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node-av / lib / AudioFifo

Class: AudioFifo ​

Defined in: src/lib/audio-fifo.ts:44

Audio FIFO (First-In-First-Out) buffer for managing audio samples.

Provides a thread-safe buffer for audio sample data, supporting both planar and interleaved formats. Automatically handles buffer reallocation when needed. Essential for audio resampling, format conversion, and buffering operations.

Direct mapping to FFmpeg's AVAudioFifo.

Example ​

typescript
import { AudioFifo, FFmpegError } from 'node-av';
import { AV_SAMPLE_FMT_FLTP } from 'node-av/constants';

// Create FIFO for stereo float planar audio
const fifo = new AudioFifo();
fifo.alloc(AV_SAMPLE_FMT_FLTP, 2, 4096);

// Write samples
const leftChannel = Buffer.alloc(1024 * 4);  // 1024 float samples
const rightChannel = Buffer.alloc(1024 * 4);
const written = await fifo.write([leftChannel, rightChannel], 1024);
FFmpegError.throwIfError(written, 'write');

// Read samples when enough available
if (fifo.size >= 512) {
  const outLeft = Buffer.alloc(512 * 4);
  const outRight = Buffer.alloc(512 * 4);
  const read = await fifo.read([outLeft, outRight], 512);
  FFmpegError.throwIfError(read, 'read');
}

// Cleanup
fifo.free();

See ​

AudioFifo - FFmpeg Doxygen

Implements ​

Constructors ​

Constructor ​

new AudioFifo(): AudioFifo

Defined in: src/lib/audio-fifo.ts:47

Returns ​

AudioFifo

Accessors ​

size ​

Get Signature ​

get size(): number

Defined in: src/lib/audio-fifo.ts:56

Number of samples currently in the FIFO.

Direct mapping to av_audio_fifo_size().

Returns ​

number

space ​

Get Signature ​

get space(): number

Defined in: src/lib/audio-fifo.ts:65

Number of samples that can be written without reallocation.

Direct mapping to av_audio_fifo_space().

Returns ​

number

Methods ​

[dispose]() ​

[dispose](): void

Defined in: src/lib/audio-fifo.ts:447

Dispose of the audio FIFO buffer.

Implements the Disposable interface for automatic cleanup. Equivalent to calling free().

Returns ​

void

Example ​

typescript
{
  using fifo = new AudioFifo();
  fifo.alloc(AV_SAMPLE_FMT_FLTP, 2, 4096);
  // Use fifo...
} // Automatically freed when leaving scope

Implementation of ​

Disposable.[dispose]

alloc() ​

alloc(sampleFmt, channels, nbSamples): void

Defined in: src/lib/audio-fifo.ts:102

Allocate an AVAudioFifo buffer.

Creates a FIFO buffer for the specified audio format and size. The FIFO will automatically grow if more data is written than allocated.

Direct mapping to av_audio_fifo_alloc().

Parameters ​

sampleFmt ​

AVSampleFormat

Sample format (e.g., AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_FLTP)

channels ​

number

Number of audio channels

nbSamples ​

number

Initial buffer size in samples

Returns ​

void

Throws ​

If allocation fails (ENOMEM)

Example ​

typescript
import { AudioFifo } from 'node-av';
import { AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_FLTP } from 'node-av/constants';

// For interleaved 16-bit stereo
const fifo1 = new AudioFifo();
fifo1.alloc(AV_SAMPLE_FMT_S16, 2, 4096);

// For planar float 5.1 audio
const fifo2 = new AudioFifo();
fifo2.alloc(AV_SAMPLE_FMT_FLTP, 6, 8192);

See ​

drain() ​

drain(nbSamples): void

Defined in: src/lib/audio-fifo.ts:366

Remove samples from the FIFO without reading them.

Discards the specified number of samples from the FIFO. Useful for skipping unwanted audio data.

Direct mapping to av_audio_fifo_drain().

Parameters ​

nbSamples ​

number

Number of samples to discard

Returns ​

void

Example ​

typescript
// Skip 100 samples
fifo.drain(100);
console.log(`FIFO now has ${fifo.size} samples`);

See ​

reset To remove all samples

free() ​

free(): void

Defined in: src/lib/audio-fifo.ts:122

Free the FIFO buffer and all associated resources.

After calling this, the FIFO is invalid and must be reallocated before use.

Direct mapping to av_audio_fifo_free().

Returns ​

void

Example ​

typescript
fifo.free();
// FIFO is now invalid, must call alloc() before using again

See ​

getNative() ​

getNative(): NativeAudioFifo

Defined in: src/lib/audio-fifo.ts:428

Internal

Get the underlying native AudioFifo object.

Returns ​

NativeAudioFifo

The native AudioFifo binding object

Implementation of ​

NativeWrapper.getNative

peek() ​

peek(data, nbSamples): Promise<number>

Defined in: src/lib/audio-fifo.ts:308

Read samples from the FIFO without removing them.

Similar to read() but leaves the samples in the FIFO. Useful for inspecting upcoming data without consuming it.

Direct mapping to av_audio_fifo_peek().

Parameters ​

data ​

Pre-allocated buffer(s) to peek into. Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Maximum number of samples to peek

Returns ​

Promise<number>

Number of samples peeked, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters

Example ​

typescript
import { FFmpegError } from 'node-av';

// Peek at next samples without removing them
const peekBuffer = Buffer.alloc(256 * 4);
const peeked = await fifo.peek(peekBuffer, 256);
FFmpegError.throwIfError(peeked, 'peek');

// Samples are still in FIFO
console.log(`FIFO still has ${fifo.size} samples`);

See ​

read To read and remove samples

peekSync() ​

peekSync(data, nbSamples): number

Defined in: src/lib/audio-fifo.ts:343

Read samples from the FIFO without removing them synchronously. Synchronous version of peek.

Similar to readSync() but leaves the samples in the FIFO. Useful for inspecting upcoming data without consuming it.

Direct mapping to av_audio_fifo_peek().

Parameters ​

data ​

Pre-allocated buffer(s) to peek into. Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Maximum number of samples to peek

Returns ​

number

Number of samples peeked, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters

Example ​

typescript
import { FFmpegError } from 'node-av';

// Peek at next samples without removing them
const peekBuffer = Buffer.alloc(256 * 4);
const peeked = fifo.peekSync(peekBuffer, 256);
FFmpegError.throwIfError(peeked, 'peekSync');

// Samples are still in FIFO
console.log(`FIFO still has ${fifo.size} samples`);

See ​

peek For async version

read() ​

read(data, nbSamples): Promise<number>

Defined in: src/lib/audio-fifo.ts:238

Read and remove samples from the FIFO.

Reads up to the specified number of samples from the FIFO. The samples are removed from the FIFO after reading. Buffers must be pre-allocated with sufficient size.

Direct mapping to av_audio_fifo_read().

Parameters ​

data ​

Pre-allocated buffer(s) to read into. Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Maximum number of samples to read

Returns ​

Promise<number>

Number of samples read, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters

Example ​

typescript
import { FFmpegError } from 'node-av';

// Check available samples
const available = fifo.size;
if (available >= 1024) {
  // Planar format
  const leftOut = Buffer.alloc(1024 * 4);
  const rightOut = Buffer.alloc(1024 * 4);
  const read = await fifo.read([leftOut, rightOut], 1024);
  FFmpegError.throwIfError(read, 'read');
  console.log(`Read ${read} samples`);
}

See ​

  • peek To read without removing
  • size To check available samples

readSync() ​

readSync(data, nbSamples): number

Defined in: src/lib/audio-fifo.ts:274

Read and remove samples from the FIFO synchronously. Synchronous version of read.

Reads up to the specified number of samples from the FIFO. The samples are removed from the FIFO after reading. Buffers must be pre-allocated with sufficient size.

Direct mapping to av_audio_fifo_read().

Parameters ​

data ​

Pre-allocated buffer(s) to read into. Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Maximum number of samples to read

Returns ​

number

Number of samples read, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters

Example ​

typescript
import { FFmpegError } from 'node-av';

// Read up to 1024 samples
const readBuffer = Buffer.alloc(2 * 1024 * 4); // stereo float32
const read = fifo.readSync(readBuffer, 1024);
FFmpegError.throwIfError(read, 'readSync');

console.log(`Read ${read} samples from FIFO`);
console.log(`FIFO now has ${fifo.size} samples remaining`);

See ​

read For async version

realloc() ​

realloc(nbSamples): number

Defined in: src/lib/audio-fifo.ts:417

Resize the FIFO buffer.

Changes the allocated size of the FIFO. Can grow or shrink the buffer. Existing samples are preserved up to the new size.

Direct mapping to av_audio_fifo_realloc().

Parameters ​

nbSamples ​

number

New allocation size in samples

Returns ​

number

0 on success, negative AVERROR on error:

  • AVERROR_EINVAL: Invalid size
  • AVERROR_ENOMEM: Memory allocation failure

Example ​

typescript
import { FFmpegError } from 'node-av';

// Grow FIFO to handle larger buffers
const ret = fifo.realloc(16384);
FFmpegError.throwIfError(ret, 'realloc');
console.log(`New space: ${fifo.space} samples`);

See ​

alloc For initial allocation

reset() ​

reset(): void

Defined in: src/lib/audio-fifo.ts:387

Remove all samples from the FIFO.

Empties the FIFO buffer without deallocating it. The FIFO remains allocated and ready for new data.

Direct mapping to av_audio_fifo_reset().

Returns ​

void

Example ​

typescript
fifo.reset();
console.log(fifo.size);  // 0
console.log(fifo.space); // Original allocation size

See ​

drain To remove specific number of samples

write() ​

write(data, nbSamples): Promise<number>

Defined in: src/lib/audio-fifo.ts:163

Write audio samples to the FIFO.

Writes samples to the FIFO buffer. Automatically reallocates if more space is needed. For planar formats, provide an array of buffers (one per channel). For interleaved formats, provide a single buffer.

Direct mapping to av_audio_fifo_write().

Parameters ​

data ​

Audio data buffer(s). Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Number of samples to write

Returns ​

Promise<number>

Number of samples written, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters
  • AVERROR_ENOMEM: Memory allocation failure

Example ​

typescript
import { FFmpegError } from 'node-av';

// Planar format (e.g., FLTP) - separate buffers per channel
const leftData = Buffer.alloc(1024 * 4);  // 1024 float samples
const rightData = Buffer.alloc(1024 * 4);
const written = await fifo.write([leftData, rightData], 1024);
FFmpegError.throwIfError(written, 'write');
console.log(`Wrote ${written} samples`);

// Interleaved format (e.g., S16) - single buffer
const interleavedData = Buffer.alloc(1024 * 2 * 2);  // 1024 stereo S16 samples
const written2 = await fifo.write(interleavedData, 1024);
FFmpegError.throwIfError(written2, 'write');

See ​

  • read To retrieve samples from FIFO
  • space To check available space

writeSync() ​

writeSync(data, nbSamples): number

Defined in: src/lib/audio-fifo.ts:199

Write samples to the FIFO synchronously. Synchronous version of write.

Adds audio samples to the FIFO buffer. The FIFO automatically handles format and layout conversions. Can write fewer samples than requested if space is limited.

Direct mapping to av_audio_fifo_write().

Parameters ​

data ​

Audio data buffer(s). Array for planar, single Buffer for interleaved

Buffer<ArrayBufferLike> | Buffer<ArrayBufferLike>[]

nbSamples ​

number

Number of samples to write per channel

Returns ​

number

Number of samples written, or negative AVERROR:

  • AVERROR_EINVAL: Invalid parameters

Example ​

typescript
import { FFmpegError } from 'node-av';

// Interleaved stereo data (2 channels * 1024 samples * 4 bytes)
const buffer = Buffer.alloc(2 * 1024 * 4);
// Fill with audio data...

const written = fifo.writeSync(buffer, 1024);
FFmpegError.throwIfError(written, 'writeSync');
console.log(`Wrote ${written} samples`);

See ​

write For async version