Audio exports
Extract AAC audio from a video or audio Source and save it in an M4A file.
Select m4a_aac to create an audio-only file from a Source that contains audio. Video Sources and audio-only Sources use the same request.
Defaults are 128000 bits per second, 48000 Hz, and two channels. Set audio_bitrate, audio_samplerate, and channels when you need different audio settings.
Create an M4A transcode
Run these examples on your server after setting up your SDK and Source. Replace the token and Source ID.
These examples save the file in your Project's output storage. Set storage.path to the filename you want to use.
import Chunkify from '@chunkify/chunkify';
async function main() {
const client = new Chunkify({
projectAccessToken: 'My Project Access Token',
});
const transcoding = await client.transcodings.create({
source_id: 'src_2G6MJiNz71bHQGNzGwKx5cJwPFS',
format: {
id: "m4a_aac",
audio_bitrate: 128000,
},
storage: {
path: 'exports/audio.m4a',
},
});
console.log(transcoding.id, transcoding.status);
}
main().catch((error) => {
console.error(error);
process.exitCode = 1;
});
Select an interval
Use seek and duration to export part of the Source. The accepted interval is aligned to audio samples and capped at the Source end. It must retain at least 0.001 seconds.
The response omits video dimensions, video codec, and video encoding progress for audio-only output. Follow status and processing_stage, then read the published files collection.
Audio-only selection from a video format
Setting disable_video: true on a video format also resolves to AAC M4A. Its output filename must end in .m4a. Omit video-specific settings, including dimensions, per-title optimization, CRF, and video bitrate.
Encoding parameters
AAC audio-only export from a video or audio Source.
Id specifies an AAC M4A export.
AudioBitrate specifies the output audio bitrate in bits per second. Defaults to 128000.
32000 <= x <= 512000AudioSamplerate specifies the output sample rate in Hz. Defaults to 48000. WebM Opus audio uses 48000.
80001102512000160002205024000320004410048000640008820096000Channels specifies the output channel count. Defaults to stereo. Six channels means 5.1; eight means 7.1.
1268Duration specifies the requested output length in seconds. Defaults to the remaining source duration and is capped at the source end. Audio-only output must resolve to at least 0.001 seconds after trimming and sample rounding. The accepted interval determines the fixed price.
Seek specifies the start in source seconds. Defaults to zero and must precede the source end. The accepted interval uses the output frame or sample timeline. Audio-only output must retain at least 0.001 seconds after sample rounding.
x >= 0