My app takes time-lapse photos, and also records audio to go with it. The problem is, I have absolutely no idea how to go about turning it into a .mov/.mpeg file (I am new to this type of iPhone development). I have heard some things about FFMPEG, but apparently the license doesn't cover the public distribution of iPhone apps. Anyone have any suggestions?
you can use Theora aka VP3. it is free to use in any application and has a pretty decent quality/bitrate ratio
I do not know whether the necessary parts of FFmpeg to do this is GPL or not, but there are parts of FFmpeg that are LGPL-licensed.
They have a legal page that covers this in detail, so FFmpeg might be worth a closer look.
FFmpeg itself can be used in iphone apps distributed on the appstore. See wunderradio as an example: http://www.wunderradio.com/code.html
BUT... I am experimenting with it right now and I am kinda disappointed with the quality of the result. (not to mention that encoding is sloooow on the iphone) It seems to me that without the x264 library it is impossible to create mpeg-4 videos with decent quality. And x264 is GPL licensed, so if you use it, you must disclose the full source of your project. (Or did anyone figure out how to select some usable codec from the LGPL-d FFmpeg?)
What I don't understand is that the appstore has now a lot of video editing apps. How do they work? I made a pretty thorough search, and couldn't find any mpeg-4 codec with a permissive enough license. Do they violate GPL? Do they use private API? I really don't believe that they built a homebrew mpeg4 encoder.
Related
i'm trying to make a C++ engine that will read a mp3 file, and make some image zoom/translation depending on the time of the reading sound file. I think I could use OpenGL ES to render what I want, and calling some OpenGL ES instructions in my C++ files, and init my drawing context in Obj-C/Java. I want to do the same for the sound, but i don't really know what to use, and if I can really do it or not in C++.
I searched for library so I found Bass and Fmod (which is not free for commercial use). They said it's multicross platform (Windows, Unix, MacOS) but I dont understand if it manners for mobile, and if I can really use it. Does anyone have been through this? Do you recommand me another free library?
Thanks again, and I apologize for my poor english,
Arnaud
Have a look at libpd (Pure Data for embedded applications)
http://download.puredata.info/libpd (the library has been released very recently, but the code is very mature indeed)
http://createdigitalmusic.com/2010/10/libpd-put-pure-data-in-your-app-on-an-iphone-or-android-and-everywhere-free/
Audio is often problematic and it is pretty much always a good idea to write your own high-level API that does exactly what you want to do (and nothing else) and to assume you will then be writing a thin layer between it and whatever audio library you are using underneath. If you're lucky and there's a library available that does things the way you would do them then it's trivial. If not, at least it's still possible. In either case, your app code is not tied to an external sound API.
I have used FMOD on multiple different commercial projects over the years for PC, Mac and iPhone, and have always liked it - but it's not free. OpenAL has always seemed sorta, I dunno: clunky? But you only have to deal with it when writing your API layer, and your app code never has to see it.
It's easy for me to say "write your own API" since I've been writing commercial games for 20 years and so know what I think an audio API should look like. If you don't have your own idea how you think it should be, then I suggest you look at a 3rd party library that makes sense to you and take the functions from it that you will be using and write your own API to do be a set of functions that do nothing but call those.
Since you have both OpenAL and FMOD available to you free for development you can then make your API work with both, and chances are it's then going to work with anything else you might come across.
OpenAL may be your best bet. Look at this answer: Android OpenAL?
It seems possible to compile OpenAL on Android.
If you are looking for just PCM audio input/output ( and not MP3 decoding ) try PortAudio or RTAudio
RtAudio or PortAudio, which one to use?
I'm looking for a way (doesn't need to be app-store save!!) to get ahold of video-streaming-relevant debugging information.
What I'm trying to do, is to write an application that opens a video stream and displays information like:
framerate
bitrate audio / video
etc etc.
codec information
basically i want to display as much information for any given stream.
Thanks for any information in advance,
best regards
sam
Even though you tagged your question with MPMoviePlayerController, that class probably isn't going to help you out very much. First of all, there's a limited amount of information you can access from it at a high level, certainly nothing about codecs and audio bitrate. And even if the class does store this type of information somehow, your app would be disqualified from being in the iTunes App Store if you access non-public methods or properties.
Secondly, MPMoviePlayerController only supports a limited number of codecs itself, namely the ones that can be decoded in hardware on the iPhone/iPad (H.264 baseline and MPEG-4 videos).
Anyways, a good option could be FFMpeg for the iPhone. Getting the information you need seems to be much more straightforward this way; check out this blog post for a nice tutorial for using the libraries.
I'm not sure about the potential legal issues concerning distributing such a program in the App Store, but if you statically link it with your binary that would at least satisfy Apple... you'll have to check the FFMpeg Legal Site for their end.
I need to convert image sequences(ie,png) to video file in iPhone. How i can convert the images to video.
Regards,
Just ignore bad advice like "use ffmpeg". That would work on the desktop, but the license issue makes including ffmpeg source code in your iPhone app legally questionable. Apple provides a class named AVAssetWriter that you would use in your app to encode a series of images as h.264 stored in a .m4v quicktime container file. While the apple provided logic does work, it is not so easy to actually use and you will need to read quite a lot of documentation to get the code working. If you want to skip implementing it yourself (and likely save yourself 3 or 4 days of work), please consider using my AVAnimator library for iOS as the h.264 encoding logic is already implemented in the class AVAssetWriterConvertFromMaxvid. Once encoded as h.264, the video can be played with the standard player and it is small enough to upload to a remote server.
You are likely going to need something like FFMPEG
I'd like to be able to take a screenshot of an MPEG recorded using the iPhone camera at set intervals.
I've seen a few ways to do this; namely compiling and using FFmpeg (Using FFMPEG library with iPhone SDK for video encoding), however it seems it's quite difficult to comply with the LGPL (http://ffmpeg.org/legal.html) for commercial use.
This term of the contract pretty much makes it useless to us:
Q: Is it perfectly alright to incorporate the whole FFmpeg core into my own commercial product?
A: You might have a problem here. There have been cases where companies have used FFmpeg in their products. These companies found out that once you start trying to make money from patented technologies, the owners of the patents will come after their licensing fees. Notably, MPEG LA is vigilant and diligent about collecting for MPEG-related technologies.
Is there any other way? - or simply by accessing the rendering layer of an MPEG am I going to be "making money from patented technologies"?
As usual - any help on this would be greatly appreciated.
Cheers!
Yes, you can do it - if I am not wrong, since iOS 3.2... at least for the videos you have on your library. After loading the movie on your MPMoviePlayerController object, do this
UIImage *aThumbnail = [player thumbnailImageAtTime:timeCode timeOption:MPMovieTimeOptionExact];
//timeCode is a time within de video length, for example: 3.12 seconds.
//player is the MPMoviePlayerController object.
Unfortunately there is no official way to grab image frames from the camera in realtime.
I encourage you to file a bug report / feature request with Apple. Many people want this. If many people request a specific feature then they might consider to actually put this in.
The iPhone app I am working on captures images in series within certain user-defined time interval, I am looking for a way to combine these images into H264 encoded videos. I have done some research on Google, it looks like I will have to use something like ffmpeg/mencoder on iPhone? (Also found someone ported ffmpeg to iPhone, ffmpeg4iPhone)
However, I found that x264 is under GPL license, and requires me to open source my project if I use ffmpeg. Also found some people suggested to use Ogg Theora, but I will need to port it to iPhone if I use it. (Which I am not sure how to do it now).
Is there any workaround for this? Any ideas? Thanks.
I think you are in a GPL-bind there and have two suggestions:
Just go ahead and GPL your project. There is no reason you cannot sell open source software, and the app store's delay/penalty period will give you a nice lead time over any potential completing project with the GPL'd code. Your place on iTunes store, your motivation and any branding is probably more valuable than the source code. Plus, you can get other people to fix bugs for you. Update: As of January 2011, GPL and App Store do not mix.
Have the iPhone app upload the raw images to a server and do the processing there. That way you are not releasing and distributing the FFmpeg and x264 code, and are hence not required to distribute it.
Good luck and let us know here if you get it published!
Appears ffmpeg now has support for cisco's "openh264" (BSD FWIW) encoding codec:
https://www.ffmpeg.org/ffmpeg-codecs.html#libopenh264
FWIW here is what I get from my LGPL build:
ffmpeg.exe -codecs | grep h264
...
ffmpeg version n3.1.2 Copyright (c) 2000-2016 the FFmpeg developers
DEV.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_qsv ) (encoders: libopenh264 h264_nvenc h264_qsv nvenc nvenc_h264 )
which mentions a few other encoders FWIW, and FFmpeg might support even others.
I believe you'll only be able to find commercial versions of x264 implementations if you don't intend to use ffmpeg (there might exist a few other opensource versions but with very low quality). Also, you need to bear in mind that if you make use of those codecs and you decide not to use the platform/iPhone ones you will have to pay royalties because of the patents (I think it's roughly 1 dollar per download).
If this is still affordable to you, then I believe you might be able to find an older version of ffmpeg that was LGPL'ed. You can use this in your code without having to open source the whole project. You only need to opensource changes that you might make to ffmpeg.
Hope this helps!