I want record screen (by capturing 15 screenshots per second). This part I know how to do. But I don't know how to write this to some popular video format. Best option which I found is write frames to separated PNG files and use commandline Mencoder which can convert them to many output formats. But maybe someone have another idea?
Requirements:
Must be multi-platform solutions (I'm using Free Pascal / Lazarus). Windows, Linux, MacOS
Exists some librarys for that?
Could be complex commandline application which record screen for me too, but I must have possibility to edit frames before converting whole raw data to popular video format
All materials which could give me some idea are appreciated. API, librarys, anything even in other languages than FPC (I would try rewrite it or find some equivalent)
I considered also writting frames to video RAW format and then use Mencoder (he can handle it) or other solution, but can't find any API/doc for video RAW data
Regards
Argalatyr mentioned ffmpeg already.
There are two ways that you can get that to work:
By spawning an new process. All you have to do is prepare the right input (could be a series of jpeg images for example), and the right commandline parameters. After that you just call ffmpeg.exe and wait for it to finish.
ffmpeg makes use of some dll's that do the actual work. You can use those dll's directly from within your Delphi application. It's a bit more work, because it's more low-level, but in the end it'll give you a finer control over what happens, and what you show the user while you're processing.
Here are some solutions to check out:
FFVCL Commercial. Actually looks quite good, but I was too greedy to spend money on this.
Open Source Delphi headers for FFMpeg. I've tried it, but I never managed to get it to work.
I ended up pulling the DLL wrappers from an open source karaoke program (UltraStar Deluxe). I had to remove some dependencies, but in the end it worked like a charm. The relevant (pascal) code can be found here:
http://ultrastardx.svn.sourceforge.net/viewvc/ultrastardx/trunk/src/lib/ffmpeg-0.10/
There was some earlier discussion with a Delphi component here. It's a very simple component that sometimes generates some weird movies. Maybe a start.
Related
My goal is as follows: I have to read in a video that is stored on the sd card, process it frame for frame and then store it in a new file on the SD card again，In each image to do image processing.
At first I wanted to use opencv for android but I did not seem to be able to read the video
here.
I am guessing you already know that doing this on a mobile device or any compute limited devices is not ideal, simply because video manipulation is very computer intensive which translates to slow execution and heavy battery usage on many devices. If you do have the option to do the processing on the server side it is definitely worth considering.
Assuming that for your use case you need to do it on the mobile device, then OpenCV on Android will now allow you to read in a video and access each frame - #StephenG mentions this in his answer to the question you refer to above.
In the past, functionality like this did not get ported to the Android OpenCv as the guidance was to use ffmpeg for frame grabbing on Android devices.
According to more recent documentation, however, this should be available for Android now using the VideoCapture class (note I have not used this myself...):
http://docs.opencv.org/java/2.4.11/org/opencv/highgui/VideoCapture.html
It is worth noting that OpenCV Android examples are all currently based around Eclipse and if you want to use Studio, getting things up an running initially can be quite tricky. The following worked for me recently, but as both studio and OpenCV can change over time you may find you have to do some forum hunting if it does not work for you:
https://stackoverflow.com/a/35135495/334402
Taking a different approach, you can use ffmpeg itself, in a wrapper in Android, for tasks like this.
The advantage of the wrapper approach is that you can use all the usual command line syntax and there is a lot of info on the web to help you get the right parameters.
The disadvantage is that ffmpeg was not really designed to be wrapped in this way so you do sometimes see issues. Having said that it is a common approach now and so long as you choose a well used wrapper library you should at least have a good community to discuss any issues you come across with. I have used this approach in a hand crafted way in the past but if I was doing it again I would use one of the popular examples such as:
https://github.com/WritingMinds/ffmpeg-android-java
I have sound, video source file and I have to verify my program which open and play this file is work correctly.
I don't know how to verify file like this!
I think i should capture (sound/video) and then compare it to source file.
Till this time, I've searched on the internet but didn't get any solution.
This is going to be a real challange for you, I personally have never done this but hopefully I can provide you with some help to set you on your way...
First you need to know that robotframework is run on python so anything you will need to be in python or have python bindings so asking there may be a good start.
In terms of capturing sound I believe it would be eaiser to use a program with a api you can use, I found a document here of someone doing this, as to whether this is still correct I am not sure:
http://www.nektra.com/files/DirectSound_Capture_With_Deviare.pdf
For video capture try looking here:
https://www.youtube.com/watch?v=j344j34JBRs
Next would be stripping the video, seperating the audio and video frames and comparing them seperatly. For this you are going to need a video editor, audio comparison library and a tool for comparing images.
In terms of how this would work I dont know as I have never done this...
Why do you need to do this tho, is there not a better way of doing this? Does you application make the video? In which case could just doing some checks on frames, length, file size suffice? You need to provide for information.
This is a bit long for a comment but this answer is incomplete.
Let me know how you get on?
I was wondering so long that how can people analyze the trait of each file extension (of course open it in notepad is not readable)
For example, I want to write a program that can read everything from .fla file like timeline, movie clips, position of each MCs or all the motion tween values. And get the image embeded in it. (I'm planning to use flash as IDE for another project.)
(The reason that I tried to read proprietary format is I want to utilize their awesome editor. What I actually want to do is, I want to make an iOS game with cocos2d. There is a code to move things around in cocos2d but there is no decent editor. So I'd like to use Flash as an editor, then convert the motion to objective-C cocos2D code by reading the .fla file.)
If you would like to be able to import timeline animation from flash into cocos2d, this tool might help. More information in this thread.
The grapefrukt-exporter might also help as it can export keyframe data, and various other formats for animation.
Instead of creating the tool yourself, it might be much easier (and time saving) to use one of these and integrate it into your workflow :)
Finally, if none of the above works, how about just exporting the flash animation as an animated GIF or a movie file?
Im assuming you want to write a decompiler, this is possible and there are several available on the internet, price varies.
It is not possible for flash to achieve this, Most programs, software are built on a native language such as C, Native meaning it can independly run in its own with out initially setting up an invironment to support it.
Flash is not independent enough to be available to have this much power.
Try looking at c++ or C# as this would be possible, also these languages are a lot more powerful.
I am trying to deserialize an old file format that was serialized in Delphi, it uses binary seralization. I know nothing about the structure of the file except some very high level records that are in it.
What steps would you take to solve this problem? Any tools etc?
A good hexeditor, and use the gray matter to identify structures.
If you get a hint what kind of file it is, you can search for more specialized tools.
Running the unix/Linux "file" command can be good too (*) See Barry's comment below for how it works. It can be a quick check for common filetypes like DBF,ZIP etc hidden by using a different extension.
(*) there are 3rd party builds for windows, but they might lag in versions. If you can do it on a recent *nix distro, it is advised to do so.
The serialization process simply loops over all published properties and streams their value to a text file. If you do not know the exact classes that were streamed to the file you will have a very hard time deserializing the file. (if not impossible)
A good hex editor is first. If the file is read without buffering (eg read directly from a TFileStream) you could gain some information when using ProcMon from SysInternals; You can see exactly what data is read in what chunks and thus determine more quickly where the boundaries are between the structures you already identified.
My next project will be all about language tools, parsing and such. Because of that reason I've decided to write a simple language which can be used for video editing. So instead of those desktop applications (Sony vegas, Adobe Premiere, ..) it's basically a language where you define the effects and all and it will generate a video for you.
Since I've got no experience in this kind of business I need some help. The goal of the project is to create a simple language which is able to do some basic things (such as text fading in, etc). I am looking for articles/projects/blogs/whatever related with this which could help me writing this language. (Note that I don't need articles about language parsing since I'm pretty familar with that, just the video editing part).
Thanks,
William v. Doorn
I if understand right your goal, you should take a look at Avisynth. I use it -and like it. It's for Windows only, but conceptually it seems to have what you are going after: a script language for non-linear video editing.
I'm having trouble understanding the purpose of writing such code.
If you are intending on creating a tool that a user can use to edit a video by supplying a set of commands, how is forcing the user to write text better than the GUI video editors that are available? Its going to have a pretty low usability in this situation.
If you are looking for a way to automate some kind of editing process, some video editors like VirtualDub already contain tools for batching and plugins to allow them to be automated.
Are you actually looking to make a tool that will be used by someone to edit video or is this for your own intellectual curiosity?
The best starting point can be installing trial version of the common video editing softwares and see what they offer.
When it comes to writing video editing software, I always see ffmpeg mentioned.
From the site:
FFmpeg is a complete, cross-platform solution to record, convert and stream audio and video. It includes libavcodec - the leading audio/video codec library.