FFmpeg code examples

FFmpeg coding tutorial - learn how to code custom transmuxing, transcoding, metadata extraction, frame-by-frame reading and more

Intro

Welcome, weary traveller! Let me guess why you're here ;) Maybe because you've been trying to figure out how to use libav libraries (libavformat/libavcodec/etc) and failed miserably? Well, it's no suprise, given the fact that ffmpeg is a product made by engineers for engineers. Existing documentation is either lacking or outdated, examples you find online don't work for whatever reason (most probably they are not compatible with latest FFmpeg source). This repo will hopefully help :3 I've spent a bit of time to research on ffmpeg internals while trying to figure out how to do remuxing and transcoding with libav. This repo is my attempt to share my findings and spare you some time. Code in this repo is not just some snippets, each file is fully finished example that compiles and runs. This repo was inspired by https://github.com/leandromoreira/ffmpeg-libav-tutorial, some other really useful pointers can also be found here: https://ffmpeg.org/doxygen/trunk/examples.html and here: https://github.com/FFmpeg/FFmpeg/tree/master/doc/examples

Required software and dependencies

We will need 3 things:

• linux (my examples are tested on centos and ubuntu only)
• c++ compiler (even though c++ is used marginally in my examples)
• compiled ffmpeg libraries

Installing dependencies

2 DO: compiler, dep libs

Compiling FFmpeg

It's possible to install libav binaries from ready packages, for example sudo apt-get install -y libav-tools, but I prefer to use the latest stable release of FFmpeg for this and compile everything from source.

2 DO: ffmpeg compilation and installation of libav libs, static and dynamic

Compiling all examples

git clone [email protected]:tinybit/ffmpeg_code_examples.git
cd ffmpeg_code_examples
make

Examples

WARNING: THIS IS NOT PRODUCTION READY CODE! It's intended use is to get familiar with libav and compile working examples.

After compilation you will find a bunch of binaries in project root. Their meaning and usage are described below. These examples are not ordered in any particular way, "Example 1" does not mean it's simplier that others, even though I've tried keeping code clean and well commented for ease of understanding. Any suggestions / bugfixes are welcome.

Example 1 - Remuxing

Source: 01-remuxing.cpp
Binary: remux
Function: Remuxes from any container with h264 encoded video to FLV container
Notes: None
Usage: Tool takes 2 input arguments

1. Path to video file. file should be encoded with h264 codec, in whatever container (mpeg ts, for example)
2. Output filename. output file will be written to current directory you're in

./remux test_x264.mp4 test.flv

Example 2 - Reading input stream from memory

Source: 02-reading-from-memory.cpp
Binary: remux_from_memory
Function: Reads mpeg ts h264 data from file, puts it into memory buffer and remuxes to FLV on the fly
Notes: Shows how to create AVFormatContext that reads from memory buffer using customized i/o context (AVIOContext)
Usage: Tool takes 2 input arguments

1. Path to video file. file should be encoded with h264 codec, in whatever container (mpeg ts, for example)
2. Output filename. output file will be written to current directory you're in

./read_from_memory test_x264.mp4 test.flv

Example 3 - Writing output stream to memory

Source: 03-writing-to-memory.cpp
Binary: remux_to_memory
Function: Reads mpeg ts h264 data from file stream, remuxes it to FLV on the fly and writes results to memory buffer Notes: Shows how to create AVFormatContext that reads from memory buffer using customized i/o context (AVIOContext)
Usage: Tool takes 2 input arguments

1. Path to video file. file should be encoded with h264 codec, in whatever container (mpeg ts, for example)
2. Output filename. output file will be written to current directory you're in

./write_to_memory test_x264.mp4 test.flv

Example 4 - Reading input stream from SRT, remux to FLV and write result to file

Source: 04-reading-from-srt.cpp
Binary: srt_to_flv
Function: Receives mpeg ts h264 data from SRT stream, puts it into memory buffer and remuxes to FLV on the fly
Notes: Advanced example. Shows how to create simple SRT server and process received media stream with libav. Similar to example 2, but we're reading data sent over the network. Please note that this is not a full-fledged server, it will correctly handle one incoming connection only.
Usage: Tool takes 3 input arguments

1. ip. for SRT server to bind to
2. port. for SRT server to run on
3. Output filename. output file will be written to current directory you're in

./srt_to_flv 0.0.0.0 9999 test.flv

Example 5 - Get media info

2 DO

Example 6 - Transcoding

2 DO

Example 7 - Streaming to rtmp server

2 DO