Audio Transcoding allows you to convert audio files to different formats, adjust quality settings, and modify channel layouts. This service helps you optimize audio files for sharing, ensure compatibility across devices, and customize output for specific requirements.

Supported Formats and Codecs

Atomile supports a wide range of media formats.

Video Formats:

• MP4, FLV, HLS, DASH, TS, MKV, MOV
• WMV, AVI, VP8, VP9, RealVideo
• Windows Media Video, and more

Audio Formats:

• AAC, AC-3, MP1, MP2, MP3
• PCM, RealAudio, Windows Media Audio (WMA)
• OGG, and more

Codecs:

• H.266, H.265, H.264, H.263
• MPEG, and more

How to Use

Structure your fops command as shown below:

<op>/<Format>
    /an/<value>
    /vn/<value>
    /acodec/<value>
    /volume/<value>
    /loudnorm/<value>
    /aq/<value>
    /ab/<value>
    /ar/<value>
    /ac/<value>
|saveas/<Urlsafe_Base64_Encode(bucket:filekey)>

Parameters

Parameter	Required	Description
op	Yes	Operation type. Use avthumb for audio transcoding.
format	Yes	Target format, such as mp3, aac, or wma.
an	No	Audio track control: • 0 (default) - Keep the audio track • 1 - Remove the audio track
vn	No	Video stream control: • 0 (default) - Keep the video stream • 1 - Remove the video stream
acodec	No	Audio codec selection, such as MP3, AAC, or OGG. If not specified, the system attempts to preserve the original codec.
volume	No	Audio volume adjustment: By multiplier: Range 0 to 2 • 0 - Silence • 1 - Original volume • 2 - Double volume • 1.5 - 1.5× original volume By decibel: Range -10dB to 10dB • Negative values decrease volume • Positive values increase volume Note: High settings may cause distortion.
loudnorm	No	Target loudness in LUFS (Loudness Units relative to Full Scale): • Range: -70 to -5 LUFS • Lower values (closer to -70) produce quieter output • Higher values (closer to -5) produce louder output Important: It is not recommended to use this parameter together with volume. Format restrictions: • For eac3, ar must be set to 48000, 44100, or 32000 • For ac3, ar must be set to 48000 or 44100
aq	No	Audio quality: • MP3: Range 0 to 9 (lower is better) • AAC: Range 10 to 500 (higher is better) Notes: 1. Currently supports only MP3 and AAC. 2. Cannot be used together with ab.
ab	No	Audio bitrate in bits per second, such as 64k, 128k, 192k, 256k, or 320k.
ar	No	Audio sample rate in Hertz, such as 8000, 12050, 22050, or 44100. Note: FLV format supports only 44100, 22050, and 11025 Hz.
ac	No	Audio channel layout: • 1 - Mono (single channel) • 2 - Stereo (dual channel)
saveas	Yes	Output location as a URL-safe Base64-encoded string, in the format Urlsafe_Base64_Encode(bucket:savedfilename).