使用 android MediaCodec api 压缩视频

Question

我想将本地保存的视频文件压缩到较小的大小，以便上传到服务器。

自从我使用 MediaCodec 以来，我发现了一些压缩视频的技巧。这是我遵循的步骤

1) 。使用 MediaExrtactor 提取媒体文件并对其进行解码。 2) 。创建具有所需文件格式的编码器 3) 。创建复用器以将文件保存在本地存储中。 （不完整）

问题：但我不知道如何编码已经解码的流并使用 MediaMuxer 将流保存到本地存储中。

public class CompressMedia {

    private static final String SAMPLE = Environment
            .getExternalStorageDirectory() + "/DCIM/Camera/20140506_174959.mp4";

    private static final String OUTPUT_PATH = Environment
            .getExternalStorageDirectory()
            + "/DCIM/Camera/20140506_174959_REC.mp4";

    private MediaExtractor extractor;
    private MediaCodec decoder;
    private MediaCodec encoder;
    String mime;

    private static final String MIME_TYPE = "video/avc";

    public void extractMediaFile() {

        // work plan
        // locate media file
        // extract media file using Media Extractor
        // retrieve decoded frames

        extractor = new MediaExtractor();
        try {
            extractor.setDataSource(SAMPLE);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            // file not found
            e.printStackTrace();
        }

        // add decoded frames
        for (int i = 0; i < extractor.getTrackCount(); i++) {
            MediaFormat format = extractor.getTrackFormat(i);
            mime = format.getString(MediaFormat.KEY_MIME);
            if (mime.startsWith("video/")) {
                extractor.selectTrack(i);
                decoder = MediaCodec.createDecoderByType(mime);
                decoder.configure(format, null, null, 0);
                break;
            }
        }

        if (decoder == null) {
            Log.e("DecodeActivity", "Can't find video info!");
            return;
        }

        // - start decoder -
        decoder.start();
        extractor.selectTrack(0);

        // - decoded frames can obtain in here -

    }

    private void createsEncoder() {

        // creates media encoder to set formats
        encoder = MediaCodec.createDecoderByType(MIME_TYPE);

        // init media format
        MediaFormat mediaFormat = MediaFormat.createVideoFormat(MIME_TYPE, /* 640 */
                320, /* 480 */240);
        mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 400000);
        mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 25);
        mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT,
                MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420SemiPlanar);
        mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 5);
        encoder.configure(mediaFormat, null, null,
                MediaCodec.CONFIGURE_FLAG_ENCODE);
        encoder.start();

        // - encoded data format is avaiable in here

    }

    private void createMuxer() {

        // creates media muxer - media muxer will be used to write the final
        // strem in to a desired file :)

        try {
            MediaMuxer muxer = new MediaMuxer(OUTPUT_PATH,
                    OutputFormat.MUXER_OUTPUT_MPEG_4);

            int videoTrackIndex = muxer.addTrack(encoder.getOutputFormat());

            //muxer.writeSampleData(videoTrackIndex, inputBuffers, bufferInfo);
            muxer.start();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

这是我关注的链接 Android MediaCodec: Reduce mp4 video size 和

Video compression on android using new MediaCodec Library

Answer 1

您可以在https://software.intel.com/en-us/intel-inde 上尝试 Intel INDE 和作为 INDE 一部分的 Android 媒体包，https://software.intel.com/en-us/articles/intel-inde-media-pack-for-android-tutorials 上的教程。它有一个示例，显示如何使用媒体包转码=重新压缩视频文件。您可以设置更小的分辨率和/或比特率来输出以获得更小的文件

在 ComposerTranscodeCoreActivity.java 中

protected void setTranscodeParameters(MediaComposer mediaComposer) throws IOException {

    mediaComposer.addSourceFile(mediaUri1);
    mediaComposer.setTargetFile(dstMediaPath);

    configureVideoEncoder(mediaComposer, videoWidthOut, videoHeightOut);
    configureAudioEncoder(mediaComposer);
}

protected void transcode() throws Exception {

    factory = new AndroidMediaObjectFactory(getApplicationContext());
    mediaComposer = new MediaComposer(factory, progressListener);
    setTranscodeParameters(mediaComposer);
    mediaComposer.start();
}