如何修復由 MediaMuxer 生成的損壞的 Mp4 文件？

Question

我使用MediaMuxer和MediaCodec來生成一個 mp4 視頻。

調用mMediaMuxer.stop()后視頻可播放

但是，當用戶在我獲得調用stop()方法的更改之前退出應用程序時，我會留下一個無法播放的大 mp4 文件。

有沒有辦法修復這個 mp4 文件以使其可播放？

編輯

這是損壞的 mp4 文件的一個示例

我能夠使用此在線工具修復文件，但此工具要求上傳未損壞的視頻作為參考。

這是我用作參考的未損壞的 mp4 視頻。 當我上傳此視頻時，該工具修復了我損壞的 mp4 文件。

所以可以修復文件，但他們是怎么做的呢？

如果有用，這是我用來生成損壞和未損壞的代碼

package com.tolotra.images_to_video

import android.content.ContentValues.TAG
import android.content.Context
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.media.*
import android.opengl.*
import android.util.Log
import android.util.TimingLogger
import android.view.Surface
import java.io.File
import java.nio.ByteBuffer
import java.nio.ByteOrder
import java.nio.FloatBuffer
import java.nio.IntBuffer
import java.text.SimpleDateFormat
import java.util.*


class VideoBuilder(applicationContext: Context) {


    private var frameId: Long = 0
    private lateinit var muxer: MediaMuxer
    private lateinit var glTool: OverlayRenderer
    private lateinit var encoder: MediaCodec
    private lateinit var outVideoFilePath: String
    private var context = applicationContext
    private var trackIndex: Int = 0
    private lateinit var bufferInfo: MediaCodec.BufferInfo
    private var eglContext: EGLContext? = null
    private var eglDisplay: EGLDisplay? = null
    private var eglSurface: EGLSurface? = null
    private lateinit var surface: Surface


    val timeoutUs = 10000L
    val frameRate = 5
    var presentationTimeUs: Long = 0


    fun setup() {
        encoder = createEncoder()
        initInputSurface(encoder)
        encoder.start()

        outVideoFilePath = getScreenshotPath("tolotra-screen-recoder-${Date().time}.mp4")
        muxer = MediaMuxer(outVideoFilePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)

        glTool = OverlayRenderer()
        glTool.initGl()
    }

    /**
     * Laspse is the duration between the current frame and the previous frame
     */
    fun feed(bitmap: Bitmap, timelapse: Long) {

        frameId++
        Log.d("FEED_PROFILE", "feed frame:$frameId")
        val timings = TimingLogger("FEED_PROFILE", "feed frame:$frameId")
        // Get encoded data and feed it to muxer
        drainEncoder(encoder, muxer, false, timelapse)

        timings.addSplit("drainEncoder done");
        // Render the bitmap/texture with OpenGL here
        glTool.render(bitmap)
        timings.addSplit("render done");

        // Set timestamp with EGL extension
        EGLExt.eglPresentationTimeANDROID(eglDisplay, eglSurface, presentationTimeUs * 1000)

        // Feed encoder with next frame produced by OpenGL
        EGL14.eglSwapBuffers(eglDisplay, eglSurface)

        timings.dumpToLog();
    }

    fun finish() {
        Log.d(TAG, "Finishing")

        // Drain last encoded data and finalize the video file
        drainEncoder(encoder, muxer, true, 0)
        _cleanUp(encoder, muxer)

        val file = File(outVideoFilePath)

        val file_size = (file.length() / 1024).toString().toInt()
        val retriever = MediaMetadataRetriever()
        retriever.setDataSource(outVideoFilePath)
        val width =
            retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH)
        val height =
            retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT)
        val rotation =
            retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_ROTATION)

        val bitRate =
            retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_BITRATE)

        val duration =
            java.lang.Long.valueOf(retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION)) * 1000

        Log.d("Result", "bitrate $bitRate duration $duration  fileSize $file_size ")

    }

    fun getScreenshotPath(fileName: String): String {
        val f = context.externalCacheDir
        val externalDir: String = f!!.path;
        val sDir: String = externalDir + File.separator + "Screen Recorder";
        val dir = File(sDir);
        val dirPath: String;
        if (dir.exists() || dir.mkdir()) {
            dirPath = sDir + File.separator + fileName;
        } else {
            dirPath = externalDir + File.separator + fileName
        }
        Log.d("Mp4 file path", "Path: $dirPath")

        return dirPath;
    } //


    fun createEncoder(): MediaCodec {

        bufferInfo = MediaCodec.BufferInfo()
        val MIME = "video/avc"
        val encoder = MediaCodec.createEncoderByType(MIME)
        val width = 320
        val heigh = 512
        val format = MediaFormat.createVideoFormat(MIME, width, heigh)
        format.setInteger(
            MediaFormat.KEY_COLOR_FORMAT,
            MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface
        )
//        format.setInteger(MediaFormat.KEY_BIT_RATE, 2_000_000)
        format.setInteger(MediaFormat.KEY_BIT_RATE, 350_000)
        format.setInteger(MediaFormat.KEY_FRAME_RATE, 45)
        format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 5)

        encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
        trackIndex = -1;
        return encoder
    }

    fun drainEncoder(
        encoder: MediaCodec,
        muxer: MediaMuxer,
        endOfStream: Boolean,
        timelapseUs: Long
    ) {
        if (endOfStream)
            encoder.signalEndOfInputStream()

        while (true) {
            val outBufferId = encoder.dequeueOutputBuffer(bufferInfo, timeoutUs)

            if (outBufferId >= 0) {
                val encodedBuffer = encoder.getOutputBuffer(outBufferId)

                // MediaMuxer is ignoring KEY_FRAMERATE, so I set it manually here
                // to achieve the desired frame rate
                bufferInfo.presentationTimeUs = presentationTimeUs
                if (encodedBuffer != null) {
                    muxer.writeSampleData(trackIndex, encodedBuffer, bufferInfo)
                }

                presentationTimeUs += timelapseUs

                encoder.releaseOutputBuffer(outBufferId, false)

                // Are we finished here?
                if ((bufferInfo.flags and MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0)
                    break
            } else if (outBufferId == MediaCodec.INFO_TRY_AGAIN_LATER) {
                if (!endOfStream)
                    break

                // End of stream, but still no output available. Try again.
            } else if (outBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
                trackIndex = muxer.addTrack(encoder.outputFormat)
                muxer.start()
            }
        }
    }

    private fun initInputSurface(encoder: MediaCodec) {

        val surface = encoder.createInputSurface()

        val eglDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY)
        if (eglDisplay == EGL14.EGL_NO_DISPLAY)
            throw RuntimeException(
                "eglDisplay == EGL14.EGL_NO_DISPLAY: "
                        + GLUtils.getEGLErrorString(EGL14.eglGetError())
            )

        val version = IntArray(2)
        if (!EGL14.eglInitialize(eglDisplay, version, 0, version, 1))
            throw RuntimeException("eglInitialize(): " + GLUtils.getEGLErrorString(EGL14.eglGetError()))

        val attribList = intArrayOf(
            EGL14.EGL_RED_SIZE, 8,
            EGL14.EGL_GREEN_SIZE, 8,
            EGL14.EGL_BLUE_SIZE, 8,
            EGL14.EGL_ALPHA_SIZE, 8,
            EGL14.EGL_RENDERABLE_TYPE, EGL14.EGL_OPENGL_ES2_BIT,
            EGLExt.EGL_RECORDABLE_ANDROID, 1,
            EGL14.EGL_NONE
        )
        val configs = arrayOfNulls<EGLConfig>(1)
        val nConfigs = IntArray(1)
        EGL14.eglChooseConfig(eglDisplay, attribList, 0, configs, 0, configs.size, nConfigs, 0)

        var err = EGL14.eglGetError()
        if (err != EGL14.EGL_SUCCESS)
            throw RuntimeException(GLUtils.getEGLErrorString(err))

        val ctxAttribs = intArrayOf(
            EGL14.EGL_CONTEXT_CLIENT_VERSION, 2,
            EGL14.EGL_NONE
        )
        val eglContext =
            EGL14.eglCreateContext(eglDisplay, configs[0], EGL14.EGL_NO_CONTEXT, ctxAttribs, 0)

        err = EGL14.eglGetError()
        if (err != EGL14.EGL_SUCCESS)
            throw RuntimeException(GLUtils.getEGLErrorString(err))

        val surfaceAttribs = intArrayOf(
            EGL14.EGL_NONE
        )
        val eglSurface =
            EGL14.eglCreateWindowSurface(eglDisplay, configs[0], surface, surfaceAttribs, 0)
        err = EGL14.eglGetError()
        if (err != EGL14.EGL_SUCCESS)
            throw RuntimeException(GLUtils.getEGLErrorString(err))

        if (!EGL14.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext))
            throw RuntimeException("eglMakeCurrent(): " + GLUtils.getEGLErrorString(EGL14.eglGetError()))


        this.eglSurface = eglSurface
        this.eglDisplay = eglDisplay
        this.eglContext = eglContext
        this.surface = surface
    }

    private fun _cleanUp(encoder: MediaCodec, muxer: MediaMuxer) {
        if (eglDisplay != EGL14.EGL_NO_DISPLAY) {
            EGL14.eglDestroySurface(eglDisplay, eglSurface)
            EGL14.eglDestroyContext(eglDisplay, eglContext)
            EGL14.eglReleaseThread()
            EGL14.eglTerminate(eglDisplay);
        }
        surface?.release();
        eglDisplay = EGL14.EGL_NO_DISPLAY
        eglContext = EGL14.EGL_NO_CONTEXT
        eglSurface = EGL14.EGL_NO_SURFACE

        encoder.stop()
        encoder.release()

        muxer.stop()
        muxer.release()
    }


}

class OverlayRenderer() {

    private val mvpMatrix = FloatArray(16)
    private val projectionMatrix = FloatArray(16)
    private val viewMatrix = FloatArray(16)

    private val vertexShaderCode =
        "precision highp float;\n" +
                "attribute vec3 vertexPosition;\n" +
                "attribute vec2 uvs;\n" +
                "varying vec2 varUvs;\n" +
                "uniform mat4 mvp;\n" +
                "\n" +
                "void main()\n" +
                "{\n" +
                "\tvarUvs = uvs;\n" +
                "\tgl_Position = mvp * vec4(vertexPosition, 1.0);\n" +
                "}"

    private val fragmentShaderCode =
        "precision mediump float;\n" +
                "\n" +
                "varying vec2 varUvs;\n" +
                "uniform sampler2D texSampler;\n" +
                "\n" +
                "void main()\n" +
                "{\t\n" +
                "\tgl_FragColor = texture2D(texSampler, varUvs);\n" +
                "}"

    private var vertices = floatArrayOf(
        // x, y, z, u, v
        -1.0f, -1.0f, 0.0f, 0f, 0f,
        -1.0f, 1.0f, 0.0f, 0f, 1f,
        1.0f, 1.0f, 0.0f, 1f, 1f,
        1.0f, -1.0f, 0.0f, 1f, 0f
    )

    private var indices = intArrayOf(
        2, 1, 0, 0, 3, 2
    )

    private var program: Int = 0
    private var vertexHandle: Int = 0
    private var bufferHandles = IntArray(2)
    private var uvsHandle: Int = 0
    private var mvpHandle: Int = 0
    private var samplerHandle: Int = 0
    private val textureHandle = IntArray(1)


    val viewportWidth = 320
    val viewportHeight = 486


    var vertexBuffer: FloatBuffer = ByteBuffer.allocateDirect(vertices.size * 4).run {
        order(ByteOrder.nativeOrder())
        asFloatBuffer().apply {
            put(vertices)
            position(0)
        }
    }

    var indexBuffer: IntBuffer = ByteBuffer.allocateDirect(indices.size * 4).run {
        order(ByteOrder.nativeOrder())
        asIntBuffer().apply {
            put(indices)
            position(0)
        }
    }

    fun render(bitmap: Bitmap) {

        Log.d("Bitmap", "width ${bitmap.width} height ${bitmap.height}")


// Prepare some transformations
        val mvp = FloatArray(16)
        Matrix.setIdentityM(mvp, 0)
        Matrix.scaleM(mvp, 0, 1f, -1f, 1f)

        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT or GLES20.GL_DEPTH_BUFFER_BIT)
        GLES20.glClearColor(0f, 0f, 0f, 0f)

        GLES20.glViewport(0, 0, viewportWidth, viewportHeight)

        GLES20.glUseProgram(program)

// Pass transformations to shader
        GLES20.glUniformMatrix4fv(mvpHandle, 1, false, mvp, 0)

// Prepare texture for drawing
        GLES20.glActiveTexture(GLES20.GL_TEXTURE0)
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0])
        GLES20.glPixelStorei(GLES20.GL_UNPACK_ALIGNMENT, 1)

// Pass the Bitmap to OpenGL here
        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0)

        GLES20.glTexParameteri(
            GLES20.GL_TEXTURE_2D,
            GLES20.GL_TEXTURE_MIN_FILTER,
            GLES20.GL_NEAREST
        )
        GLES20.glTexParameteri(
            GLES20.GL_TEXTURE_2D,
            GLES20.GL_TEXTURE_MAG_FILTER,
            GLES20.GL_NEAREST
        )

// Prepare buffers with vertices and indices & draw
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, bufferHandles[0])
        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, bufferHandles[1])

        GLES20.glEnableVertexAttribArray(vertexHandle)
        GLES20.glVertexAttribPointer(vertexHandle, 3, GLES20.GL_FLOAT, false, 4 * 5, 0)

        GLES20.glEnableVertexAttribArray(uvsHandle)
        GLES20.glVertexAttribPointer(uvsHandle, 2, GLES20.GL_FLOAT, false, 4 * 5, 3 * 4)

        GLES20.glDrawElements(GLES20.GL_TRIANGLES, 6, GLES20.GL_UNSIGNED_INT, 0)
    }


    fun initGl() {
        val vertexShader = GLES20.glCreateShader(GLES20.GL_VERTEX_SHADER).also { shader ->
            GLES20.glShaderSource(shader, vertexShaderCode)
            GLES20.glCompileShader(shader)
        }

        val fragmentShader = GLES20.glCreateShader(GLES20.GL_FRAGMENT_SHADER).also { shader ->
            GLES20.glShaderSource(shader, fragmentShaderCode)
            GLES20.glCompileShader(shader)
        }

        program = GLES20.glCreateProgram().also {
            GLES20.glAttachShader(it, vertexShader)
            GLES20.glAttachShader(it, fragmentShader)
            GLES20.glLinkProgram(it)

            vertexHandle = GLES20.glGetAttribLocation(it, "vertexPosition")
            uvsHandle = GLES20.glGetAttribLocation(it, "uvs")
            mvpHandle = GLES20.glGetUniformLocation(it, "mvp")
            samplerHandle = GLES20.glGetUniformLocation(it, "texSampler")
        }

        // Initialize buffers
        GLES20.glGenBuffers(2, bufferHandles, 0)

        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, bufferHandles[0])
        GLES20.glBufferData(
            GLES20.GL_ARRAY_BUFFER,
            vertices.size * 4,
            vertexBuffer,
            GLES20.GL_DYNAMIC_DRAW
        )

        GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, bufferHandles[1])
        GLES20.glBufferData(
            GLES20.GL_ELEMENT_ARRAY_BUFFER,
            indices.size * 4,
            indexBuffer,
            GLES20.GL_DYNAMIC_DRAW
        )

        // Init texture handle
        GLES20.glGenTextures(1, textureHandle, 0)

        // Ensure I can draw transparent stuff that overlaps properly
        GLES20.glEnable(GLES20.GL_BLEND)
        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA)
    }
}

Answer 1

一般來說，MP4 不是一種好的錄音格式。 通常樣本表保存在內存中並在關閉時寫入。 因此，如果出現斷電或應用程序錯誤 - 您會丟失錄音。 使用 MPEG-2 傳輸流或碎片化的 MP4，則大多數寫入的媒體仍可播放。 您的文件很可能只包含一個 MP4 'ftyp' 和 'mdat' 原子，音頻和視頻交錯。 通過對視頻流的一些有根據的猜測和知識 - 有機會提取音頻和視頻。 https://fix.video似乎做到了。

Correct MP4:
[ftyp]
[mdat]
[moov]
-end-

Truncated MP4:
[ftyp]
[mdat]
-end-

Fix.video 解析你的好文件，提取音頻和視頻的設置。 它使用來自好文件的信息來重新創建大部分“moov”原子。 缺少的示例表 'stXX' 是通過解析您的 'mdat' 原子重新創建的。 'mdat' atom 內的視頻塊都以長度為前綴，其余的必須是 AAC 音頻。