Tagged with mjpeg - Personal View Talks

GH2 - MJPEG resolution findings and Myth Busting

duartix — Wed, 25 Jan 2012 20:07:41 +0000

Tackling MJPEG for 2fps timelapses, I drew some conclusions that are less than obvious, and that I feel that should be shared with the rest of the community.

For this I filmed a resolution chart on my computer screen from a distance, using Quantum 50-100 settings which use quality settings that are already over the line for 2fps be it AVCHD or MJPEG. I loaded the MOV files into AVIDemux and extracted 100% lossless snapshots to compare the various modes. Shot on M Movie Mode, aperture and shutter speed were both fixed.

Note: I'm only showing the relevant 100% screen captures but all the files generated in this test (and I tested both HD and VGA modes) weight in at 38.5MB and can be d/l here: http://www.mediafire.com/?u2h8ycc2c6vmj0a

Unless marked as AVCHD all other files are MJPEG.

Myth 1 - MJPEG 1080p is MJPEG 720p up-scaled.

Result: Plausible.

It's too close to call, really! Even though there is evidence of a very very small resolution advantage to 1080p, it is hardly noticeable and it could be a consequence of the input-output workflow of 720 being done in a smaller resolution.

Evidence: (look at the second image, I can't delete the first which is similar)

GH2: MJPEG 100Mbps Low Light 1080p Settings

LPowell — Sun, 24 Jul 2011 16:53:31 +0000

UPDATE: This MJPEG patch is compatible with the latest version of PTool 3.65d. The standard non-anamorphic version is also included in Flow Motion v2, which is available for download here:

http://www.personal-view.com./talks/discussion/3337/gh2-flow-motion-v2.02-720p-reliability-in-auto-exposure-modes/p1

As numerous GH2 owners have discovered, Vitaliy's recent updates to PTool have enabled the newly hacked GH2 to sustain remarkably high bitrates in MJPEG HD mode. What's even more impressive is that the GH2 maintains error-free recording stability at bitrates significantly exceeding those that can be used reliably on the GH1. And where the GH1 struggled to produce FHD-size videos in MJPEG mode, the GH2 can be readily patched to record in any MJPEG frame size, all the way up to 1920x1080p.

The MJPEG encoder's most valuable asset has always been its ability to record each video frame as a JPEG-encoded key frame. This enables it to track high-speed action at 30fps without any of the smeared motion artifacts that plague low-bitrate AVCHD videos. To produce high-quality, detailed key frames at 1080p, however, an Intra-frame encoder must work at higher average bitrates than the GH1 was able to sustain. With PTool's support of the GH2, it is now possible to use MJPEG HD mode to produce reliable 1080p videos at an average bitrate of 100Mbps in sharply-focused, highly-detailed scenes.

The MJPEG encoder also excels in difficult low-light conditions where the AVCHD encoder cuts down its bitrate to minimum quality levels. On the GH1, MJPEG HD mode could be relied on to produce bitrates over 24Mbps even in dimly-lit scenes. With patch settings optimized for consistent bitrate production, the GH2 can maintain high bitrates of up to 100Mbps across the entire exposure range, producing high-quality images under any and all illumination levels. Combined with the GH2's low-noise image sensor, MJPEG HD mode can render clean, gradable images in conditions that the GH1 would have found hopelessly underexposed.

MJPEG image quality with exposure bracketing

Below are 100% crops of two series of four bracketed exposures I took in MJPEG HD mode, patched to 1920x1080 resolution. For each shot, I set up the GH2 on a tripod with a fixed aperture at ISO160, and varied the shutter speed from 1/60 to 1/500 second, producing videos bracketed at one-stop exposure steps. Frame grabs were then composited in Photoshop and saved at maximum JPEG image quality. These scenes were selected as typical outdoor subjects shot in natural lighting, as opposed to shots of extremely detailed foliage. The GH2 exhibited no reliability issues whatsoever, and recorded all videos at impressively consistent bitrates of around 90Mbps.

iPad compatible MJPEG VGA video mode

In addition to MJPEG HD mode, recent versions of PTool have provided patches for adjusting the frame size and image quality of MJPEG VGA mode as well. Unlike the HD 16:9 aspect ratio of HD mode, VGA video mode records with an SD aspect ratio of 4:3. I've optimized VGA mode to produce 960x720 videos at consistent average bitrates of about 30Mbps. These videos are compatible with the maximum-quality download specifications of the Apple iPad, with its 1024x768 screen resolution.

GH2 Patch Considerations

Patches for the GH2 are currently in active development by numerous testers, and Vitaliy has updated PTool several times with exciting new features. The patches in the downloadable PTool INI settings file below have been systematically tested using PTool version 3.61d and have produced no reliability issues to date. This patch is designed and tested only for the fastest Class 10 SDHC cards currently available.

Additional points of interest:

* The 100Mbps GH2 Low Light MJPEG 1080p Patch is compatible with all GH2 cameras, and is switchable between NTSC and PAL modes.

* I recommend using the camera to format your SD card at the start of each shoot, to guard against SD card memory fragmentation.

* Peak bitrates are obtained only with sharply-focused, highly-detailed subject matter. Average scenes will produce average bitrates.

* High bitrate MJPEG videos may not play back reliably in-camera or on low-powered computers.

* If shutter speed is set longer than the frame rate (e.g. slower than 1/30 at 30p), low-quality video files may be produced.

*** WARNING ***

The 100Mbps GH2 Low Light MJPEG 1080p Patch will not work properly with previous versions of PTool. My thanks once again go to Vitaliy Kiselev, for his pioneering work on PTool, and to cbrandin for his invaluable Stream Parser tool.

The best way to insure that you have the latest PTool release is to download it directly from the following link:

Download PTool here: https://www.personal-view.com/faqs/gh2-hack/ptool-software

100Mbps GH2 Low Light MJPEG 1080p Patch Settings File:

For use with PTool v3.62d and above, I've prepared anamorphic as well as standard aspect ratio settings files:

* For use with standard lenses, the standard patch will produce two types of MJPEG 30p videos:

HD mode: 1920x1080 HD videos, with peak bitrates up to 100Mbps.
VGA mode: 960x720 iPad-compatible videos, with peak bitrates up to 30Mbps.

* For use with anamorphic lenses, the anamorphic patch supports two different squeeze ratios:

HD mode: 1920x810 videos for 1.33X anamorphic adapters, with peak bitrates of 100Mbps.
VGA mode: 2160x810 videos for 2X anamorphic adapters, with peak bitrates of 100Mbps.

These zipped INI files can be used to apply complete patch settings to firmware loaded into PTool. To use, unzip the INI file into the same folder as the PTool application. Launch PTool and load the firmware for GH2 v1.0. The settings contained in the INI file will automatically be installed in the "C" button at the bottom of the PTool main window.

Note that with the following PTool Settings files, you may at any time re-install the original Panasonic GH2 v1.0 firmware into the camera. You may also copy each type of patched or original firmware to separate SD cards, and use them to quickly switch between patches as often as you like.

A Few Questions About: Hacked Bitrates, Auto ISO, EV, Modes

Heatshiver — Wed, 29 Jan 2014 22:14:07 +0000

I bought a GH2 mostly for the hacked patches. I have spent hours researching to try to learn what to do and how to use the camera for video purposes. I am hoping that someone can help answer a few questions as most of my information tends to originate from this site:

Setup - In order to achieve the higher bitrates I had to use M from the dial atop the GH2. The camera icon with the M would not allow this. The tradeoff was Auto ISO with M, and adjustable ISO with the camera icon with the M. I use mostly Canon FD lenses.

1a) Bitrates - I have tried a few hacks with varying success. The best I have got is about 100MB with Flow Motion v2.02, however, most of the shots I got with this hack seem to be from 70MB-90MB. I tried Flow Motion, Driftwood's Moon T7, and two Driftwood hacks (176MB & 220MB) from a pack made by the user Sohus on this forum.

Is it common to be well below the stated bitrate amounts?

1b) AVCHD vs MJPEG - I never seemed to get very high bitrates when using 1080i, despite the hacks stating to be much higher. They would range from 15MB-40MB. To achieve higher bitrates with Flow Motion, I used MJPEG which boosted them much higher.

Shouldn't I be achieving high bitrates with AVCHD?

2) Auto ISO - Whenever I use M (from PASM) the ISO would always be set to Auto ISO. I could adjust the ISO when using the camera icon mode (with the M), but then the bitrates would suffer. I tried changing the ISO before shooting, but Auto ISO would kick in no matter what.

How do I change the ISO while in M mode?

3) EV - I know that EV depends upon shutter, aperture, and ISO, but I can see the EV when I push the Display button so I was hoping there was still a way to change it.

Am I correct to assume that because I am using Canon FD lenses I cannot use EV? Even if using a Panasonic lens, how do I change the EV (I tried, but failed).

4) Modes - I have only been able to use the hacked bitrates - and only to a certain degree - by using M with MJPEG.

What modes should I be using to use the hacked patches? The camera icon with M? High Bitrate? 24P? 1080i?

Sorry for all the questions. I am not unhappy with the camera, but I really want to know why the bitrates are not working? And moreso, why the Auto ISO can't be changed (as I don't like the amount of noise it can introduce)? Thank you!

AVCHD VS MJPEG

Manoosh — Thu, 22 Aug 2013 12:45:42 +0000

Hi everybody.

Thanks to every workers and tester for your job.

I see lot of post about Mjpeg vs avchd, the majority of people say avchd better than Mjpeg. But today I'm not sure...

I was making a shot test between 24h/HBR/Mjpeg with "Driftwood Cluster X series 3:│moon T7" The scene is very contrasted with highlights and black.

I prefer Mjpeg...!!! Because the noise is the same and I see more details and more sharpen.

I want know if somebody testing Mjpeg and say the same thing.

25p and 2K possible? with the option Mpjeg fps of ptools?

The time limite?

Mjpeg in 2K 25p no limited time, It 's dream for me.

Thanks for your answers!

ST: MJPEG Encoder team

Vitaliy_Kiselev — Fri, 12 Aug 2011 17:05:32 +0000

This one is easy.

Anyone with systematic approach can participate.

I need very stable MJPEG settings (for table) from default bitrate up to highest possible (4-5 steps):
a) 720p mode
b) 720p upscaled to 1080p
c) 720p upscaled anamorphic
d) 480p upscaled
e) 480p upscaled anamorphic

MJPEG Why don't make GH2 render lossless image sequence instead of QT?

vadimvadimman — Tue, 25 Jun 2013 08:14:47 +0000

Hey, I got this idea. What if GH2 could render image sequence instead of compressed video in QuickTime container? I mean this would be great since each frame is compressed as an independent JPEG image, and then into QuickTime file. Is there any way to bypass QT container and get just lossless image sequence on card?

Macro-blocking on AVCHD but not on MJPEG ?

TruHype — Sat, 01 Jun 2013 13:21:59 +0000

Hi, I've discovered that there was Macro-blocking on AVCHD 24p video (even when transcoded with 5d2RGB), but not with MJPEG ! I was using the 'Apocalypse now Cluster v7 DREWNET 444 Soft Matrix' (MJPEG 2k and changed 30p to 24p with ptools).

How do I get rid of it ?

Motion JPEG unaffected?

pdlumina — Sun, 25 Mar 2012 21:43:26 +0000

Other than 720p20 width/height, E/F tables, and 720pXfps.. do any other settings actually affect the quality produced by the Motion-Jpeg encoder? do the FSH/SH values have any effect? (I think not), do the Auto Quantizer/Quantizer for 720 mode affects the quality?

Does the initial quantizer, video buffer, Top/Bottom settings, 720p IPB scaling/fallback, other modes top/bottom settings? Do any of these affect the 720p 30fps Motion Jpeg encoding? because it seems to me they are only meant for AVC modes.. but I could be wrong of course.

2.35:1 Display aspect ratio in MJPEG 30fps mode

Tommyboy — Wed, 15 Feb 2012 21:37:07 +0000

So, I just did a quick test by setting up one of the custom dials to be fully automatic (P Mode for exposure), just in case I need to get the camera rolling quickly. I tested all the footage to be surprised by the mjpeg HD footage. This footage has 2.35:1 display aspect ratio.

Video
ID                               : 1
Format                           : JPEG
Codec ID                         : jpeg
Duration                         : 11s 500ms
Bit rate mode                    : Variable
Bit rate                         : 102 Mbps
Width                            : 2 048 pixels
Height                           : 864 pixels
Display aspect ratio             : 2.35:1
Frame rate mode                  : Constant
Frame rate                       : 30.000 fps
Compression mode                 : Lossy

Any Ideas?

JPEG estimator and quantization

Vitaliy_Kiselev — Thu, 25 Aug 2011 18:29:59 +0000

New interesting article about company

Q: How does the JPEG format works?

A: JPEG is a lossy compression, meaning that any JPEG compression involves some loss of information. The compression consists of several steps:

•Color space transformation from RGB to YCBCR
•Reducing the spatial resolution of the CB and CR components by a factor of 2 in the horizontal axis, or both in the horizontal and the vertical axis (this step is optional).
•Dividing each color components to blocks of 8×8 pixels.
•Transforming each 8×8 block to the frequency domain using a DCT transform.
•Quantization (reduction of precision by representation with a lower number of bits) of each of the frequency components using a quantization matrix. This is the main stage that causes loss of information.
•Entropy coding (a lossless compression, similar to ZIP) on the frequency components which have undergone quantization.

Q: Is saving an image in Photoshop in minimum JPEG compression (i.e. 12) lossless?

A: Even at quality 12, the Photoshop quantization matrix has values which are greater than 1, so the precision of some of the frequency components is reduced, meaning that some information is lost (you can view the quantization matrixes for Photoshop’s quality 12 here).

Actually, even when using a quantization matrix that has all values set to 1, there is a loss of quality due to the DCT transform and the conversion from floating point values to integer values.

Read the rest at: http://www.megapixel.co.il/english/archive/21907

Other interesting read on JPEGSnoop author page:

http://www.impulseadventure.com/photo/jpeg-quantization.html

http://www.impulseadventure.com/photo/jpeg-huffman-coding.html

GH2 MJPEG 1080p 25 fps.

Athiril — Mon, 12 Dec 2011 07:00:37 +0000

Odd. Last time I tried the Change fps function for MJPEG it just fubar'ed all the time.

Now I went to stock settings (original GH2) for MJPEG with 25 fps, worked. So loaded the LPOWELL 100mbps/night 1080p settings, added 25 fps changed, works on my GH2. I'm not sure if it's merely dropping 5 frames out of every second (don't think it is). But if you shoot 1/25th, not sure if that it'd matter?

I'll try to examine it at some point with some linear motion at fixed speed, and look for 'jumps' in space.

My test file is reported as 75,697 kbps. Or 74 mbps. Which would be 88.7 mbps @ 30 fps, at the same average size/compression per frame. Available recording time is reported as 3m 12s. Recording on a Transcend 32gb class 10.

Test file was shot at ISO 2500, probably a stop underexposed still by the looks, just messing around in indoor light.

I'll do some slow panning on a monopod tomorrow with shutters @ and greater than 1/30th, and upload that.

Also I have gotten sizes a bit above 1080p working fine before too, which is useful I think for stabilising software if (such as deshaker) if you can shooter slightly wider than you want/need, so you don't have to blow up (or blow up as much) back to 1080p frame size for a 1080p output workflow. Combined with 25 fps would be great.

Real MJPEG 1080p resolution.

pedro — Fri, 11 Nov 2011 15:20:12 +0000

Hi everyone,

I'm not sure is this is the right way to ask a question of everyone on the issue of resolution regarding the Mjpeg codec but I didn't see a category anywhere that pushed this issue.

The reason why I have a concern over this is that I noticed with the ex. Telescopic conversion (ex.tel) on that when shifting between 24H and 720p 60p the image automatically zooms forward a bit more. Since in ex-tel mode the camera is no longer downsampling off the entire 4k sensor it makes sense since this is the equivalent of a digital zoom. It uses a central 1080p sized piece of the sensor and then it zoomed in even further to get a smaller 720p sized piece of the sensor. If I switch it VGA mode it the image will zoom in just a tiny bit more. I can only assume it is at that point jumping into an even smaller 480p sized piece of the 4k sensor.

This is all fine, what worries me is that if I switch back to 720p60p and am thus on the 720p sized piece of the sensor, and then switch to HD Mjpeg, which I have set for 2K (2048 by 1152) level of resolution, the image does NOT, repeat does not jump back out to at 1080p or 2K sized image from the sensor. It's exactly the same. This suggests, in ex-tel mode that as only a 720p sized piece of the sensor is used to film 720p60p mode, the exact same sized piece of the sensor is used to film HD MJPEG mode as well. In other words even if you reset the HD MJEG resolution away from its native 720p settings and push it up to 1080p or even 2K, it may still be only recording 720 level of resolution. In other words its possible the HD Mjpeg system merely upsamples its native 720p footage such that when we assess that footage in quicktime or VLC it will state that it is 1080p or 2K but in terms of literal optical quality we still only have 720 lines to play with.

I've noticed with identical shots I've taken with HD MJPEG 2K and 1080p 2p AVCHD that the resolution was almost identical but I somehow felt there was more clarity off of the 1080p footage. Technically the 2K I had with 2048 by 1152 should have been a bit better, but it wasn't.

Has anyone done a resolution test on the HD MJPEG, 720p and 1080p modes to confirm what kind of resolution we're actually getting off these different codecs?

Official high fps MJPEG topic

Vitaliy_Kiselev — Mon, 07 Nov 2011 17:15:32 +0000

Topic made specifically to talk about it.

80Mbit MJPEG 4:3 for 2x anamorphic shooting

EOSHD — Thu, 07 Jul 2011 14:58:02 +0000

Yesterday I shot this footage (but only at 9Mbit) in 1440x1080, 4:3.

No settings for this apart from the resolution / size change as was default in PTools for MJPEG.

Today I am testing new MJPEG encoder settings for improved image quality.

I have started off with these settings by CRFilms and LPowell as a basis http://www.personal-view.com/talks/discussion/comment/1762#Comment_1762

The purpose of these settings is for those with 2x stretch anamorphic lenses to get true 2.35:1 cinemascope from the GH2, rather than the more extreme 3.55:1 aspect ratio generated the lenses when used in 1080p 16:9 mode. I much prefer the less extreme cinema standard of 2.35:1 or 2.39:1, since that is what these anamorphic lenses were intended to make with 4:3 35mm film.

Today I have found MJPEG settings that seem to work well for recording quality and so sharing them here. I'll also share my further tests here. There is always room for improvement and new discoveries. The GH2 is good hardware, faster than the GH1 so who knows how high we can push it?

Rather than use 1440x1080, 1280x960 is necessary to avoid corruption, unexpected clip curtailment and enable the much higher bitrates.

Bitrate with my settings is approx. 80Mbit (variable). VLC Player reports a stream between 65,000kb and 85,000kb per second. 80,000kb is 78Mbit (http://www.google.co.uk/search?hl=en&safe=off&biw=1504&bih=877&q=80000+kb+in+megabits&aq=f&aqi=&aql=&oq=). Please correct me if I am wrong on anything technical. The footage looks great so far in this mode.

I need to do more reliability testing and see how far we can push it. Yet to find the final 'sweet-spot' but these settings are a good starting point for fellow testers.

480p Width: 1280
480p Height: 960
F1 Quality=280
F1 Table=4
F2 Quality=250
F2 Table=10
F3 Quality=225
F3 Table=24
F4 Quality=200
F4 Table=48

Lens was a LOMO 35mm 2x anamorphic in OCT18 mount.

I did not change any other settings.

A big thanks to Vitaliy and every tester, giving up valuable time for the good of the community. I salute you! - Andrew

GH1 - Real 1920x1080 MJPEG possible?

enim — Sat, 30 Jul 2011 20:04:45 +0000

Can the MJPEG frame size @ 30 FPS be increased? Is 1920x1080 achievable? I'm looking at "MJPEG Size Adjustments" in PTool v.3.61d, and that's what it says. But does it just do upscaling, which should probably be left to editing, or are the individual frames shot by the camera actually that size?
I'd appreciate any input you guys might have. Have been reading lots of discussions here with great interest.
Thanks!

Why Nikon can do 24fps MJPEG, how about panasonic?

kool — Tue, 26 Jul 2011 07:35:31 +0000

Why Nikon can do 24fps MJPEG, how about panasonic?