40Mbps AVCHD High Reliability Patch
- Thread starter Lpowell
- Start date
Yes, I was under the impression that the design of the patch was to deliver the highest bitrate/quality possible whilst retaining full functionality under all circumstances.
At my current level of ability full functionality under all circumstances in the camera is very useful. It means I know it's me when things get frelled.
At my current level of ability full functionality under all circumstances in the camera is very useful. It means I know it's me when things get frelled.
Lucas Adamson
Well-known member
It has been tested to be the highest bitrate possible before there is a reliability breakdown, so yes it will apply to the 720p60 mode too. It works, and the images look great.
Ok, because I've been using the C settings with 24p native, and 1080p24 is mostly reliable for me, but 720p60 has been pretty bad. So this will make both reliable? Does the 24p native patch affect the reliability of the 720p60 mode as well as 1080p24?
No, the Native 24p patch shouldn't affect 720p60 mode. However, in my testing, I found the "C" settings to be less stable in 720p60 mode than in 1080p24. The maximum bitrate of the "C" settings can range as high as 55Mbps. While my Fast Action 3-Frame GOP Patch can also reach 55Mbps, I had to fine tune additional patches to stabilize it for 720p30 video.
The maximum bitrate of the High Reliability Patch is 44Mbps, which I've found to work reliably with Class 6 SD cards and higher. I fine tuned the patches to produce the highest average bitrate obtainable while maintaining this 44Mbps limit. Unfortunately, the AVCHD encoder's maximum bitrate cannot be set to intermediate values between 44 and 55Mbps. If you try to increase the bitrate beyond the High Reliability Patch settings, the max bitrate will jump to 55Mbps, and the encoder will be operating at sub-optimal "C" settings.
So can we make a stable 720p60 patch that works at a maximum bitrate of 55Mbps? Stay tuned, I will have an answer for you shortly...
So the high-reliability patch (the one at the beginning of this thread) is currently the highest-quality settings that are stable in both 1080p24 and 720p60? I'd like the image quality of the "C" 1080p24, with the ability to get optimal 60p image quality for slow motion, while having stable slow motion performance (having the camera die while your talent flies by is pretty tiresome). I know you've probably already answered this, I just want to make sure.
Ok, I hacked my GH1 to your settings and did some tests. With an extremely narrow shutter angle and wide depth of field, on very detailed, high-speed motion, I could see some loss of detail in the most detailed areas of the image, but honestly, even if you step through the video frame-by-frame, it's difficult to tell if the less of detail is due to very slight mud, or just regular motion blur. The images are still sharper than many other cameras I've used (including high-end HD cameras) and now the camera is equally reliable. I could make the camera fail any time I wanted (and many times I didn't) when I had the C settings installed, and in my tests today, I couldn't get the camera to seize up. Thank you very much!
JB_frenchy
Active member
hello,
first thank you Lpowell for your settings, i use it for a few months now and it's great with my class 6 card.
Just a question that must have been already asked, is there a way to avoid the mud that come under 1/50 shutter speed with 720 (i'm in pal land)
I upload Lpowell settings a while ago and didn't change anything after that, so maybe new versions of ptool or settings might have fix that issue (i hope so since i think slow shutter speed are useful)
thanks
first thank you Lpowell for your settings, i use it for a few months now and it's great with my class 6 card.
Just a question that must have been already asked, is there a way to avoid the mud that come under 1/50 shutter speed with 720 (i'm in pal land)
I upload Lpowell settings a while ago and didn't change anything after that, so maybe new versions of ptool or settings might have fix that issue (i hope so since i think slow shutter speed are useful)
thanks
No, this is an inherent limitation of the camera itself. If you set the shutter speed to less than 1/50 sec in 720p50 mode (or less than 1/60 sec in 720p60) you are forcing the camera to open the shutter for a longer duration than your frame rate. As a result, the camera cuts its frame rate in half (down to 720p25 or 720p30) in order to maintain the slow shutter speed you have set. This also causes the bitrate to drop to very low values.
bronxjragon
Well-known member
Is it possible to combine this patch with also your 720p high bit rate patch? IF so, how do I do it?
Trucci
Well-known member
While 1080p24fps has been working flawlessly, 720p60fps is not completely reliable for me with this patch. I even bought a Panasonic class 10 gold card hoping that I wouldn't get write errors, but I still get the same amount as my Patriot class 6 card. I did similar stress tests on both cards and I got errors at the same moments. A shutter of 1/125 with my Panny 20mm at f1.7 didn't freeze, but as soon as I stopped down to 2.5, both cards froze after about 10 seconds of wild whip pans. I thought moving from class 6 to class 10 would have at least improved performance by a little bit, but I was wrong apparently.
It's reliable enough to do 60p slow motion shots every once in awhile with care though. Since I shoot mostly 1080p24fps, it won't be a big problem for me.
It's reliable enough to do 60p slow motion shots every once in awhile with care though. Since I shoot mostly 1080p24fps, it won't be a big problem for me.
Lucas Adamson
Well-known member
HI Lpowell,
Regarding the native tickbox in the patch, and problems and lockups it has caused, could you tell me, what is your feeling about the performance and reliability difference between 24pN and 25pN please?
I am well aware that you are in NTSC land, and I in PAL land, and am wondering, because I can cope with knowing that I may get a lock up on a static, deep focus, detailed scene with 25pN, but so far I haven't used 25pN because of reading about random I frames, deformities that sound a bit too freaky to risk. Are these restricted to the specific problems inherent to the 30-24 pulldown process, or will I potentially get such issues in 25pN as well?
Many thanks
Lucas
Regarding the native tickbox in the patch, and problems and lockups it has caused, could you tell me, what is your feeling about the performance and reliability difference between 24pN and 25pN please?
I am well aware that you are in NTSC land, and I in PAL land, and am wondering, because I can cope with knowing that I may get a lock up on a static, deep focus, detailed scene with 25pN, but so far I haven't used 25pN because of reading about random I frames, deformities that sound a bit too freaky to risk. Are these restricted to the specific problems inherent to the 30-24 pulldown process, or will I potentially get such issues in 25pN as well?
Many thanks
Lucas
That's an interesting question, Lucas, I had ruled out using Native 25p since you can't enable that patch without also enabling Native 24p. However, I just did a test with Native 25p, and Stream Parser didn't reveal any errors. Would you like to try it out for a while and see if it causes any long term issues?
I just shot some rather important footage and a few of the clips (720p60 AVCHD with the high-reliability hack in this thread) looked horrible. I think at some point in the shoot my shutter speed got bumped down to 1/50. Is that the likely reason for the awful mud in these few clips, the shutter speed dropped and the bitrate tanked as a result?
Yes, that sounds like it alright.
Yes, that sounds like it alright.
It's ok, I noticed the shutter speed early enough to have mostly great footage.
Lucas Adamson
Well-known member
OK. I will do. It it likely that 25pN footage would look better than 25p(50i) footage, because of the increased bandwidth?
I have had 25pN lock up on grass at 1metre, deep focus, static tripod. It takes all of 3 seconds and works every time.
I've actually had 24p NTSC be completely stable. With this patch and 24p, I haven't had a failure since I installed this patch.