我正在关注 this创建我的第一个 ffmpeg 应用程序的教程。我已经成功地构建了共享库并编译了项目，没有任何错误。但是当我在我的 nexus 5 上运行应用程序时，输出是这个

这是原生代码

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/pixfmt.h>

#include <stdio.h>
#include <pthread.h>

#include <jni.h>
#include <android/native_window.h>
#include <android/native_window_jni.h>

#define LOG_TAG "android-ffmpeg-tutorial02"
#define LOGI(...) __android_log_print(4, LOG_TAG, __VA_ARGS__);
#define LOGE(...) __android_log_print(6, LOG_TAG, __VA_ARGS__);

ANativeWindow*      window;
char                *videoFileName;
AVFormatContext     *formatCtx = NULL;
int                 videoStream;
AVCodecContext      *codecCtx = NULL;
AVFrame             *decodedFrame = NULL;
AVFrame             *frameRGBA = NULL;
jobject             bitmap;
void*               buffer;
struct SwsContext   *sws_ctx = NULL;
int                 width;
int                 height;
int                 stop;

jint naInit(JNIEnv *pEnv, jobject pObj, jstring pFileName) {
    AVCodec         *pCodec = NULL;
    int             i;
    AVDictionary    *optionsDict = NULL;

    videoFileName = (char *)(*pEnv)->GetStringUTFChars(pEnv, pFileName, NULL);
    LOGI("video file name is %s", videoFileName);
    // Register all formats and codecs
    av_register_all();
    // Open video file
    if(avformat_open_input(&formatCtx, videoFileName, NULL, NULL)!=0)
        return -1; // Couldn't open file
    // Retrieve stream information
    if(avformat_find_stream_info(formatCtx, NULL)<0)
        return -1; // Couldn't find stream information
    // Dump information about file onto standard error
    av_dump_format(formatCtx, 0, videoFileName, 0);
    // Find the first video stream
    videoStream=-1;
    for(i=0; i<formatCtx->nb_streams; i++) {
        if(formatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
            videoStream=i;
            break;
        }
    }
    if(videoStream==-1)
        return -1; // Didn't find a video stream
    // Get a pointer to the codec context for the video stream
    codecCtx=formatCtx->streams[videoStream]->codec;
    // Find the decoder for the video stream
    pCodec=avcodec_find_decoder(codecCtx->codec_id);
    if(pCodec==NULL) {
        fprintf(stderr, "Unsupported codec!\n");
        return -1; // Codec not found
    }
    // Open codec
    if(avcodec_open2(codecCtx, pCodec, &optionsDict)<0)
        return -1; // Could not open codec
    // Allocate video frame
    decodedFrame=avcodec_alloc_frame();
    // Allocate an AVFrame structure
    frameRGBA=avcodec_alloc_frame();
    if(frameRGBA==NULL)
        return -1;
    return 0;
}

jobject createBitmap(JNIEnv *pEnv, int pWidth, int pHeight) {
    int i;
    //get Bitmap class and createBitmap method ID
    jclass javaBitmapClass = (jclass)(*pEnv)->FindClass(pEnv, "android/graphics/Bitmap");
    jmethodID mid = (*pEnv)->GetStaticMethodID(pEnv, javaBitmapClass, "createBitmap", "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
    //create Bitmap.Config
    //reference: https://forums.oracle.com/thread/1548728
    const wchar_t* configName = L"ARGB_8888";
    int len = wcslen(configName);
    jstring jConfigName;
    if (sizeof(wchar_t) != sizeof(jchar)) {
        //wchar_t is defined as different length than jchar(2 bytes)
        jchar* str = (jchar*)malloc((len+1)*sizeof(jchar));
        for (i = 0; i < len; ++i) {
            str[i] = (jchar)configName[i];
        }
        str[len] = 0;
        jConfigName = (*pEnv)->NewString(pEnv, (const jchar*)str, len);
    } else {
        //wchar_t is defined same length as jchar(2 bytes)
        jConfigName = (*pEnv)->NewString(pEnv, (const jchar*)configName, len);
    }
    jclass bitmapConfigClass = (*pEnv)->FindClass(pEnv, "android/graphics/Bitmap$Config");
    jobject javaBitmapConfig = (*pEnv)->CallStaticObjectMethod(pEnv, bitmapConfigClass,
            (*pEnv)->GetStaticMethodID(pEnv, bitmapConfigClass, "valueOf", "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;"), jConfigName);
    //create the bitmap
    return (*pEnv)->CallStaticObjectMethod(pEnv, javaBitmapClass, mid, pWidth, pHeight, javaBitmapConfig);
}

jintArray naGetVideoRes(JNIEnv *pEnv, jobject pObj) {
    jintArray lRes;
    if (NULL == codecCtx) {
        return NULL;
    }
    lRes = (*pEnv)->NewIntArray(pEnv, 2);
    if (lRes == NULL) {
        LOGI(1, "cannot allocate memory for video size");
        return NULL;
    }
    jint lVideoRes[2];
    lVideoRes[0] = codecCtx->width;
    lVideoRes[1] = codecCtx->height;
    (*pEnv)->SetIntArrayRegion(pEnv, lRes, 0, 2, lVideoRes);
    return lRes;
}

void naSetSurface(JNIEnv *pEnv, jobject pObj, jobject pSurface) {
    if (0 != pSurface) {
        // get the native window reference
        window = ANativeWindow_fromSurface(pEnv, pSurface);
        // set format and size of window buffer
        ANativeWindow_setBuffersGeometry(window, 0, 0, WINDOW_FORMAT_RGBA_8888);
    } else {
        // release the native window
        ANativeWindow_release(window);
    }
}

jint naSetup(JNIEnv *pEnv, jobject pObj, int pWidth, int pHeight) {
    width = pWidth;
    height = pHeight;
    //create a bitmap as the buffer for frameRGBA
    bitmap = createBitmap(pEnv, pWidth, pHeight);
    if (AndroidBitmap_lockPixels(pEnv, bitmap, &buffer) < 0)
        return -1;
    //get the scaling context
    sws_ctx = sws_getContext (
            codecCtx->width,
            codecCtx->height,
            codecCtx->pix_fmt,
            pWidth,
            pHeight,
            AV_PIX_FMT_RGBA,
            SWS_BILINEAR,
            NULL,
            NULL,
            NULL
    );
    // Assign appropriate parts of bitmap to image planes in pFrameRGBA
    // Note that pFrameRGBA is an AVFrame, but AVFrame is a superset
    // of AVPicture
    avpicture_fill((AVPicture *)frameRGBA, buffer, AV_PIX_FMT_RGBA,
            pWidth, pHeight);
    return 0;
}

void finish(JNIEnv *pEnv) {
    //unlock the bitmap
    AndroidBitmap_unlockPixels(pEnv, bitmap);
    av_free(buffer);
    // Free the RGB image
    av_free(frameRGBA);
    // Free the YUV frame
    av_free(decodedFrame);
    // Close the codec
    avcodec_close(codecCtx);
    // Close the video file
    avformat_close_input(&formatCtx);
}

void decodeAndRender(JNIEnv *pEnv) {
    ANativeWindow_Buffer    windowBuffer;
    AVPacket                packet;
    int                     i=0;
    int                     frameFinished;
    int                     lineCnt;
    while(av_read_frame(formatCtx, &packet)>=0 && !stop) {
        // Is this a packet from the video stream?
        if(packet.stream_index==videoStream) {
            // Decode video frame
            avcodec_decode_video2(codecCtx, decodedFrame, &frameFinished,
               &packet);
            // Did we get a video frame?
            if(frameFinished) {
                // Convert the image from its native format to RGBA
                sws_scale
                (
                    sws_ctx,
                    (uint8_t const * const *)decodedFrame->data,
                    decodedFrame->linesize,
                    0,
                    codecCtx->height,
                    frameRGBA->data,
                    frameRGBA->linesize
                );
                // lock the window buffer
                if (ANativeWindow_lock(window, &windowBuffer, NULL) < 0) {
                    LOGE("cannot lock window");
                } else {
                    // draw the frame on buffer
                    LOGI("copy buffer %d:%d:%d", width, height, width*height*4);
                    LOGI("window buffer: %d:%d:%d", windowBuffer.width,
                            windowBuffer.height, windowBuffer.stride);
                    memcpy(windowBuffer.bits, buffer,  width * height * 4);
                    // unlock the window buffer and post it to display
                    ANativeWindow_unlockAndPost(window);
                    // count number of frames
                    ++i;
                }
            }
        }
        // Free the packet that was allocated by av_read_frame
        av_free_packet(&packet);
    }
    LOGI("total No. of frames decoded and rendered %d", i);
    finish(pEnv);
}

/**
 * start the video playback
 */
void naPlay(JNIEnv *pEnv, jobject pObj) {
    //create a new thread for video decode and render
    pthread_t decodeThread;
    stop = 0;
    pthread_create(&decodeThread, NULL, decodeAndRender, NULL);
}

/**
 * stop the video playback
 */
void naStop(JNIEnv *pEnv, jobject pObj) {
    stop = 1;
}

jint JNI_OnLoad(JavaVM* pVm, void* reserved) {
    JNIEnv* env;
    if ((*pVm)->GetEnv(pVm, (void **)&env, JNI_VERSION_1_6) != JNI_OK) {
         return -1;
    }
    JNINativeMethod nm[8];
    nm[0].name = "naInit";
    nm[0].signature = "(Ljava/lang/String;)I";
    nm[0].fnPtr = (void*)naInit;

    nm[1].name = "naSetSurface";
    nm[1].signature = "(Landroid/view/Surface;)V";
    nm[1].fnPtr = (void*)naSetSurface;

    nm[2].name = "naGetVideoRes";
    nm[2].signature = "()[I";
    nm[2].fnPtr = (void*)naGetVideoRes;

    nm[3].name = "naSetup";
    nm[3].signature = "(II)I";
    nm[3].fnPtr = (void*)naSetup;

    nm[4].name = "naPlay";
    nm[4].signature = "()V";
    nm[4].fnPtr = (void*)naPlay;

    nm[5].name = "naStop";
    nm[5].signature = "()V";
    nm[5].fnPtr = (void*)naStop;

    jclass cls = (*env)->FindClass(env, "roman10/tutorial/android_ffmpeg_tutorial02/MainActivity");
    //Register methods with env->RegisterNatives.
    (*env)->RegisterNatives(env, cls, nm, 6);
    return JNI_VERSION_1_6;
}

这是build.sh

#!/bin/bash
NDK=$HOME/Desktop/adt/android-ndk-r9
SYSROOT=$NDK/platforms/android-9/arch-arm/
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64
function build_one
{
./configure \
    --prefix=$PREFIX \
    --enable-shared \
    --disable-static \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-ffserver \
    --disable-avdevice \
    --disable-doc \
    --disable-symver \
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
    --target-os=linux \
    --arch=arm \
    --enable-cross-compile \
    --sysroot=$SYSROOT \
    --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
    --extra-ldflags="$ADDI_LDFLAGS" \
    $ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install
}
CPU=arm
PREFIX=$(pwd)/android/$CPU 
ADDI_CFLAGS="-marm"
build_one

它适用于 Galaxy tab2。我该怎么做才能让它在所有设备上工作？请帮助我..

最佳答案

图像伪影特征表明解码图像的步幅与窗口缓冲区的步幅不匹配。这个地方最有可能的问题:

memcpy(windowBuffer.bits, buffer,  width * height * 4);

相反，您必须逐行复制:

for (int h = 0; h < height; h++)
{
  memcpy(windowBuffer.bits + h * windowBuffer.stride,
         buffer + h * frameRGBA->linesize[0],
         width*4);    
}

关于android ffmpeg 错误的视频输出，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24675618/