50Mbps AVCHD Fast Action 3-Frame GOP Patch
- Thread starter Lpowell
- Start date
Nothing in particular, though maybe the fact that I happen to work at Dolby Labs might suggest something to you?
Maybe not pristine, but with good lighting it certainly makes MJPEG look redundant. With a 3-frame GOP, you can edit it directly in post, and easily conform it down to 24p. I optimized this patch specifically for video documentaries, solid action tracking and lengthy one-shot takes. I've yet to see it fail to span across 4GB files and it packs 1:15 mins on a 16GB SD card.
I didn't see this in the thread but can you tell us what brand of card of Class 6 and Class 10 cards have worked reliably for you in this new 50Mbps AVCHD Fast Action 3-Frame GOP Patch. I've used SanDisk Ultra 16GB Class 6 and SanDisk Ultra Extreme 8GB Class 10 on your 40Mbps reliable setting with very solid results. I do a lot of documentary work so before I switch over to this setting I'd like to test it out the cards I have but also get cards that you've worked with and have seen reliable results. Thanks again for your great work on this.
LPowell is making a very clever audio geek joke. Dolby specializes in compressed audio codecs like AC3, which aim to keep bit rate as low as possible while still preserving subjective audio quality. Simply raising bit rate when there's no perceivable benefit runs counter to the whole Dolby philosophy, which I happen to agree with.
As long as you're going down the compression road, there's no point in raising bit rate unless you can hear improvement. I would bet that nobody here could hear any difference between 448Kbps audio on the GH/F13 and the stock setting. So it's pointless to up the bit rate, as that only eats up card space. I don't think slightly lower compression on the audio gives the CPU a few more puffs of Albuterol to devote to the video side -- the audio compression is CBR, not VBR, so it's not that processor intensive.
But the real reason not to tick the 448Kbps option is because it kills in-camera playback.
As long as you're going down the compression road, there's no point in raising bit rate unless you can hear improvement. I would bet that nobody here could hear any difference between 448Kbps audio on the GH/F13 and the stock setting. So it's pointless to up the bit rate, as that only eats up card space. I don't think slightly lower compression on the audio gives the CPU a few more puffs of Albuterol to devote to the video side -- the audio compression is CBR, not VBR, so it's not that processor intensive.
But the real reason not to tick the 448Kbps option is because it kills in-camera playback.
Depends on which video mode you use. 720p30 tends to produce low bitrates since it has half as much resolution as 1080p24, and I tweaked it for the max bitrate it could put out for moderate-detail scenes that needed around 24Mbps. In 1080p24 I had the opposite problem, its bitrate was already close to the max a decent Class 6 SD card can handle. If I let it run free it would throw write-speed errors on a tripod, but when I throttled it too hard it would choke on quick pans. There was fortunately a stable sweet spot in the middle, which convinced me that 55Mbps is likely the peak reliable bitrate for 1080p in a 60i wrapper.
720p30 could probably sustain a higher peak bitrate, but that would likely leave you with an unstable 1080p mode. For extreme low-light shots I'd switch to MJPEG anyway, as its 65Mbps peak bitrate holds up much better than AVCHD. For a good example, check out the aluminum briefcase shot in my 60Mbps MJPEG Patch thread.
For non-interlaced streams, the codec doesn't care whether an even number of key frames fit into each second. Having a key frame every 0.1 sec in 30p is very convenient for editing. You can safely use a 5-frame GOP at 25p if you like, though you may get lower average bitrates from the reduced number of keyframes.
Thank you for this lPowell. I was playing around with the same idea, but never got the low GOPs to give reliable recording (I could always get a failure by recording in darkness). My thinking has been that really deep and pristine 720p is better than compressed-looking 1080p. The mjpeg is absolutely fantastic (I use modulr's settings, which make huge files but they look wonderful), but only being able to record 3 minutes or so is a real limiter. I look forward to trying these 720p 30fps settings. I wonder if in future versions we'd have the option to record 1440X1080 in this codec, as I have been doing in mjpeg...
Have you been working in PAL at all? It seem slike GOP3 would make more sense for 30fps than 25 as far as divisibility.
I will report back my findings with this new system. I'm particularly interested in how well the mjpeg and the avchd will combine with eachother on the timeline.
Have you been working in PAL at all? It seem slike GOP3 would make more sense for 30fps than 25 as far as divisibility.
I will report back my findings with this new system. I'm particularly interested in how well the mjpeg and the avchd will combine with eachother on the timeline.
I get 'card speed error' failure with these settings-- the same problem I had seen before shooting with low GoP. I'm using a Sandisk Class 10 that has been very realiable with high bitrate mjpeg. I get it within 30 seconds of shooting, using a manual lens with manual setting within movie mode with GH1. The camera is set to NTSC.
Am I correct that you are shooting in SH mode? Or some other mode?
Is there anything I am doing in my operation that is different from you that are not getting errors?
Am I correct that you are shooting in SH mode? Or some other mode?
Is there anything I am doing in my operation that is different from you that are not getting errors?
Or perhaps because my camera is the N. American GH1?
This is the same effect I saw a month ago when experimenting with low GoP. In any of the avchd 720p modes it always gave a write error...
For this firmware I used the link to the most recent on the first page of this thread... updated Sept. 17.
This is the same effect I saw a month ago when experimenting with low GoP. In any of the avchd 720p modes it always gave a write error...
For this firmware I used the link to the most recent on the first page of this thread... updated Sept. 17.
Used both patches, Fast Action and High reliability, very strange results. The MJPEG was as described, averaging 40s 50s for I settings and 20s for J settings, yet AVC on both was extremely poor quality, in the Kilo bits for some of them. Quite surprised as high reliability used to work.
Any insight?
Any insight?
As always, be certain to download the latest version of PTool at the same time you download the INI file for this patch. Obsolete versions will install the patch but it will fail to record properly.
I had a similar issue. Used these settings and shot some 1080p/24 AVCHD, got the most mud I've seen from this camera since these patches began. I'm not totally clear on whether this is targeted at just 720p30 though... the description mentions 1080p several times?
rambooc1
Well-known member
Ipowell. nice work again. Been using your reliable 40Mb patch with Sandisc Class10 in a native PAL GH1. But would like to try this new 50Mbps AVCHD patch. I read somewhere this patch only works on an original NTSC GH1 but post seems to have been removed , is this correct or can it be adapted to PAL camera as well.
Cheers Rambo
Cheers Rambo
So what's the deal with 1080p. Should this be used for it or is it strictly for 720p?
Yes, the Fast Action 3-Frame GOP Patch should now work as intended in all video modes on all GH1 and GF1 cameras, and is switchable between NTSC & PAL. It will only work properly, however, once you download the latest version of PTool.
The 1080p FHD video mode is stabilized to record reliably at a maximum bitrate of up to 55Mbps with a fast Class 6 or higher SD card. However, the AVCHD codec will only reach its peak bitrate with well-lit, highly detailed images such as the Windy Tree samples I posted. As with any lossy encoder, your mileage will vary depending on the details of your shooting conditions.
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I can't explain it. After lpowell's comments about using the newest ptools I re-downloaded the ptools3.exe file and seti.ini file on the first page of this thread. Put them in their own directory with a fresh download of the GH1_132.bin file. I created a new firmware without changing any settings. Installed it. Recording in SH mode the camera crashed with a write speed error within 7 seconds, just shooting a dark spot on the floor here at my desk. Same for PAL and NTSC. Same for a Class 10 Sandisk and a Class 6 Transcend. I assume I am doing everything exactly the same. All I can assume is it's some veriability in the hardware.
I am dissappointed. I really wanted to see the results of this low GoP high bitrate 720p.
Does anyone but me get this result?
I am dissappointed. I really wanted to see the results of this low GoP high bitrate 720p.
Does anyone but me get this result?
Thanks to your Analysis and Guide, Ipowell.
I like recording soccer game. Then 720@60 fps is prefered for fast actions and slow replay.
If I want to use 60 fps and achive the same quality of your 3-GOP fast action patch,
do I use just 6 GOP at 60 fps?
(because then I have 10 I frame in 1 second)
Do I think right?
But it seems need more size and card speed much more that of 3GOP in 30 fps.
*at 3GOP, 30fps = 10 I frame + 20 P frame
*at 6GOP, 60fps = 10 I frame + 50 P frame ( 30 P frame is needed)
If the CARD cover the speed, is there nothing make problem?
Thanks in advance.
I like recording soccer game. Then 720@60 fps is prefered for fast actions and slow replay.
If I want to use 60 fps and achive the same quality of your 3-GOP fast action patch,
do I use just 6 GOP at 60 fps?
(because then I have 10 I frame in 1 second)
Do I think right?
But it seems need more size and card speed much more that of 3GOP in 30 fps.
*at 3GOP, 30fps = 10 I frame + 20 P frame
*at 6GOP, 60fps = 10 I frame + 50 P frame ( 30 P frame is needed)
If the CARD cover the speed, is there nothing make problem?
Thanks in advance.
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