Documentation Index
Fetch the complete documentation index at: https://rendi.dev/docs/llms.txt
Use this file to discover all available pages before exploring further.
Render an SRT subtitle file permanently onto a video (burned-in captions). Useful when the target player doesn’t support subtitle tracks or you need guaranteed rendering.
Code
const API_KEY = process.env.RENDI_API_KEY;
const submit = await fetch("https://api.rendi.dev/v1/run-ffmpeg-command", {
method: "POST",
headers: {
"Content-Type": "application/json",
"X-API-KEY": API_KEY,
},
body: JSON.stringify({
input_files: {
in_video: "https://storage.rendi.dev/sample/sample.avi",
in_srt: "https://storage.rendi.dev/sample/subtitles.srt",
},
output_files: {
out_1: "subtitled.mp4",
},
ffmpeg_command:
"-i {{in_video}} -ss 00:00 -to 01:00 -vf subtitles={{in_srt}} -c:v libx264 -crf 20 -c:a aac -b:a 192k {{out_1}}",
}),
});
const { command_id } = await submit.json();
while (true) {
const res = await fetch(`https://api.rendi.dev/v1/commands/${command_id}`, {
headers: { "X-API-KEY": API_KEY },
});
const data = await res.json();
if (data.status === "SUCCESS") {
console.log("Subtitled URL:", data.output_files.out_1.storage_url);
break;
}
if (data.status === "FAILED") throw new Error("Command failed");
await new Promise((r) => setTimeout(r, 2000));
}
import os
import time
import requests
API_KEY = os.environ["RENDI_API_KEY"]
BASE = "https://api.rendi.dev/v1"
headers = {"X-API-KEY": API_KEY}
submit = requests.post(
f"{BASE}/run-ffmpeg-command",
headers=headers,
json={
"input_files": {
"in_video": "https://storage.rendi.dev/sample/sample.avi",
"in_srt": "https://storage.rendi.dev/sample/subtitles.srt",
},
"output_files": {"out_1": "subtitled.mp4"},
"ffmpeg_command": "-i {{in_video}} -ss 00:00 -to 01:00 -vf subtitles={{in_srt}} -c:v libx264 -crf 20 -c:a aac -b:a 192k {{out_1}}",
},
)
command_id = submit.json()["command_id"]
while True:
res = requests.get(f"{BASE}/commands/{command_id}", headers=headers).json()
if res["status"] == "SUCCESS":
print("Subtitled URL:", res["output_files"]["out_1"]["storage_url"])
break
if res["status"] == "FAILED":
raise RuntimeError("Command failed")
time.sleep(2)
curl --request POST \
--url https://api.rendi.dev/v1/run-ffmpeg-command \
--header 'Content-Type: application/json' \
--header 'X-API-KEY: <api-key>' \
--data '{
"input_files": {
"in_video": "https://storage.rendi.dev/sample/sample.avi",
"in_srt": "https://storage.rendi.dev/sample/subtitles.srt"
},
"output_files": {"out_1": "subtitled.mp4"},
"ffmpeg_command": "-i {{in_video}} -ss 00:00 -to 01:00 -vf subtitles={{in_srt}} -c:v libx264 -crf 20 -c:a aac -b:a 192k {{out_1}}"
}'
curl --request GET \
--url https://api.rendi.dev/v1/commands/<command_id> \
--header 'X-API-KEY: <api-key>'
How the FFmpeg command works
-i {{in_video}} — input video-ss 00:00 -to 01:00 — only burn subtitles into the first minute (drop this to process the full video)-vf subtitles={{in_srt}} — subtitles video filter reads the SRT file-c:v libx264 -crf 20 — re-encode video (required, since the filter modifies frames)-c:a aac -b:a 192k — re-encode audio{{out_1}} — output file
For soft subtitles (a separate subtitle track that can be toggled off), use -c:s mov_text with an MP4 container and skip the -vf filter.
Response
{
"output_files": {
"out_1": {
"file_id": "cb5b9186-...",
"size_mbytes": 13.95,
"duration": 60.0,
"file_type": "video",
"file_format": "mp4",
"storage_url": "https://storage.rendi.dev/temp_files/.../subtitled.mp4",
"width": 854,
"height": 480,
"codec": "h264"
}
},
"status": "SUCCESS",
"command_type": "FFMPEG_COMMAND"
}
