how to use ffmpeg in android? [duplicate]

Question

I have got FFmpeg compiled (libffmpeg.so) on Android. Now I have to build either an application like RockPlayer or use existing Android multimedia framework to invoke FFmpeg.

1. Do you have steps / procedures / code / example on integrating FFmpeg on Android / StageFright?

2. Can you please guide me on how can I use this library for multimedia playback?

3. I have a requirement where I have already audio and video transport streams, which I need to feed to FFmpeg and get it decoded / rendered. How can I do this on Android, since IOMX APIs are OMX based and cannot plug-in FFmpeg here?

4. Also I could not find documentation on the FFmpeg APIs which need to be used for playback.

Answer 1

Here are the steps I went through in getting ffmpeg to work on Android:

1. Build static libraries of ffmpeg for Android. This was achieved by building olvaffe's ffmpeg android port (libffmpeg) using the Android Build System. Simply place the sources under /external and make away. You'll need to extract bionic(libc) and zlib(libz) from the Android build as well, as ffmpeg libraries depend on them.

2. Create a dynamic library wrapping ffmpeg functionality using the Android NDK. There's a lot of documentation out there on how to work with the NDK. Basically you'll need to write some C/C++ code to export the functionality you need out of ffmpeg into a library java can interact with through JNI. The NDK allows you to easily link against the static libraries you've generated in step 1, just add a line similar to this to Android.mk: LOCAL_STATIC_LIBRARIES := libavcodec libavformat libavutil libc libz

3. Use the ffmpeg-wrapping dynamic library from your java sources. There's enough documentation on JNI out there, you should be fine.

Regarding using ffmpeg for playback, there are many examples (the ffmpeg binary itself is a good example), here's a basic tutorial. The best documentation can be found in the headers.

Good luck :)

Answer 2

For various reasons, Multimedia was and is never easy in terms of achieving the task without compromising on efficiency. ffmpeg is an effort in improving it day by day. It supports different formats of codecs and containers.

Now to answer the question of how to use this library, i would say that it is not so simple to write it here. But i can guide you in following ways.

1) Inside the ffmpeg directory of source code, you have output_example.c or api_example.c. Here, you can see the code where encoding/decoding is done. You will get an idea as to which API's inside ffmpeg you should call. This would be your first step.

2) Dolphin player is a open source project for Android. Currently it is having bugs but developers are working continuously. In that project you have the whole setup ready which you can use to continue your investigation. Here is a link to the project from code.google.com or run the command "git clone https://code.google.com/p/dolphin-player/" in a terminal. You can see two projects named P and P86 . You can use either of them.

Extra tip i would like to offer is that when you are building the ffmpeg code, inside build.sh you need to enable the muxers/demuxers/encoders/decoders of the formats you want to use. Else the corresponding code will not be included in the libraries. It took a lot of time for me to realize this. So thought of sharing it with you.

Few Basics : When we say a video file, ex : avi, it is combination of both audio and video

Video file = Video + Audio

---

Video = Codec + Muxer + Demuxer

codec = encoder + Decoder

=> Video = encoder + decoder + Muxer + Demuxer(Mpeg4 + Mpeg4 + avi +avi - Example for avi container)

---

Audio = Codec + Muxer + Demuxer

codec = encoder + Decoder

=> Audio = encoder + decoder + Muxer + Demuxer(mp2 + mp2 + avi + avi - Example for avi container)

---

Codec(name is deriverd from a combination of en*co*der/*dec*oder) is just a part of format which defines the algorithms used to encode/decode a frame. AVI is not a codec, it is a container which uses Video codec of Mpeg4 and Audio codec of mp2.

Muxer/demuxer is used to combine/separate the frames from a file used while encoding/decoding.

So if you want to use avi format, you need to enable Video components + Audio components.

Ex, for avi, you need to enable the following. mpeg4 Encoder, mpeg4 decoder, mp2 encoder, mp2 decoder, avi muxer, avi demuxer.

phewwwwwww...

Programmatically build.sh should contain the following code:

--enable-muxer=avi --enable-demuxer=avi (Generic for both audio/video. generally Specific to a container)
--enable-encoder=mpeg4 --enable-decoder=mpeg4(For video support)
--enable-encoder=mp2 --enable-decoder=mp2 (For Audio support)

Hope i idid not confuse you more after all this...

Thanks, Any assistance needed, please let me know.