Right now, what I'm trying to do is to make a new GUI, essentially a software using directX (more exact, direct3D), that display streaming images from Axis IP cameras.
For the time being I figured that the flow for the entire program would be like this:
1. Get the Axis program to get streaming images
2. Pass the images to the Direct3D program.
3. Display the program, on the screen.
Currently I have made a somewhat basic Direct3D app that loads and display video frames from avi videos(for testing). I dunno how to load images directly from videos using DirectX, so I used OpenCV to save frames from the video and have DX upload them up. Very slow.
Right now I have some unclear things:
1. How to Get an Axis program that works in C++ (gonna look up examples later, prolly no big deal)
2. How to upload images directly from the Axis IP camera program.
So guys, do you have any recommendations or suggestions on how to make my program work more efficiently? Anything just let me know.
Well you may find it faster to use directshow and add a custom renderer at the far end that, directly, copies the decompressed video data directly to a Direct3D texture.
Its well worth double buffering that texture. ie have texture 0 displaying and texture 1 being uploaded too and then swap the 2 over when a new frame is available (ie display texture 1 while uploading to texture 0).
This way you can de-couple the video frame rate from the rendering frame rate which makes dropped frames a little easier to handle.
I use in-place update of Direct3D textures (using IDirect3DTexture9::LockRect) and it works very fast. What part of your program works slow?
For capture images from Axis cams you may use iPSi c++ library: http://sourceforge.net/projects/ipsi/
It can be used for capturing images and control camera zoom and rotation (if available).
Related
I'm about to generate 2D and 3D music animations and render them to video using C++. I was thinking about using OpenGL, but I've read that, unfortunately, it is being discontinued in favour of Vulkan, which seems to offer higher performance using a GPU, but is also a lower-level API, making it more difficult to learn. I still have almost no knowledge in both OpenGL and Vulkan, beginning to learn now.
My question is:
is there a way to encode the Vulkan render output (showing a window or not) into a video file, preferentially through FFPMEG? If so, how could I do that?
Requisites:
Speed: the decrease in performance should be nearly that of encoding the video only, not much more than that (e.g. by having to save lossless frames as images first and then encoding a video from them).
Controllable FPS and resolution: the video fps and frame resolution can be freely chosen.
Reliability, reproducibility: running a code that gives a same Vulkan output twice should result in 2 equal videos independently of the system, i.e. no dropping frames, async problems (I want to sync with audio) or whatsoever. The chosen video fps should stay fixed (e.g. 60 fps), no matter if the computer can render 300 or 3 fps.
What I found out so far:
An example of taking "screenshots" from Vulkan output: it writes to a ppm image at the end, which is a binary uncompressed image file.
An encoder for rendering videos from OpenGL output, which is what I want, but using OpenGL in that case.
That Khronos includes in the Vulkan API a video subset.
A video tool to decode, demux, process videos using FFMPEG and Vulkan.
That is possible to render the output into a buffer without the need of a screen to display it.
First of all, ffmpeg is a framework used for video encoding and decoding. Second, if you have no experience with any of the GPU rendering API you should start with OpenGL. Vulkan is very low-level and complicated. OpenGL will be here for a very long time and will not be immediately replaced with Vulkan.
The off-screen rendering option you mentioned is probably the best one. It doesn't really matter though, you can also use the image from the framebuffer. The image is just a matrix of RGBA pixels. You need these data as the input for the video encoding. Please take a look at how ffmpeg works. You need to send the rendered frame data in the encoder which produces video packets that are stored in a video file. You need to chose a container (mp4, mkv, avi,...) and video format (h265, av1, vp9,...). You can of course implement a frame limiter and render the scene with a constant framerate or just pick the frames that have a constant timestep.
The performance problem happens, when you transfer the data from RAM to GPU memory and vice versa. For example, when downloading the rendered image from the buffer and passing it to the CPU encoder. Therefore, the most optimal approach would be with Vulkan, using the new video extension and directly sending the rendered frames in the HW accelerated encoder without any transfers from the GPU memory. You can also run the encoder in a different thread to make it work asynchronously.
But honestly, it's not trivial. The most simple solution (not realtime) for you to create a video from 3D render would be to:
Create a fixed FPS game loop
Make screenshots of the scene by downloading the framebuffer data in OGL or Vulkan
Process the frames by ffmpeg binary to create a video file
Another hack would be to use a screen recording software (OBS, Fraps, etc.) to create the video form your 3D app.
I am extending an existing OpenGL project with new functionality.
I can play a video stream using OpenGL with FFMPEG.
Some objects are moving in the video stream. Co-ordinates of those objects are know to me.
I need to show tracking of motion for that object, like continuously drawing a point or rectangle around the object as it moves on the screen.
Any idea how to start with it?
Are you sure you want to use OpenGL for this task? Usually for computer vision algorithms, like motion tracking one uses OpenCV. In this case you could simply use the drawing functions of OpenCV as documented here.
If you are using OpenGL you might have a look at this question because in this case I guess you draw the frames as textures.
I'm trying to use OpenGL's texture compression on a large image. My image is a world map that I'm painting on the screen as a series of 128x128 tiles as part of a learning exercise. I want the user to be able to pan and zoom around the image. It's a JPG that is rather large (20k by 10k pixels) and so I wanted each of my tiles (I tiled the image) to be compressed in order to lower the memory footprint of my program.
I picked an arbitrary texture compression format when I called glTexImage2D and each of my tiles become white squares. I dug a little deeper into this and figured "maybe my video card doesn't support all these formats." The video card is an Nvidia NVS 3100M on an IBM ThinkPad laptop and I did a glGetString to try to see what the supported texture compression formats were, but it didn't return anything (GL_COMPRESSED_TEXTURE_FORMATS). I also checked what GL_EXTENSIONS were supported and it returned "GL_WIN_swap_hint GL_EXT_bgra GL_EXT_paletted_texture" which doesn't look like much.
My program is in C# using the SharpGL library.
What other things can I check to see to try to figure this one out?
How about checking those texture minification filtering settings?
I am making a simple game for fun and learning using SFML for 2D stuff. The game is rather simple.. I loath to say it is a HoG (hidden object game) but I guess that would be a way to get my point across quickly. Basically I am using SFML to load and display 2D still art and capture mouse events.
Anyway... I would like to add video clips to my project. All the art is rendered and for example.. if my image is of a park with a fountain, I would like to have a looping video of the water running so the image has some life even though it is just a still.
All I need is the ability to play videos in the window, preferably compatible with sfml but I am in the planning projects I can swap to something else if needed. The project will have a set resolution (not scalable) and I just want to load the video and play them at a certain pixel location in x,y. So if I have a 1200x720 image I play a 100x100 pixel video on loop at a certain location to make the water of the fountain move.
Now then I am thinking I can just load 2D sprites onto of the video matching the background image to do simple masking. There are some formats like quicktime that can embed an alpha channel directly into the video and if that is supported awesome.. but some planning in the set design should mean that is not really needed. Though if that was supported more options open in set design.
I am pretty good with video as I am a 3D animator by profession, new to programming as a learning hobby. So the format and container of the video is not really an issue though I have been working with OGV a lot recently.
What I see as it needing is
Load multiple videos at once
Play with out any boarders or anything
Play at specific locations in a window.
loop seamlessly
Allow zdepth so I can place sprites onto of it
Dose anyone know were I would go to start looking into this? It seams like something that could possibly be a library I could use? Preferably an open source one as this is just a for fun project nothing commercial.
Thanks in advance for any ideas you may have.
I am looking for a tutorial or documentation on how to overlay direct3d on top of a video (webcam) feed in directshow.
I want to provide a virtual web cam (a virtual device that looks like a web cam to the system (ie. so that it be used where ever a normal webcam could be used like IM video chats)
I want to capture a video feed from a webcam attached to the computer.
I want to overlay a 3d model on top of the video feed and provide that as the output.
I had planned on doing this in directshow only because it looked possible to do this in it. If you have any ideas about possible alternatives, I am all ears.
I am writing c++ using visual studio 2008.
Use the Video Mixing Renderer Filter to render the video to a texture, then render it to the scene as a full screen quad. After that you can render the rest of the 3D stuff on top and then present the scene.
Are you after a filter that sits somewhere in the graph that renders D3D stuff over the video?
If so then you need to look at deriving a filter from CTransformFilter. Something like the EZRGB example will give you something to work from. Basically once you have this sorted your filter needs to do the Direct 3D rendering and, literally, insert the resulting image into the direct show stream. Alas you can't render the Direct3D directly to a direct show video frame so you will have to do your rendering then lock the front/back buffer and copy the 3D data out and into the direct show stream. This isn't ideal as it WILL be quite slow (compared to standard D3D rendering) but its the best you can do, to my knowledge.
Edit: In light of your update what you want is quite complicated. You need to create a source filter (You should look at the CPushSource example) to begin with. Once you've done that you will need to register it as a video capture source. Basically you need to do this by using the IFilterMapper2::RegisterFilter call in your DLLRegisterServer function and pass in a class ID of "CLSID_VideoInputDeviceCategory". Adding the Direct3D will be as I stated above.
All round you want to spend as much time reading through the DirectShow samples in the windows SDK and start modifying them to do what YOU want them to do.