mediaCodec 异步编解码视频,修改pts 实现视频 变速,放弃modeacodec的同步模式,因为要慢一些,短视频编辑中的视频裁剪 音频变速/视频变速

       地址:https://gitee.com/dahai2070/mytx-android  这个是我们的创业项目开源地址,欢迎加入,共谋发展,以下所有代码都在这个链接中。

因为自己的创业项目中一直没有视频上传功能,只有视频录制了上传,好久前就想着要写一个视频编辑上传的功能,目前这个功能差不多完成了。

一开始是用的modiacodec的同步模式,在魅族16th上测试了和火山小视频的差距,火山40s变速40s 的视频,耗时20s左右,一开始是我用的同步方式,时间在29s 左右,一番折腾,仍然在25秒左右,我知道有异步的写法,对于我这样的不懂底层内核的野程序员来说,遇到问题先百度,百度下搜了看了下,开始写,在调用

outputSurface.awaitNewImage();

的时候,报错:Unable to update texture contents (see logcat for details) ,

后来google搜了 异步编解码模式,在stackoverflow 上看到帖子,最终解决了问题。目前在速度设为2倍,编解码40s视频时间在23s,可能还有提升吧,暂时不折腾了,

贴上初始化编解码的代码:关键是

inputSurface.releaseEGLContext(); 必须要,
   private void initVideoCodec() {
        for (int i = 0; i < mVideoExtractor.getTrackCount(); i++) {
            MediaFormat format = mVideoExtractor.getTrackFormat(i);
            if (format.getString(MediaFormat.KEY_MIME).startsWith("video/")) {
                videoTrackIndex = i;
                videoFormat = format;
                break;
            }
        }
        mVideoExtractor.selectTrack(videoTrackIndex);
        long firstVideoTime = mVideoExtractor.getSampleTime();
        mVideoExtractor.seekTo(firstVideoTime + videoStartPositionUs, SEEK_TO_PREVIOUS_SYNC);
        if (videoFormat == null) {
            Log.e(TAG, "initVideoCodec: 没有获取到视频格式");
            return;
        }
        try {
            // videoDecoder = MediaCodec.createDecoderByType(videoFormat.getString(MediaFormat.KEY_MIME));
            videoEncoder = MediaCodec.createEncoderByType("video/avc");
        } catch (IOException e) {
            e.printStackTrace();
        }
        videoEncoder.setCallback(new VideoEncoderCallBack());
        videoEncoder.configure(compressMediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        Surface surface = videoEncoder.createInputSurface();
        this.inputSurface = new InputSurface_v1(surface);
        this.inputSurface.makeCurrent();
        videoEncoder.start();

        outputSurface = new OutputSurface_v1();
        mVideoDecoderHandlerThread = new HandlerThread("DecoderThread");
        mVideoDecoderHandlerThread.start();
        mVideoDecoderHandler = new CallbackHandler(mVideoDecoderHandlerThread.getLooper());
        mVideoDecoderHandler.create(false, videoFormat.getString(MediaFormat.KEY_MIME), new VideoDecoderCallBack());
        videoDecoder = mVideoDecoderHandler.getCodec();

        videoDecoder.configure(videoFormat, outputSurface.getSurface(), null, 0);
        videoDecoder.start();//解码器启动
        inputSurface.releaseEGLContext();//必须释放,否则报线程错


    }

接下来是 编码器和解码器的回调,和同步写法不同的是在 解码器的

onOutputBufferAvailable()回调中,需要调用 以下两个方法。
inputSurface.makeCurrent();和inputSurface.releaseEGLContext();

因为解码器又是在另外一个线程中,解码器工作在另外一个线程中(看解码器decoder初始化哪儿,后面会跟上那个handler),我的理解是这样。而同步模式却不需要。

视频变速的关键是根据原来的pts/速度倍数

inputSurface.setPresentationTime((long) ((info.presentationTimeUs - videoStartPositionUs) / speed * 1000));

这样能实现视频变速,本来我想这从视频文件中提取数据的时候,根据给定的速度值,丢掉一些数据,确实这样编解码速度速度确实变快了,几乎耗时减半,但是编码出的视频,却在一些画面变化相对快一些的地方,花屏了,我的测试视频是我坐着削橙子的皮,手部位置就花了,,,,,,, 有大佬知道的有好方法的,请告诉我。

 private class VideoDecoderCallBack extends MediaCodec.Callback {

        @Override
        public void onInputBufferAvailable(@NonNull MediaCodec codec, int index) {

            ByteBuffer inputBuffer = codec.getInputBuffer(index);//取到一个字节缓冲区
            inputBuffer.clear();
            int readSampleData = mVideoExtractor.readSampleData(inputBuffer, 0);//往字节缓冲区中填充数据
            long dur = mVideoExtractor.getSampleTime() - videoStartPositionUs;//当前已经截取的视频长度
            if ((dur < clipDur * speed) && readSampleData > 0) {
                codec.queueInputBuffer(index, 0, readSampleData, mVideoExtractor.getSampleTime(), 0); //queueInputBuffer 开始处理(解码)数据,inputIndex 告诉解码器数据所在的位置索引
                mVideoExtractor.advance();
//                        if (speed == 2&&frameCount%2==0) { //如果速度是2,跳过一帧
//
//                            extractor.advance();
//                        } else if (speed == 3&&frameCount%3==0) {//如果速度是3,跳过2帧
//                            extractor.advance();
//                            extractor.advance();
//                        }

            } else {
                codec.queueInputBuffer(index, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
                Log.e(TAG, "onInputBufferAvailable:视频数据提取完成");
            }
        }

        @Override
        public void onOutputBufferAvailable(@NonNull MediaCodec codec, int index, @NonNull MediaCodec.BufferInfo info) {
            if ((info.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
                Log.d(TAG, "video decoder: codec config buffer");
                codec.releaseOutputBuffer(index, false);
                return;
            }
            boolean doRender = (info.size != 0 && info.presentationTimeUs > videoStartPositionUs);
            codec.releaseOutputBuffer(index, doRender);//起到把数据给到 encoder的作用,相当于执行了 encoder.queueInputBuffer()
            if (doRender) {
                inputSurface.makeCurrent();//因为这个回调在另外一个线程中,所以需要在 这儿调用 makeCurrent(),和同步写法不一样的地方
                outputSurface.awaitNewImage();
                outputSurface.drawImage();
                inputSurface.setPresentationTime((long) ((info.presentationTimeUs - videoStartPositionUs) / speed * 1000));
                inputSurface.swapBuffers();
                inputSurface.releaseEGLContext();
            }
            if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                videoEncoder.signalEndOfInputStream();
            }
        }

        @Override
        public void onError(@NonNull MediaCodec codec, @NonNull MediaCodec.CodecException e) {

        }

        @Override
        public void onOutputFormatChanged(@NonNull MediaCodec codec, @NonNull MediaFormat format) {

        }
    }

    private class VideoEncoderCallBack extends MediaCodec.Callback {

        @Override
        public void onInputBufferAvailable(@NonNull MediaCodec codec, int index) {


        }

        @Override
        public void onOutputBufferAvailable(@NonNull MediaCodec codec, int index, @NonNull MediaCodec.BufferInfo info) {


            if (info.size != 0) {
                ByteBuffer outputBuffer = codec.getOutputBuffer(index);
                if (outputBuffer != null) {
//                    byte[] dataSources = new byte[outputBuffer.remaining()];
//                    outputBuffer.get(dataSources);
                    if (!muxStarted) {
                        synchronized (lock) {
                            if (!muxStarted) {
                                try {
                                    lock.wait();
                                } catch (InterruptedException e) {
                                    e.printStackTrace();
                                }
                            }
                        }
                    }
                    mMediaMuxer.writeSampleData(muxVideoTrack, outputBuffer, info);

                    if (listener != null) {
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                listener.onProgress((int) (((float) info.presentationTimeUs / clipDur) * 100));
                            }
                        });

                    }
                }
            }
            codec.releaseOutputBuffer(index, false);
            if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
                videoFinish = true;
                release();
                Log.e(TAG, "run: 视频编解码结束+mOutputVideoPath:" + mOutputVideoPath +
                        "\n 视频编解码所需时间是:" + (System.currentTimeMillis() - before));
            }

        }

        @Override
        public void onError(@NonNull MediaCodec codec, @NonNull MediaCodec.CodecException e) {

        }

        @Override
        public void onOutputFormatChanged(@NonNull MediaCodec codec, @NonNull MediaFormat format) {
            startMux(format, 0);
        }
    }

用于解码器的 handler ,用于在解码器设置回调的时候使用:

 static class CallbackHandler extends Handler {
        CallbackHandler(Looper l) {
            super(l);
        }

        private MediaCodec mCodec;
        private boolean mEncoder;
        private MediaCodec.Callback mCallback;
        private String mMime;
        private boolean mSetDone;

        @Override
        public void handleMessage(Message msg) {
            try {
                mCodec = mEncoder ? MediaCodec.createEncoderByType(mMime) : MediaCodec.createDecoderByType(mMime);
            } catch (IOException ioe) {
            }
            mCodec.setCallback(mCallback);
            synchronized (this) {
                mSetDone = true;
                notifyAll();
            }
        }

        void create(boolean encoder, String mime, MediaCodec.Callback callback) {
            mEncoder = encoder;
            mMime = mime;
            mCallback = callback;
            mSetDone = false;
            sendEmptyMessage(0);
            synchronized (this) {
                while (!mSetDone) {
                    try {
                        wait();
                    } catch (InterruptedException ie) {
                    }
                }
            }
        }

        MediaCodec getCodec() {
            return mCodec;
        }
    }

音频变速不能修改pts的方式,我尝试过,把音频和视频的pts 都按速度值做除法处理后,通过mediaMuxer 合并,会出现视频卡顿的问题。音频变速需要一个转码器,把解码后的音频数据交给转码器转码,解码完成后,交给音频编码器编码。

音频编解码的过程就是用的同步模式,因为音频的处理几乎都是远远快过视频处理,就没折腾音频的异步模式了,同步模式冗长,且看起繁杂,就不贴完全代码了,只贴上调用转码器的这一部分代码:

下面代码中 mAudioTranscoder 就是转码器
    if (!decodeDone) {
                int index = decoder.dequeueOutputBuffer(info, TIMEOUT_USEC);
                if (index == MediaCodec.INFO_TRY_AGAIN_LATER) {
                    // no output available yet
                } else if (index == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
                    // expected before first buffer of data
                    MediaFormat newFormat = decoder.getOutputFormat();
                } else if (index < 0) {
                } else {
                    boolean canEncode = (info.size != 0 && info.presentationTimeUs - firstSampleTime > startPosition); //根据给定的开始时间,判断当前的数据是否需要编码,不需要就丢弃
                    boolean endOfStream = (info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0;
                    if (canEncode && !endOfStream) {
                        ByteBuffer decoderOutputBuffer;
                        decoderOutputBuffer = decoder.getOutputBuffer(index);

                        mAudioTranscoder.queueInput(decoderOutputBuffer);
                        ByteBuffer output = mAudioTranscoder.getOutput();
                        if (output != null && output.hasRemaining()) {
                            info.presentationTimeUs = (long) ((info.presentationTimeUs - startPosition) / speed);
                            int size = output.remaining();
                            mTotalBytesRead += size;
                            int encodeInputIndex = encoder.dequeueInputBuffer(TIMEOUT_USEC);
                            if (encodeInputIndex >= 0) {
                                ByteBuffer encoderInputBuffer = encoder.getInputBuffer(encodeInputIndex);
                                encoderInputBuffer.clear();
                                encoderInputBuffer.put(output);
                                encoder.queueInputBuffer(encodeInputIndex, info.offset, size, info.presentationTimeUs, 0);
                                encodeinput++;
                                Log.d(TAG, "startAudioCodec: audio encodeInput" + encodeinput + " dataSize" + size + " sampeTime" + info.presentationTimeUs);
                                mPresentationTimeUs = 1000000L * (mTotalBytesRead / 2 / 2) / sampleRate;//计算pts
                            }
                        }
                    }

,要完整代码的去帖子顶部的开源项目中看,就这几天同步进去,视频的同步编解码代码也项目中,下面贴下转码器的完整代码:

package com.cgfay.media.recorder;

import android.media.AudioFormat;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.ShortBuffer;

/**
 * 音频倍速转码器, reference from ExoPlayer's SonicAudioProcessor
 */
public final class AudioTranscoder {

    /**
     * A value for various fields to indicate that the field's value is unknown or not applicable.
     */
    public static final int NO_VALUE = -1;

    /**
     * An empty, direct {@link ByteBuffer}.
     */
    private ByteBuffer EMPTY_BUFFER = ByteBuffer.allocateDirect(0).order(ByteOrder.nativeOrder());

    /**
     * The maximum allowed playback speed in {@link #setSpeed(float)}.
     */
    public static final float MAXIMUM_SPEED = 8.0f;
    /**
     * The minimum allowed playback speed in {@link #setSpeed(float)}.
     */
    public static final float MINIMUM_SPEED = 0.1f;
    /**
     * The maximum allowed pitch in {@link #setPitch(float)}.
     */
    public static final float MAXIMUM_PITCH = 8.0f;
    /**
     * The minimum allowed pitch in {@link #setPitch(float)}.
     */
    public static final float MINIMUM_PITCH = 0.1f;
    /**
     * Indicates that the output sample rate should be the same as the input.
     */
    public static final int SAMPLE_RATE_NO_CHANGE = -1;

    /**
     * The threshold below which the difference between two pitch/speed factors is negligible.
     */
    private static final float CLOSE_THRESHOLD = 0.01f;

    /**
     * The minimum number of output bytes at which the speedup is calculated using the input/output
     * byte counts, rather than using the current playback parameters speed.
     */
    private static final int MIN_BYTES_FOR_SPEEDUP_CALCULATION = 1024;

    private int pendingOutputSampleRateHz;
    private int channelCount;
    private int sampleRateHz;

    private Sonic sonic;
    private float speed;
    private float pitch;
    private int outputSampleRateHz;

    private ByteBuffer buffer;
    private ShortBuffer shortBuffer;
    private ByteBuffer outputBuffer;
    private long inputBytes;
    private long outputBytes;
    private boolean inputEnded;

    /**
     * Creates a new audio processor.
     */
    public AudioTranscoder() {
        speed = 1f;
        pitch = 1f;
        channelCount = NO_VALUE;
        sampleRateHz = NO_VALUE;
        outputSampleRateHz = NO_VALUE;
        buffer = EMPTY_BUFFER;
        shortBuffer = buffer.asShortBuffer();
        outputBuffer = EMPTY_BUFFER;
        pendingOutputSampleRateHz = SAMPLE_RATE_NO_CHANGE;
    }

    /**
     * Sets the playback speed. The new speed will take effect after a call to {@link #flush()}.
     *
     * @param speed The requested new playback speed.
     * @return The actual new playback speed.
     */
    public float setSpeed(float speed) {
        this.speed = constrainValue(speed, MINIMUM_SPEED, MAXIMUM_SPEED);
        return this.speed;
    }

    /**
     * Sets the playback pitch. The new pitch will take effect after a call to {@link #flush()}.
     *
     * @param pitch The requested new pitch.
     * @return The actual new pitch.
     */
    public float setPitch(float pitch) {
        this.pitch = constrainValue(pitch, MINIMUM_PITCH, MAXIMUM_PITCH);
        return pitch;
    }

    /**
     * Sets the sample rate for output audio, in hertz. Pass {@link #SAMPLE_RATE_NO_CHANGE} to output
     * audio at the same sample rate as the input. After calling this method, call
     * {@link #configure(int, int, int)} to start using the new sample rate.
     *
     * @param sampleRateHz The sample rate for output audio, in hertz.
     * @see #configure(int, int, int)
     */
    public void setOutputSampleRateHz(int sampleRateHz) {
        pendingOutputSampleRateHz = sampleRateHz;
    }

    /**
     * Returns the specified duration scaled to take into account the speedup factor of this instance,
     * in the same units as {@code duration}.
     *
     * @param duration The duration to scale taking into account speedup.
     * @return The specified duration scaled to take into account speedup, in the same units as
     *     {@code duration}.
     */
    public long scaleDurationForSpeedup(long duration) {
        if (outputBytes >= MIN_BYTES_FOR_SPEEDUP_CALCULATION) {
            return outputSampleRateHz == sampleRateHz
                    ? scaleLargeTimestamp(duration, inputBytes, outputBytes)
                    : scaleLargeTimestamp(duration, inputBytes * outputSampleRateHz,
                    outputBytes * sampleRateHz);
        } else {
            return (long) ((double) speed * duration);
        }
    }

    /**
     * Configures the processor to process input audio with the specified format. After calling this
     * method, {@link #isActive()} returns whether the processor needs to handle buffers; if not, the
     * processor will not accept any buffers until it is reconfigured. Returns {@code true} if the
     * processor must be flushed, or if the value returned by {@link #isActive()} has changed as a
     * result of the call. If it's active, {@link #getOutputSampleRateHz()},
     * {@link #getOutputChannelCount()} and {@link #getOutputEncoding()} return the processor's output
     * format.
     *
     * @param sampleRateHz The sample rate of input audio in Hz.
     * @param channelCount The number of interleaved channels in input audio.
     * @param encoding The encoding of input audio.
     * @return {@code true} if the processor must be flushed or the value returned by
     *     {@link #isActive()} has changed as a result of the call.
     * @throws UnhandledFormatException Thrown if the specified format can't be handled as input.
     */
    public boolean configure(int sampleRateHz, int channelCount, int encoding)
            throws UnhandledFormatException {
        if (encoding != AudioFormat.ENCODING_PCM_16BIT) {
            throw new UnhandledFormatException(sampleRateHz, channelCount, encoding);
        }
        int outputSampleRateHz = pendingOutputSampleRateHz == SAMPLE_RATE_NO_CHANGE
                ? sampleRateHz : pendingOutputSampleRateHz;
        if (this.sampleRateHz == sampleRateHz && this.channelCount == channelCount
                && this.outputSampleRateHz == outputSampleRateHz) {
            return false;
        }
        this.sampleRateHz = sampleRateHz;
        this.channelCount = channelCount;
        this.outputSampleRateHz = outputSampleRateHz;
        return true;
    }

    /**
     * Returns whether the processor is configured and active.
     */
    public boolean isActive() {
        return Math.abs(speed - 1f) >= CLOSE_THRESHOLD || Math.abs(pitch - 1f) >= CLOSE_THRESHOLD
                || outputSampleRateHz != sampleRateHz;
    }

    /**
     * Returns the number of audio channels in the data output by the processor. The value may change
     * as a result of calling {@link #configure(int, int, int)} and is undefined if the instance is
     * not active.
     */
    public int getOutputChannelCount() {
        return channelCount;
    }

    /**
     * Returns the audio encoding used in the data output by the processor. The value may change as a
     * result of calling {@link #configure(int, int, int)} and is undefined if the instance is not
     * active.
     */
    public int getOutputEncoding() {
        return AudioFormat.ENCODING_PCM_16BIT;
    }

    /**
     * Returns the sample rate of audio output by the processor, in hertz. The value may change as a
     * result of calling {@link #configure(int, int, int)} and is undefined if the instance is not
     * active.
     */
    public int getOutputSampleRateHz() {
        return outputSampleRateHz;
    }

    /**
     * Queues audio data between the position and limit of the input {@code buffer} for processing.
     * {@code buffer} must be a direct byte buffer with native byte order. Its contents are treated as
     * read-only. Its position will be advanced by the number of bytes consumed (which may be zero).
     * The caller retains ownership of the provided buffer. Calling this method invalidates any
     * previous buffer returned by {@link #getOutput()}.
     *
     * @param inputBuffer The input buffer to process.
     */
    public void queueInput(ByteBuffer inputBuffer) {
        if (inputBuffer.hasRemaining()) {
            ShortBuffer shortBuffer = inputBuffer.asShortBuffer();
            int inputSize = inputBuffer.remaining();
            inputBytes += inputSize;
            sonic.queueInput(shortBuffer);
            inputBuffer.position(inputBuffer.position() + inputSize);
        }
        int outputSize = sonic.getSamplesAvailable() * channelCount * 2;
        if (outputSize > 0) {
            if (buffer.capacity() < outputSize) {
                buffer = ByteBuffer.allocateDirect(outputSize).order(ByteOrder.nativeOrder());
                shortBuffer = buffer.asShortBuffer();
            } else {
                buffer.clear();
                shortBuffer.clear();
            }
            sonic.getOutput(shortBuffer);
            outputBytes += outputSize;
            buffer.limit(outputSize);
            outputBuffer = buffer;
        }
    }

    /**
     * Queues an end of stream signal. After this method has been called,
     * {@link #queueInput(ByteBuffer)} may not be called until after the next call to
     * {@link #flush()}. Calling {@link #getOutput()} will return any remaining output data. Multiple
     * calls may be required to read all of the remaining output data. {@link #isEnded()} will return
     * {@code true} once all remaining output data has been read.
     */
    public void endOfStream() {
        sonic.queueEndOfStream();
        inputEnded = true;
    }

    /**
     * Returns a buffer containing processed output data between its position and limit. The buffer
     * will always be a direct byte buffer with native byte order. Calling this method invalidates any
     * previously returned buffer. The buffer will be empty if no output is available.
     *
     * @return A buffer containing processed output data between its position and limit.
     */
    public ByteBuffer getOutput() {
        ByteBuffer outputBuffer = this.outputBuffer;
        this.outputBuffer = EMPTY_BUFFER;
        return outputBuffer;
    }

    /**
     * Returns whether this processor will return no more output from {@link #getOutput()} until it
     * has been {@link #flush()}ed and more input has been queued.
     */
    public boolean isEnded() {
        return inputEnded && (sonic == null || sonic.getSamplesAvailable() == 0);
    }

    /**
     * Clears any state in preparation for receiving a new stream of input buffers.
     */
    public void flush() {
        sonic = new Sonic(sampleRateHz, channelCount, speed, pitch, outputSampleRateHz);
        outputBuffer = EMPTY_BUFFER;
        inputBytes = 0;
        outputBytes = 0;
        inputEnded = false;
    }

    /**
     * Resets the processor to its unconfigured state.
     */
    public void reset() {
        sonic = null;
        buffer = EMPTY_BUFFER;
        shortBuffer = buffer.asShortBuffer();
        outputBuffer = EMPTY_BUFFER;
        channelCount = NO_VALUE;
        sampleRateHz = NO_VALUE;
        outputSampleRateHz = NO_VALUE;
        inputBytes = 0;
        outputBytes = 0;
        inputEnded = false;
        pendingOutputSampleRateHz = SAMPLE_RATE_NO_CHANGE;
    }

    /**
     * Constrains a value to the specified bounds.
     *
     * @param value The value to constrain.
     * @param min The lower bound.
     * @param max The upper bound.
     * @return The constrained value {@code Math.max(min, Math.min(value, max))}.
     */
    private static float constrainValue(float value, float min, float max) {
        return Math.max(min, Math.min(value, max));
    }

    /**
     * Scales a large timestamp.
     * 

* Logically, scaling consists of a multiplication followed by a division. The actual operations * performed are designed to minimize the probability of overflow. * * @param timestamp The timestamp to scale. * @param multiplier The multiplier. * @param divisor The divisor. * @return The scaled timestamp. */ private static long scaleLargeTimestamp(long timestamp, long multiplier, long divisor) { if (divisor >= multiplier && (divisor % multiplier) == 0) { long divisionFactor = divisor / multiplier; return timestamp / divisionFactor; } else if (divisor < multiplier && (multiplier % divisor) == 0) { long multiplicationFactor = multiplier / divisor; return timestamp * multiplicationFactor; } else { double multiplicationFactor = (double) multiplier / divisor; return (long) (timestamp * multiplicationFactor); } } /** * Exception thrown when a processor can't be configured for a given input audio format. */ final class UnhandledFormatException extends Exception { public UnhandledFormatException(int sampleRateHz, int channelCount, int encoding) { super("Unhandled format: " + sampleRateHz + " Hz, " + channelCount + " channels in encoding " + encoding); } } }

 

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