ffmpeg | a java library interface to access ffmpeg | Wrapper library
kandi X-RAY | ffmpeg Summary
kandi X-RAY | ffmpeg Summary
example demuxing.c → demuxing.java compiles.
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Top functions reviewed by kandi - BETA
- Convert timestamp to timestamp string
- Set the number field
- Set the den denominator
- Convert a timestamp to a time string
- Returns the dummy variable
- Sets the post_help text
- Get post_help text
- Set dummy variable
- Sets the AVDevice_capabilities
- Returns the camera device capabilities
- The main entry point
- Allocate memory allocation
- Get the license of the post process
- Get context pointer
- Allocate a buffer
- Return the native license
- Get the libproc configuration
- Return a human - readable version string
- Convert a double to a byte pointer
- Allocate a AVFrame
- Returns the native build - time configuration
- Set field s alignment
- Allocate a memory block
- Returns the name of a channel
- Get a description of a channel
- This method is used to generate a pointer to a memory allocated array
ffmpeg Key Features
ffmpeg Examples and Code Snippets
Community Discussions
Trending Discussions on ffmpeg
QUESTION
I am creating a custom video player, I would like to add a video preview when the user hovers a progress bar.
I am able to generate thumbnails using FFmpeg as follows.
...ANSWER
Answered 2022-Mar-27 at 18:50You will have to make your own tool for creating the WEBVTT file. And it's a simple process, you just need to get the information you need and fill it in the following format:
QUESTION
I want to convert my mp4 file to gif format. I was used the command that is working in command prompt. i.e., converting my .mp4 into gif but in go lang it is not done anything. Here is my command:
...ANSWER
Answered 2022-Jan-06 at 16:09This is not exactly what you are looking for, but it is possible to do it like this:
QUESTION
I have an electron repo (https://github.com/MartinBarker/RenderTune) which used to work on windows 10 fine when ran with command prompt. After a couple months I come back on a new fresh windows 10 machine with an Nvidia GPU, and the electron app prints an error in the window when starting up:
...ANSWER
Answered 2022-Jan-03 at 01:54You can try disabling hardware acceleration using app.disableHardwareAcceleration()
(See the docs). I don't think this is a fix though, it just makes the message go away for me.
main.js
QUESTION
I have been trying to convert a BGR captured frame into the YUYV format.
In OpenCV Python I can do convert YUYV into BGR with COLOR_YUV2BGR_YUY2
conversion code but I cannot do the reverse of this operation (there is no conversion code for this operation, I have tried COLOR_BGR2YUV
but it is not converting correctly). I am curious about how to convert 3-channel BGR frame into the 2-channel YUYV frame.
Here you can see the code that I am using to change camera mode to capture YUYV and converting it into BGR, I am looking for the replacement of the cap.set(cv2.CAP_PROP_CONVERT_RGB, 0)
so I can capture BGR and convert it into YUYV without cap.set(cv2.CAP_PROP_CONVERT_RGB, 0)
(Because it is an optional capture setting and Windows DirectShow ignores this flag)
ANSWER
Answered 2021-Dec-27 at 14:34You can use the following code to convert your image to YUV and after that create YUYV from YUV. In this example an image is given as input to the program:
QUESTION
I'm looking to do some in-browser video work using good-ol' FFmpeg
and Rust. Simple examples, where the caller is interacting with the ffmpeg command-line abound. More complex examples are harder to find. In my case I wish to extract, process and rotate discrete frames.
Clipchamp makes impressive use of WASM and FFmpeg
, however the downloaded WASM file (there's only one) will not reveal itself to wasm-nm
nor wasm-decompile
, both complaining about the same opcode:
- wasm-nm:
Unknown opcode 253
- wasm-decompile:
unexpected opcode: 0xfd 0x0
Has anyone wisdom to share on how I can (1) introspect the WASM module in use or (2) more generally advise on how I can (using WASM and Rust, most likely) work with video files?
...ANSWER
Answered 2021-Dec-25 at 14:45The WASM module uses SIMD instructions (prefixed with 0xfd
, and also known as vector instructions), which were merged into the spec just last month. The latest release of wasm-decompile
therefore doesn't have these enabled by default yet, but will in the next release. Meanwhile, you can enable them manually with the --enable-simd
command line option. This invocation works for me with the latest release:
QUESTION
I wrote a python script that generates a xstack complex filter command. The video inputs is a mixture of several formats described here:
I have 2 commands generated, one for the xstack filter, and one for the audio mixing.
Here is the stack command: (sorry the text doesn't wrap!)
...ANSWER
Answered 2021-Dec-16 at 21:11I'm a bit confused as how FFMPEG handles diverse framerates
It doesn't, which would cause a misalignment in your case. The vast majority of filters (any which deal with multiple sources and make use of frames, essentially), including the Concatenate filter require that be the sources have the same framerate.
For the concat filter to work, the inputs have to be of the same frame dimensions (e.g., 1920⨉1080 pixels) and should have the same framerate.
(emphasis added)
The documentation also adds:
Therefore, you may at least have to add a scale or scale2ref filter before concatenating videos. A handful of other attributes have to match as well, like the stream aspect ratio. Refer to the documentation of the filter for more info.
You should convert your sources to the same framerate first.
QUESTION
In case of invalid parameters, cv2.VideoWriter
writes stuff to stderr. here is a minimal example:
ANSWER
Answered 2021-Dec-07 at 13:29I've found the wurlitzer library, which can do exactly that, i.e., capture the streams written to by a C library:
QUESTION
I have implemented a simple randomized, population-based optimization method - Grey Wolf optimizer. I am having some trouble with properly capturing the Matplotlib plots at each iteration using the camera
package.
I am running GWO for the objective function f(x,y) = x^2 + y^2. I can only see the candidate solutions converging to the minima, but the contour plot doesn't show up.
Do you have any suggestions, how can I display the contour plot in the background?
GWO Algorithm implementation
...ANSWER
Answered 2021-Nov-29 at 00:57Is it possible that the line x = np.linspace(LB[0],LB[1],1000)
should be x = np.linspace(LB[0],UB[1],1000)
instead? With your current definition of x
, x
is an array only filled with the value -10
which means that you are unlikely to find a contour.
Another thing that you might want to do is to move the cont = plt.contour(X1,X2,Z,20,linewidths=0.75)
line inside of your plot_search_agent_positions
function to ensure that the contour is plotted at each iteration of the animation.
Once you make those changes, the code looks like that:
QUESTION
Yesterday i pushed the base image layer for my app that contained the environment needed to run my_app
.
That push was massive but it is done and up in my repo.
This is currently the image situation in my local machine:
...ANSWER
Answered 2021-Nov-26 at 13:41docker push
pushes all layers (5 at the time by default) of the image that are not equal to the image in the repository (aka the layers that did not change), not a single layer, in the end resulting in a new image in your repository.
You can see it as if Docker made a diff between the local and the remote image and pushed only the differences between those two, which will end up being a new image - equal to the one you have in your machine but with "less work" to reach the desired result since it doesn't need to push literally all the layers.
In your case it's taking a lot of time since the 4 Gb layer changed (since the content of what you are copying is different now), making Docker push a big part of the size of your image.
Link for the docker push
documentation, if needed: https://docs.docker.com/engine/reference/commandline/push/
QUESTION
In order to record the composite-video signal from a variety of analog cameras, I use a basic USB video capture device produced by AverMedia (C039).
I have two analog cameras, one produces a PAL signal, the other produces an NTSC signal:
- PAL B, 625 lines, 25 fps
- NTSC M, 525 lines, 29.97 fps (i.e. 30/1.001)
Unfortunately, the driver for the AverMedia C039 capture card does not automatically set the correct video standard based on which camera is connected.
GoalI would like the capture driver to be configured automatically for the correct video standard, either PAL or NTSC, based on the camera that is connected.
ApproachThe basic idea is to set one video standard, e.g. PAL, check for signal, and switch to the other standard if no signal is detected.
By cobbling together some examples from the DirectShow documentation, I am able to set the correct video standard manually, from the command line.
So, all I need to do is figure out how to detect whether a signal is present, after switching to PAL or NTSC.
I know it must be possible to auto-detect the type of signal, as described e.g. in the book "Video Demystified". Moreover, the (commercial) AMCap viewer software actually proves it can be done.
However, despite my best efforts, I have not been able to make this work.
Could someone explain how to detect whether a PAL or NTSC signal is present, using DirectShow in C++?
The world of Windows/COM/DirectShow programming is still new to me, so any help is welcome.
What I triedUsing the IAMAnalogVideoDecoder interface, I can read the current standard (get_TVFormat()
), write the standard (put_TVFormat()
), read the number of lines, and so on.
The steps I took can be summarized as follows:
...ANSWER
Answered 2021-Nov-16 at 15:35The mentioned property page is likely to pull the data using IAMAnalogVideoDecoder
and get_HorizontalLocked
method in particular. Note that you might be limited in receiving valid status by requirement to have the filter graph in paused or running state, which in turn might require that you connect a renderer to complete the data path (Video Renderer or Null Renderer, or another renderer of your choice).
See also this question on Null Renderer deprecation and source code for the worst case scenario replacement.
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