How to create a video from an array of images in Android?

You can use jcodec SequenceEncoder to convert sequence of images to MP4 file.

Sample code :

import org.jcodec.api.awt.SequenceEncoder;
...
SequenceEncoder enc = new SequenceEncoder(new File("filename"));
// GOP size will be supported in 0.2
// enc.getEncoder().setKeyInterval(25);
for(...) {
    BufferedImage image = ... // Obtain an image to encode
    enc.encodeImage(image);
}
enc.finish();

It's a java library so it's easy to import it into Android project, you don't have to use NDK unlike ffmpeg.

Refer http://jcodec.org/ for sample code & downloads.

Using JCodec as demonstrated by Stanislav Vitvitskyy here.

public static void main(String[] args) throws IOException {
    SequenceEncoder encoder = new SequenceEncoder(new File("video.mp4"));
    for (int i = 1; i < 100; i++) {
        BufferedImage bi = ImageIO.read(new File(String.format("img%08d.png", i)));
        encoder.encodeImage(bi);
        }
    encoder.finish();}

Now to convert your Bitmap to BufferedImage you can use this class:

import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.DataBufferInt;
import java.io.IOException;
import java.io.InputStream;

/**
  * Utility class for loading windows bitmap files
  * <p>
  * Based on code from author Abdul Bezrati and Pepijn Van Eeckhoudt
  */
public class BitmapLoader {

/**
 * Static method to load a bitmap file based on the filename passed in.
 * Based on the bit count, this method will either call the 8 or 24 bit
 * bitmap reader methods
 *
 * @param file The name of the bitmap file to read
 * @throws IOException
 * @return A BufferedImage of the bitmap
 */
public static BufferedImage loadBitmap(String file) throws IOException {
    BufferedImage image;
    InputStream input = null;
    try {
        input = ResourceRetriever.getResourceAsStream(file);

        int bitmapFileHeaderLength = 14;
        int bitmapInfoHeaderLength = 40;

        byte bitmapFileHeader[] = new byte[bitmapFileHeaderLength];
        byte bitmapInfoHeader[] = new byte[bitmapInfoHeaderLength];

        input.read(bitmapFileHeader, 0, bitmapFileHeaderLength);
        input.read(bitmapInfoHeader, 0, bitmapInfoHeaderLength);

        int nSize = bytesToInt(bitmapFileHeader, 2);
        int nWidth = bytesToInt(bitmapInfoHeader, 4);
        int nHeight = bytesToInt(bitmapInfoHeader, 8);
        int nBiSize = bytesToInt(bitmapInfoHeader, 0);
        int nPlanes = bytesToShort(bitmapInfoHeader, 12);
        int nBitCount = bytesToShort(bitmapInfoHeader, 14);
        int nSizeImage = bytesToInt(bitmapInfoHeader, 20);
        int nCompression = bytesToInt(bitmapInfoHeader, 16);
        int nColoursUsed = bytesToInt(bitmapInfoHeader, 32);
        int nXPixelsMeter = bytesToInt(bitmapInfoHeader, 24);
        int nYPixelsMeter = bytesToInt(bitmapInfoHeader, 28);
        int nImportantColours = bytesToInt(bitmapInfoHeader, 36);

        if (nBitCount == 24) {
            image = read24BitBitmap(nSizeImage, nHeight, nWidth, input);
        } else if (nBitCount == 8) {
            image = read8BitBitmap(nColoursUsed, nBitCount, nSizeImage, nWidth, nHeight, input);
        } else {
            System.out.println("Not a 24-bit or 8-bit Windows Bitmap, aborting...");
            image = null;
        }
    } finally {
        try {
            if (input != null)
                input.close();
        } catch (IOException e) {
        }
    }
    return image;
}

/**
 * Static method to read a 8 bit bitmap
 *
 * @param nColoursUsed Number of colors used
 * @param nBitCount The bit count
 * @param nSizeImage The size of the image in bytes
 * @param nWidth The width of the image
 * @param input The input stream corresponding to the image
 * @throws IOException
 * @return A BufferedImage of the bitmap
 */
private static BufferedImage read8BitBitmap(int nColoursUsed, int nBitCount, int nSizeImage, int nWidth, int nHeight, InputStream input) throws IOException {
    int nNumColors = (nColoursUsed > 0) ? nColoursUsed : (1 & 0xff) << nBitCount;

    if (nSizeImage == 0) {
        nSizeImage = ((((nWidth * nBitCount) + 31) & ~31) >> 3);
        nSizeImage *= nHeight;
    }

    int npalette[] = new int[nNumColors];
    byte bpalette[] = new byte[nNumColors * 4];
    readBuffer(input, bpalette);
    int nindex8 = 0;

    for (int n = 0; n < nNumColors; n++) {
        npalette[n] = (255 & 0xff) << 24 |
                (bpalette[nindex8 + 2] & 0xff) << 16 |
                (bpalette[nindex8 + 1] & 0xff) << 8 |
                (bpalette[nindex8 + 0] & 0xff);

        nindex8 += 4;
    }

    int npad8 = (nSizeImage / nHeight) - nWidth;
    BufferedImage bufferedImage = new BufferedImage(nWidth, nHeight, BufferedImage.TYPE_INT_ARGB);
    DataBufferInt dataBufferByte = ((DataBufferInt) bufferedImage.getRaster().getDataBuffer());
    int[][] bankData = dataBufferByte.getBankData();
    byte bdata[] = new byte[(nWidth + npad8) * nHeight];

    readBuffer(input, bdata);
    nindex8 = 0;

    for (int j8 = nHeight - 1; j8 >= 0; j8--) {
        for (int i8 = 0; i8 < nWidth; i8++) {
            bankData[0][j8 * nWidth + i8] = npalette[((int) bdata[nindex8] & 0xff)];
            nindex8++;
        }
        nindex8 += npad8;
    }

    return bufferedImage;
}

/**
 * Static method to read a 24 bit bitmap
 *
 * @param nSizeImage size of the image  in bytes
 * @param nHeight The height of the image
 * @param nWidth The width of the image
 * @param input The input stream corresponding to the image
 * @throws IOException
 * @return A BufferedImage of the bitmap
 */
private static BufferedImage read24BitBitmap(int nSizeImage, int nHeight, int nWidth, InputStream input) throws IOException {
    int npad = (nSizeImage / nHeight) - nWidth * 3;
    if (npad == 4 || npad < 0)
        npad = 0;
    int nindex = 0;
    BufferedImage bufferedImage = new BufferedImage(nWidth, nHeight, BufferedImage.TYPE_4BYTE_ABGR);
    DataBufferByte dataBufferByte = ((DataBufferByte) bufferedImage.getRaster().getDataBuffer());
    byte[][] bankData = dataBufferByte.getBankData();
    byte brgb[] = new byte[(nWidth + npad) * 3 * nHeight];

    readBuffer(input, brgb);

    for (int j = nHeight - 1; j >= 0; j--) {
        for (int i = 0; i < nWidth; i++) {
            int base = (j * nWidth + i) * 4;
            bankData[0][base] = (byte) 255;
            bankData[0][base + 1] = brgb[nindex];
            bankData[0][base + 2] = brgb[nindex + 1];
            bankData[0][base + 3] = brgb[nindex + 2];
            nindex += 3;
        }
        nindex += npad;
    }

    return bufferedImage;
}

/**
 * Converts bytes to an int
 *
 * @param bytes An array of bytes
 * @param index
 * @returns A int representation of the bytes
 */
private static int bytesToInt(byte[] bytes, int index) {
    return (bytes[index + 3] & 0xff) << 24 |
            (bytes[index + 2] & 0xff) << 16 |
            (bytes[index + 1] & 0xff) << 8 |
            bytes[index + 0] & 0xff;
}

/**
 * Converts bytes to a short
 *
 * @param bytes An array of bytes
 * @param index
 * @returns A short representation of the bytes
 */
private static short bytesToShort(byte[] bytes, int index) {
    return (short) (((bytes[index + 1] & 0xff) << 8) |
            (bytes[index + 0] & 0xff));
}

/**
 * Reads the buffer
 *
 * @param in An InputStream
 * @param buffer An array of bytes
 * @throws IOException
 */
private static void readBuffer(InputStream in, byte[] buffer) throws IOException {
    int bytesRead = 0;
    int bytesToRead = buffer.length;
    while (bytesToRead > 0) {
        int read = in.read(buffer, bytesRead, bytesToRead);
        bytesRead += read;
        bytesToRead -= read;
    }
}
}