This is a Golang library to natively demux and mux MPEG Transport Streams (ts) in GO.

WARNING: this library is not yet production ready. Use at your own risks!

Installation

To install the library use the following:

go get -u github.com/asticode/go-astits/...

To install the executables use the following:

go install github.com/asticode/go-astits/cmd

Before looking at the code...

The transport stream is made of packets.
Each packet has a header, an optional adaptation field and a payload.
Several payloads can be appended and parsed as a data.

                                           TRANSPORT STREAM
 +--------------------------------------------------------------------------------------------------+
 |                                                                                                  |
 
                       PACKET                                         PACKET
 +----------------------------------------------+----------------------------------------------+----
 |                                              |                                              |
 
 +--------+---------------------------+---------+--------+---------------------------+---------+
 | HEADER | OPTIONAL ADAPTATION FIELD | PAYLOAD | HEADER | OPTIONAL ADAPTATION FIELD | PAYLOAD | ...
 +--------+---------------------------+---------+--------+---------------------------+---------+
 
                                      |         |                                    |         |
                                      +---------+                                    +---------+
                                           |                                              |
                                           +----------------------------------------------+
                                                                DATA

Using the library in your code

WARNING: the code below doesn't handle errors for readability purposes. However you SHOULD!

Demux

// Create a cancellable context in case you want to stop reading packets/data any time you want
ctx, cancel := context.WithCancel(context.Background())

// Handle SIGTERM signal
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGTERM)
go func() {
    <-ch
    cancel()
}()

// Open your file or initialize any kind of io.Reader
// Buffering using bufio.Reader is recommended for performance
f, _ := os.Open("/path/to/file.ts")
defer f.Close()

// Create the demuxer
dmx := astits.NewDemuxer(ctx, f)
for {
    // Get the next data
    d, _ := dmx.NextData()
    
    // Data is a PMT data
    if d.PMT != nil {
        // Loop through elementary streams
        for _, es := range d.PMT.ElementaryStreams {
                fmt.Printf("Stream detected: %d\n", es.ElementaryPID)
        }
        return
    }
}

Mux

// Create a cancellable context in case you want to stop writing packets/data any time you want
ctx, cancel := context.WithCancel(context.Background())

// Handle SIGTERM signal
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGTERM)
go func() {
    <-ch
    cancel()
}()

// Create your file or initialize any kind of io.Writer
// Buffering using bufio.Writer is recommended for performance
f, _ := os.Create("/path/to/file.ts")
defer f.Close()

// Create the muxer
mx := astits.NewMuxer(ctx, f)

// Add an elementary stream
mx.AddElementaryStream(astits.PMTElementaryStream{
    ElementaryPID: 1,
    StreamType:    astits.StreamTypeMetadata,
})

// Write tables
// Using that function is not mandatory, WriteData will retransmit tables from time to time 
mx.WriteTables()

// Write data
mx.WriteData(&astits.MuxerData{
    PES: &astits.PESData{
        Data: []byte("test"),
    },
    PID: 1,
})

Options

In order to pass options to the demuxer or the muxer, look for the methods prefixed with DemuxerOpt or MuxerOpt and add them upon calling NewDemuxer or NewMuxer :

// This is your custom packets parser
p := func(ps []*astits.Packet) (ds []*astits.Data, skip bool, err error) {
        // This is your logic
        skip = true
        return
}

// Now you can create a demuxer with the proper options
dmx := NewDemuxer(ctx, f, DemuxerOptPacketSize(192), DemuxerOptPacketsParser(p))

CLI

This library provides 2 CLIs that will automatically get installed in GOPATH/bin on go get execution.

astits-probe

List streams

$ astits-probe -i <path to your file> -f <format: text|json (default: text)>

List packets

$ astits-probe packets -i <path to your file>

List data

$ astits-probe data -i <path to your file> -d <data type: eit|nit|... (repeatable argument | if empty, all data types are shown)>

astits-es-split

Split streams into separate .ts files

$ astits-es-split <path to your file> -o <path to output dir>

asticode/go-astits

asticode

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