| 1 | package kaka.cakelight; |
| 2 | |
| 3 | import javax.imageio.ImageIO; |
| 4 | import java.awt.image.BufferedImage; |
| 5 | import java.io.*; |
| 6 | import java.util.Optional; |
| 7 | |
| 8 | import static kaka.cakelight.Main.log; |
| 9 | |
| 10 | public class FrameGrabber implements Closeable { |
| 11 | private Configuration config; |
| 12 | private File file; |
| 13 | private int bytesPerFrame; |
| 14 | private InputStream fileStream; |
| 15 | private final ByteArrayOutputStream bufferedBytes = new ByteArrayOutputStream(); |
| 16 | |
| 17 | private FrameGrabber() { |
| 18 | } |
| 19 | |
| 20 | public static FrameGrabber from(File videoDevice, Configuration config) { |
| 21 | FrameGrabber fg = new FrameGrabber(); |
| 22 | fg.config = config; |
| 23 | fg.file = videoDevice; |
| 24 | fg.bytesPerFrame = config.video.width * config.video.height * config.video.bpp; |
| 25 | fg.prepare(); |
| 26 | return fg; |
| 27 | } |
| 28 | |
| 29 | private boolean prepare() { |
| 30 | try { |
| 31 | fileStream = new FileInputStream(file); |
| 32 | return true; |
| 33 | } catch (FileNotFoundException e) { |
| 34 | // TODO: handle java.io.FileNotFoundException: /dev/video1 (Permission denied) |
| 35 | e.printStackTrace(); |
| 36 | return false; |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | /** |
| 41 | * Must be run in the same thread as {@link #prepare}. |
| 42 | */ |
| 43 | public Optional<VideoFrame> grabFrame() { |
| 44 | try { |
| 45 | byte[] data; |
| 46 | if (config.video.mjpg) { |
| 47 | byte[] jpgData = readStreamingJpgData(); |
| 48 | if (jpgData == null) { |
| 49 | return Optional.empty(); |
| 50 | } |
| 51 | saveTemporaryJpgFile(jpgData); |
| 52 | byte[] bmpData = convertJpgFileToByteArray(); |
| 53 | if (bmpData == null) { |
| 54 | return Optional.empty(); |
| 55 | } |
| 56 | data = bmpData; |
| 57 | } else { |
| 58 | data = new byte[bytesPerFrame]; |
| 59 | int count = fileStream.read(data); |
| 60 | if (count != bytesPerFrame) { |
| 61 | log("Expected to read " + bytesPerFrame + " bytes per frame but read " + count); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | return Optional.of(VideoFrame.of(data, config)); |
| 66 | } catch (IOException e) { |
| 67 | e.printStackTrace(); |
| 68 | } |
| 69 | |
| 70 | return Optional.empty(); |
| 71 | } |
| 72 | |
| 73 | private byte[] readStreamingJpgData() throws IOException { |
| 74 | byte[] data; |
| 75 | byte[] batch = new byte[1024]; |
| 76 | boolean lastByteIsXX = false; |
| 77 | loop: |
| 78 | while (true) { |
| 79 | int batchCount = fileStream.read(batch); |
| 80 | if (batchCount == -1) { |
| 81 | return null; |
| 82 | } |
| 83 | if (lastByteIsXX) { |
| 84 | if (batch[0] == (byte) 0xd8) { |
| 85 | data = bufferedBytes.toByteArray(); |
| 86 | bufferedBytes.reset(); |
| 87 | bufferedBytes.write(0xff); |
| 88 | bufferedBytes.write(batch, 0, batchCount); |
| 89 | break; |
| 90 | } |
| 91 | bufferedBytes.write(0xff); |
| 92 | } |
| 93 | for (int i = 0; i < batchCount - 1; i++) { |
| 94 | if (batch[i] == (byte) 0xff && batch[i + 1] == (byte) 0xd8) { // start of jpeg |
| 95 | if (i > 0) { |
| 96 | bufferedBytes.write(batch, 0, i); |
| 97 | } |
| 98 | data = bufferedBytes.toByteArray(); |
| 99 | bufferedBytes.reset(); |
| 100 | bufferedBytes.write(batch, i, batchCount - i); |
| 101 | break loop; |
| 102 | } |
| 103 | } |
| 104 | lastByteIsXX = batch[batchCount - 1] == (byte) 0xff; |
| 105 | bufferedBytes.write(batch, 0, batchCount - (lastByteIsXX ? 1 : 0)); |
| 106 | } |
| 107 | return data; |
| 108 | } |
| 109 | |
| 110 | private void saveTemporaryJpgFile(byte[] data) throws IOException { |
| 111 | try (FileOutputStream fos = new FileOutputStream("/tmp/cakelight-video-stream.jpg")) { |
| 112 | fos.write(data); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | private byte[] convertJpgFileToByteArray() throws IOException { |
| 117 | BufferedImage image = ImageIO.read(new File("/tmp/cakelight-video-stream.jpg")); |
| 118 | if (image != null) { // will almost always be null the first time |
| 119 | try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) { |
| 120 | ImageIO.write(image, "bmp", baos); |
| 121 | baos.flush(); |
| 122 | return baos.toByteArray(); |
| 123 | } |
| 124 | } else { |
| 125 | return null; |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | @Override |
| 130 | public void close() throws IOException { |
| 131 | fileStream.close(); |
| 132 | } |
| 133 | } |