Manipulate subtitles in GO (.srt, .stl, .ttml, .webvtt, .ssa/.ass, teletext, .smi, etc.).

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This is a Golang library to manipulate subtitles. 

It allows you to manipulate `srt`, `stl`, `ttml`, `ssa/ass`, `webvtt` and `teletext` files for now.

Available operations are `parsing`, `writing`, `applying linear correction`, `syncing`, `fragmenting`, `unfragmenting`, `merging` and `optimizing`.

# Installation

To install the library:

    go get github.com/asticode/go-astisub

To install the CLI:

    go install github.com/asticode/go-astisub/astisub        

# Using the library in your code

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

```go
// Open subtitles
s1, _ := astisub.OpenFile("/path/to/example.ttml")
s2, _ := astisub.ReadFromSRT(bytes.NewReader([]byte("1\n00:01:00.000 --> 00:02:00.000\nCredits")))

// Add a duration to every subtitles (syncing)
s1.Add(-2*time.Second)

// Fragment the subtitles
s1.Fragment(2*time.Second)

// Merge subtitles
s1.Merge(s2)

// Optimize subtitles
s1.Optimize()

// Unfragment the subtitles
s1.Unfragment()

// Apply linear correction
s1.ApplyLinearCorrection(1*time.Second, 2*time.Second, 5*time.Second, 7*time.Second)

// Write subtitles
s1.Write("/path/to/example.srt")
var buf = &bytes.Buffer{}
s2.WriteToTTML(buf)
```

# Using the CLI

If **astisub** has been installed properly you can:

- convert any type of subtitle to any other type of subtitle:

        astisub convert -i example.srt -o example.ttml

- apply linear correction to any type of subtitle:

        astisub apply-linear-correction -i example.srt -a1 1s -d1 2s -a2 5s -d2 7s -o example.out.srt

- fragment any type of subtitle:

        astisub fragment -i example.srt -f 2s -o example.out.srt

- merge any type of subtitle into any other type of subtitle:

        astisub merge -i example.srt -i example.ttml -o example.out.srt

- optimize any type of subtitle:

        astisub optimize -i example.srt -o example.out.srt

- unfragment any type of subtitle:

        astisub unfragment -i example.srt -o example.out.srt

- sync any type of subtitle:

        astisub sync -i example.srt -s "-2s" -o example.out.srt

# Features and roadmap

- [x] parsing
- [x] writing
- [x] syncing
- [x] fragmenting/unfragmenting
- [x] merging
- [x] ordering
- [x] optimizing
- [x] linear correction
- [x] .srt
- [x] .ttml
- [x] .vtt
- [x] .stl
- [x] .ssa/.ass
- [x] .teletext
- [ ] .smi


go-astisub

Parse and demux MPEG Transport Streams (.ts) natively in GO.

go-astits

# Deprecation Notice

This repository is no longer maintained.

# goav
Golang binding for FFmpeg

A comprehensive binding to the ffmpeg video/audio manipulation library.

[![GoDoc](https://godoc.org/github.com/giorgisio/goav?status.svg)](https://godoc.org/github.com/giorgisio/goav)

## Usage

`````go

import "github.com/giorgisio/goav/avformat"

func main() {

	filename := "sample.mp4"

	// Register all formats and codecs
	avformat.AvRegisterAll()

	ctx := avformat.AvformatAllocContext()

	// Open video file
	if avformat.AvformatOpenInput(&ctx, filename, nil, nil) != 0 {
		log.Println("Error: Couldn't open file.")
		return
	}

	// Retrieve stream information
	if ctx.AvformatFindStreamInfo(nil) < 0 {
		log.Println("Error: Couldn't find stream information.")

		// Close input file and free context
		ctx.AvformatCloseInput()
		return
	}

	//...

}
`````

## Libraries

* `avcodec` corresponds to the ffmpeg library: libavcodec [provides implementation of a wider range of codecs]
* `avformat` corresponds to the ffmpeg library: libavformat [implements streaming protocols, container formats and basic I/O access]
* `avutil` corresponds to the ffmpeg library: libavutil [includes hashers, decompressors and miscellaneous utility functions]
* `avfilter` corresponds to the ffmpeg library: libavfilter [provides a mean to alter decoded Audio and Video through chain of filters]
* `avdevice` corresponds to the ffmpeg library: libavdevice [provides an abstraction to access capture and playback devices]
* `swresample` corresponds to the ffmpeg library: libswresample [implements audio mixing and resampling routines]
* `swscale` corresponds to the ffmpeg library: libswscale [implements color conversion and scaling routines]


## Installation

[FFMPEG INSTALL INSTRUCTIONS](https://github.com/FFmpeg/FFmpeg/blob/master/INSTALL.md)

``` sh
sudo apt-get -y install autoconf automake build-essential libass-dev libfreetype6-dev libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev libvorbis-dev libxcb1-dev libxcb-shm0-dev libxcb-xfixes0-dev pkg-config texi2html zlib1g-dev

sudo apt install -y libavdevice-dev libavfilter-dev libswscale-dev libavcodec-dev libavformat-dev libswresample-dev libavutil-dev

sudo apt-get install yasm

export FFMPEG_ROOT=$HOME/ffmpeg
export CGO_LDFLAGS="-L$FFMPEG_ROOT/lib/ -lavcodec -lavformat -lavutil -lswscale -lswresample -lavdevice -lavfilter"
export CGO_CFLAGS="-I$FFMPEG_ROOT/include"
export LD_LIBRARY_PATH=$HOME/ffmpeg/lib
``` 

``` 
go get github.com/giorgisio/goav

``` 

## More Examples

Coding examples are available in the examples/ directory.

## Note
- Function names in Go are consistent with that of the libraries to help with easy search
- [cgo: Extending Go with C](http://blog.giorgis.io/cgo-examples)
- goav comes with absolutely no warranty.

## Contribute
- Fork this repo and create your own feature branch.
- Follow standard Go conventions
- Test your code.
- Create pull request

## TODO

- [ ] Returning Errors
- [ ] Garbage Collection
- [X] Review included/excluded functions from each library
- [ ] Go Tests
- [ ] Possible restructuring packages
- [x] Tutorial01.c
- [ ] More Tutorial

## License
This library is under the [MIT License](http://opensource.org/licenses/MIT)


The Best Go Libraries For Video (4)

go-astisub

go-astits

goav

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