flv

A library to read/write Flash Video file format (only supports AAC/AVC)

Install

Usage

Example of reading FLV file

const {readFile, print} = require('@mediafish/flv');

const buf = fs.readFileSync('test.flv');
const [offset, flv] = readFile(buf, offset);
print(flv);
/*
FLVFile {
  FLVHeader: {
    version: 1,
    hasAudio: true,
    hasVideo: true
  },
  body: [
    FLVTag: {
      timestamp: 0,
      AVC: {
        frameType: 'keyframe',
        codec: 'AVC',
        packetType: 'NALU',
        data: <Buffer length=1024 >
      }
    },
    FLVTag: {
      timestamp: 0,
      AAC: {
        format: 'AAC',
        sampleRate: '44kHz',
        size: '16Bit',
        isStereo: true,
        packetType: 'raw',
        data: <Buffer length=1024 >
      }
    },
    ...
  ]
}
*/

Example of reading Video and Audio

const {readVideo, readAudio, print} = require('@mediafish/flv');

const [offset, video] = readVideo(buf1, offset);
print(video);
/*
AVC: {
  frameType: 'keyframe',
  codec: 'AVC',
  packetType: 'NALU',
  data: <Buffer length=1024 >
}
*/

const [offset, audio] = readAudio(buf2, offset);
print(audio);
/*
AAC: {
  format: 'AAC',
  sampleRate: '44kHz',
  size: '16Bit',
  isStereo: true,
  packetType: 'raw',
  data: <Buffer length=1024 >
}
*/

Example of writing FLV

const {writeData, type: {Video, AVC, Audio, AAC, FLVFile, FLVHeader, FLVTag}} = require('@mediafish/flv');

const video = new AVC({
  frameType: Video.FrameType.keyframe,
  codec: Video.Codec.AVC,
  packetType: AVC.PacketType.NALU,
  compositionTimeOffset: 0,
  data: buf1
});


const audio = new AAC({
  format: Audio.SoundFormat.AAC,
  sampleRate: Audio.SampleRate._44kHz,
  size: Audio.SampleLength._16Bit,
  isStereo: true,
  packetType: AAC.PacketType.Raw,
  data: buf2
});

const header = new FLVHeader({version: 1, hasAudio: true, hasVideo: true});

const tags = [
  new FLVTag({type: FLVTag.TagType.audio, timestamp: 0, data: audio}),
  new FLVTag({type: FLVTag.TagType.video, timestamp: 0, data: video})
];

const flv = new FLVFile(header, tags);

// First, pass null instead of a buffer to detect how many bytes are needed
const byteLength = writeData(flv, null, 0);
// And then alloc a buff
const buffer = Buffer.alloc(byteLength);
// Finally, write the data actually to the buffer
writeData(flv, buffer, 0);

Example of writing Video and Audio

const {writeData, type: {Video, AVC, Audio, AAC}} = require('@mediafish/flv');

const video = new AVC({
  frameType: Video.FrameType.keyframe,
  codec: Video.Codec.AVC,
  packetType: AVC.PacketType.NALU,
  compositionTimeOffset: 0,
  data: buf1
});


const audio = new AAC({
  format: Audio.SoundFormat.AAC,
  sampleRate: Audio.SampleRate._44kHz,
  size: Audio.SampleLength._16Bit,
  isStereo: true,
  packetType: AAC.PacketType.Raw,
  data: buf2
});

// First, pass null instead of a buffer to detect how many bytes are needed
const videoLength = writeData(video, null, 0);
const audioLength = writeData(audio, null, 0);
// And then alloc a buff
const buffer = Buffer.alloc(videoLength + audioLength);
// Finally, write the data actually to the buffer
let offset = 0;
offset = writeData(video, buffer, offset);
offset = writeData(audio, buffer, offset);

API

readFile(buffer, offset)

Read FLV file from the buffer

params

| Name | Type | Required | Default | Description | | -------- | ------- | -------- | ------- | ------------- | | buffer | Buffer or Uint8Array | Yes | N/A | The buffer from which the data is read | | offset | number | Yes | N/A | An integer to specify the position within the buffer |

return value

An array containing the following pair of values

| Index | Type | Description | | ----- | ------ | ------------ | | [0] | number | An integer to indicate the position from which the next data should be read | | [1] | FLVFile | The read data (See Data format) |

readVideo(buffer, offset, length)

Read video data from the buffer

params

| Name | Type | Required | Default | Description | | -------- | ------- | -------- | ------- | ------------- | | buffer | Buffer or Uint8Array | Yes | N/A | The buffer from which the data is read | | offset | number | Yes | N/A | An integer to specify the position within the buffer | | length | number | Yes | N/A | An integer to specify how many bytes to read |

return value

An array containing the following pair of values

| Index | Type | Description | | ----- | ------ | ------------ | | [0] | number | An integer to indicate the position from which the next data should be read | | [1] | AVC | The read data (See Data format) |

readAudio(buffer, offset)

Read audio data from the buffer

params

| Name | Type | Required | Default | Description | | -------- | ------- | -------- | ------- | ------------- | | buffer | Buffer or Uint8Array | Yes | N/A | The buffer from which the data is read | | offset | number | Yes | N/A | An integer to specify the position within the buffer | | length | number | Yes | N/A | An integer to specify how many bytes to read |

return value

An array containing the following pair of values

| Index | Type | Description | | ----- | ------ | ------------ | | [0] | number | An integer to indicate the position from which the next data should be read | | [1] | AAC | The read data (See Data format) |

writeData(data, buffer, offset)

Write data to the buffer

params

| Name | Type | Required | Default | Description | | -------- | ------- | -------- | ------- | ------------- | | data | AVC/AAC/FLVHeader/FLVTag/FLVFile | Yes | N/A | The data to be written to the buffer | | buffer | Buffer | No | null | The buffer to which the data is written. If null, only the necessary buffer size is calculated | | offset | number | Yes | N/A | An integer to specify the position within the buffer |

return value

An integer to indicate the position from which the next data should be read

setOptions(obj)

Updates the option values

params

| Name | Type | Required | Default | Description | | ------- | ------ | -------- | ------- | ------------- | | obj | Object | Yes | {} | An object holding option values which will be used to overwrite the internal option values. |

supported options

| Name | Type | Default | Description | | ---------- | ------- | ------- | ------------- | | strictMode | boolean | false | If true, the function throws an error when the method invocations failed. If false, the function just logs the error and continues to run.|

getOptions()

Retrieves the current option values

return value

A cloned object containing the current option values

Data format

This section describes the structure of the data that can be read / written using readFile/readAudio/readVideo

FLVFile

| Property | Type | Description | | -------- | ----------- | ------------- | | header | FLVHeader | An instance of FLVHeader | | body | [FLVTag] | An array of FLVTag |

FLVHeader

| Property | Type | Description | | ---------- | ------- | ------------- | | version | number | FLV version | | hasAudio | boolean | Audio tags are present | | hasVideo | boolean | Video tags are present |

FLVTag

| Property | Type | Description | | ----------- | --------------------- | ------------- | | type | enum FLVTag.TagType | Type of this tag | | timestamp | number | Time in milliseconds at which the data in this tag applies | | data | Audio or Video | An instance of Audio / Video |

Audio

| Property | Type | Description | | ------------ | ------------------------- | ------------- | | format | enum Audio.SoundFormat | Type of this tag. Only AAC is supported. | | sampleRate | enum Audio.SampleRate | sample rate | | size | enum Audio.SampleLength | bits per sample | | isStereo | boolean | mono / stereo | | data | Buffer or Uint8Array | Format specific data. |

AAC extends Audio

| Property | Type | Description | | ------------ | --------------------- | --------------- | | packetType | enum AAC.PacketType | AAC packet type |

Video

| Property | Type | Description | | ----------- | ------------------------ | ------------- | | frameType | enum Video.FrameType | Type of the frame included in this tag | | codec | enum Video.Codec | Type of codec used to compress the frame. Only AVC is supported. | | data | Buffer or Uint8Array | Codec specific data. |

AVC extends Video

| Property | Type | Description | | ----------------------- | --------------------- | --------------- | | packetType | enum AVC.PacketType | AVC packet type | | compositionTimeOffset | number | Composition time offset |