MediaExtractor,MediaCodec和opengl抽取mp4视频文件的帧缩略图.
时间: 2023-07-16 16:13:36 浏览: 64
可以使用以下步骤从mp4视频文件中提取帧缩略图:
1. 使用MediaExtractor从mp4文件中提取视频轨道数据。
```java
MediaExtractor extractor = new MediaExtractor();
extractor.setDataSource(filePath);
int trackCount = extractor.getTrackCount();
for (int i = 0; i < trackCount; i++) {
MediaFormat format = extractor.getTrackFormat(i);
String mime = format.getString(MediaFormat.KEY_MIME);
if (mime.startsWith("video/")) {
extractor.selectTrack(i);
ByteBuffer inputBuffer = ByteBuffer.allocate(1024 * 1024);
MediaCodec codec = MediaCodec.createDecoderByType(mime);
codec.configure(format, null, null, 0);
codec.start();
boolean isEOS = false;
while (!isEOS) {
int sampleSize = extractor.readSampleData(inputBuffer, 0);
if (sampleSize < 0) {
isEOS = true;
} else {
long presentationTimeUs = extractor.getSampleTime();
codec.queueInputBuffer(inputBuffer.position(), sampleSize, presentationTimeUs, 0, isEOS ? MediaCodec.BUFFER_FLAG_END_OF_STREAM : 0);
extractor.advance();
}
MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
int outputBufferIndex = codec.dequeueOutputBuffer(bufferInfo, TIMEOUT_US);
while (outputBufferIndex >= 0) {
Image image = codec.getOutputImage(outputBufferIndex);
// 处理image,生成缩略图
codec.releaseOutputBuffer(outputBufferIndex, true);
outputBufferIndex = codec.dequeueOutputBuffer(bufferInfo, TIMEOUT_US);
}
}
codec.stop();
codec.release();
extractor.unselectTrack(i);
}
}
extractor.release();
```
2. 使用MediaCodec进行视频解码,获取每一帧的Image对象。
3. 将Image对象转换为Bitmap对象,生成缩略图。
```java
Image.Plane[] planes = image.getPlanes();
ByteBuffer buffer = planes[0].getBuffer();
int pixelStride = planes[0].getPixelStride();
int rowStride = planes[0].getRowStride();
int rowPadding = rowStride - pixelStride * width;
Bitmap bitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
bitmap.copyPixelsFromBuffer(buffer);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height);
```
4. 可以使用OpenGL对缩略图进行后期处理,如旋转、缩放等操作。