видео стеганография с использованием медиакодека

Question

Мне нужно создавать видео со скрытыми данными. Мне удалось извлечь видеокадры, используя медиа-кодек-декодер в качестве буфера NV21, и сохранить их, затем я создал mp4-файл из кадров, используя медиа-кодек. класс ниже отвечает за сохранение файлов кадров, если мы находимся в процессе кодирования или проверяем значение, если мы хотим извлечь данные из stego-video.

public class ExtractMpegFramesBufferDecoder {
private static final String TAG = "ExtractMpegFramesDec";
private static final boolean VERBOSE = true;           // lots of logging

// where to find files (note: requires WRITE_EXTERNAL_STORAGE permission)
private File STORE_FRAME_DIRECTORY;
private String INPUT_FILE;
private int frameRate;       // stop extracting after this many
private int saveWidth;
private int saveHeight;
private int decodeCount;
private Handler _progressBarHandler;
private int duration;
//
private int MAX_FRAMES;
private boolean fromDecode;
//

public ExtractMpegFramesBufferDecoder(File storeFrameDirectory, String inputVideoPath, int frameRate
        , int saveWidth, int saveHeight
        , double duration, int rotation
        , Handler _progressBarHandler) {
    this.STORE_FRAME_DIRECTORY = storeFrameDirectory;
    this.INPUT_FILE = inputVideoPath;
    this.frameRate = frameRate;
    this.saveWidth = saveWidth;
    this.saveHeight = saveHeight;
    this._progressBarHandler = _progressBarHandler;
    this.duration = (int) duration;
}


/**
 * Tests extraction from an MP4 to a series of PNG files.
 * <p>
 * We scale the video to 640x480 for the PNG just to demonstrate that we can scale the
 * video with the GPU.  If the input video has a different aspect ratio, we could preserve
 * it by adjusting the GL viewport to get letterboxing or pillarboxing, but generally if
 * you're extracting frames you don't want black bars.
 */
public void extractMpegFrames(int maxFrame, boolean fromDecode) throws IOException {
    MediaCodec decoder = null;
    MediaExtractor extractor = null;
    MAX_FRAMES = maxFrame;
    this.fromDecode = fromDecode;

    try {
        File inputFile = new File(INPUT_FILE);   // must be an absolute path
        // The MediaExtractor error messages aren't very useful.  Check to see if the input
        // file exists so we can throw a better one if it's not there.
        if (!inputFile.canRead()) {
            throw new FileNotFoundException("Unable to read " + inputFile);
        }

        extractor = new MediaExtractor();
        extractor.setDataSource(inputFile.toString());
        int trackIndex = selectTrack(extractor);
        if (trackIndex < 0) {
            throw new RuntimeException("No video track found in " + inputFile);
        }
        extractor.selectTrack(trackIndex);

        MediaFormat format = extractor.getTrackFormat(trackIndex);
        if (VERBOSE) {
            Log.d(TAG, "Video size is " + format.getInteger(MediaFormat.KEY_WIDTH) + "x" +
                    format.getInteger(MediaFormat.KEY_HEIGHT));
        }

        // Create a MediaCodec decoder, and configure it with the MediaFormat from the
        // extractor.  It's very important to use the format from the extractor because
        // it contains a copy of the CSD-0/CSD-1 codec-specific data chunks.
        String mime = format.getString(MediaFormat.KEY_MIME);
        decoder = MediaCodec.createDecoderByType(mime);
        decoder.configure(format, null, null, 0);
        decoder.start();

        doExtract(extractor, trackIndex, decoder);
    } finally {
        if (decoder != null) {
            decoder.stop();
            decoder.release();
            decoder = null;
        }
        if (extractor != null) {
            extractor.release();
            extractor = null;
        }
    }
}

/**
 * Selects the video track, if any.
 *
 * @return the track index, or -1 if no video track is found.
 */
private int selectTrack(MediaExtractor extractor) {
    // Select the first video track we find, ignore the rest.
    int numTracks = extractor.getTrackCount();
    for (int i = 0; i < numTracks; i++) {
        MediaFormat format = extractor.getTrackFormat(i);
        String mime = format.getString(MediaFormat.KEY_MIME);
        if (mime.startsWith("video/")) {
            if (VERBOSE) {
                Log.d(TAG, "Extractor selected track " + i + " (" + mime + "): " + format);
            }
            return i;
        }
    }

    return -1;
}

/**
 * Work loop.
 */
public void doExtract(MediaExtractor extractor, int trackIndex, MediaCodec decoder) throws IOException {
    final int TIMEOUT_USEC = 10000;
    ByteBuffer[] decoderInputBuffers = decoder.getInputBuffers();
    MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
    int inputChunk = 0;
    decodeCount = 0;
    long frameSaveTime = 0;

    boolean outputDone = false;
    boolean inputDone = false;


    ByteBuffer[] decoderOutputBuffers = decoder.getOutputBuffers();
    MediaFormat decoderOutputFormat = null;
    long rawSize = 0;


    while (!outputDone) {
        if (VERBOSE) Log.d(TAG, "loop");

        // Feed more data to the decoder.
        if (!inputDone) {
            int inputBufIndex = decoder.dequeueInputBuffer(TIMEOUT_USEC);
            if (inputBufIndex >= 0) {
                ByteBuffer inputBuf = decoderInputBuffers[inputBufIndex];
                // Read the sample data into the ByteBuffer.  This neither respects nor
                // updates inputBuf's position, limit, etc.
                int chunkSize = extractor.readSampleData(inputBuf, 0);
                if (chunkSize < 0) {
                    // End of stream -- send empty frame with EOS flag set.
                    decoder.queueInputBuffer(inputBufIndex, 0, 0, 0L,
                            MediaCodec.BUFFER_FLAG_END_OF_STREAM);
                    inputDone = true;
                    if (VERBOSE) Log.d(TAG, "sent input EOS");
                } else {
                    if (extractor.getSampleTrackIndex() != trackIndex) {
                        Log.w(TAG, "WEIRD: got sample from track " +
                                extractor.getSampleTrackIndex() + ", expected " + trackIndex);
                    }
                    long presentationTimeUs = extractor.getSampleTime();
                    decoder.queueInputBuffer(inputBufIndex, 0, chunkSize,
                            presentationTimeUs, 0 /*flags*/);
                    if (VERBOSE) {
                        Log.d(TAG, "submitted frame " + inputChunk + " to dec, size=" +
                                chunkSize);
                    }
                    inputChunk++;
                    extractor.advance();
                }
            } else {
                if (VERBOSE) Log.d(TAG, "input buffer not available");
            }
        }

        if (!outputDone) {
            int decoderStatus = decoder.dequeueOutputBuffer(info, TIMEOUT_USEC);
            if (decoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
                // no output available yet
                if (VERBOSE) Log.d(TAG, "no output from decoder available");
            } else if (decoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
                // not important for us, since we're using Surface
                if (VERBOSE) Log.d(TAG, "decoder output buffers changed");
                decoderOutputBuffers = decoder.getOutputBuffers();
            } else if (decoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
                MediaFormat newFormat = decoder.getOutputFormat();
                decoderOutputFormat = newFormat;
                if (VERBOSE) Log.d(TAG, "decoder output format changed: " + newFormat);
            } else if (decoderStatus < 0) {
                Log.e(TAG, "unexpected result from decoder.dequeueOutputBuffer: " + decoderStatus);
            } else { // decoderStatus >= 0
                if (VERBOSE) Log.d(TAG, "surface decoder given buffer " + decoderStatus +
                        " (size=" + info.size + ")");
                if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                    if (VERBOSE) Log.d(TAG, "output EOS");
                    outputDone = true;
                }
                ByteBuffer outputFrame = decoderOutputBuffers[decoderStatus];
                outputFrame.position(info.offset);
                outputFrame.limit(info.offset + info.size);
                rawSize += info.size;

                if (info.size == 0) {
                    if (VERBOSE) Log.d(TAG, "got empty frame");
                } else {
                    // if it's decode then check the altered value
                    // else save the frames
                    if (fromDecode) {
                        outputFrame.rewind();
                        byte[] data = new byte[outputFrame.remaining()];
                        outputFrame.get(data);
                        int size = saveWidth * saveHeight;
                        int offset = size;
                        int[] pixels = new int[size];
                        int u, v, y1, y2, y3, y4;
                        int uvIndex = 0;

                        if (decodeCount == 1) {
                            // i percorre os Y and the final pixels
                            // k percorre os pixles U e V
                            for (int i = 0, k = 0; i < size; i += 2, k += 2) {
                                y1 = data[i] & 0xff;
                                y2 = data[i + 1] & 0xff;
                                y3 = data[saveWidth + i] & 0xff;
                                y4 = data[saveWidth + i + 1] & 0xff;

                                u = data[offset + k] & 0xff;
                                v = data[offset + k + 1] & 0xff;

                                // getting size
                                if (uvIndex == 0) {
                                    int specialByte1P1 = u & 15;
                                    int specialByte1P2 = v & 15;
                                    int specialCharacter1 = (specialByte1P1 << 4) | specialByte1P2;
                                    if (specialCharacter1 != 17) {
                                        throw new IllegalArgumentException("value has changed");
                                    }
                                }

                                uvIndex++;
                                if (i != 0 && (i + 2) % saveWidth == 0)
                                    i += saveWidth;
                            }
                        }
                    } else {
                        outputFrame.rewind();
                        byte[] data = new byte[outputFrame.remaining()];
                        outputFrame.get(data);
                        try {
                            File outputFile = new File(STORE_FRAME_DIRECTORY,
                                    String.format(Locale.US, "frame_%d.frame", decodeCount));
                            FileOutputStream stream = new FileOutputStream(outputFile.getAbsoluteFile());
                            stream.write(data);
                        } catch (FileNotFoundException e1) {
                            e1.printStackTrace();
                        }
                    }

                    decodeCount++;
                }
                if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                    if (VERBOSE) Log.d(TAG, "output EOS");
                    outputDone = true;
                }

                decoder.releaseOutputBuffer(decoderStatus, false);

            }
        }
    }

    int numSaved = (frameRate < decodeCount) ? frameRate : decodeCount;
    Log.d(TAG, "Saving " + numSaved + " frames took " +
            (frameSaveTime / numSaved / 1000) + " us per frame");
}

public int getDecodeCount() {
    return decodeCount;
}
}

в классе ниже, я кодирую кадры, изменяя одно значение uvиз (кадр 1), сохранить цифру 17 в lsb первых u и v и построить mp4 с помощью кодировщика mediacodec.

public class YUVFrameBufferToVideoEncoder {
private static final String TAG = BitmapToVideoEncoder.class.getSimpleName();
private static final int ERROR_IN_PROCESS = 0;

private IBitmapToVideoEncoderCallback mCallback;
private File mOutputFile;
private Queue<File> mEncodeQueue = new ConcurrentLinkedQueue();
private MediaCodec mediaCodec;
private MediaMuxer mediaMuxer;

private Object mFrameSync = new Object();
private CountDownLatch mNewFrameLatch;

private static final String MIME_TYPE = "video/avc"; // H.264 Advanced Video Coding
private static int mWidth;
private static int mHeight;
private static int BIT_RATE;
private static int FRAME_RATE; // Frames per second
private int frameCount;
private Handler _progressBarHandler;
private Handler _processHandler;

private static final int I_FRAME_INTERVAL = 1;

private int mGenerateIndex = 0;
private int mTrackIndex;
private boolean mNoMoreFrames = false;
private boolean mAbort = false;
//
private byte[] dataToHide;

public interface IBitmapToVideoEncoderCallback {
    void onEncodingComplete(File outputFile);
}

public YUVFrameBufferToVideoEncoder(IBitmapToVideoEncoderCallback callback) {
    mCallback = callback;
}

public boolean isEncodingStarted() {
    return (mediaCodec != null) && (mediaMuxer != null) && !mNoMoreFrames && !mAbort;
}

public int getActiveBitmaps() {
    return mEncodeQueue.size();
}

public boolean startEncoding(int width, int height, int fps, int bitrate, int frameCount
        , byte[] dataToHide, Handler _progressBarHandler, Handler _processHandler
        , File outputFile) {
    mWidth = width;
    mHeight = height;
    FRAME_RATE = fps;
    BIT_RATE = bitrate;
    this.frameCount = frameCount;
    this._progressBarHandler = _progressBarHandler;
    this._processHandler = _processHandler;
    mOutputFile = outputFile;
    this.dataToHide = dataToHide;

    String outputFileString;
    try {
        outputFileString = outputFile.getCanonicalPath();
    } catch (IOException e) {
        Log.e(TAG, "Unable to get path for " + outputFile);
        ErrorManager.getInstance().addErrorMessage("Unable to get path for " + outputFile);
        return false;
    }

    MediaCodecInfo codecInfo = selectCodec(MIME_TYPE);
    if (codecInfo == null) {
        Log.e(TAG, "Unable to find an appropriate codec for " + MIME_TYPE);
        ErrorManager.getInstance().addErrorMessage("Unable to find an appropriate codec for " + MIME_TYPE);
        return false;
    }
    Log.d(TAG, "found codec: " + codecInfo.getName());
    int colorFormat;
    try {
        colorFormat = MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar;
    } catch (Exception e) {
        colorFormat = MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar;
    }

    try {
        mediaCodec = MediaCodec.createByCodecName(codecInfo.getName());
    } catch (IOException e) {
        Log.e(TAG, "Unable to create MediaCodec " + e.getMessage());
        ErrorManager.getInstance().addErrorMessage("Unable to create MediaCodec " + e.getMessage());
        return false;
    }

    MediaFormat mediaFormat = MediaFormat.createVideoFormat(MIME_TYPE, mWidth, mHeight);
    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE);
    mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, FRAME_RATE);
    mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, colorFormat);
    mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, I_FRAME_INTERVAL);
    mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
    mediaCodec.start();
    try {
        mediaMuxer = new MediaMuxer(outputFileString, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
    } catch (IOException e) {
        Log.e(TAG, "MediaMuxer creation failed. " + e.getMessage());
        ErrorManager.getInstance().addErrorMessage("MediaMuxer creation failed. " + e.getMessage());
        return false;
    }

    Log.d(TAG, "Initialization complete. Starting encoder...");

    Completable.fromAction(this::encode)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe();
    return true;
}

public void stopEncoding() {
    if (mediaCodec == null || mediaMuxer == null) {
        Log.d(TAG, "Failed to stop encoding since it never started");
        return;
    }
    Log.d(TAG, "Stopping encoding");

    mNoMoreFrames = true;

    synchronized (mFrameSync) {
        if ((mNewFrameLatch != null) && (mNewFrameLatch.getCount() > 0)) {
            mNewFrameLatch.countDown();
        }
    }
}

public void abortEncoding() {
    if (mediaCodec == null || mediaMuxer == null) {
        Log.d(TAG, "Failed to abort encoding since it never started");
        return;
    }
    Log.d(TAG, "Aborting encoding");

    mNoMoreFrames = true;
    mAbort = true;
    mEncodeQueue = new ConcurrentLinkedQueue(); // Drop all frames

    synchronized (mFrameSync) {
        if ((mNewFrameLatch != null) && (mNewFrameLatch.getCount() > 0)) {
            mNewFrameLatch.countDown();
        }
    }
}

public void queueFrame(File frame) {
    if (mediaCodec == null || mediaMuxer == null) {
        Log.d(TAG, "Failed to queue frame. Encoding not started");
        return;
    }

    Log.d(TAG, "Queueing frame");
    mEncodeQueue.add(frame);

    synchronized (mFrameSync) {
        if ((mNewFrameLatch != null) && (mNewFrameLatch.getCount() > 0)) {
            mNewFrameLatch.countDown();
        }
    }
}

private void encode() {

    Log.d(TAG, "Encoder started");

    while (true) {
        if (mNoMoreFrames && (mEncodeQueue.size() == 0)) break;

        File frame = mEncodeQueue.poll();
        if (frame == null) {
            synchronized (mFrameSync) {
                mNewFrameLatch = new CountDownLatch(1);
            }

            try {
                mNewFrameLatch.await();
            } catch (InterruptedException e) {
            }

            frame = mEncodeQueue.poll();
        }

        if (frame == null) continue;

        int size = (int) frame.length();
        byte[] bytesNV21 = new byte[size];

        try {
            BufferedInputStream buf = new BufferedInputStream(new FileInputStream(frame));
            buf.read(bytesNV21, 0, bytesNV21.length);
            buf.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        int offsetSize = mWidth * mHeight;
        int byteNV21Offset = offsetSize;
        int u, v, y1, y2, y3, y4;

        //
        int dataToHideLength = 0;
        if (dataToHide != null)
            dataToHideLength = dataToHide.length;

        boolean isLastIndexInserted1 = false;
        boolean isLastIndexInserted2 = false;
        boolean isLastIndexInserted3 = false;

        int uvIndex = 0;
        int frameByteCapacity = ((mWidth * mHeight) / 4) / 20;
        Log.e(TAG, "encode: dataToHideLength: " + dataToHideLength);
        Log.e(TAG, "encode: frameByteCapacity: " + dataToHideLength);
        //

        // i percorre os Y and the final pixels
        // k percorre os pixles U e V
        for (int i = 0, k = 0; i < offsetSize; i += 2, k += 2) {
            y1 = bytesNV21[i] & 0xff;
            y2 = bytesNV21[i + 1] & 0xff;
            y3 = bytesNV21[mWidth + i] & 0xff;
            y4 = bytesNV21[mWidth + i + 1] & 0xff;

            u = bytesNV21[byteNV21Offset + k] & 0xff;
            v = bytesNV21[byteNV21Offset + k + 1] & 0xff;


            // frame 1
            // altering u and v for test
            if (mGenerateIndex == 1) {
                int Unew = u & 240;
                int Vnew = v & 240;

                if (uvIndex == 0) {
                    // used in start and end of stego bytes
                    int specialByte1Integer = 17;
                    int specialByte1P1 = specialByte1Integer & 240;
                    int specialByte1P2 = specialByte1Integer & 15;

                    // shift p1 right 4 position
                    specialByte1P1 = specialByte1P1 >> 4;

                    u = Unew | specialByte1P1;
                    v = Vnew | specialByte1P2;

                }

                bytesNV21[byteNV21Offset + k] = (byte) u;
                bytesNV21[byteNV21Offset + k + 1] = (byte) v;
            }


            uvIndex++;

            if (i != 0 && (i + 2) % mWidth == 0)
                i += mWidth;
        }

        long TIMEOUT_USEC = 500000;
        int inputBufIndex = mediaCodec.dequeueInputBuffer(TIMEOUT_USEC);
        long ptsUsec = computePresentationTime(mGenerateIndex, FRAME_RATE);
        if (inputBufIndex >= 0) {
            final ByteBuffer inputBuffer = mediaCodec.getInputBuffers()[inputBufIndex];
            inputBuffer.clear();
            inputBuffer.put(bytesNV21);
            mediaCodec.queueInputBuffer(inputBufIndex, 0, bytesNV21.length, ptsUsec, 0);
            mGenerateIndex++;

            int percentComplete = 70 + (int) ((((double) mGenerateIndex) / (frameCount)) * 30);
            if (_progressBarHandler != null) {
                _progressBarHandler.sendMessage(_progressBarHandler.obtainMessage(percentComplete));
            }
            Log.w("creatingVideo: ", "is:" + percentComplete);
        }
        MediaCodec.BufferInfo mBufferInfo = new MediaCodec.BufferInfo();
        int encoderStatus = mediaCodec.dequeueOutputBuffer(mBufferInfo, TIMEOUT_USEC);
        if (encoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
            // no output available yet
            Log.e(TAG, "No output from encoder available");
        } else if (encoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
            // not expected for an encoder
            MediaFormat newFormat = mediaCodec.getOutputFormat();
            mTrackIndex = mediaMuxer.addTrack(newFormat);
            mediaMuxer.start();
        } else if (encoderStatus < 0) {
            Log.e(TAG, "unexpected result from encoder.dequeueOutputBuffer: " + encoderStatus);
        } else if (mBufferInfo.size != 0) {
            ByteBuffer encodedData = mediaCodec.getOutputBuffers()[encoderStatus];
            if (encodedData == null) {
                Log.e(TAG, "encoderOutputBuffer " + encoderStatus + " was null");
            } else {
                encodedData.position(mBufferInfo.offset);
                encodedData.limit(mBufferInfo.offset + mBufferInfo.size);
                mediaMuxer.writeSampleData(mTrackIndex, encodedData, mBufferInfo);
                mediaCodec.releaseOutputBuffer(encoderStatus, false);
            }
        }
    }

    release();

    if (mAbort) {
        mOutputFile.delete();
    } else {
        mCallback.onEncodingComplete(mOutputFile);
    }
}

private void release() {
    try {
        if (mediaCodec != null) {
            mediaCodec.stop();
            mediaCodec.release();
            mediaCodec = null;
            Log.d(TAG, "RELEASE CODEC");
        }
        if (mediaMuxer != null) {
            mediaMuxer.stop();
            mediaMuxer.release();
            mediaMuxer = null;
            Log.d(TAG, "RELEASE MUXER");
        }
    } catch (Exception ignored) {
        ErrorManager.getInstance().addErrorMessage("unsupported video file");
        Message res = _processHandler.obtainMessage(ERROR_IN_PROCESS);
        _processHandler.sendMessage(res);
    }
}

private static MediaCodecInfo selectCodec(String mimeType) {
    int numCodecs = MediaCodecList.getCodecCount();
    for (int i = 0; i < numCodecs; i++) {
        MediaCodecInfo codecInfo = MediaCodecList.getCodecInfoAt(i);
        if (!codecInfo.isEncoder()) {
            continue;
        }
        String[] types = codecInfo.getSupportedTypes();
        for (int j = 0; j < types.length; j++) {
            if (types[j].equalsIgnoreCase(mimeType)) {
                return codecInfo;
            }
        }
    }
    return null;
}

private static int selectColorFormat(MediaCodecInfo codecInfo,
                                     String mimeType) {
    MediaCodecInfo.CodecCapabilities capabilities = codecInfo
            .getCapabilitiesForType(mimeType);
    for (int i = 0; i < capabilities.colorFormats.length; i++) {
        int colorFormat = capabilities.colorFormats[i];
        if (isRecognizedFormat(colorFormat)) {
            return colorFormat;
        }
    }
    return 0; // not reached
}

private static boolean isRecognizedFormat(int colorFormat) {
    switch (colorFormat) {
        // these are the formats we know how to handle for
        case MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar:
        case MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420PackedPlanar:
        case MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar:
        case MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420PackedSemiPlanar:
        case MediaCodecInfo.CodecCapabilities.COLOR_TI_FormatYUV420PackedSemiPlanar:
            return true;
        default:
            return false;
    }
}

private long computePresentationTime(long frameIndex, int framerate) {
    return 132 + frameIndex * 1000000 / framerate;
}}

Выходное видео успешно создано без каких-либо проблем, но mediacodec изменил измененное значение тестаи я не могу получить его.

вот мой вопрос, это правильный подход для выполнения видео-стеганографии в Android? если это не правильный путь, не могли бы вы сделать предложение?

Answer 1

Стеганография поставляется с обязательным условием - кодирование без потерь .

На данный момент ни один из кодеков, доступных в Android, не поддерживает кодирование без потерь.

Так что ябоюсь, ваши LSB никогда не останутся прежними после кодирования / декодирования.

Предложение : Если у вас не так много кадров, я бы предложил использовать формат без потерь. Вы можете закодировать свои кадры в последовательность изображений PNG.