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Adding Captions to a Video

Choose your preferred language to add captions to videos using the ZapCap API

import axios, { isAxiosError } from "axios";
import { createReadStream, createWriteStream } from "fs";
import FormData from "form-data";

// Get this from https://platform.zapcap.ai/dashboard/api-key
const API_KEY = "YOUR_API_KEY";
const API_BASE = "https://api.zapcap.ai";
const VIDEO_PATH = "/path/to/your/video.mp4";

export async function addCaptions(videoPath) {
  try {
    // 1. Get available templates
    console.log("Fetching templates...");
    const templatesResponse = await axios.get(`${API_BASE}/templates`, {
      headers: { "x-api-key": API_KEY },
    });
    const templateId = templatesResponse.data[0].id;
    console.log("Using template:", templateId);

    // 2. Upload video
    console.log("Uploading video...");
    const form = new FormData();
    form.append("file", createReadStream(videoPath));

    const uploadResponse = await axios.post(`${API_BASE}/videos`, form, {
      headers: {
        "x-api-key": API_KEY,
      },
    });
    const videoId = uploadResponse.data.id;
    console.log("Video uploaded, Video ID:", videoId);

    // 3. Create task
    console.log("Creating captioning task...");
    const taskResponse = await axios.post(
      `${API_BASE}/videos/${videoId}/task`,
      {
        templateId,
        // Read about it here: https://platform.zapcap.ai/docs/guides/tasks#-transcript-approval
        autoApprove: true,
        language: "en",
      },
      {
        headers: {
          "x-api-key": API_KEY,
          "Content-Type": "application/json",
        },
      }
    );
    const taskId = taskResponse.data.taskId;
    console.log("Task created, Task ID:", taskId);

    // 4. Poll for completion
    console.log("Processing video...");
    let attempts = 0;
    while (true) {
      const statusResponse = await axios.get(
        `${API_BASE}/videos/${videoId}/task/${taskId}`,
        {
          headers: { "x-api-key": API_KEY },
        }
      );

      const { status, downloadUrl, error } = statusResponse.data;
      console.log("Status:", status);

      if (status === "completed") {
        // Download the video
        console.log("Downloading captioned video...");
        const videoResponse = await axios.get(downloadUrl, {
          responseType: "stream",
        });

        const outputPath = "./captioned_video.mp4";

        await new Promise<void>((resolve, reject) => {
          const writeStream = createWriteStream(outputPath);
          videoResponse.data.pipe(writeStream);

          writeStream.on("finish", () => {
            console.log("Video saved to:", outputPath);
            resolve();
          });

          writeStream.on("error", reject);
        });

        console.log("Video saved to:", outputPath);
        break;
      } else if (status === "failed") {
        throw new Error(`Task failed: ${error}`);
      }

      const delay = 2000;
      await new Promise((resolve) => setTimeout(resolve, delay));
      attempts++;
    }
  } catch (error) {
    if (isAxiosError(error)) {
      console.log(error.response?.data);
    }
    console.error("Error:", error.message);
  }
}

const main = async () => {
  await addCaptions(VIDEO_PATH);
};
main().then(() => process.exit(0));