如何使用FFmpeg或JCodec将图像转换为而不是，只能使用android MediaCodec。视频图像是位图文件，可以是ARGB888或YUV420（我的选择）。最重要的是视频必须在Android设备上播放，最大API为16.我知道所有关于API 18 MediaMuxer而我不能使用它。
请帮助我，我坚持了很多天。 （JCodec要慢，FFmpeg使用起来很复杂）。
答案 0 :(得分：13)
在API 16中没有简单的方法可以在所有设备上运行。
您会遇到buffer alignment，color spaces的问题，以及需要在不同的layouts上使用不同的YUV devices。
考虑缓冲区对齐问题。在具有Qualcomm SOC的API 18之前的设备上，您必须将CbCr平面与缓冲区的起始位置偏移2K。在API 18上，所有设备都使用相同的布局;这是由Android 4.3中添加的CTS测试强制执行的。
即使使用API 18，您仍然需要运行时检测编码器是否需要平面值或半平面值。 （这可能与您的情况无关，但MediaCodec不接受摄像机输出的YUV格式。）请注意MediaCodec没有RGB输入。
如果不考虑可移植性，即您的目标是特定设备，则代码将更加简单。
上面链接的SO页面中有代码片段。最接近的“官方”示例是EncodeDecodeTest中的缓冲区到缓冲区/缓冲区到表面的测试。这些是API 18测试，这意味着他们没有“如果QC和API16然后更改缓冲区对齐”舞蹈，但他们确实展示了如何进行平面与半平面布局检测。它不包括RGB-to-YUV颜色转换器，但在网络上也有这样的例子。
从好的方面来看，编码器输出在任何设备和API版本上似乎都没问题。
将原始H.264流转换为.mp4文件需要第三方库，因为您注意到MediaMuxer不可用。我相信有些人已经安装ffmpeg作为命令行实用程序并以这种方式执行（可能像this？）。
答案 1 :(得分：5)
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaCodecList;
import android.media.MediaFormat;
import android.media.MediaMuxer;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class MMediaMuxer {
private static final String MIME_TYPE = "video/avc"; // H.264 Advanced Video Coding
private static int _width = 512;
private static int _height = 512;
private static final int BIT_RATE = 800000;
private static final int INFLAME_INTERVAL = 1;
private static final int FRAME_RATE = 10;
private static boolean DEBUG = false;
private MediaCodec mediaCodec;
private MediaMuxer mediaMuxer;
private boolean mRunning;
private int generateIndex = 0;
private int mTrackIndex;
private int MAX_FRAME_VIDEO = 0;
private List<byte[]> bitList;
private List<byte[]> bitFirst;
private List<byte[]> bitLast;
private int current_index_frame = 0;
private static final String TAG = "CODEC";
private String outputPath;
private Activity _activity;
private ProgressDialog pd;
private String _title;
private String _mess;
public void Init(Activity activity, int width, int height, String title, String mess) {
_title = title;
_mess = mess;
_activity = activity;
_width = width;
_height = height;
Logd("MMediaMuxer Init");
ShowProgressBar();
}
private Handler aHandler = new Handler();
public void AddFrame(final byte[] byteFrame) {
CheckDataListState();
new Thread(new Runnable() {
@Override
public void run() {
Logd("Android get Frame");
Bitmap bit = BitmapFactory.decodeByteArray(byteFrame, 0, byteFrame.length);
Logd("Android convert Bitmap");
byte[] byteConvertFrame = getNV21(bit.getWidth(), bit.getHeight(), bit);
Logd("Android convert getNV21");
bitList.add(byteConvertFrame);
}
}).start();
}
public void AddFrame(byte[] byteFrame, int count, boolean isLast) {
CheckDataListState();
Logd("Android get Frames = " + count);
Bitmap bit = BitmapFactory.decodeByteArray(byteFrame, 0, byteFrame.length);
Logd("Android convert Bitmap");
byteFrame = getNV21(bit.getWidth(), bit.getHeight(), bit);
Logd("Android convert getNV21");
for (int i = 0; i < count; i++) {
if (isLast) {
bitLast.add(byteFrame);
} else {
bitFirst.add(byteFrame);
}
}
}
public void CreateVideo() {
current_index_frame = 0;
Logd("Prepare Frames Data");
bitFirst.addAll(bitList);
bitFirst.addAll(bitLast);
MAX_FRAME_VIDEO = bitFirst.size();
Logd("CreateVideo");
mRunning = true;
bufferEncoder();
}
public boolean GetStateEncoder() {
return mRunning;
}
public String GetPath() {
return outputPath;
}
public void onBackPressed() {
mRunning = false;
}
public void ShowProgressBar() {
_activity.runOnUiThread(new Runnable() {
public void run() {
pd = new ProgressDialog(_activity);
pd.setTitle(_title);
pd.setCancelable(false);
pd.setMessage(_mess);
pd.setCanceledOnTouchOutside(false);
pd.show();
}
});
}
public void HideProgressBar() {
new Thread(new Runnable() {
@Override
public void run() {
_activity.runOnUiThread(new Runnable() {
@Override
public void run() {
pd.dismiss();
}
});
}
}).start();
}
private void bufferEncoder() {
Runnable runnable = new Runnable() {
@Override
public void run() {
try {
Logd("PrepareEncoder start");
PrepareEncoder();
Logd("PrepareEncoder end");
} catch (IOException e) {
Loge(e.getMessage());
}
try {
while (mRunning) {
Encode();
}
} finally {
Logd("release");
Release();
HideProgressBar();
bitFirst = null;
bitLast = null;
}
}
};
Thread thread = new Thread(runnable);
thread.start();
}
public void ClearTask() {
bitList = null;
bitFirst = null;
bitLast = null;
}
private void PrepareEncoder() throws IOException {
MediaCodecInfo codecInfo = selectCodec(MIME_TYPE);
if (codecInfo == null) {
Loge("Unable to find an appropriate codec for " + MIME_TYPE);
}
Logd("found codec: " + codecInfo.getName());
int colorFormat;
try {
colorFormat = selectColorFormat(codecInfo, MIME_TYPE);
} catch (Exception e) {
colorFormat = MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar;
}
mediaCodec = MediaCodec.createByCodecName(codecInfo.getName());
MediaFormat mediaFormat = MediaFormat.createVideoFormat(MIME_TYPE, _width, _height);
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, INFLAME_INTERVAL);
mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
mediaCodec.start();
try {
String currentDateTimeString = DateFormat.getDateTimeInstance().format(new Date());
outputPath = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES),
"pixel"+currentDateTimeString+".mp4").toString();
mediaMuxer = new MediaMuxer(outputPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
} catch (IOException ioe) {
Loge("MediaMuxer creation failed");
}
}
private void Encode() {
while (true) {
if (!mRunning) {
break;
}
Logd("Encode start");
long TIMEOUT_USEC = 5000;
int inputBufIndex = mediaCodec.dequeueInputBuffer(TIMEOUT_USEC);
long ptsUsec = computePresentationTime(generateIndex, FRAME_RATE);
if (inputBufIndex >= 0) {
byte[] input = bitFirst.get(current_index_frame);
final ByteBuffer inputBuffer = mediaCodec.getInputBuffer(inputBufIndex);
inputBuffer.clear();
inputBuffer.put(input);
mediaCodec.queueInputBuffer(inputBufIndex, 0, input.length, ptsUsec, 0);
generateIndex++;
}
MediaCodec.BufferInfo mBufferInfo = new MediaCodec.BufferInfo();
int encoderStatus = mediaCodec.dequeueOutputBuffer(mBufferInfo, TIMEOUT_USEC);
if (encoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
// no output available yet
Loge("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) {
Loge("unexpected result from encoder.dequeueOutputBuffer: " + encoderStatus);
} else if (mBufferInfo.size != 0) {
ByteBuffer encodedData = mediaCodec.getOutputBuffer(encoderStatus);
if (encodedData == null) {
Loge("encoderOutputBuffer " + encoderStatus + " was null");
} else {
encodedData.position(mBufferInfo.offset);
encodedData.limit(mBufferInfo.offset + mBufferInfo.size);
mediaMuxer.writeSampleData(mTrackIndex, encodedData, mBufferInfo);
mediaCodec.releaseOutputBuffer(encoderStatus, false);
}
}
current_index_frame++;
if (current_index_frame > MAX_FRAME_VIDEO - 1) {
Log.d(TAG, "mRunning = false;");
mRunning = false;
}
Logd("Encode end");
}
}
private void Release() {
if (mediaCodec != null) {
mediaCodec.stop();
mediaCodec.release();
mediaCodec = null;
Logd("RELEASE CODEC");
}
if (mediaMuxer != null) {
mediaMuxer.stop();
mediaMuxer.release();
mediaMuxer = null;
Logd("RELEASE MUXER");
}
}
/**
* Returns the first codec capable of encoding the specified MIME type, or
* null if no match was found.
*/
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;
}
/**
* Returns a color format that is supported by the codec and by this test
* code. If no match is found, this throws a test failure -- the set of
* formats known to the test should be expanded for new platforms.
*/
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
}
/**
* Returns true if this is a color format that this test code understands
* (i.e. we know how to read and generate frames in this format).
*/
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 byte[] getNV21(int inputWidth, int inputHeight, Bitmap scaled) {
int[] argb = new int[inputWidth * inputHeight];
scaled.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight);
byte[] yuv = new byte[inputWidth * inputHeight * 3 / 2];
encodeYUV420SP(yuv, argb, inputWidth, inputHeight);
scaled.recycle();
return yuv;
}
private void encodeYUV420SP(byte[] yuv420sp, int[] argb, int width, int height) {
final int frameSize = width * height;
int yIndex = 0;
int uvIndex = frameSize;
int a, R, G, B, Y, U, V;
int index = 0;
for (int j = 0; j < height; j++) {
for (int i = 0; i < width; i++) {
a = (argb[index] & 0xff000000) >> 24; // a is not used obviously
R = (argb[index] & 0xff0000) >> 16;
G = (argb[index] & 0xff00) >> 8;
B = (argb[index] & 0xff) >> 0;
Y = ((66 * R + 129 * G + 25 * B + 128) >> 8) + 16;
U = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128;
V = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128;
yuv420sp[yIndex++] = (byte) ((Y < 0) ? 0 : ((Y > 255) ? 255 : Y));
if (j % 2 == 0 && index % 2 == 0) {
yuv420sp[uvIndex++] = (byte) ((U < 0) ? 0 : ((U > 255) ? 255 : U));
yuv420sp[uvIndex++] = (byte) ((V < 0) ? 0 : ((V > 255) ? 255 : V));
}
index++;
}
}
}
private void CheckDataListState() {
if (bitList == null) {
bitList = new ArrayList<>();
}
if (bitFirst == null) {
bitFirst = new ArrayList<>();
}
if (bitLast == null) {
bitLast = new ArrayList<>();
}
}
private long computePresentationTime(long frameIndex, int framerate) {
return 132 + frameIndex * 1000000 / framerate;
}
private static void Logd(String Mess) {
if (DEBUG) {
Log.d(TAG, Mess);
}
}
private static void Loge(String Mess) {
Log.e(TAG, Mess);
}
}
使用21 SDK。不要注意几个清单。所以它已经完成，因为一段数据的转换是在运行时进行的。