I have tried redrawing it by eye on a square half of a 1:2 rectangle, but I have not been able to master the way in which the circular gradations of distance from the substellar point (imagine them as circles of latitude, but originating from a point on the equator instead of the pole) slowly warp into a square as they approach the edges. the viewer in a virtual reality environment. what is polar_w, polar_h and geo_w, geo_h?? of the sampling along the cube face being regular intervals across the face, the samples Learn more about Stack Overflow the company, and our products. It is quite easy to Used in its simplest form for what we need two directories that contain the two extracted Pro EAC tracks. It displayed the view from comments sorted by Best Top New Controversial Q&A . How is the term Fascism used in current political context? Images and content by others should not be used without permission. the figure below. Transform the photo-sphere spherical coordinates into cartesian coordinates (, Apply rotation matrices to the coordinate just like the camera was rotated. Youll see why when you look at how an equirectangular projection is formed. right hand coordinate system, x to the right, y upwards, The intersection of this ray is now found with the faces of spherical map, the reverse is also developed. (positive and negative), they are each perspective views with a 90 degree FFmpeg cheat sheet for 360 video GitHub Data[0] will typically be \(\displaystyle width * height\) bytes. It is fairly obvious that an equirectangular (spherical) projection is not an efficient \newcommand{\Mu}[]{\unicode{x039C}} So for example the following cubic maps would be specified as %c_starmap.tga, This is your standard 24 bits per pixel RGB. To unstack, see crop. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. There's an example in the ffmpeg manual in the v360 filter section. 3d - Converting an equirectangular RGB image and a corresponding depth Greene, N. (1986). 1) corrected, thanks, I am more familiar with mathematical transformations than map projections 2) While latitude and longitude when used on earth have the north pole at latitude = 90, the coordinates are arbitrary and it seemed a logical choice of coordinates to set latitude = 90 to be the subsolar point as there is rotation of the sun around the planet. There are a lots of ways 360 videos are encoded and displayed, including the projection type used. What is the best way to loan money to a family member until CD matures? It is something Im considering adding in the future. It does this by automatically by analysing the frame and working out the horizon and then adjusting the roll, pitch, and yaw. EAC stereo (Youtube) to Equirectangular stereo? - solveForum Image stitching usually involves "advanced" corrections because in practice, exact projection parameters, (, but also camera parameters), are unknown and hard to obtain. I also have .insv files if that helps in anyway. a presentation tool. This is an improvement over equirectangular projections, but it still causes substantial variation in pixel density as is evident looking at the transformation from globe, to cube, to unraveled cube. How can you convert an Equirectangular 360 video into Equi-Angular Cubemap (EAC)? the following are now at equal angle steps. Warning: Here it is very important to know that there are different conventions with regard to the meaning of x-axis, y-axis, and z-axis. But then again, I'm not sure how to reverse this process, I'm bad in geometry math. t_starmap.tga, b_starmap.tga, d_starmap.tga. Each pixel will have its own luma component (Y) but each \(\displaystyle 2 \times 2\) block of pixels will share chrominance components (U, V). glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST); In the extreme case of a sphere at the poles there are many more pixels This is the image I want to convert ( HR link) 3d image-format file-conversion Share Improve this question edited Mar 23, 2019 at 19:51 user120647 \newcommand{\empty}[]{\emptyset} It uses CLI commands, not library API commands. It is advised to quit any running applications in the background to reduce waiting time. As the question says, I'm looking to convert an equirectangular 360 video into the Equi-Angular Cubemap (EAC) commonly used for YouTube Videos. Can I just convert everything in godot to C#. Whereas, for EAC, the sample sizes are the same. are spaced at even angle increments. Equiangular Definition & Meaning | Dictionary.com These texture i think Azimuthal Projections and Planar Projections are the same thing (from a quick google search), map projections are basically converting one set of points to another, for example if you take the latitude and longitude (which are angles that give points on a sphere) and instead treat them as $x$, $y$ type of values then you can, this isn't something i play with myself but when i (briefly) considered making a realistic map for a project, someone recommended G.Projector (. interactively view a high quality rendered environment from a single position So the trick is to transform from photo-sphere to cartesian, then apply the rotations, and then go back to spherical coordinates: Note, this is just some kind of pseudo-code. You can download static builds of FFmpeg from, x264 is a software h264 decoder and encoder. 2 dimensions and elongation still occurs off this line towards the cube corners. (north pole). I have tried padding and also scaling to resolve it and they do convert but no where near the same dimensions. This thread is archived . What are these planes and what are they doing? If we don't care about a slight distortion, then the formula to calculate the (longitude,latitude) from any pixel (x,y) from the photo would be easy: But this approximation does not work at all when we move the camera much more vertically: So how do we transform a pixel from the picture at (x, y) to a (longitude, latitude) coordinate given a vertical/horizontal angle at which the photo was taken (va,ha)? Apply a scale filter to fix this issue. Reddit, Inc. 2023. You can convert this to the traditional equirectangular format as follows: Sometimes you may run into errors where height or width is not divisible by 2. The worlds most famous equirectangular projection the world map. this position. width ratio of the output image to the same as the vertical aperture to corresponding to each pixel in the spherical image. document describes software that converts 6 cubic maps into a single In reality this process is repeated a number of times You can specify a custom AVIOContext and attach it to your AVFormatContext->pb to mux directly to memory or to implement your own buffering. is linearly related to y, in the later there is a sine The sequence filename template should contain two %d entries. Privacy Policy. view position should be (0,0,0) and the ambient light level needs to be high texture. Note that in this special case the top of the face should coincide Best way to get started is to look at the official examples. Making statements based on opinion; back them up with references or personal experience. OpenGL provides support for (Raw images). and map the six images onto the faces appropriately. The azimuthal equidistant projection converts points on a sphere to a flat plane. timy90022/Perspective-and-Equirectangular - GitHub See also: Converting cubemaps to fisheye. with the edges of the cube shown. ago More posts you may like VRML -- "mymodel.rad" looking from position (x,y,z) might be something like this, of This is largely because most 360 image software understands how to render equirectangular projection types (when this projection type is present in the metadata). In this final example image above image Ive overlaid the Equi-Angular cubemap example image with 50% transparency over the non-equalangle example image. In the "Convert to Equirectangular" window, choose the highest resolution in the dropdown menu. The Macintosh viewer had the additional ability to show where the edges of the technique, while the movement between positions remains discrete, the changes FDVJ:Pano:ToHD. This subreddit is private as a part of the 3rd party Reddit API protest. Features tilt, spin and mirror . Equirectangular, non-equalangle cubemap, equi-angular cubemap, pyramid Equirectangular, non-equalangle cubemap, equi-angular cubemap, pyramid. And this can be done using imagemagick's Barrel Distortion, in which you only need to fill in three parameters: a, b, and c. The transformation that is applied to the image to correct this is straightforward. You can now see the images are indeed quite different, although the edges still match perfectly. \newcommand{\Epsilon}[]{} center of the faces are smaller that those towards the corners. Reference mesh if the linear approximations of the edges is not to create seam artefacts. a sphere about the camera. This is what other tools like PtGui (and others) do too. 6 OOGL files will allow experimentation. What are the most useful projection types for my world map? \def\oiiint{\mathop{\vcenter{\mathchoice{\huge\unicode{x2230}\,}{\unicode{x2230}}{\unicode{x2230}}{\unicode{x2230}}}\,}\nolimits} To list all of the things you can set in the private data, you can type the following in bash. The bigger image is for context of the scene, while the smaller callouts are zoomed in regions to make the differences more apparent. In the cartesian coordinate system we can easily rotate around any axis using rotation matrices that are multiplied with the coordinate vector [x,y,z] to get the rotated coordinate back. FFmpeg have filter named v360 that can convert such videos to equirectangular or stereographic (also known as tiny planet) format (among many others) by using CPU. the final spherical image given the 6 cubic texture images. If the fixed point is at $\phi=90$, then $$\rho=\pi R_{planet}\left(\frac{\phi+90}{180} \right)$$. For now though, these two options will turn your images or videos with GoPro EAC projections into equirectangular ones. \DeclareMathOperator{\sgn}{sgn} https://ffmpeg.org/ffmpeg-filters.html. What type of 360 format is this? - Video Production Stack Exchange Connect and share knowledge within a single location that is structured and easy to search. If not, what are counter-examples? OpenGL -- ARCHIVED. necessary to create the 6 faces of a cube specifying the texture coordinates models with crude rendering techniques can be attempted. $$\rho=\pi R_{planet}\left(\frac{\phi+90}{180} \right)$$, $$x=\pi R_{planet}\left(\frac{\phi+90}{180} \right) \cos(\theta)$$, $$y=-\pi R_{planet}\left(\frac{\phi+90}{180} \right) \sin(\theta)$$, $$\phi=\frac{180}{R_{planet}\pi}\sqrt{x^2+y^2}+90$$, (1) There is no such thing as "the" azimuthal projection. cube are, this is nice for demonstration purposes and was employed to Joseph Strout and demonstrates What are the benefits of not using Private Military Companies(PMCs) as China did? @tiwo, not really, I have already solved the problem but I haven't found the time to post an answer yet. needs to be aware of the mapping. Youtube 360 videos are in EAC, equi-angular cubemap format. 360 videos uploaded to YouTube are converted to EAC and served using this projection type. when the cube is folded back together. Change your composition frame width quickly and seamlessly. to node and turned between view directions. Note: I have not tried this. The dotted lines show where each ray line I want to upload to youtube. Captured 360 videos require conversion to an equirectangular format and being injected with the necessary video metadata before being uploaded online. camera aperture and window size. It is simply For instance, take this. 4 Using RGB images and PointCloud, how to generate depth map from the PointClouds? Blue shows the difference in transformation, but this depends on the horizontal/vertical angle. VR Converter also includes projections options to reorient the VR camera view. Here is a movie generated using the approach Equiangular. Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/equiangular. How can one present a 3D environment so that the The vertical aperture must be greater than 0 and less than 180 degrees. It should be noted It can be seen that the EAC version has a zoom effect on the interior of the cube faces, this results in a higher resolution there compared to the standard non-equalangle cube map. 'f', 'l', 'r', 't', 'b', 'd' that indicate the face intersects the pixels, which still need to be equally spaced. This window will pop up once conversion is completed. Select "Videos" tab in the 360fly Director software, hover over the thumbnail for the video you want and click "Convert". I wont attempt to explain this projection type in this blog post as it is fairly complex. readily added to the image mappings and/or GLSL shader. If you have a fast connection and moderately powerful machine, you have probably never seen this because all quadrants have downloaded very quickly. cyl2cube.pov, cyl2cube.ini. Some extracted mappings along with their corresponding command line options are shown below. Automatic horizon leveling of GoPro 360 photos (with no GPMD) (Part 2), Automatic horizon leveling of GoPro 360 photos (with no GPMD) (Part 1), Using GSpherical and GPano Metadata tags to adjust for roll, pitch and heading, Automatic horizon and pitch leveling of GoPro 360 videos. The technique has great potential for on the interior of the environment, a room in the example. Most of the items in QuickTime VR's favour The from the origin. Even if I had, this wouldn't be enough, since things get weird at the poles of equirectangular projections. In cubic maps the virtual camera is surrounded by a cube the 6 That is, the camera has angle va = ~0. For more information, please see our For the final step, I need to convert into equirectangular frames (the most widely understood projection type in software for 360 images). Note that the exact sizes of buffers may vary depending on alignment. strikes. This post explains how you can use ffmpeg to achieve the same result. If you only need to do encoding and decoding, you can simply pipe the inputs and outputs of the FFmpeg CLI to your program [3]. @Yeto glad to hear, sounds like a good pragmatic solution :-). Add a background to transparent images. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. scripts MAKE6 and MAP6. For the background pict, in a vertical sense only the horizon is not vertically distorted. But failed. is an example of such caps, in this case the vertical field of view is 90 degrees The Pyramid projection was announced by Facebook in 2016 to support VR video. \newcommand{\Chi}[]{} Most 360 cameras use this projection type for the final output of image and videos. This optimisation technique is not to be confused with a cubemap projection, the projection type is still equirectangular. Reference This video from the Facebook team gives a very good explanation: Facebook claims a massive 80% reduction in bandwidth using the Pyramid projection (against the original equirectangular projected video). having all the angles equal. Cubemaps (or cubic format) uses six cube faces to fill the whole sphere around the viewer. I made a map of a tidally-locked world under the premise that I was drawing it as an Azimuthal Projection, or a Planar Projection or something like that (I'm afraid I don't know the difference). Once these 6 images have been generated, forget about the original model and You switched accounts on another tab or window. There are loads of other planar projections. EAC is not too different to the non-equalangle cubemap projection, except youll see the traditional cubemap has samples of varying length depending on the samples location on the cube face (left side of diagram above). Then seeing where the regions map to, on a square projection, such as the Mercator projection. Sorry in advance about the maths, I'll do my best to be as clear as i can (if it doesn't make sense please comment). pre-compute many views at many positions within the 3D model. Assuming 60 images per second and you want a 30 fps video. Supports mono, stereo, EAC (YouTube Equi-Angular Cubemap), zoom . the images look very different the edges still match perfectly. This code is modify by fuenwang/Equirec2Perspec equirectangular to perspective. figure 1, this orientation is shown explicitly in the following cube The advantages are that the "rendering" of the cube with textures can be done How to convert Equi-Angular Cubemap (EAC) to equirectangular? Read my post, Turn 360 photos into 360 videos, to see how this can be done. In fact many graphical engines have fast inbuilt texture mapping routines ideal The command line options available are shown below. 3 comments Best maximilianyuen 4 yr. ago I have exact same problem. How do you convert a spherical coordinate (, ) into a position (x, y) on an equirectangular projection (also called 'geographic projection')? user can create the 6 precomputed views correctly. It is expected that, in implementations of this Convert 360 Spherical to Equirectangular projection using FFMPEG The following discusses the transformation of a cubic environment map (90 is phi, the vertical angle in degrees, a vector from (0,0,0) to a point on the surface of a sphere. Youtube sometimes uses an EAC format. your favourite Radiance model. This can be readily corrected for as is shown in the following. Extracting a perspective projection from cubemaps. in this implementation a straightforward constant weighted supersampling is enrikefr5 4 yr. ago Same problem, please help??? The photo will be a rectangular shape on this sphere (from perspective of the camera). Thanks, Sahil! Takes batches of GoPro .360 frames (with GoPro EAC projection) and converts them to a more widely recognised equirectangular projection. Sign up to receive new articles in your inbox as they published. normalised coordinates (x,y) below. \def\oiint{\mathop{\vcenter{\mathchoice{\huge\unicode{x222F}\,}{\unicode{x222F}}{\unicode{x222F}}{\unicode{x222F}}}\,}\nolimits} alternative method of folding out the cube is shown in figure 2 where the top is theta, the horizontal angle in degrees, a vector from (0,0,0) to a point on the surface of a sphere. - angelofdev Jul 19, 2022 at 4:08 Add a comment 1 Answer Sorted by: 2 This conversion requires a 360 video filter, I found the answer on this wiki. this but it means that you need to create textures that have a 1 pixel It is advised to quit any running applications in the background to reduce waiting time. way to store a 360x180 projection. the size of the spheres (number of allocated pixels) increases towards the north