Extract audio as MP3
Drop the video with -vn and encode the audio with libmp3lame. The response holds the MP3’s download URL.
The request
Request
curl https://media.logicboostkit.com/ffmpeg/process \
-H "Authorization: Basic $MEDIA_KEY" \
-H "Content-Type: application/json" \
-d '{
"task": {
"inputs": [
{
"file_path": "dir_pi23jgy1yxlmigi873bz/source.mp4"
}
],
"outputs": [
{
"file": "audio.mp3",
"options": [
"-vn",
"-c:a",
"libmp3lame",
"-q:a",
"2"
]
}
]
}
}'Response
HTTP/1.1 200 OK
X-Request-Id: job_0mv6ihz6vfx5ua0h05x8bmql
{
"ok": true,
"result": [
{
"file_name": "audio.mp3",
"size_bytes": 12582912,
"download_url": "https://…"
}
],
"usage": {
"time_sec": 7,
"input_size_gb": 0.4,
"output_size_gb": 0.01171875,
"gb_sec": 2.882031253
},
"request_id": "job_0mv6ihz6vfx5ua0h05x8bmql",
"amount_usd": 0.038388656
}The options, explained
| -vn | No video in the output. |
|---|---|
| -c:a libmp3lame | Encode the audio as MP3. |
| -q:a 2 | Variable bitrate, high quality: about 190 kbit/s. 0 is the best and largest, 9 the smallest. |
Variations
A fixed bitrate
For players that expect one.
In the output: "options": ["-vn", "-c:a", "libmp3lame", "-b:a", "192k"]Keep the original audio
Copy the AAC track as it is, without re-encoding.
In the output: "file": "audio.m4a", "options": ["-vn", "-c:a", "copy"]WAV for editing
Uncompressed audio.
In the output: "file": "audio.wav", "options": ["-vn", "-c:a", "pcm_s16le"]What it costs
The audio of a 0.4 GB video, as a 12 MB MP3 in 7 seconds: (0.4 GB + 0.012 GB) × 7 s = 2.884 GB-seconds, which is USD 0.0384 at USD 0.01332 per GB-second.