Anamorphic Cinemascope in Native 1920x810 MJPEG Mode

[Lpowell]

Update: See below for a new INI file which combines Anamorphic Cinemascope with my 100Mbps Max Latitude Native 24/25p Patch

Widescreen Video Frames in MJPEG
One of the more intriguing patches in PTool allows you to alter the dimensions of the video frame in MJPEG HD mode. Back in the early days of the GH1 hack, it was hoped that this might enable recording of FHD-sized 1920x1080 videos using the MJPEG encoder. Unfortunately, the high bitrates required to support a 1080p30 frame rate produced sporatic recording failures. Though stable settings were found for narrower 1440x1080 and 1280x1080 MJPEG frame sizes, these non-standard aspect ratios produced warped videos that required post-processing to restore normal-looking dimensions. With these difficulties, the practical value of resizing MJPEG video frames soon lost its appeal.

When you set a non-standard MJPEG aspect ratio, both GH1 and GF1 cameras extract the specified number of horizontal and vertical pixels from the 16:9 image sensor. And on playback, the pixel width and height you have set are used by the video player to size the video frame that is displayed on-screen. For instance, if you patched in a 1440x1080 video mode, the normal 1280x720 MJPEG frame would be expanded into a 1440x1080 frame. While it would look similar to simply stretching the video player's display window, what's different is that the MJPEG encoder would actually pack 1440x1080 pixels into each frame of the video.

Anamorphic Widescreen Video Dimensions
The warped appearance of these altered video modes reminded me of the horizontal squeeze effect that is produced by an anamorphic lens. Anamorphics have been used in film production since the 1950's to produce the widescreen cinemascope effect of movies with an impressive 2.35:1 aspect ratio. Anamorphic adapters were also used in the pre-HD video days to expand the 4:3 aspect ratio of SD videocameras out to the 16:9 aspect ration of HDTV. When these SD anamorphic adapters are used with a lens on the GH1, it expands the GH1's native 16:9 screen out to the same 2.35:1 dimensions of widescreen movies.

When a commercial widescreen movie is mastered for distribution on Blu-Ray disc, it's rendered at the full 1920-pixel width of the FHD format. Due to its wide aspect ratio, however, the movie's height covers only about 810 pixels of the 1080-pixel height of the screen, with upper and lower borders letterboxed. This 1920x810 frame is the native size of widescreen Blu-Ray video.

Native Anamorphic Video Modes on the GH1 and GF1
Using PTool, the GH1's MJPEG encoder can be readily hacked to produce a 1920x810 video mode, and my 60Mbps MJPEG Patch works very well with frames of this size. But like the other non-standard MJPEG modes, the images turn out warped. When you combine this mode with an anamorphic adapter, however, the anamorphic squeeze compensates for the warped aspect ratio, resulting in native widescreen videos produced directly in-camera! (This requires an anamorphic adapter with a 1.33x ratio, such as the Panasonic LA7200.)

This Anamorphic 1920x810 MJPEG Patch gives the GH1 and GF1 the unique ability to record in anamorphic widescreen cinemascope, producing videos that can be viewed directly off the SD card, with no need for post-processing in a video editor.

For those without an anamorphic adapter, this patch can also be used with a standard lens to record clips that can be post-processed to produce FHD-sized 1920x1080 MJPEG videos at 30p. To do so, simply take the 1920x810 video produced by the patch and use a video editor to stretch it vertically to 1080p. The resulting image will have the correct, undistorted FHD aspect ratio and show only a minimal decrease in sharpness from the vertical resampling (preferably using bicubic interpolation).

Anamorphic 1920x810 MJPEG Patch Settings File:
This zipped INI file can be used to apply complete patch settings to firmware loaded into PTool 3.50d. To use, unzip the INI file into the same folder as the PTool application. Launch PTool and load the firmware for either GH1 v1.32 or GF1 v1.22. The settings contained in the INI file will automatically be installed in the lower row of buttons in the PTool main window.

Note that with the following PTool Settings File, you may at any time re-install the original Panasonic GH1 v1.32 or GF1 v1.22 firmware into the appropriate camera model. 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.

*** WARNING ***

The Anamorphic 1920x810 MJPEG Patch will not work properly with previous versions of PTool.
The best way to insure that you have the latest PTool release is to download it directly from the following link:

Download PTool here: http://www.gh1-hack.info/ptool3d.zip

AVCHD patch files for use with PTool: http://www.dvxuser.com/V6/showthread...=1#post2039780

In the PTool INI file below, I've combined the Anamorphic 1920x810 MJPEG Patch with my100Mbps Max Latitude Native 24/25p Patch. Once installed in PTool, you can use the "A" button to apply both patches together.

LPowell - 100Mbps Max Latitude Native 24-25p Anamorphic Patch.zip

[Lpowell]

Click here to see a gallery of anamorphic lens and sample shots:
http://www.dvxuser.com/V6/showthread...=1#post2126471

To illustrate how the Anamorphic 1920x810 MJPEG Patch works, I exported sample frames from a test shot in three related MJPEG video modes:

1280x720 MJPEG - Standard 720p30 HD video mode
1440x810 MJPEG - Standard 16:9 frame encoded at 810p resolution
1920x810 MJPEG - Anamorphic 2.35:1 video mode (requires an anamorphic lens)

Here are half-scale shots of a metal ruler, illustrating the relative frame sizes:

1280x720 MJPEG:



1440x810 MJPEG :



1920x810 MJPEG(Anamorphic):


Notice how the ruler in the above 1920x810 image is distorted by the GH1's anamorphic MJPEG video mode. Attaching a 1.33x anamorphic adapter to the front of the camera lens would compensate for this distortion, producing a perfectly scaled widescreen cinemascope image.

There has been speculation that the GH1 may produce larger MJPEG frames simply by scaling the default 1280x720 video frame up in size, much as Photoshop would do. To evaluate the resolution of these three frame samples, I magnified them in Photoshop by 500%, using the "nearest neighbor" scaling algorithm to preserve the contents of the original pixels:



The preceding comparison displayed all three frames with the same size magnified pixels. In the following comparison, I scaled up both the 1280x720 and 1440x810 frames to the same dimensions as the 1920x810 frame, using "bicubic interpolation" to produce high-quality upscaling results. This shows how detailed the GH1's real-time 1920x810 mode is compared to post-processing the video frames in Photoshop:

[kprince]

Saweet, any video samples online yet?

[kprince]

PS: any good leads on where to pick one up. I just trolled around and they seem quite hard to find : )

[raymondluo]

what about a 1.85:1 aspect ratio? (to negate the use of an expensive or hard to acquire anamorhpic adapter)

[ryancglover]

Very nice, clear testing lpowell.

I tried doing this with my 2x anamorphic lenses and a 2560x720 frame size earlier this summer, those hasty test shots are here if anyone's interested, doesn't seem to hold up that well when pushed that far though.

Keep up the great work!

[gmoe]

Wow! Great Stuff lpowell. Nicely done!

I tried doing this with my 2x anamorphic lenses and a 2560x720 frame size earlier this summer, those hasty test shots are here if anyone's interested, doesn't seem to hold up that well when pushed that far though.

Is it possible to adjust frame size settings that would work with 2x anamorphics?

Can't wait to try this with the Pany 7200 adapter.

[Lpowell]

Is it possible to adjust frame size settings that would work with 2x anamorphics?

As Ryan mentioned above, the native MJPEG frame size for a 2x anamorphic adapter would be 2560x720, producing an exaggerated 3.56:1 screen aspect ratio. Not only is this much wider than any commercial film or video format, it's also not possible to patch MJPEG widths greater than 1920 in current versions of PTool.

Of the types of anamorphic adapters that are usable on the GH1, almost all have a horizontal "squeeze factor" of 1.33x, 1.5x, or 2x. The 1.33x adapters are perfectly suited to the 1920x810 Native Anamorphic MJPEG video mode. 1.5x and 2x adapters can also be used in 1920x810 mode; they simply require additional horizontal stretch in post-production.

I use Adobe After Effects for this purpose, others familiar with Final Cut Pro may want to comment on what works best for them. After Effects provides an "Interpret Footage" dialog for each clip you import into a project. Here you can set the clip's pixel aspect ratio to automatically handle anamorphic footage with 1.33x, 1.5x, or 2x squeeze factors. Once this factor is set, you can drag the clip into a Composition and it will be expanded to the correct aspect ratio and centered in the Composition's video frame. With a 1920-pixel-wide Composition, 1.33x anamorphic footage will fit perfectly in the frame, while 1.5x and 2x footage will stretch beyond the frame's vertical borders. This is often convenient, as it gives you an opportunity to center the image in a 1.5x or 2x clip as you like, and also eliminates any residual vignetting at the corners of the footage.

Once my editing and compositing in After Effects is complete, I simply render the Composition to the target format and the footage is automatically cropped to the size of the Composition's video frame.

[dts]

I am a cinemascope fan too and would like to know if i can

a) increase the avc resolution to 2512x1080 in ptool sensor mode 4??
b) or is it possible to record electronically stretch the image in the 1920x1080 dimension?
c) can i via sensorcut option (mode4) set it to 1080x800 and what about the liveview?

Thank you

[gmoe]

I use Adobe After Effects for this purpose, others familiar with Final Cut Pro may want to comment on what works best for them. After Effects provides an "Interpret Footage" dialog for each clip you import into a project. Here you can set the clip's pixel aspect ratio to automatically handle anamorphic footage with 1.33x, 1.5x, or 2x squeeze factors. Once this factor is set, you can drag the clip into a Composition and it will be expanded to the correct aspect ratio and centered in the Composition's video frame. With a 1920-pixel-wide Composition, 1.33x anamorphic footage will fit perfectly in the frame, while 1.5x and 2x footage will stretch beyond the frame's vertical borders. This is often convenient, as it gives you an opportunity to center the image in a 1.5x or 2x clip as you like, and also eliminates any residual vignetting at the corners of the footage.

Thanks lpowell. That's fantastic help. I have both a Panny anamorphic 1.33x and Kowa 2x so that's great to hear that I can still shoot with this hack with my Kowa and use AE via interpret footage and pixel aspect ratio. Much easier and better than I was doing before. Many thanks!