Background music

Mix a music track under the original sound at the level you choose.

audio.mix puts more sound under the output's own: a music bed under a voice. The original keeps its level and the output ends with the video.

The request#

bash

curl "$VIDEXO_API_URL/v1/transcode" \
  -H "Authorization: Bearer $VIDEXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": "https://example.com/talk.mp4",
  "filename": "talk-music.mp4",
  "extra_inputs": {
    "music": "https://example.com/music.mp3"
  },
  "video": {
    "codec": "copy"
  },
  "audio": {
    "mix": [
      {
        "input": "music",
        "volume": 0.2
      }
    ]
  }
}'

JavaScript

const response = await fetch(`${process.env.VIDEXO_API_URL}/v1/transcode`, {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.VIDEXO_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "input": "https://example.com/talk.mp4",
    "filename": "talk-music.mp4",
    "extra_inputs": {
      "music": "https://example.com/music.mp3"
    },
    "video": {
      "codec": "copy"
    },
    "audio": {
      "mix": [
        {
          "input": "music",
          "volume": 0.2
        }
      ]
    }
  }),
});
const job = await response.json();

bash

ffmpeg \
  -i https://example.com/talk.mp4 \
  -i https://example.com/music.mp3 \
  -filter_complex "[1:a]volume=0.2[o0m0];[0:a:0][o0m0]amix=inputs=2:duration=first:normalize=0[o0a]" \
  -map 0:v:0 \
  -c:v copy \
  -map "[o0a]" \
  -c:a aac -b:a 128k -movflags +faststart \
  talk-music.mp4

talk-music.mp4: the same picture, the music at a fifth of its volume under the voice, ending with the video.

The music is an extra input (extra_inputs on a per-operation endpoint, or another entry in inputs on POST /v1/jobs); volume sets its level, 0.2 is a fifth.

A video without sound#

Mixing needs an audio track to mix under. For a silent video, take the sound from the music instead; the output ends with the video, the music cut there or padded with silence:

bash

curl "$VIDEXO_API_URL/v1/transcode" \
  -H "Authorization: Bearer $VIDEXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": "https://example.com/talk.mp4",
  "filename": "slideshow.mp4",
  "extra_inputs": {
    "music": "https://example.com/music.mp3"
  },
  "video": {
    "codec": "copy"
  },
  "audio": {
    "input": "music"
  }
}'

JavaScript

const response = await fetch(`${process.env.VIDEXO_API_URL}/v1/transcode`, {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.VIDEXO_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "input": "https://example.com/talk.mp4",
    "filename": "slideshow.mp4",
    "extra_inputs": {
      "music": "https://example.com/music.mp3"
    },
    "video": {
      "codec": "copy"
    },
    "audio": {
      "input": "music"
    }
  }),
});
const job = await response.json();

bash

ffmpeg \
  -i https://example.com/talk.mp4 \
  -i https://example.com/music.mp3 \
  -map 0:v:0 \
  -c:v copy \
  -map 1:a:0 \
  -af apad \
  -c:a aac -b:a 128k -shortest -movflags +faststart \
  slideshow.mp4