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AKED
06-17-2010, 04:23 AM
Has there been a solution for the pulsing Iframes in the AVCHS 25p hack?

I searched for it but I did not find anything.
Was somebody more successful and found a solutoin?

nubins
06-17-2010, 06:05 AM
A lower GOP setting should smooth out the pulsing.

If you use the C settings and change your GOP to something like 8 (6 and lower seem to freeze the camera) your quality should improve dramatically. I have not noticed any pulsing over the last week using these settings.

cbrandin
06-17-2010, 06:09 AM
I did manage to get some pulsing with the GOP set to 8, though not as much. I looked at the frames where pulsing occurred and they looked fine. I have no idea what the pulsing is affecting because I can't see anything visually wrong with those frames. Strange...

Chris

AKED
06-17-2010, 07:47 AM
OK, I changed the GOP to 8 and then the pumping is gone.
But then what Svart writes, if I put it on a tripod, after a few seconds in FHD, the class 10 card 16 GB from Sandisc stops recoreding due too high write speed and it does not have the clip that has been recorded to up that time on the SD cars.
I have to draw the battery and the3e clip is lost.
To avoid this it was said, to change GOP to 12. I try this now.


OK, I tried GOP 12 and it did not work. Also freezes the camera.

nubins
06-17-2010, 10:36 AM
OK, I changed the GOP to 8 and then the pumping is gone.
But then what Svart writes, if I put it on a tripod, after a few seconds in FHD, the class 10 card 16 GB from Sandisc stops recoreding due too high write speed and it does not have the clip that has been recorded to up that time on the SD cars.
I have to draw the battery and the3e clip is lost.
To avoid this it was said, to change GOP to 12. I try this now.


OK, I tried GOP 12 and it did not work. Also freezes the camera.

I have been using the C settings, GOP of 8 and a Transcend 32GB class 6 card for about a week and shot at least 3 hours with it in all sorts of conditions with no problems.

Svart
06-17-2010, 10:43 AM
OK, I changed the GOP to 8 and then the pumping is gone.
But then what Svart writes, if I put it on a tripod, after a few seconds in FHD, the class 10 card 16 GB from Sandisc stops recoreding due too high write speed and it does not have the clip that has been recorded to up that time on the SD cars.
I have to draw the battery and the3e clip is lost.
To avoid this it was said, to change GOP to 12. I try this now.


OK, I tried GOP 12 and it did not work. Also freezes the camera.

I'm guessing this is somewhat related to the problem I've seen.

Vitaliy suggested moving the GOP up, not down. This means, in the native 24p problem, that you would move from 12 up to 15. Again, that was fairly specific to my issue and I do not know if it would fix the pumping issue, but try going upwards.

AKED
06-17-2010, 10:51 AM
OK, I have solved my problem.

I have NOT ticked native 24p, because it does not work for me.
I have NOT tiicked and GOP change.

I only used for AVCHD the suggested b setting of the ptool.

Noe no pulsing any more and no stop of the recording while on a tripod.

But no 25p at 1080.

But that's ok for me.

Thanks for the help and the thoughts

cbrandin
06-17-2010, 11:08 AM
nibins - do you have 24p native checked?

chris

cbrandin
06-17-2010, 11:09 AM
Has anybody determined whether the pulsing is really a problem? I don't see anything funny visually. I've checked it frame by frame - and nothing looks funny.

chris

sammysammy
06-17-2010, 11:12 AM
Aked, are you saying so far we can only get rid of the pulsing by not having native 24p checked?

Svart
06-17-2010, 11:14 AM
I think he's suggested it, however, I would try changing the GOP up slightly to see if things change. As always, we need more testing before we determine anything as a fix.

AKED
06-17-2010, 01:37 PM
Well, I got rid of the pulsing by changing the GOP to 8 or to 12.
but then the camera was on a tripod and there was no movement, it stopped recording due to speed limitations of the card.
That is all I can say.
i am not technician enough to have other solutions, that may be there when once can use the ptool better than I can.

mrduck
06-17-2010, 01:43 PM
I took 30 minutes of continuos recording on a tripod with settings "C" in 720p mode, just avchd bitrate changed. I GOT pulses. I was able to see them while pixel-peeping the recording on a 50" screen from 10 cm... From a standard viewing distance of 2mt I could not see any pulsing. The same on a computer monitor, no pulsing visible

cbrandin
06-17-2010, 03:49 PM
Can you describe what the pulsing looked like on your screen? I don't know what to look for.

Chris

mrduck
06-17-2010, 04:12 PM
Can you describe what the pulsing looked like on your screen? I don't know what to look for.

I try

It was a recording of a theater show. Light is low, gh-1 set on 800 iso, manual 50mm f/1.8 lens set at 1.8, SH (720 50p)**, camera on a tripod

At the back of the actor there were some curtains, and curtains have "waves" (don't know the word,... look at your house curtains, they have "waves") and these waves generate shadows.

So in the backgrounds there were some small shadows... going very near to a 50" fullhd screen I could see these shadows changing from mud/not shown to very detailed in 26/27 frame and then back to mud/not shown in 1 frame..... bigger shadows doesn't show such behaviour... also actors doesn't show this behaviour.

So, to me, it seems a problem with static little defined objects...

If you tell me which software to use, I may try to cut a couple of seconds from the avchd stream but the software should not recompress the stream...

**: I just upped avchd bitrate

I try to attach 2 crops that are about 1 second from each other... I had to use jpg,...

the more detailed is on the right, you can see more shadows... or waves... :-)

Ozpeter
06-17-2010, 06:59 PM
I've just seen pulsing for the first time- almost like very fast focus hunting, on FHD. Probably much easier to see on running video of a static detail shot than on frozen frames.

PAL camera,

native 24/25p
Video bitrate adjustment 38000000
Overall bitrate adjustment 40000000
Limiting bitrate adjustment 42000000

I'll try turning off native 24/25p.

cbrandin
06-17-2010, 07:35 PM
Thanks guys. The only time I got pulses was during quick pans - where everything is blurry anyway. Now I understand why I couldn't see it.

Chris

rawdod
06-17-2010, 07:46 PM
Here is my 2 cents:

The GH1 has some AVCHD codec issues, pretty nasty at times, a painful thing because often the picture is very good. The GH13 has the same exact codec issues, regardless of gop or bitrate setting, but they are much more mitigated due to brute force bitrate increase. So this is the same stuff as seen on stock firmware. The codec in the GH1 seems to hate large areas that are in focus but are simple, such as solid wall colors, and like to put 'pulsing' or noticeable artifactyness there. I wish we could replace the codec with the code from x264, which is better than many commercial coders, how impossibly hard this might be I don't even fathom, even with hardware encoding many routines could still be tweakable, but finding them and changing them in the way we are changing values now in the firmware... I can only hope.. anyway I digress, I just don't think some of the pulsing, and artifacting on blank surfaces is fixable with the existing bitrate and gop tunables.

AKED
06-17-2010, 11:12 PM
I Only had the pulsing in FHD with 25p turned on. Never in 72050p.

Ozpeter
06-17-2010, 11:37 PM
I've now seen the same pulsing I saw before in PTool firmware, but this time in original Panasonic firmware. But the pulsing I'm seeing may be different from what others are seeing.

GMC
06-18-2010, 01:41 AM
I try

It was a recording of a theater show. Light is low, gh-1 set on 800 iso, manual 50mm f/1.8 lens set at 1.8, SH (720 50p)**, camera on a tripod

At the back of the actor there were some curtains, and curtains have "waves" (don't know the word,... look at your house curtains, they have "waves") and these waves generate shadows.

So in the backgrounds there were some small shadows... going very near to a 50" fullhd screen I could see these shadows changing from mud/not shown to very detailed in 26/27 frame and then back to mud/not shown in 1 frame..... bigger shadows doesn't show such behaviour... also actors doesn't show this behaviour.

So, to me, it seems a problem with static little defined objects...

If you tell me which software to use, I may try to cut a couple of seconds from the avchd stream but the software should not recompress the stream...

**: I just upped avchd bitrate

I try to attach 2 crops that are about 1 second from each other... I had to use jpg,...

the more detailed is on the right, you can see more shadows... or waves... :-)

In the link to the post below you can see the pulsing (NTSC version), resulting from more bandwidth on p-frames but the same old bandwith on the I frames. Therefore, the p-frames push the IQ up until the next (low bandwidth) I-frame comes up which suddenly degrades the image again (posted a screenshot of this earlier in this post):

http://www.dvxuser.com/V6/showthread...54#post2019854 (http://www.dvxuser.com/V6/showthread.php?p=2019854#post2019854)

jobless
06-18-2010, 01:51 AM
Does somebody with NTSC model has problem with pulsing?

GMC
06-18-2010, 04:25 AM
Does somebody with NTSC model has problem with pulsing?

See my above post, I have the NTSC version.

jobless
06-18-2010, 07:40 AM
See my above post, I have the NTSC version.

Just one more question...
Was it Video Bitrate Adjustment or Video bitrate Adjustment simplified?

mrduck
06-18-2010, 02:53 PM
In the link to the post below you can see the pulsing (NTSC version), resulting from more bandwidth on p-frames but the same old bandwith on the I frames. Therefore, the p-frames push the IQ up until the next (low bandwidth) I-frame comes up which suddenly degrades the image again (posted a screenshot of this earlier in this post):

http://www.dvxuser.com/V6/showthread...54#post2019854 (http://www.dvxuser.com/V6/showthread.php?p=2019854#post2019854)

Yes, it is the same pulsing I get. My gh.1 is a pal one. I got pulsing also this evening in another theater show, also on background curtains details but this time there was light. No visible pulsing/artifacts on foreground elements, both static or moving...

Kellar42
06-18-2010, 05:39 PM
Were you guys changing the GOP settings anyways, or is just an attempt to fix the pulsing? I've been using C settings with native 24p and have never touched the GOP length, haven't seen any pulsing.

GMC
06-18-2010, 11:03 PM
Just one more question...
Was it Video Bitrate Adjustment or Video bitrate Adjustment simplified?

It was bitrate adjustment (not simplified)

GMC
06-18-2010, 11:04 PM
Were you guys changing the GOP settings anyways, or is just an attempt to fix the pulsing? I've been using C settings with native 24p and have never touched the GOP length, haven't seen any pulsing.

I didn't change the GOP. But Vitaliy says, for native 24p the ptool changes GOP automatically to 12.

jobless
06-19-2010, 01:37 AM
It was bitrate adjustment (not simplified).

Have you tried simplified? I notice at LOW LEVEL a difference on static scenes in P frames ( they look much better)...

GMC
06-19-2010, 05:37 AM
Have you tried simplified? I notice at LOW LEVEL a difference on static scenes in P frames ( they look much better)...

Oh, thats interesting. I will try it.

Rocketfuel
06-19-2010, 07:54 AM
Does somebody with NTSC model has problem with pulsing?
Thanks for your research jobless. I have noticed pulsing at 24pN, in B and C settings, but only when I hold a shot steady, and at dense foliage. This also sometimes causes my Panasonic Class 10 card to freeze. When I uncheck the Native 24p, I don't get pulsing or card freezing. But the only drawback is that when I remove pulldown in post to get back to progressive frames, the smoothness on edges of objects is not as good as 24pN.

For those that have not seen the phenomenon, pulsing happens once about every second, and if you play frame by frame, you will notice that once every second, a frame is poorly compressed. That poorly compressed frame gives the illusion of pulsing.

zcream
06-19-2010, 08:02 AM
For the pulsing have you tried a setting without a big difference between mid and high bitrates. Maybe a 50, 55, 60 instead of a 50, 52,60. 60, 65, 70 instead of a 60,65,70 etc

cbrandin
06-19-2010, 09:48 AM
I've been testing several modes to see if pulsing can ever be eliminated if Native 24p is checked.

The attached image shows what happens if all you check is Native 24p (nothing else was changed, so otherwise this is factory deault FHD/AVCHD).


I tried different GOP settings, etc... It looks like the pulse is caused by native 24p/25p and that setting alone.

Chris

alignment1
06-21-2010, 08:43 PM
PULSE...PULSE...PULSE....that's all I see now is PULSE...PULSE...PULSE.

What's the deal!?!? How come I never noticed this before?? I even went back to old footy from months ago- (way PRE-GH13) days- factory firmware 720p60 tripod shot of mountain ...PULSE...PULSE...PULSE...

Has anyone anywhere else in this myriad of hack pages found any resolution to this??

STOP THE PULSE!!!! and please make me stop staring at monitors from 2.75 inches!! PLEASE---

Kholi
06-21-2010, 08:47 PM
I dunno what you guys are doing but I literally scrubbed frame by frame of some static footage and CANNOT locate the pulsing in my footage.

alignment1
06-21-2010, 09:07 PM
I dunno what you guys are doing but I literally scrubbed frame by frame of some static footage and CANNOT locate the pulsing in my footage.

I can't really even see it 'scrubbing' you just have to let it run and see...it's almost like in dark areas- I see what looks like a fine grain- but on closer look... it has a beat to it...a pulse- about every second..

I see it both in QT and in FCP timeline

alignment1
06-21-2010, 09:11 PM
...I'm thinking about making every single one of my pieces....(a house remix)

boom-tis, boom-tis, boom-tis, boom-tis.....

cbrandin
06-21-2010, 09:22 PM
I had a hell of a time seeing it too. The guys gave me some screenshots that showed it and then I could see it. It's pretty subtle, though. With testing, however, I've never been able to make it foillow any sort of beat - for me it's been irregular.

Chris

Mike@AF
06-21-2010, 09:31 PM
I don't understand what the pulsing is. Could someone post an example, maybe frame without and a frame with it?

EDIT: Nevermind. I just saw it in Oedipax's anamorphic video. Interesting. First time I've ever seen it in anything. Some kind of issue with no being able to handle too much detail for a long time.

EDIT 2: This is probably related to 24pN not working properly and causing camera freezes. These could be those frames that are suddenly recorded with too much information causing the camera to stop recording, error out, and/or freeze. Has this "pulsing" occurred with any non 24pN footage?

John Caballero
06-21-2010, 09:36 PM
I don't know but some people see lots and lots of mud, others lots and lots of pulsing, others lots and lots of UFOs, a friend of mine lots and lots of ghosts... While others are shooting great stuff with the GH1 AND NOW THE GH13. LOL!

cbrandin
06-21-2010, 09:50 PM
The pulsing shows up as a huge P frame that appears immediately before an I frame, and evidentially it contains mostly garbage data. It's generally much bigger than any of the P frames. I frames are frames that are "fresh" in that they don't depend on any prior frames; they are complete images. P frames are "delta" frames in that they only contain the difference between the current frame and the previous one, which is more efficient than having every frame be a complete image. Generally I frames are bigger than P frames (twice as big, or better). Having a huge P frame makes no sense because an I frame is the entire image, which is about as uncompressed as you can get. P frames that are bigger than I frames effectively defeat the purpose of having P frames in the first place. Typically, the ratio of I frames to P frames is the number of frames in 1/2 second of video, so for 60 FPS video that would be one I frame for every 29 P frames.

The main problem with the "pulses" is that they are apparently filled with garbage, not image data, which is not a good thing.

Chris

svecher
06-21-2010, 10:21 PM
I don't understand what the pulsing is. Could someone post an example, maybe frame without and a frame with it?

EDIT 2: This is probably related to 24pN not working properly and causing camera freezes. These could be those frames that are suddenly recorded with too much information causing the camera to stop recording, error out, and/or freeze. Has this "pulsing" occurred with any non 24pN footage?
I have yet to see them in 60i footage.

cbrandin
06-21-2010, 10:32 PM
Right, I've only ever seen them with the Native 24p/25p option checked. Sorry if my reference to 60 FPS caused confusion.

Chris

Martti Ekstrand
06-22-2010, 01:34 AM
I have 'the pulse' in footage shoot last year with a totally unmodified PAL model. It can appear on fine-grained detail areas with low contrast and low light, around 10 - 25% black. Like darker parts of foliage. Never been a biggie for me as I typically have something in the foreground keeping the audience's attention and seldom stays on a take for more than 4 seconds. Once I drew a garbage matte around such a area and applied a average frame filter to smooth away the pulse.

wturber
06-22-2010, 02:45 AM
The pulsing shows up as a huge P frame that appears immediately before an I frame, and evidentially it contains mostly garbage data. It's generally much bigger than any of the P frames. I frames are frames that are "fresh" in that they don't depend on any prior frames; they are complete images. P frames are "delta" frames in that they only contain the difference between the current frame and the previous one, which is more efficient than having every frame be a complete image. Generally I frames are bigger than P frames (twice as big, or better). Having a huge P frame makes no sense because an I frame is the entire image, which is about as uncompressed as you can get. P frames that are bigger than I frames effectively defeat the purpose of having P frames in the first place. Typically, the ratio of I frames to P frames is the number of frames in 1/2 second of video, so for 60 FPS video that would be one I frame for every 29 P frames.

The main problem with the "pulses" is that they are apparently filled with garbage, not image data, which is not a good thing.

Chris

I don't think the extra large P or I frames (sometimes they are I frames) are the cause of the pulsing. From what I've observed, the pulse is actually a lower quality bump. It is easier to see it in things like low contrast textured walls. What you will see is that at the pulse, some of the wall detail goes away and it then slowly builds over the following frames. I think what is happening actually pretty much the opposite of what you described.

I think what happens is that the I frame is displayed and then each subsequent P frame adds more data. More P frames on a static shot results in a building of detail. Finally, at the end of the GOP, you have the most detailed image yet. Then whammo - you get a new I frame with less detail - and that's the visible pulse.

Higher bitrates and smaller GOPs seem to help, though they don't eliminate the problem. Pulsing seems to be significantly reduced when using a 10 frame GOP for 720p and a 12 frame GOP for 1080p24. Part of the reason for this may be that there is less image building with the smaller GOP. And while I haven't verified this, it does seem that with smaller GOP settings, the I frames tend to be a lot larger than the P frames.

GMC
06-22-2010, 04:06 AM
I don't think the extra large P or I frames (sometimes they are I frames) are the cause of the pulsing. From what I've observed, the pulse is actually a lower quality bump. It is easier to see it in things like low contrast textured walls. What you will see is that at the pulse, some of the wall detail goes away and it then slowly builds over the following frames. I think what is happening actually pretty much the opposite of what you described.

I think what happens is that the I frame is displayed and then each subsequent P frame adds more data. More P frames on a static shot results in a building of detail. Finally, at the end of the GOP, you have the most detailed image yet. Then whammo - you get a new I frame with less detail - and that's the visible pulse.

Higher bitrates and smaller GOPs seem to help, though they don't eliminate the problem. Pulsing seems to be significantly reduced when using a 10 frame GOP for 720p and a 12 frame GOP for 1080p24. Part of the reason for this may be that there is less image building with the smaller GOP. And while I haven't verified this, it does seem that with smaller GOP settings, the I frames tend to be a lot larger than the P frames.

I agree totally to your first explanation, the I frames don't seem to have enough bandwidth. I am not shure about the smaller GOP part. But I hope that the research on Vitaliys end continues.

alignment1
06-22-2010, 04:09 AM
EDIT 2: This is probably related to 24pN not working properly and causing camera freezes. These could be those frames that are suddenly recorded with too much information causing the camera to stop recording, error out, and/or freeze. Has this "pulsing" occurred with any non 24pN footage?

I'm using 'jobless' old 'D' settings (now 'C'), w/ 24p checked...I've never had the camera freeze, stop recording error out, etc.. I've been shooting quite a bit this way with no issue, (fingers crossed):Drogar-Kriz(DBG):.

As I said in earlier post, I went back to old footage and found it there as well..?!?




What's the deal!?!? How come I never noticed this before?? I even went back to old footy from months ago- (way PRE-GH13) days- factory firmware 720p60 tripod shot of mountain ...PULSE...PULSE...PULSE...

Nitsuj
06-22-2010, 06:48 AM
When the GH1 first came out I did a lot of testing because I noticed it. I found it shows up much easier when there is a lot of detail, motionless, and a contrast in the image.

Here is the old test I did.

http://exposureroom.com/60839febfaa540f8964174db9c269468/
You can really see it good on HD/full screen

I will repeat it today with the gh13 at the same location to see how much difference there is and post it up later. It has been a long known issue. That is why in high detail shots you want to go soft or avoid due to the long GOP on these HDSLRs.

[edit] Old solutions were
1. Avoid high detail like forests when possible.
2. If have detail avoid high contrast (evenly light if possible)
3. Soften up the image
4. Provide movement in the shot
5. Focus on subject in foreground and blur out the detail with long lens

cbrandin
06-22-2010, 08:54 AM
The pulse is definitely a bug, and not just the build-up of data. In some cases it simply shows up as two I frames in a row (corresponding to a GOP of 1) with no Pframes between them. As far as I know, this should be impossible.

Chris

cbrandin
06-22-2010, 09:15 AM
Can someone with a good "pulsed" clip run a little test? Locate the pulsed frame with StreamEyE. Then examine the clip frame-by frame around that location to see when the visual change occurrs. Does it start before, at, or after the pulse? Is the pulse when it gets worse or better? Or, when does the image get worse, and when does it get better?

This way we'll be able to determine whether the pulse is trying to fix something or whether it is just a bug that degrades the image for no reason.

The idea that it puts a bunch of detail in the stream right before the image is to be replaced with an I frame anyway seems rather odd to me.

I would do this test except I don't have any clips that show an obvious visual change during pulses.

Chris

mrduck
06-22-2010, 09:16 AM
It seems that pulsing in PAL gh-1 was present from the start - only on some recording scenes. It seems to be totally absent from NTSC cameras in 60i and present if 24p mode is selected... My idea is that gh-1 was engineered for NTSC, 60i, and I/P frames were allocated precise amounts of bandwidth. Going PAL they were not able to allocate bandwidth evenly, due to a limited hardware encoder or a wrongly written bandwidth allocator formula or parameters... In case of a limited hardware encoder (buffers, for example) we can do nothing... in case of a wrongly written formalus is difficult but not impossible, for wrong parameters we should find their location in the firmware first.... and test test test...
The pulse is definitely a bug, and not just the build-up of data. In some cases it simply shows up as two I frames in a row (corresponding to a GOP of 1) with no Pframes between them. As far as I know, this should be impossible.
I don't think two consecutive I frames I are forbidden....

cbrandin
06-22-2010, 09:21 AM
Yes, but the GOP length in the GH1 is a fixed number, implying that it is intended to operate with a fixed GOP.

Chris

cbrandin
06-22-2010, 09:25 AM
Are you saying that the GH1 can produce pulses even when Native 24p/25p is not being used? Or, when the firmware has not been patched at all?

Chris

mrduck
06-22-2010, 09:34 AM
Are you saying that the GH1 can produce pulses even when Native 24p/25p is not being used? Or, when the firmware has not been patched at all?

Chris

this has been reported in this thread, read the previous page, from PAL users. I have pulses too, but I only go 720... and I recognized pulsing only when I saw my images on a 50" screen .... I didn't notice before...

cbrandin
06-22-2010, 09:46 AM
Do the pulses show up in EyeStream, or are we assuming that they are based on image examination?

Chris

wturber
06-22-2010, 10:32 AM
The pulse is definitely a bug, and not just the build-up of data. In some cases it simply shows up as two I frames in a row (corresponding to a GOP of 1) with no Pframes between them. As far as I know, this should be impossible.

Chris

Again, you are attributing the visual "pulse" with some of the interesting spiked I and P frames. But it seems very likely that the real issue is that the I frame simply isn't providing a high enough initial quality when the displayed frame is generated completely from the single I frame.

When you go through a clip frame by frame, you can see that the first frame is somewhat lower quality and that the image quality improves as the clip steps through each subsequent P frame. When there is movement in the image, the extra data from the P frames is used almost exclusively to describe that motion. But when the image is static, the extra data from the P frames improves on the quality of the static image. You can watch the detail build as the clip steps through the GOP. So when the next GOP begins with a new I frame, we see an instant quality drop - and that's the "pulse" we are seeing. You can see this pulse on clips that don't have a spiked last P frame or unusually large "spiked" I frames.

The spiked I and P frames you are referring to seem to be connected to the camera freezing on static, high detail shots. They don't seem to be the cause of the pulsing.

wturber
06-22-2010, 10:36 AM
Can someone with a good "pulsed" clip run a little test? Locate the pulsed frame with StreamEyE. Then examine the clip frame-by frame around that location to see when the visual change occurrs. Does it start before, at, or after the pulse? Is the pulse when it gets worse or better? Or, when does the image get worse, and when does it get better?

Chris

The visual "pulse" is the I frame. I checked this out this morning with about a dozen clips. The pulse is always at the I frame. It is an instantaneous reduction in image quality.

Shorter GOPs seem to make the visual pulse less visible because the frequency goes up and it becomes visually similar to the random noise in the image.

Nitsuj
06-22-2010, 10:40 AM
In a post somewhere Barry Green asked Tester13 if he could up the bit rate for that frame and Tester13 was positive about it. So hopefully that will work out. That is one of the things that has bugged me about the GH1 since I got it last year. Hopefully that can be addressed.

wturber
06-22-2010, 10:41 AM
[quote=mrduck;2027089It seems to be totally absent from NTSC cameras in 60i and present if 24p mode is selected... My idea is that gh-1 was engineered for NTSC, 60i, and I/P frames were allocated precise amounts of bandwidth. [/quote]

I saw pulsing from the start with 720p60. I don't recall if it was in the 1080 clips in the 60i wrapper, but I suspect it was. I doubt this has anything to do with being designed for NTSC. I think it has everything to do with the lack of B frames and a pretty crappy implementation of the AVCHD CODEC. Well, maybe "crappy" is too strong. Most of the people that see the footage from my GH1 oooooh and aaaaah over it. But then they just aren't looking at it as critically as I am. So for the consumer crowd, the CODEC is probably not "crappy" but is generally OK.

cbrandin
06-22-2010, 10:42 AM
I think we've used the term "pulse" to describe two different things. I thought this thread started off being about the "pulse" seen in AVCHD Native 24p/25p mode, which seems to always appear right before an I frame as either a huge P frame or an extra I frame devoid of subsequent P frames, and is apparently a bug in the CODEC. The pulsing you're describing seems to be a normal result of a limited CODEC. Maybe I've misunderstood.

Chris

wturber
06-22-2010, 11:00 AM
I think we've used the term "pulse" to describe two different things. I thought this thread started off being about the "pulse" seen in AVCHD Native 24p/25p mode, which seems to always appear right before an I frame as either a huge P frame or an extra I frame devoid of subsequent P frames, and is apparently a bug in the CODEC. The pulsing you're describing seems to be a normal result of a limited CODEC. Maybe I've misunderstood.

Chris

Or maybe I got it wrong. Either way, it seems like the thread is going back and forth in a somewhat confused way. I hope my posts helped clarify and did not add to any confusion.

In short, there are three things that might be considered "pulsing."

1) The visual "pulsing" we see in the actual image. This is, as you say, a CODEC artifact.
2) The measured P frame pulses that spike to much greater values than the previous P frames and often even the I frames and can be seen as the last P frame in a GOP.
3) The measured I frame pulses that spike to extraordinarily large sizes and sometimes show up as an extra I frame (back to back I frames).

Items 2 and 3 seems to be associated to the 24P hack that sidesteps the 60i wrapper. One or both of these are implicated in causing recording failures of high detailed and highly static scenes.

Item 1 seems to occur regardless of the wrapper and is usually seen in subtle fine detail in the middle tones or on detailed edges. Shoot a static shot of a textured wall if you want to be sure to see it.

svecher
06-22-2010, 11:13 AM
Or maybe I got it wrong. Either way, it seems like the thread is going back and forth in a somewhat confused way. I hope my posts helped clarify and did not add to any confusion.

In short, there are three things that might be considered "pulsing."

1) The visual "pulsing" we see in the actual image. This is, as you say, a CODEC artifact.
2) The measured P frame pulses that spike to much greater values than the previous P frames and often even the I frames and can be seen as the last P frame in a GOP.
3) The measured I frame pulses that spike to extraordinarily large sizes and sometimes show up as an extra I frame (back to back I frames).

Items 2 and 3 seems to be associated to the 24P hack that sidesteps the 60i wrapper. One or both of these are implicated in causing recording failures of high detailed and highly static scenes.

Item 1 seems to occur regardless of the wrapper and is usually seen in subtle fine detail in the middle tones or on detailed edges. Shoot a static shot of a textured wall if you want to be sure to see it.
Yeah, let's standardize on terminology then.
1) Pulsing.
2), 3) Rogue/spiked I or P frames

The solution OP was looking for is rogue frames leading to camera freezing. I think their appearance was fairly conclusively linked to 24p/25p Native patch and high bitrates ("high" determined by the card used).

Now, I don't believe I've seen a StreamEye analisys screenshot of "Pulsing" footage yet. I would think that it should consist of a relatively small I frames and relatively large P frames. Can someone post?

wturber
06-22-2010, 11:44 AM
Yeah, let's standardize on terminology then.
1) Pulsing.
2), 3) Rogue/spiked I or P frames

The solution OP was looking for is rogue frames leading to camera freezing. I think their appearance was fairly conclusively linked to 24p/25p Native patch and high bitrates ("high" determined by the card used).

Now, I don't believe I've seen a StreamEye analisys screenshot of "Pulsing" footage yet. I would think that it should consist of a relatively small I frames and relatively large P frames. Can someone post?

I can post a clip since I recorded about a dozen this morning. But I won't be able to run them through StreamEye until tonight. My bet is that we'll see I frames that are 4-5 times the size of the P frames.

svecher
06-22-2010, 11:52 AM
My bet is that we'll see I frames that are 4-5 times the size of the P frames.
Oh, so your expectations are exact opposite of mine. Alright, I'm intrigued ... Go ahead and post a clip somewhere and I'll run it through StreamEye.

cbrandin
06-22-2010, 11:59 AM
Not quite true that it's related to high bit rates. I've gotten the rogue frame when all I set was the Native 24p patch (the data rates were left at factory defaults). I can get rogue frames no matter how I set anything else as long as Native 24p is checked. I tried all sorts of variations of bitrates, GOP settings, etc....

Here is what I got when I only set Native 24p and nothing else:

http://www.dvxuser.com/V6/attachment.php?attachmentid=18475&d=1276967763 (http://www.dvxuser.com/V6/attachment.php?attachmentid=18475&d=1276967763)

Chris

wturber
06-22-2010, 12:25 PM
Oh, so your expectations are exact opposite of mine. Alright, I'm intrigued ... Go ahead and post a clip somewhere and I'll run it through StreamEye.

I'm uploading two clips to my website now. You can find them here:

http://www.jayandwanda.com/gh13/

00025.mts and 00026.mts

These use the "c" settings (Ptool "c"). One is 1080 24p (no 60i) and the other is a 720p. GOP is 12 for the 1080 24p and 10 for the 720p. The upload should finish by 12:45P Mountain Standard time - about fifteen minutes from now.

Interestingly, it is easier to see the pulsing when watching the clip on my HDTV via an HDMI connection to my camera. When played back on my PC, the pulsing is muck harder to see. I wonder if better playback software does a better job of displaying the image. There's no reason to assume that the camera playback is optimal.

svecher
06-22-2010, 01:13 PM
Not quite true that it's related to high bit rates. I've gotten the rogue frame when all I set was the Native 24p patch (the data rates were left at factory defaults). I can get rogue frames no matter how I set anything else as long as Native 24p is checked. I tried all sorts of variations of bitrates, GOP settings, etc....

Here is what I got when I only set Native 24p and nothing else:


Chris
Chris you right, what I meant and should have said is that camera freezing is a result of native patch and high bitrates. Because very large rogue P or I frames appear as soon as you apply native patch, it is reasonable to assume that when bitrate is juiced up at the same time they become so monstrous as to cause buffer overflow and we all know how that usually ends ;)

svecher
06-22-2010, 01:46 PM
I'm uploading two clips to my website now. You can find them here:

http://www.jayandwanda.com/gh13/

00025.mts and 00026.mts

These use the "c" settings (Ptool "c"). One is 1080 24p (no 60i) and the other is a 720p. GOP is 12 for the 1080 24p and 10 for the 720p. The upload should finish by 12:45P Mountain Standard time - about fifteen minutes from now.

You were right (see attachment). Now, I will admit this makes little sense to me.

cbrandin
06-22-2010, 02:32 PM
I did some more testing. The results are in the AVCHD Research thread in the tester sub-forum. It's pretty depressing - Native 24p mode looks pretty broken. I can manifest all forms of failures now and get write errors easily even when running 50,52,60, 24pN on a class 10 card. It's just a matter of having lots of static detail.

Chris

cbrandin
06-22-2010, 03:15 PM
But 50,52,60 without native 24p set is still fantastic and totally stable for me.:thumbsup:

Chris

Svart
06-22-2010, 07:13 PM
Kinda late to the game to mention this but I noticed the dark-area pulsing when I was running my camera with the Native 24p enabled. Without it, I don't have the dark area pulsing.

Nitsuj
06-22-2010, 07:53 PM
I did some more testing. The results are in the AVCHD Research thread in the tester sub-forum. It's pretty depressing - Native 24p mode looks pretty broken. I can manifest all forms of failures now and get write errors easily even when running 50,52,60, 24pN on a class 10 card. It's just a matter of having lots of static detail.

Chris

Strange. I have 24pN on mine with a class 6 16GB Patriot card with no troubles. When I used C settings I was getting write errors all the time. I tried lower settings suggested for 720p but was still too high. I then changed to B settings and it worked. I just got back from shooting downtown for 3 hours without one write error. I will go through the stuff tomorrow but my first testing showed good results.