Mbps is hardly a fixed cap on AVCHD format. Blu-ray discs and players support video bitrates up 40Mbps and as we've discovered, Class 6 SD cards are reliable at 50Mbps. Adobe CS5, Final Cut, and Sony Vegas routinely handle such bitrates on modern workstations as well.

In my experience, the long-GOP, half-second intervals between key frames is the main stumbling block that makes consumer AVCHD distribution formats unsuitable for post-processing. That's why I was motivated to develop my GH13 Fast Action 3-Frame GOP Patch, which produces 50Mbps 720p30 files that are directly suitable for editing in post, without need for transcoding. With stock GH1 footage, I prefer to transcode it to 40Mbps H.264 High Profile format with a key frame every 1/5th to 1/4th of a second. Ideally, I would like to use H.264 High 4:2:2 Profile, not to "improve" on the original, but merely to minimize degradation of its captured 8-bit 4:2:0 quality. This however requires the Main Concept Broadcast codec plug-in for Adobe CS5, with a licensing cost I haven't yet been able to justify.

Your 3 GOP 720p @ 30 FPS is awesome. However, I tried it with some test scenes today and it just wouldn't work no matter what I did to it. I was trying it with a GF1 so maybe it works with a GH1. However, I couldn't get anything less than a 5 GOP setting to work on this scene with very colorful leaves blowing in the wind.

Has your 3 GOP setting been completely stable for GF1 cameras? What AVC-HD settings do you recommend for high bit rate but completely stable GF1 recordings? I have the 30 mb/sec Sandisk cards so that shouldn't be a factor.

 

[Lpowell]

Has your 3 GOP setting been completely stable for GF1 cameras? What AVC-HD settings do you recommend for high bit rate but completely stable GF1 recordings? I have the 30 mb/sec Sandisk cards so that shouldn't be a factor.

Yes, I just shot a few test videos on the GF1 with my Fast Action 3-Frame GOP Patch, using a Transend Class 6 SD card. The 3-frame GOP patterns look perfect in Stream Parser with a 20Mbps bitrate on both dim and brightly lit subjects under incandescent light. The only problems I've seen with this patch are in very dark conditions, where the bitrate can drop below 5Mbps long enough to abort the recording. This appears to be a pitfall with all reduced GOP-length patches, but only when there's barely any light at all. Tomorrow when there's sunlight again, I'll test it with dense foliage as well.